From 6715d03d9f74f2cf47e65ec8e194e942d525cfd2 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Tue, 27 Oct 2020 12:49:17 +0100
Subject: [PATCH 01/39] Add error labels on failure and new functions for
 templates.

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>
---
 pkg/logql/log/error.go    |   1 +
 pkg/logql/log/fmt.go      |  75 ++++++++++++++++++++++++--
 pkg/logql/log/fmt_test.go | 111 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 182 insertions(+), 5 deletions(-)

diff --git a/pkg/logql/log/error.go b/pkg/logql/log/error.go
index 04dd20ecdcd15..a518b08c5e590 100644
--- a/pkg/logql/log/error.go
+++ b/pkg/logql/log/error.go
@@ -6,6 +6,7 @@ var (
 	errLogfmt           = "LogfmtParserErr"
 	errSampleExtraction = "SampleExtractionErr"
 	errLabelFilter      = "LabelFilterErr"
+	errTemplateFormat   = "TemplateFormatErr"
 
 	ErrorLabel = "__error__"
 )
diff --git a/pkg/logql/log/fmt.go b/pkg/logql/log/fmt.go
index 231fa37719043..89d921ab443b6 100644
--- a/pkg/logql/log/fmt.go
+++ b/pkg/logql/log/fmt.go
@@ -14,6 +14,7 @@ var (
 
 	// Available map of functions for the text template engine.
 	functionMap = template.FuncMap{
+		// olds function deprecated.
 		"ToLower":    strings.ToLower,
 		"ToUpper":    strings.ToUpper,
 		"Replace":    strings.Replace,
@@ -23,6 +24,26 @@ var (
 		"TrimPrefix": strings.TrimPrefix,
 		"TrimSuffix": strings.TrimSuffix,
 		"TrimSpace":  strings.TrimSpace,
+
+		// new function ported from https://github.com/Masterminds/sprig/
+		"lower":     strings.ToLower,
+		"upper":     strings.ToUpper,
+		"title":     strings.Title,
+		"trunc":     trunc,
+		"substr":    substring,
+		"contains":  func(substr string, str string) bool { return strings.Contains(str, substr) },
+		"hasPrefix": func(substr string, str string) bool { return strings.HasPrefix(str, substr) },
+		"hasSuffix": func(substr string, str string) bool { return strings.HasSuffix(str, substr) },
+		"indent":    indent,
+		"nindent":   nindent,
+		"replace":   replace,
+		"repeat":    func(count int, str string) string { return strings.Repeat(str, count) },
+		"trim":      strings.TrimSpace,
+		// Switch order so that "$foo" | trimall "$"
+		"trimAll":    func(a, b string) string { return strings.Trim(b, a) },
+		"trimSuffix": func(a, b string) string { return strings.TrimSuffix(b, a) },
+		"trimPrefix": func(a, b string) string { return strings.TrimPrefix(b, a) },
+
 		"regexReplaceAll": func(regex string, s string, repl string) string {
 			r := regexp.MustCompile(regex)
 			return r.ReplaceAllString(s, repl)
@@ -51,10 +72,12 @@ func NewFormatter(tmpl string) (*LineFormatter, error) {
 	}, nil
 }
 
-func (lf *LineFormatter) Process(_ []byte, lbs *LabelsBuilder) ([]byte, bool) {
+func (lf *LineFormatter) Process(line []byte, lbs *LabelsBuilder) ([]byte, bool) {
 	lf.buf.Reset()
-	// todo(cyriltovena): handle error
-	_ = lf.Template.Execute(lf.buf, lbs.Labels().Map())
+	if err := lf.Template.Execute(lf.buf, lbs.Labels().Map()); err != nil {
+		lbs.SetErr(errTemplateFormat)
+		return line, true
+	}
 	// todo(cyriltovena): we might want to reuse the input line or a bytes buffer.
 	res := make([]byte, len(lf.buf.Bytes()))
 	copy(res, lf.buf.Bytes())
@@ -150,12 +173,54 @@ func (lf *LabelsFormatter) Process(l []byte, lbs *LabelsBuilder) ([]byte, bool)
 			continue
 		}
 		lf.buf.Reset()
-		//todo (cyriltovena): handle error
 		if data == nil {
 			data = lbs.Labels().Map()
 		}
-		_ = f.tmpl.Execute(lf.buf, data)
+		if err := f.tmpl.Execute(lf.buf, data); err != nil {
+			lbs.SetErr(errTemplateFormat)
+			continue
+		}
 		lbs.Set(f.Name, lf.buf.String())
 	}
 	return l, true
 }
+
+func trunc(c int, s string) string {
+	if c < 0 && len(s)+c > 0 {
+		return s[len(s)+c:]
+	}
+	if c >= 0 && len(s) > c {
+		return s[:c]
+	}
+	return s
+}
+
+// substring creates a substring of the given string.
+//
+// If start is < 0, this calls string[:end].
+//
+// If start is >= 0 and end < 0 or end bigger than s length, this calls string[start:]
+//
+// Otherwise, this calls string[start, end].
+func substring(start, end int, s string) string {
+	if start < 0 {
+		return s[:end]
+	}
+	if end < 0 || end > len(s) {
+		return s[start:]
+	}
+	return s[start:end]
+}
+
+func replace(old, new, src string) string {
+	return strings.Replace(src, old, new, -1)
+}
+
+func indent(spaces int, v string) string {
+	pad := strings.Repeat(" ", spaces)
+	return pad + strings.Replace(v, "\n", "\n"+pad, -1)
+}
+
+func nindent(spaces int, v string) string {
+	return "\n" + indent(spaces, v)
+}
diff --git a/pkg/logql/log/fmt_test.go b/pkg/logql/log/fmt_test.go
index b86d6ad06a27e..a6e5518255fc1 100644
--- a/pkg/logql/log/fmt_test.go
+++ b/pkg/logql/log/fmt_test.go
@@ -24,6 +24,115 @@ func Test_lineFormatter_Format(t *testing.T) {
 			[]byte("fooblipbuzzblop"),
 			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
 		},
+		{
+			"Replace",
+			newMustLineFormatter(`foo{{.foo}}buzz{{ Replace .bar "blop" "bar" -1 }}`),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+			[]byte("fooblipbuzzbar"),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"replace",
+			newMustLineFormatter(`foo{{.foo}}buzz{{ .bar | replace "blop" "bar" }}`),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+			[]byte("fooblipbuzzbar"),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"title",
+			newMustLineFormatter(`{{.foo | title }}`),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+			[]byte("Blip"),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"substr and trunc",
+			newMustLineFormatter(
+				`{{.foo | substr 1 3 }} {{ .bar  | trunc 1 }} {{ .bar  | trunc 3 }}`,
+			),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+			[]byte("li b blo"),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"trim",
+			newMustLineFormatter(
+				`{{.foo | trim }} {{ .bar  | trimAll "op" }} {{ .bar  | trimPrefix "b" }} {{ .bar  | trimSuffix "p" }}`,
+			),
+			labels.Labels{{Name: "foo", Value: "  blip "}, {Name: "bar", Value: "blop"}},
+			[]byte("blip bl lop blo"),
+			labels.Labels{{Name: "foo", Value: "  blip "}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"lower and upper",
+			newMustLineFormatter(`{{.foo | lower }} {{ .bar  | upper }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("blip BLOP"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"repeat",
+			newMustLineFormatter(`{{ "foo" | repeat 3 }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("foofoofoo"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"indent",
+			newMustLineFormatter(`{{ "foo\n bar" | indent 4 }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("    foo\n     bar"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"nindent",
+			newMustLineFormatter(`{{ "foo" | nindent 2 }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("\n  foo"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"contains",
+			newMustLineFormatter(`{{ if  .foo | contains "p"}}yes{{end}}-{{ if  .foo | contains "z"}}no{{end}}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("yes-"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"hasPrefix",
+			newMustLineFormatter(`{{ if  .foo | hasPrefix "BL" }}yes{{end}}-{{ if  .foo | hasPrefix "p"}}no{{end}}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("yes-"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"hasSuffix",
+			newMustLineFormatter(`{{ if  .foo | hasSuffix "Ip" }}yes{{end}}-{{ if  .foo | hasSuffix "pw"}}no{{end}}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("yes-"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"regexReplaceAll",
+			newMustLineFormatter(`{{ regexReplaceAll "(p)" .foo "t" }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("BLIt"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"regexReplaceAllLiteral",
+			newMustLineFormatter(`{{ regexReplaceAllLiteral "(p)" .foo "${1}" }}`),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+			[]byte("BLI${1}"),
+			labels.Labels{{Name: "foo", Value: "BLIp"}, {Name: "bar", Value: "blop"}},
+		},
+		{
+			"err",
+			newMustLineFormatter(`{{.foo Replace "foo"}}`),
+			labels.Labels{{Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+			nil,
+			labels.Labels{{Name: ErrorLabel, Value: errTemplateFormat}, {Name: "foo", Value: "blip"}, {Name: "bar", Value: "blop"}},
+		},
 		{
 			"missing",
 			newMustLineFormatter("foo {{.foo}}buzz{{  .bar  }}"),
@@ -41,6 +150,8 @@ func Test_lineFormatter_Format(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			sort.Sort(tt.lbs)
+			sort.Sort(tt.wantLbs)
 			b := NewLabelsBuilder()
 			b.Reset(tt.lbs)
 			outLine, _ := tt.fmter.Process(nil, b)

From 94adcd9142c44953c832a14ccc4647be8267d7df Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Tue, 27 Oct 2020 14:54:22 +0100
Subject: [PATCH 02/39] Updates docs.

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>
---
 docs/sources/logql/_index.md    |  79 +------
 docs/sources/logql/functions.md | 370 ++++++++++++++++++++++++++++++++
 2 files changed, 372 insertions(+), 77 deletions(-)
 create mode 100644 docs/sources/logql/functions.md

diff --git a/docs/sources/logql/_index.md b/docs/sources/logql/_index.md
index 3c2a83ff1a740..4a19133c726d8 100644
--- a/docs/sources/logql/_index.md
+++ b/docs/sources/logql/_index.md
@@ -295,7 +295,7 @@ Will extract and rewrite the log line to only contains the query and the duratio
 
 You can use double quoted string for the template or single backtick \``\{{.label_name}}`\` to avoid the need to escape special characters.
 
-See [functions](#Template-functions) to learn about available functions in the template format.
+See [functions](functions/) to learn about available functions in the template format.
 
 #### Labels Format Expression
 
@@ -303,7 +303,7 @@ The `| label_format` expression can renamed, modify or add labels. It takes as p
 
 When both side are label identifiers, for example `dst=src`, the operation will rename the `src` label into `dst`.
 
-The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, this mean labels are available as variables and you can use the same list of [functions](#Template-functions).
+The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, this mean labels are available as variables and you can use the same list of [functions](functions/).
 
 In both case if the destination label doesn't exist a new one will be created.
 
@@ -311,81 +311,6 @@ The renaming form `dst=src` will _drop_ the `src` label after remapping it to th
 
 > A single label name can only appear once per expression. This means `| label_format foo=bar,foo="new"` is not allowed but you can use two expressions for the desired effect: `| label_format foo=bar | label_format foo="new"`
 
-#### Template functions
-
-The text template format used in `| line_format` and `| label_format` support functions the following list of functions.
-
-##### ToLower & ToUpper
-
-Convert the entire string to lowercase or uppercase:
-
-Examples:
-
-```template
-"{{.request_method | ToLower}}"
-"{{.request_method | ToUpper}}"
-`{{ToUpper "This is a string" | ToLower}}`
-```
-
-##### Replace
-
-Perform simple string replacement.
-
-It takes three arguments:
-
-- string to replace
-- string to replace with
-- source string
-
-Example:
-
-```template
-`"This is a string" | Replace " " "-"`
-```
-
-The above will produce `This-is-a-string`
-
-##### Trim
-
-`Trim` returns a slice of the string s with all leading and
-trailing Unicode code points contained in cutset removed.
-
-`TrimLeft` and `TrimRight` are the same as `Trim` except that it respectively trim only leading and trailing characters.
-
-```template
-`{{ Trim .query ",. " }}`
-`{{ TrimLeft .uri ":" }}`
-`{{ TrimRight .path "/" }}`
-```
-
-`TrimSpace` TrimSpace returns string s with all leading
-and trailing white space removed, as defined by Unicode.
-
-```template
-{{ TrimSpace .latency }}
-```
-
-`TrimPrefix` and `TrimSuffix` will trim respectively the prefix or suffix supplied.
-
-```template
-{{ TrimPrefix .path "/" }}
-```
-
-##### Regex
-
-`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [docs](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
-
-```template
-`{{ regexReplaceAllLiteral "(a*)bc" .some_label "${1}a" }}`
-```
-
-`regexReplaceAllLiteral` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement The replacement string is substituted directly, without using Expand.
-
-```template
-`{{ regexReplaceAllLiteral "(ts=)" .timestamp "timestamp=" }}`
-```
-
-You can combine multiple function using pipe, for example if you want to strip out spaces and make the request method in capital you would write the following template `{{ .request_method | TrimSpace | ToUpper }}`.
 
 ### Log Queries Examples
 
diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
new file mode 100644
index 0000000000000..3147a18438f7a
--- /dev/null
+++ b/docs/sources/logql/functions.md
@@ -0,0 +1,370 @@
+---
+title: Template functions
+---
+
+The [text template](https://golang.org/pkg/text/template) format used in `| line_format` and `| label_format` support functions the usage of functions.
+
+All labels are added as variables in the template engine. They can be referenced using they label name prefixed by a `.`(e.g `.label_name`) for example the following template will output the value of the path label:
+
+```template
+{{ .path }}
+```
+
+You can take advantage of [pipeline](https://golang.org/pkg/text/template/#hdr-Pipelines) to chain multiple functions.
+In a chained pipeline, the result of each command is passed as the last argument of the following command.
+
+Example:
+
+```template
+{{ .path | replace " " "_" | trunc 5 | upper }}
+```
+
+## ToLower & ToUpper
+
+Convert the entire string to lowercase or uppercase.
+
+Signatures:
+
+- `ToLower(string) string`
+- `ToUpper(string) string`
+
+Examples:
+
+```template
+"{{.request_method | ToLower}}"
+"{{.request_method | ToUpper}}"
+`{{ToUpper "This is a string" | ToLower}}`
+```
+
+> In Loki 2.1 you can also use respectively [`lower`](#lower) and [`upper`](#upper) shortcut, e.g `{{.request_method | lower }}`
+
+## Replace string
+
+> in Loki 2.1 [`replace`](#replace) (as opposed to `Replace`) is available with a different signature but easier to chain within pipeline.
+
+Perform simple string replacement.
+
+Signature:
+
+`Replace(s, old, new string, n int) string`
+
+It takes four arguments:
+
+- `s` source string
+- `old` string to replace
+- `new` string to replace with
+- `n` the maximun amount of replacement (-1 for all)
+
+Example:
+
+```template
+`{{ Replace "This is a string" " " "-" -1 }}`
+```
+
+The above will produce `This-is-a-string`
+
+## Trim, TrimLeft, TrimRight and TrimSpace
+
+> In Loki 2.1 [trim](#trim), [trimAll](#trimAll), [trimSuffix](#trimSuffix) and [trimPrefix](trimPrefix) have been added with a different signature for better pipeline chaining.
+
+`Trim` returns a slice of the string s with all leading and
+trailing Unicode code points contained in cutset removed.
+
+Signature: `Trim(value, cutset string) string`
+
+`TrimLeft` and `TrimRight` are the same as `Trim` except that it respectively trim only leading and trailing characters.
+
+```template
+`{{ Trim .query ",. " }}`
+`{{ TrimLeft .uri ":" }}`
+`{{ TrimRight .path "/" }}`
+```
+
+`TrimSpace` TrimSpace returns string s with all leading
+and trailing white space removed, as defined by Unicode.
+
+Signature: `TrimSpace(value string) string`
+
+```template
+{{ TrimSpace .latency }}
+```
+
+`TrimPrefix` and `TrimSuffix` will trim respectively the prefix or suffix supplied.
+
+Signature:
+
+- `TrimPrefix(value string, prefix string) string`
+- `TrimSuffix(value string, suffix string) string`
+
+```template
+{{ TrimPrefix .path "/" }}
+```
+
+## regexReplaceAll & regexReplaceAllLiteral
+
+`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [docs](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
+
+```template
+`{{ regexReplaceAllLiteral "(a*)bc" .some_label "${1}a" }}`
+```
+
+`regexReplaceAllLiteral` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement The replacement string is substituted directly, without using Expand.
+
+```template
+`{{ regexReplaceAllLiteral "(ts=)" .timestamp "timestamp=" }}`
+```
+
+You can combine multiple function using pipe, for example if you want to strip out spaces and make the request method in capital you would write the following template `{{ .request_method | TrimSpace | ToUpper }}`.
+
+## lower
+
+> Added in Loki 2.1
+
+Convert to lower case.
+
+Signature:
+
+`lower(string) string`
+
+Examples:
+
+```template
+"{{ .request_method | lower }}"
+`{{ lower  "HELLO"}}`
+```
+
+The last example will return `hello`.
+
+## upper
+
+> Added in Loki 2.1
+
+Convert to upper case.
+
+Signature:
+
+`upper(string) string`
+
+Examples:
+
+```template
+"{{ .request_method | upper }}"
+`{{ upper  "hello"}}`
+```
+
+The last example will return `HELLO`.
+
+## title
+
+> Added in Loki 2.1
+
+Convert to title case.
+
+Signature:
+
+`title(string) string`
+
+Examples:
+
+```template
+"{{.request_method | title}}"
+`{{ title "hello world"}}`
+```
+
+The last example will return `Hello World`.
+
+## trunc
+
+> Added in Loki 2.1
+
+Truncate a string (and add no suffix)
+
+Signature:
+
+`trunc(count int,value string) string`
+
+Examples:
+
+```template
+"{{ .path | trunc 2 }}"
+`{{ trunc 5 "hello world"}}`   // output: hello
+`{{ trunc -5 "hello world"}}`  // output: world
+```
+
+## substr
+
+> Added in Loki 2.1
+
+Get a substring from a string.
+
+Signature:
+
+`trunc(start int,end int,value string) string`
+
+If start is < 0, this calls value[:end].
+If start is >= 0 and end < 0 or end bigger than s length, this calls value[start:]
+Otherwise, this calls value[start, end].
+
+Examples:
+
+```template
+"{{ .path | substr 2 5 }}"
+`{{ substr 0 5 "hello world"}}`  // output: hello
+`{{ substr 6 11 "hello world"}}` // output: world
+```
+
+## replace
+
+> Added in Loki 2.1
+
+Perform simple string replacement.
+
+Signature: `replace(old string, new string, src string) string`
+
+It takes three arguments:
+
+- `old` string to replace
+- `new` string to replace with
+- `src` source string
+
+Examples:
+
+```template
+{{ .cluster | replace "-cluster" "" }}
+{{ replace "hello" "world" "hello world" }}
+```
+
+The last example will return `world world`.
+
+## trim
+
+> Added in Loki 2.1
+
+The trim function removes space from either side of a string.
+
+Signature: `trim(string) string`
+
+Examples:
+
+```template
+{{ .ip | trim }}
+{{ trim "   hello    " }} // output: hello
+```
+
+## trimAll
+
+> Added in Loki 2.1
+
+Remove given characters from the front or back of a string.
+
+Signature: `trimAll(chars string,src string) string`
+
+Examples:
+
+```template
+{{ .path | trimAll "/" }}
+{{ trimAll "$" "$5.00" }} // output: 5.00
+```
+
+## trimSuffix
+
+> Added in Loki 2.1
+
+Trim just the suffix from a string.
+
+Signature: `trimSuffix(suffix string, src string) string`
+
+Examples:
+
+```template
+{{  .path | trimSuffix "/" }}
+{{ trimSuffix "-" "hello-" }} // output: hello
+```
+
+## trimPrefix
+
+> Added in Loki 2.1
+
+Trim just the prefix from a string.
+
+Signature: `trimPrefix(suffix string, src string) string`
+
+Examples:
+
+```template
+{{  .path | trimPrefix "/" }}
+{{ trimPrefix "-" "-hello" }} // output: hello
+```
+
+## indent
+
+> Added in Loki 2.1
+
+The indent function indents every line in a given string to the specified indent width. This is useful when aligning multi-line strings.
+
+Signature: `indent(spaces int,src string) string`
+
+```template
+{{ indent 4 .query }}
+```
+
+The following will indent by 4 spaces each lines contained in `.query`.
+
+## nindent
+
+> Added in Loki 2.1
+
+The nindent function is the same as the indent function, but prepends a new line to the beginning of the string.
+
+Signature: `nindent(spaces int,src string) string`
+
+```template
+{{ nindent 4 .query }}
+```
+
+The above will indent every line of text by 4 space characters and add a new line to the beginning.
+
+## repeat
+
+> Added in Loki 2.1
+
+Repeat a string multiple times.
+
+Signature: `repeat(c int,value string) string`
+
+```template
+{{ repeat 3 "hello" }} // output: hellohellohello
+```
+
+## contains
+
+> Added in Loki 2.1
+
+Test to see if one string is contained inside of another.
+
+Signature: `contains(s string, src string) bool`
+
+Examples:
+
+```template
+{{ if .err contains "ErrTimeout" }} timeout {{end}}
+{{ if contains "he" "hello" }} yes {{end}}
+```
+
+## hasPrefix & hasSuffix
+
+> Added in Loki 2.1
+
+The `hasPrefix` and `hasSuffix` functions test whether a string has a given prefix or suffix.
+
+Signatures:
+
+- `hasPrefix(prefix string, src string) bool`
+- `hasSuffix(suffix string, src string) bool`
+
+Examples:
+
+```template
+{{ if .err hasSuffix "Timeout" }} timeout {{end}}
+{{ if hasPrefix "he" "hello" }} yes {{end}}
+```

From f2b0e995fe1bdc95a82880a45c638dc5681d0cb6 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:11:28 -0500
Subject: [PATCH 03/39] Update docs/sources/logql/_index.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/_index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/_index.md b/docs/sources/logql/_index.md
index 4a19133c726d8..f42651ac7ef85 100644
--- a/docs/sources/logql/_index.md
+++ b/docs/sources/logql/_index.md
@@ -303,7 +303,7 @@ The `| label_format` expression can renamed, modify or add labels. It takes as p
 
 When both side are label identifiers, for example `dst=src`, the operation will rename the `src` label into `dst`.
 
-The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, this mean labels are available as variables and you can use the same list of [functions](functions/).
+The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, which means labels are available as variables and you can use the same list of [functions](functions/).
 
 In both case if the destination label doesn't exist a new one will be created.
 

From d28320b6c791cbb74421db955cca9bcf66e0f748 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:11:41 -0500
Subject: [PATCH 04/39] Update docs/sources/logql/_index.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/_index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/_index.md b/docs/sources/logql/_index.md
index f42651ac7ef85..d7e9beeb0b3b5 100644
--- a/docs/sources/logql/_index.md
+++ b/docs/sources/logql/_index.md
@@ -305,7 +305,7 @@ When both side are label identifiers, for example `dst=src`, the operation will
 
 The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, which means labels are available as variables and you can use the same list of [functions](functions/).
 
-In both case if the destination label doesn't exist a new one will be created.
+In both case if the destination label doesn't exist, then a new one is created.
 
 The renaming form `dst=src` will _drop_ the `src` label after remapping it to the `dst` label. However, the _template_ form will preserve the referenced labels, such that  `dst="{{.src}}"` results in both `dst` and `src` having the same value.
 

From b54c7a6cd387bddb8d17cb9ad1384dcf30a42676 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:11:51 -0500
Subject: [PATCH 05/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 3147a18438f7a..37de1409a166d 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -36,7 +36,7 @@ Examples:
 `{{ToUpper "This is a string" | ToLower}}`
 ```
 
-> In Loki 2.1 you can also use respectively [`lower`](#lower) and [`upper`](#upper) shortcut, e.g `{{.request_method | lower }}`
+> **Note:** In Loki 2.1 you can also use respectively [`lower`](#lower) and [`upper`](#upper) shortcut, e.g `{{.request_method | lower }}`
 
 ## Replace string
 

From cfec17d4e673a12908b9bd62aac2fa8c9005e27b Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:00 -0500
Subject: [PATCH 06/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 37de1409a166d..c14f102a0bd48 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -40,7 +40,7 @@ Examples:
 
 ## Replace string
 
-> in Loki 2.1 [`replace`](#replace) (as opposed to `Replace`) is available with a different signature but easier to chain within pipeline.
+> **Note:** In Loki 2.1 [`replace`](#replace) (as opposed to `Replace`) is available with a different signature but easier to chain within pipeline.
 
 Perform simple string replacement.
 

From 10846379269288e1e4bedf322bc1178c61002d26 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:14 -0500
Subject: [PATCH 07/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index c14f102a0bd48..88a48b2e419fc 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -65,7 +65,7 @@ The above will produce `This-is-a-string`
 
 ## Trim, TrimLeft, TrimRight and TrimSpace
 
-> In Loki 2.1 [trim](#trim), [trimAll](#trimAll), [trimSuffix](#trimSuffix) and [trimPrefix](trimPrefix) have been added with a different signature for better pipeline chaining.
+> **Note:** In Loki 2.1 [trim](#trim), [trimAll](#trimAll), [trimSuffix](#trimSuffix) and [trimPrefix](trimPrefix) have been added with a different signature for better pipeline chaining.
 
 `Trim` returns a slice of the string s with all leading and
 trailing Unicode code points contained in cutset removed.

From 2767d2436ca4793e38785fd569124790e11a7df1 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:27 -0500
Subject: [PATCH 08/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 88a48b2e419fc..73a46d7277608 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -61,7 +61,7 @@ Example:
 `{{ Replace "This is a string" " " "-" -1 }}`
 ```
 
-The above will produce `This-is-a-string`
+The above will produce `This-is-a-string`.
 
 ## Trim, TrimLeft, TrimRight and TrimSpace
 

From bf42dbc8923cbb4e93e88c4a3022a50bfa8a7842 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:36 -0500
Subject: [PATCH 09/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 73a46d7277608..4dbd9493e9c88 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -312,7 +312,7 @@ The following will indent by 4 spaces each lines contained in `.query`.
 
 ## nindent
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 The nindent function is the same as the indent function, but prepends a new line to the beginning of the string.
 

From 46904dd07e731eff81dea6f9a38e583001d24500 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:43 -0500
Subject: [PATCH 10/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 4dbd9493e9c88..1dc2982563105 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -338,7 +338,7 @@ Signature: `repeat(c int,value string) string`
 
 ## contains
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Test to see if one string is contained inside of another.
 

From 4a1cc243a45e530de65dcac50dd1f49dd5119dd1 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:12:51 -0500
Subject: [PATCH 11/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 1dc2982563105..28d719f0643e1 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -353,7 +353,7 @@ Examples:
 
 ## hasPrefix & hasSuffix
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 The `hasPrefix` and `hasSuffix` functions test whether a string has a given prefix or suffix.
 

From 5ed2cff6902968540363a88e0efd9a38f5d0a078 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:13:23 -0500
Subject: [PATCH 12/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 28d719f0643e1..830cd9c9d2684 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -100,7 +100,7 @@ Signature:
 {{ TrimPrefix .path "/" }}
 ```
 
-## regexReplaceAll & regexReplaceAllLiteral
+## regexReplaceAll and regexReplaceAllLiteral
 
 `regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [docs](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
 

From be9be60ed2685705e181247087a79e4b0e9e01f7 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:13:31 -0500
Subject: [PATCH 13/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 830cd9c9d2684..e5934fa8939f9 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -326,7 +326,7 @@ The above will indent every line of text by 4 space characters and add a new lin
 
 ## repeat
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Repeat a string multiple times.
 

From f32becf9256957d518042b84a35f1182c6f23dba Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:13:39 -0500
Subject: [PATCH 14/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index e5934fa8939f9..011dc13d143a8 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -351,7 +351,7 @@ Examples:
 {{ if contains "he" "hello" }} yes {{end}}
 ```
 
-## hasPrefix & hasSuffix
+## hasPrefix and hasSuffix
 
 > **Note:** Added in Loki 2.1.
 

From 1dfda03ddc7d87e51619bf657517b04d602bda16 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:13:58 -0500
Subject: [PATCH 15/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 011dc13d143a8..142771beabeb9 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -114,7 +114,7 @@ Signature:
 `{{ regexReplaceAllLiteral "(ts=)" .timestamp "timestamp=" }}`
 ```
 
-You can combine multiple function using pipe, for example if you want to strip out spaces and make the request method in capital you would write the following template `{{ .request_method | TrimSpace | ToUpper }}`.
+You can combine multiple function using pipe. For example, if you want to strip out spaces and make the request method in capital, then you would write the following template: `{{ .request_method | TrimSpace | ToUpper }}`.
 
 ## lower
 

From 38ddece837c53f52196b5686eb14fc8a1caf6538 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:14:26 -0500
Subject: [PATCH 16/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 142771beabeb9..237de13d65c00 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -156,7 +156,7 @@ The last example will return `HELLO`.
 
 ## title
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Convert to title case.
 

From 96623a7b1a7b97e3fb358f97fcdc040cf72c2129 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:14:51 -0500
Subject: [PATCH 17/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 237de13d65c00..92c850a1c94a0 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -175,7 +175,7 @@ The last example will return `Hello World`.
 
 ## trunc
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Truncate a string (and add no suffix)
 

From a92c6615c05694622ca473def5270afcc9d676af Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:15:26 -0500
Subject: [PATCH 18/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 92c850a1c94a0..339b880f33240 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -298,7 +298,7 @@ Examples:
 
 ## indent
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 The indent function indents every line in a given string to the specified indent width. This is useful when aligning multi-line strings.
 

From d8ad1b5d5176600214d36748859308467ca4ecf7 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:16:45 -0500
Subject: [PATCH 19/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 339b880f33240..20187d9168db9 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -177,7 +177,7 @@ The last example will return `Hello World`.
 
 > **Note:** Added in Loki 2.1.
 
-Truncate a string (and add no suffix)
+Truncate a string and add no suffix.
 
 Signature:
 

From d24ff399bf83bae67a5bd62874454d7c012fb8ba Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:17:05 -0500
Subject: [PATCH 20/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 20187d9168db9..1a64e2113934a 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -193,7 +193,7 @@ Examples:
 
 ## substr
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Get a substring from a string.
 

From f5d16083d5b42b0d68e280916785e63dcc309105 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:17:36 -0500
Subject: [PATCH 21/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 1a64e2113934a..9d98996fcb199 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -215,7 +215,7 @@ Examples:
 
 ## replace
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Perform simple string replacement.
 

From dfdda5cde48d60e5b896b890bea132323404d022 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:17:48 -0500
Subject: [PATCH 22/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 9d98996fcb199..08d853c6977bd 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -238,7 +238,7 @@ The last example will return `world world`.
 
 ## trim
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 The trim function removes space from either side of a string.
 

From 2cc17bd19956abcedee92f47235a2871e377902d Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:18:07 -0500
Subject: [PATCH 23/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 08d853c6977bd..95f29b101ef0d 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -253,7 +253,7 @@ Examples:
 
 ## trimAll
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Remove given characters from the front or back of a string.
 

From e4f63a75c9d1825fedce8554c33300c6082fb8e3 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:18:20 -0500
Subject: [PATCH 24/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 95f29b101ef0d..e115464011560 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -268,7 +268,7 @@ Examples:
 
 ## trimSuffix
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Trim just the suffix from a string.
 

From 565d17d3a29298d18edeae8c8493cdf9afcc8599 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 05:19:55 -0500
Subject: [PATCH 25/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index e115464011560..50b77c9be9dc4 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -283,7 +283,7 @@ Examples:
 
 ## trimPrefix
 
-> Added in Loki 2.1
+> **Note:** Added in Loki 2.1.
 
 Trim just the prefix from a string.
 

From 2fe24d836cc183fd05f4d7627119db86b0656cf9 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 11:21:15 +0100
Subject: [PATCH 26/39] Improve docs based off review feedback.

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 50b77c9be9dc4..fa72a0f2b6747 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -102,7 +102,7 @@ Signature:
 
 ## regexReplaceAll and regexReplaceAllLiteral
 
-`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [docs](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
+`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [Regexp.replaceAll documentation](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
 
 ```template
 `{{ regexReplaceAllLiteral "(a*)bc" .some_label "${1}a" }}`

From 8c55441cdc2c424db837a2c9571ea5ada1cde905 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 12:16:54 +0100
Subject: [PATCH 27/39] Review feedback.

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>
---
 pkg/logql/log/fmt.go      | 88 ++++++++++++++++++++++++---------------
 pkg/logql/log/fmt_test.go | 49 ++++++++++++++++++++++
 2 files changed, 103 insertions(+), 34 deletions(-)

diff --git a/pkg/logql/log/fmt.go b/pkg/logql/log/fmt.go
index 89d921ab443b6..b9d794bce37cc 100644
--- a/pkg/logql/log/fmt.go
+++ b/pkg/logql/log/fmt.go
@@ -25,25 +25,27 @@ var (
 		"TrimSuffix": strings.TrimSuffix,
 		"TrimSpace":  strings.TrimSpace,
 
-		// new function ported from https://github.com/Masterminds/sprig/
-		"lower":     strings.ToLower,
-		"upper":     strings.ToUpper,
-		"title":     strings.Title,
-		"trunc":     trunc,
-		"substr":    substring,
-		"contains":  func(substr string, str string) bool { return strings.Contains(str, substr) },
-		"hasPrefix": func(substr string, str string) bool { return strings.HasPrefix(str, substr) },
-		"hasSuffix": func(substr string, str string) bool { return strings.HasSuffix(str, substr) },
-		"indent":    indent,
-		"nindent":   nindent,
-		"replace":   replace,
-		"repeat":    func(count int, str string) string { return strings.Repeat(str, count) },
-		"trim":      strings.TrimSpace,
-		// Switch order so that "$foo" | trimall "$"
-		"trimAll":    func(a, b string) string { return strings.Trim(b, a) },
-		"trimSuffix": func(a, b string) string { return strings.TrimSuffix(b, a) },
-		"trimPrefix": func(a, b string) string { return strings.TrimPrefix(b, a) },
-
+		// New function ported from https://github.com/Masterminds/sprig/
+		// Those function takes the string as the last parameter, allowing pipe chaining.
+		// Example: .mylabel | lower | substring 0 5
+		"lower":      strings.ToLower,
+		"upper":      strings.ToUpper,
+		"title":      strings.Title,
+		"trunc":      trunc,
+		"substr":     substring,
+		"contains":   contains,
+		"hasPrefix":  hasPrefix,
+		"hasSuffix":  hasSuffix,
+		"indent":     indent,
+		"nindent":    nindent,
+		"replace":    replace,
+		"repeat":     repeat,
+		"trim":       strings.TrimSpace,
+		"trimAll":    trimAll,
+		"trimSuffix": trimSuffix,
+		"trimPrefix": trimPrefix,
+
+		// regex functions
 		"regexReplaceAll": func(regex string, s string, repl string) string {
 			r := regexp.MustCompile(regex)
 			return r.ReplaceAllString(s, repl)
@@ -186,11 +188,13 @@ func (lf *LabelsFormatter) Process(l []byte, lbs *LabelsBuilder) ([]byte, bool)
 }
 
 func trunc(c int, s string) string {
-	if c < 0 && len(s)+c > 0 {
-		return s[len(s)+c:]
+	runes := []rune(s)
+	l := len(s)
+	if c < 0 && l+c > 0 {
+		return string(runes[l+c:])
 	}
-	if c >= 0 && len(s) > c {
-		return s[:c]
+	if c >= 0 && l > c {
+		return string(runes[:c])
 	}
 	return s
 }
@@ -203,24 +207,40 @@ func trunc(c int, s string) string {
 //
 // Otherwise, this calls string[start, end].
 func substring(start, end int, s string) string {
+	runes := []rune(s)
+	l := len(runes)
+	if end > l {
+		end = l
+	}
+	if start > l {
+		start = l
+	}
 	if start < 0 {
-		return s[:end]
+		if end < 0 {
+			return ""
+		}
+		return string(runes[:end])
 	}
-	if end < 0 || end > len(s) {
-		return s[start:]
+	if end < 0 {
+		return string(runes[start:])
 	}
-	return s[start:end]
-}
-
-func replace(old, new, src string) string {
-	return strings.Replace(src, old, new, -1)
+	if start > end {
+		return ""
+	}
+	return string(runes[start:end])
 }
 
+func contains(substr string, str string) bool  { return strings.Contains(str, substr) }
+func hasPrefix(substr string, str string) bool { return strings.HasPrefix(str, substr) }
+func hasSuffix(substr string, str string) bool { return strings.HasSuffix(str, substr) }
+func repeat(count int, str string) string      { return strings.Repeat(str, count) }
+func replace(old, new, src string) string      { return strings.Replace(src, old, new, -1) }
+func trimAll(a, b string) string               { return strings.Trim(b, a) }
+func trimSuffix(a, b string) string            { return strings.TrimSuffix(b, a) }
+func trimPrefix(a, b string) string            { return strings.TrimPrefix(b, a) }
 func indent(spaces int, v string) string {
 	pad := strings.Repeat(" ", spaces)
 	return pad + strings.Replace(v, "\n", "\n"+pad, -1)
 }
 
-func nindent(spaces int, v string) string {
-	return "\n" + indent(spaces, v)
-}
+func nindent(spaces int, v string) string { return "\n" + indent(spaces, v) }
diff --git a/pkg/logql/log/fmt_test.go b/pkg/logql/log/fmt_test.go
index a6e5518255fc1..0668798d3edbb 100644
--- a/pkg/logql/log/fmt_test.go
+++ b/pkg/logql/log/fmt_test.go
@@ -240,3 +240,52 @@ func Test_validate(t *testing.T) {
 		})
 	}
 }
+
+func Test_trunc(t *testing.T) {
+	tests := []struct {
+		s    string
+		c    int
+		want string
+	}{
+		{"Hello, 世界", -1, "界"},
+		{"Hello, 世界", 1, "H"},
+		{"Hello, 世界", 0, ""},
+		{"Hello, 世界", 20, "Hello, 世界"},
+		{"Hello, 世界", -20, "Hello, 世界"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.s, func(t *testing.T) {
+			if got := trunc(tt.c, tt.s); got != tt.want {
+				t.Errorf("trunc() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_substring(t *testing.T) {
+
+	tests := []struct {
+		start int
+		end   int
+		s     string
+		want  string
+	}{
+		{1, 8, "Hello, 世界", "ello, 世"},
+		{-10, 8, "Hello, 世界", "Hello, 世"},
+		{1, 10, "Hello, 世界", "ello, 世界"},
+		{-1, 10, "Hello, 世界", "Hello, 世界"},
+		{-1, 1, "Hello, 世界", "H"},
+		{-1, -1, "Hello, 世界", ""},
+		{20, -1, "Hello, 世界", ""},
+		{1, 1, "Hello, 世界", ""},
+		{5, 1, "Hello, 世界", ""},
+		{3, -1, "Hello, 世界", "lo, 世界"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.s, func(t *testing.T) {
+			if got := substring(tt.start, tt.end, tt.s); got != tt.want {
+				t.Errorf("substring() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

From 0fb3dcc1bddd4896474a07e492f0c90bd21a4ed3 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:32:13 +0100
Subject: [PATCH 28/39] Fixes panic out of boundary

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>
---
 pkg/logql/log/fmt.go      | 2 +-
 pkg/logql/log/fmt_test.go | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/pkg/logql/log/fmt.go b/pkg/logql/log/fmt.go
index b9d794bce37cc..745aed711974c 100644
--- a/pkg/logql/log/fmt.go
+++ b/pkg/logql/log/fmt.go
@@ -189,7 +189,7 @@ func (lf *LabelsFormatter) Process(l []byte, lbs *LabelsBuilder) ([]byte, bool)
 
 func trunc(c int, s string) string {
 	runes := []rune(s)
-	l := len(s)
+	l := len(runes)
 	if c < 0 && l+c > 0 {
 		return string(runes[l+c:])
 	}
diff --git a/pkg/logql/log/fmt_test.go b/pkg/logql/log/fmt_test.go
index 0668798d3edbb..b01ea54edf9eb 100644
--- a/pkg/logql/log/fmt_test.go
+++ b/pkg/logql/log/fmt_test.go
@@ -1,6 +1,7 @@
 package log
 
 import (
+	"fmt"
 	"sort"
 	"testing"
 
@@ -254,7 +255,7 @@ func Test_trunc(t *testing.T) {
 		{"Hello, 世界", -20, "Hello, 世界"},
 	}
 	for _, tt := range tests {
-		t.Run(tt.s, func(t *testing.T) {
+		t.Run(fmt.Sprintf("%s%d", tt.s, tt.c), func(t *testing.T) {
 			if got := trunc(tt.c, tt.s); got != tt.want {
 				t.Errorf("trunc() = %v, want %v", got, tt.want)
 			}

From 0bfbc1ca4eb78e2056927cb1ad6a9f557d788901 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:58:08 -0500
Subject: [PATCH 29/39] Update docs/sources/logql/functions.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index fa72a0f2b6747..76a0f7186b14d 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -21,7 +21,7 @@ Example:
 
 ## ToLower & ToUpper
 
-Convert the entire string to lowercase or uppercase.
+This function converts the entire string to lowercase or uppercase.
 
 Signatures:
 

From 4c18044d576a7d91c22023e09e7656c7fafeb9b2 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:58:20 -0500
Subject: [PATCH 30/39] Update docs/sources/logql/functions.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 76a0f7186b14d..8d8b6dfa396d6 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -217,7 +217,7 @@ Examples:
 
 > **Note:** Added in Loki 2.1.
 
-Perform simple string replacement.
+This function performs simple string replacement.
 
 Signature: `replace(old string, new string, src string) string`
 

From 7bd59ecac191b7795d7dfe6790a4f57a5b0d02be Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:58:29 -0500
Subject: [PATCH 31/39] Update docs/sources/logql/functions.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 8d8b6dfa396d6..571d03f5ce771 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -255,7 +255,7 @@ Examples:
 
 > **Note:** Added in Loki 2.1.
 
-Remove given characters from the front or back of a string.
+Use this function to remove given characters from the front or back of a string.
 
 Signature: `trimAll(chars string,src string) string`
 

From 84231afc3cf404053f965579898861d92ef0f58a Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:58:40 -0500
Subject: [PATCH 32/39] Update docs/sources/logql/functions.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 571d03f5ce771..35774b414cbdf 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -270,7 +270,7 @@ Examples:
 
 > **Note:** Added in Loki 2.1.
 
-Trim just the suffix from a string.
+Use this function to trim just the suffix from a string.
 
 Signature: `trimSuffix(suffix string, src string) string`
 

From 257947eb73eb786558e8a49dbff897540f79b60f Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:59:18 -0500
Subject: [PATCH 33/39] Update docs/sources/logql/_index.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/_index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/_index.md b/docs/sources/logql/_index.md
index d7e9beeb0b3b5..cd060263724cc 100644
--- a/docs/sources/logql/_index.md
+++ b/docs/sources/logql/_index.md
@@ -303,7 +303,7 @@ The `| label_format` expression can renamed, modify or add labels. It takes as p
 
 When both side are label identifiers, for example `dst=src`, the operation will rename the `src` label into `dst`.
 
-The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value will be replace by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, which means labels are available as variables and you can use the same list of [functions](functions/).
+The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value is replaced by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, which means labels are available as variables and you can use the same list of [functions](functions/).
 
 In both case if the destination label doesn't exist, then a new one is created.
 

From 128ae1fbeeaed7ec2d1e070fd19983b11eb25368 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:59:34 -0500
Subject: [PATCH 34/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 35774b414cbdf..19f77dad9f3e2 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -4,7 +4,7 @@ title: Template functions
 
 The [text template](https://golang.org/pkg/text/template) format used in `| line_format` and `| label_format` support functions the usage of functions.
 
-All labels are added as variables in the template engine. They can be referenced using they label name prefixed by a `.`(e.g `.label_name`) for example the following template will output the value of the path label:
+All labels are added as variables in the template engine. They can be referenced using they label name prefixed by a `.`(e.g `.label_name`). For example the following template will output the value of the path label:
 
 ```template
 {{ .path }}

From 641543fb4720c6b89dbf7824ddda7cf074739e5f Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:59:44 -0500
Subject: [PATCH 35/39] Update docs/sources/logql/functions.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 19f77dad9f3e2..859908c3f32eb 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -36,7 +36,7 @@ Examples:
 `{{ToUpper "This is a string" | ToLower}}`
 ```
 
-> **Note:** In Loki 2.1 you can also use respectively [`lower`](#lower) and [`upper`](#upper) shortcut, e.g `{{.request_method | lower }}`
+> **Note:** In Loki 2.1 you can also use respectively [`lower`](#lower) and [`upper`](#upper) shortcut, e.g `{{.request_method | lower }}`.
 
 ## Replace string
 

From 3be39f3da1a380ee244f4bcadb025066e36afe6f Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 14:59:53 -0500
Subject: [PATCH 36/39] Update docs/sources/logql/_index.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/_index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sources/logql/_index.md b/docs/sources/logql/_index.md
index cd060263724cc..e2a8427416a89 100644
--- a/docs/sources/logql/_index.md
+++ b/docs/sources/logql/_index.md
@@ -305,7 +305,7 @@ When both side are label identifiers, for example `dst=src`, the operation will
 
 The left side can alternatively be a template string (double quoted or backtick), for example `dst="{{.status}} {{.query}}"`, in which case the `dst` label value is replaced by the result of the [text/template](https://golang.org/pkg/text/template/) evaluation. This is the same template engine as the `| line_format` expression, which means labels are available as variables and you can use the same list of [functions](functions/).
 
-In both case if the destination label doesn't exist, then a new one is created.
+In both cases, if the destination label doesn't exist, then a new one is created.
 
 The renaming form `dst=src` will _drop_ the `src` label after remapping it to the `dst` label. However, the _template_ form will preserve the referenced labels, such that  `dst="{{.src}}"` results in both `dst` and `src` having the same value.
 

From a9a7579a8a08653120685c40c5f02c5d700c6d68 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 15:00:52 -0500
Subject: [PATCH 37/39] Apply suggestions from code review

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 859908c3f32eb..7e7a1a84b72fc 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -2,7 +2,7 @@
 title: Template functions
 ---
 
-The [text template](https://golang.org/pkg/text/template) format used in `| line_format` and `| label_format` support functions the usage of functions.
+The [text template](https://golang.org/pkg/text/template) format used in `| line_format` and `| label_format` support the usage of functions.
 
 All labels are added as variables in the template engine. They can be referenced using they label name prefixed by a `.`(e.g `.label_name`). For example the following template will output the value of the path label:
 
@@ -10,7 +10,7 @@ All labels are added as variables in the template engine. They can be referenced
 {{ .path }}
 ```
 
-You can take advantage of [pipeline](https://golang.org/pkg/text/template/#hdr-Pipelines) to chain multiple functions.
+You can take advantage of [pipeline](https://golang.org/pkg/text/template/#hdr-Pipelines) to join together multiple functions.
 In a chained pipeline, the result of each command is passed as the last argument of the following command.
 
 Example:
@@ -19,7 +19,7 @@ Example:
 {{ .path | replace " " "_" | trunc 5 | upper }}
 ```
 
-## ToLower & ToUpper
+## ToLower and ToUpper
 
 This function converts the entire string to lowercase or uppercase.
 
@@ -42,7 +42,7 @@ Examples:
 
 > **Note:** In Loki 2.1 [`replace`](#replace) (as opposed to `Replace`) is available with a different signature but easier to chain within pipeline.
 
-Perform simple string replacement.
+Use this function to perform a simple string replacement.
 
 Signature:
 
@@ -61,9 +61,9 @@ Example:
 `{{ Replace "This is a string" " " "-" -1 }}`
 ```
 
-The above will produce `This-is-a-string`.
+The results in `This-is-a-string`.
 
-## Trim, TrimLeft, TrimRight and TrimSpace
+## Trim, TrimLeft, TrimRight, and TrimSpace
 
 > **Note:** In Loki 2.1 [trim](#trim), [trimAll](#trimAll), [trimSuffix](#trimSuffix) and [trimPrefix](trimPrefix) have been added with a different signature for better pipeline chaining.
 
@@ -72,7 +72,7 @@ trailing Unicode code points contained in cutset removed.
 
 Signature: `Trim(value, cutset string) string`
 
-`TrimLeft` and `TrimRight` are the same as `Trim` except that it respectively trim only leading and trailing characters.
+`TrimLeft` and `TrimRight` are the same as `Trim` except that it trims only leading and trailing characters respectively.
 
 ```template
 `{{ Trim .query ",. " }}`
@@ -102,7 +102,7 @@ Signature:
 
 ## regexReplaceAll and regexReplaceAllLiteral
 
-`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [Regexp.replaceAll documentation](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for detailed examples.
+`regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first sub-match. See the golang [Regexp.replaceAll documentation](https://golang.org/pkg/regexp/#Regexp.ReplaceAll) for more examples.
 
 ```template
 `{{ regexReplaceAllLiteral "(a*)bc" .some_label "${1}a" }}`

From aaee685be186056f4460a3f7b9db4c6c0ab59d41 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 15:01:48 -0500
Subject: [PATCH 38/39] Apply suggestions from code review

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 7e7a1a84b72fc..7c5a96c7d2c3d 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -108,19 +108,19 @@ Signature:
 `{{ regexReplaceAllLiteral "(a*)bc" .some_label "${1}a" }}`
 ```
 
-`regexReplaceAllLiteral` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement The replacement string is substituted directly, without using Expand.
+`regexReplaceAllLiteral` function returns a copy of the input string and replaces matches of the Regexp with the replacement string replacement. The replacement string is substituted directly, without using Expand.
 
 ```template
 `{{ regexReplaceAllLiteral "(ts=)" .timestamp "timestamp=" }}`
 ```
 
-You can combine multiple function using pipe. For example, if you want to strip out spaces and make the request method in capital, then you would write the following template: `{{ .request_method | TrimSpace | ToUpper }}`.
+You can combine multiple functions using pipe. For example, to strip out spaces and make the request method in capital, you would write the following template: `{{ .request_method | TrimSpace | ToUpper }}`.
 
 ## lower
 
 > Added in Loki 2.1
 
-Convert to lower case.
+Use this function to convert to lower case.
 
 Signature:
 
@@ -139,7 +139,7 @@ The last example will return `hello`.
 
 > Added in Loki 2.1
 
-Convert to upper case.
+Use this function to convert to upper case.
 
 Signature:
 
@@ -152,7 +152,7 @@ Examples:
 `{{ upper  "hello"}}`
 ```
 
-The last example will return `HELLO`.
+This results in `HELLO`.
 
 ## title
 
@@ -285,7 +285,7 @@ Examples:
 
 > **Note:** Added in Loki 2.1.
 
-Trim just the prefix from a string.
+Use this function to trim just the prefix from a string.
 
 Signature: `trimPrefix(suffix string, src string) string`
 
@@ -308,7 +308,7 @@ Signature: `indent(spaces int,src string) string`
 {{ indent 4 .query }}
 ```
 
-The following will indent by 4 spaces each lines contained in `.query`.
+This indents each line contained in the `.query` by four (4) spaces.
 
 ## nindent
 
@@ -322,7 +322,7 @@ Signature: `nindent(spaces int,src string) string`
 {{ nindent 4 .query }}
 ```
 
-The above will indent every line of text by 4 space characters and add a new line to the beginning.
+This will indent every line of text by 4 space characters and add a new line to the beginning.
 
 ## repeat
 

From c97fcf238d51148ffc03f3e02823a5d97af3b5cd Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Thu, 5 Nov 2020 15:02:17 -0500
Subject: [PATCH 39/39] Apply suggestions from code review

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
---
 docs/sources/logql/functions.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/sources/logql/functions.md b/docs/sources/logql/functions.md
index 7c5a96c7d2c3d..1728aea06053a 100644
--- a/docs/sources/logql/functions.md
+++ b/docs/sources/logql/functions.md
@@ -328,7 +328,7 @@ This will indent every line of text by 4 space characters and add a new line to
 
 > **Note:** Added in Loki 2.1.
 
-Repeat a string multiple times.
+Use this function to repeat a string multiple times.
 
 Signature: `repeat(c int,value string) string`
 
@@ -340,7 +340,7 @@ Signature: `repeat(c int,value string) string`
 
 > **Note:** Added in Loki 2.1.
 
-Test to see if one string is contained inside of another.
+Use this function to test to see if one string is contained inside of another.
 
 Signature: `contains(s string, src string) bool`