Initial version

README.md

@@ -1,3 +1,5 @@
-[![Tests on Linux, MacOS and Windows](https://github.com/bep/golibtemplate/workflows/Test/badge.svg)](https://github.com/bep/golibtemplate/actions?query=workflow:Test)
-[![Go Report Card](https://goreportcard.com/badge/github.com/bep/golibtemplate)](https://goreportcard.com/report/github.com/bep/golibtemplate)
-[![GoDoc](https://godoc.org/github.com/bep/golibtemplate?status.svg)](https://godoc.org/github.com/bep/golibtemplate)
+[![Tests on Linux, MacOS and Windows](https://github.com/bep/helpers/workflows/Test/badge.svg)](https://github.com/bep/helpers/actions?query=workflow:Test)
+[![Go Report Card](https://goreportcard.com/badge/github.com/bep/helpers)](https://goreportcard.com/report/github.com/bep/helpers)
+[![GoDoc](https://godoc.org/github.com/bep/helpers?status.svg)](https://godoc.org/github.com/bep/helpers)
+
+Some helper packages with some helper code that I have had a tendency to copy from project to project over the years, a clear sign that I should consider some reuse.

envhelpers/env.go

@@ -0,0 +1,27 @@
+package envhelpers
+
+import "strings"
+
+// SetEnvVars sets vars on the form key=value in the oldVars slice.
+func SetEnvVars(oldVars *[]string, keyValues ...string) {
+	for i := 0; i < len(keyValues); i += 2 {
+		setEnvVar(oldVars, keyValues[i], keyValues[i+1])
+	}
+}
+
+// SplitEnvVar splits an env var into key and value.
+func SplitEnvVar(v string) (string, string) {
+	name, value, _ := strings.Cut(v, "=")
+	return name, value
+}
+
+func setEnvVar(vars *[]string, key, value string) {
+	for i := range *vars {
+		if strings.HasPrefix((*vars)[i], key+"=") {
+			(*vars)[i] = key + "=" + value
+			return
+		}
+	}
+	// New var.
+	*vars = append(*vars, key+"="+value)
+}

envhelpers/env_test.go

@@ -0,0 +1,19 @@
+package envhelpers
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestSetEnvVars(t *testing.T) {
+	t.Parallel()
+	c := qt.New(t)
+	vars := []string{"FOO=bar", "HUGO=cool", "BAR=foo"}
+	SetEnvVars(&vars, "HUGO", "rocking!", "NEW", "bar")
+	c.Assert(vars, qt.DeepEquals, []string{"FOO=bar", "HUGO=rocking!", "BAR=foo", "NEW=bar"})
+
+	key, val := SplitEnvVar("HUGO=rocks")
+	c.Assert(key, qt.Equals, "HUGO")
+	c.Assert(val, qt.Equals, "rocks")
+}

envhelpers/varexpand.go

@@ -0,0 +1,21 @@
+package envhelpers
+
+import (
+	"regexp"
+	"strings"
+)
+
+var varRe = regexp.MustCompile(`\$\{(\w+)\}`)
+
+// Expand replaces ${var} (and only that) in the string based on the mapping function.
+// This signature is identical to the one in the Go standard library,
+// but has a more restrictive scope with less ambiguity.
+// The value inside ${} must match \w+ (see regexp.MatchString).
+func Expand(s string, mapping func(string) string) string {
+	if !strings.Contains(s, "${") {
+		return s
+	}
+	return varRe.ReplaceAllStringFunc(s, func(varName string) string {
+		return mapping(varName[2 : len(varName)-1])
+	})
+}

envhelpers/varexpand_test.go

@@ -0,0 +1,24 @@
+package envhelpers
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestExpand(t *testing.T) {
+	c := qt.New(t)
+
+	m := func(s string) string {
+		return s + "-expanded"
+	}
+
+	c.Assert(Expand("", m), qt.Equals, "")
+	c.Assert(Expand("no vars", m), qt.Equals, "no vars")
+	c.Assert(Expand("one var: ${myvar}.", m), qt.Equals, "one var: myvar-expanded.")
+	c.Assert(Expand("two vars: first:  ${first}, second ${second}.", m), qt.Equals, "two vars: first:  first-expanded, second second-expanded.")
+	c.Assert(Expand("with space: ${ myvar }.", m), qt.Equals, "with space: ${ myvar }.")
+	c.Assert(Expand("with special char: ${myvar&}.", m), qt.Equals, "with special char: ${myvar&}.")
+	c.Assert(Expand("not without brackets: $myvar", m), qt.Equals, "not without brackets: $myvar")
+	c.Assert(Expand("multiline: ${first}\n\nanother: ${second}", m), qt.Equals, "multiline: first-expanded\n\nanother: second-expanded")
+}

go.mod

@@ -1,12 +1,12 @@
-module github.com/bep/golibtemplate
+module github.com/bep/helpers
 
 go 1.18
 
+require github.com/frankban/quicktest v1.14.3
+
 require (
-	github.com/frankban/quicktest v1.14.2 // indirect
-	github.com/google/go-cmp v0.5.7 // indirect
+	github.com/google/go-cmp v0.5.8 // indirect
 	github.com/kr/pretty v0.3.0 // indirect
 	github.com/kr/text v0.2.0 // indirect
-	github.com/rogpeppe/go-internal v1.6.1 // indirect
-	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 // indirect
+	github.com/rogpeppe/go-internal v1.8.1 // indirect
 )

go.sum

@@ -1,18 +1,20 @@
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
-github.com/frankban/quicktest v1.14.2 h1:SPb1KFFmM+ybpEjPUhCCkZOM5xlovT5UbrMvWnXyBns=
-github.com/frankban/quicktest v1.14.2/go.mod h1:mgiwOwqx65TmIk1wJ6Q7wvnVMocbUorkibMOrVTHZps=
-github.com/google/go-cmp v0.5.7 h1:81/ik6ipDQS2aGcBfIN5dHDB36BwrStyeAQquSYCV4o=
+github.com/frankban/quicktest v1.14.3 h1:FJKSZTDHjyhriyC81FLQ0LY93eSai0ZyR/ZIkd3ZUKE=
+github.com/frankban/quicktest v1.14.3/go.mod h1:mgiwOwqx65TmIk1wJ6Q7wvnVMocbUorkibMOrVTHZps=
 github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
+github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
+github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
 github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/rogpeppe/go-internal v1.6.1 h1:/FiVV8dS/e+YqF2JvO3yXRFbBLTIuSDkuC7aBOAvL+k=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/rogpeppe/go-internal v1.6.1/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTEfhy4qGm1nDQc=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+github.com/rogpeppe/go-internal v1.8.1 h1:geMPLpDpQOgVyCg5z5GoRwLHepNdb71NXb67XFkP+Eg=
+github.com/rogpeppe/go-internal v1.8.1/go.mod h1:JeRgkft04UBgHMgCIwADu4Pn6Mtm5d4nPKWu0nJ5d+o=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=