[receiver/file] add file receiver skeleton 1/3 (#16827)

* add file receiver skeleton

.chloggen/filereceiver.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: filereceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: A receiver for reading the output of a File Exporter
+
+# One or more tracking issues related to the change
+issues: [14638]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: This component is not yet enabled.

.github/CODEOWNERS

@@ -172,6 +172,7 @@ receiver/dockerstatsreceiver/                            @open-telemetry/collect
 receiver/elasticsearchreceiver/                          @open-telemetry/collector-contrib-approvers @djaglowski @binaryfissiongames
 receiver/expvarreceiver/                                 @open-telemetry/collector-contrib-approvers @jamesmoessis @MovieStoreGuy
 receiver/filelogreceiver/                                @open-telemetry/collector-contrib-approvers @djaglowski
+receiver/filereceiver/                               @open-telemetry/collector-contrib-approvers @pmcollins @djaglowski
 receiver/flinkmetricsreceiver/                           @open-telemetry/collector-contrib-approvers @jonathanwamsley @djaglowski
 receiver/fluentforwardreceiver/                          @open-telemetry/collector-contrib-approvers @dmitryax
 receiver/googlecloudpubsubreceiver/                      @open-telemetry/collector-contrib-approvers @alexvanboxel

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -159,6 +159,7 @@ body:
       - receiver/dockerstats
       - receiver/elasticsearch
       - receiver/expvar
+      - receiver/file
       - receiver/filelog
       - receiver/flinkmetrics
       - receiver/fluentforward

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -153,6 +153,7 @@ body:
       - receiver/dockerstats
       - receiver/elasticsearch
       - receiver/expvar
+      - receiver/file
       - receiver/filelog
       - receiver/flinkmetrics
       - receiver/fluentforward

.github/ISSUE_TEMPLATE/other.yaml

@@ -153,6 +153,7 @@ body:
       - receiver/dockerstats
       - receiver/elasticsearch
       - receiver/expvar
+      - receiver/file
       - receiver/filelog
       - receiver/flinkmetrics
       - receiver/fluentforward

receiver/filereceiver/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

receiver/filereceiver/README.md

@@ -0,0 +1,28 @@
+# File Receiver
+
+| Status                   |                       |
+|--------------------------|-----------------------|
+| Stability                | [development]         |
+| Supported pipeline types | metrics, traces, logs |
+| Distributions            | [contrib]             |
+
+The File Receiver reads the output of a
+[File Exporter](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/exporter/fileexporter),
+converting that output to metrics, and sending the metrics down the pipeline.
+
+Currently, the only file format supported is the File Exporter's JSON format.
+Reading compressed output, rotated files, or telemetry other than metrics are not supported at this time.
+
+## Getting Started
+
+The following settings are required:
+
+- `path` [no default]: the file containing the metrics written by a File Exporter.
+
+## Example
+
+```yaml
+receivers:
+  file:
+    path: ./foo
+```

receiver/filereceiver/config.go

@@ -0,0 +1,38 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filereceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/filereceiver"
+
+import (
+	"errors"
+
+	"go.opentelemetry.io/collector/component"
+)
+
+// Config defines the configuration for the file receiver.
+type Config struct {
+	// Path of the file to read from. Path is relative to current directory.
+	Path string `mapstructure:"path"`
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{}
+}
+
+func (c Config) Validate() error {
+	if c.Path == "" {
+		return errors.New("path cannot be empty")
+	}
+	return nil
+}

receiver/filereceiver/config_test.go

@@ -0,0 +1,76 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filereceiver
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap/confmaptest"
+)
+
+func TestLoadConfig_Validate_Invalid(t *testing.T) {
+	cfg := Config{}
+	assert.Error(t, cfg.Validate())
+}
+
+func TestConfig_Validate_Valid(t *testing.T) {
+	cfg := Config{Path: "/foo/bar"}
+	assert.NoError(t, cfg.Validate())
+}
+
+func TestLoadConfig(t *testing.T) {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+
+	tests := []struct {
+		id           component.ID
+		expected     component.Config
+		errorMessage string
+	}{
+		{
+			id:           component.NewIDWithName(typeStr, ""),
+			errorMessage: "path cannot be empty",
+		},
+		{
+			id: component.NewIDWithName(typeStr, "1"),
+			expected: &Config{
+				Path: "./filename.json",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.id.String(), func(t *testing.T) {
+			factory := NewFactory()
+			cfg := factory.CreateDefaultConfig()
+
+			sub, err := cm.Sub(tt.id.String())
+			require.NoError(t, err)
+			require.NoError(t, component.UnmarshalConfig(sub, cfg))
+
+			if tt.errorMessage != "" {
+				assert.EqualError(t, component.ValidateConfig(cfg), tt.errorMessage)
+				return
+			}
+
+			assert.NoError(t, component.ValidateConfig(cfg))
+			assert.Equal(t, tt.expected, cfg)
+		})
+	}
+}

receiver/filereceiver/factory.go

@@ -0,0 +1,45 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filereceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/filereceiver"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver"
+)
+
+const (
+	typeStr   = "file"
+	stability = component.StabilityLevelDevelopment
+)
+
+func NewFactory() receiver.Factory {
+	return receiver.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		receiver.WithMetrics(createMetricsFunc, component.StabilityLevelDevelopment),
+	)
+}
+
+func createMetricsFunc(
+	ctx context.Context,
+	settings receiver.CreateSettings,
+	config component.Config,
+	metrics consumer.Metrics,
+) (receiver.Metrics, error) {
+	return fileReceiver{}, nil
+}

receiver/filereceiver/factory_test.go

@@ -0,0 +1,35 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filereceiver
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/consumer/consumertest"
+	"go.opentelemetry.io/collector/receiver/receivertest"
+)
+
+func TestNewFactory(t *testing.T) {
+	f := NewFactory()
+	_, err := f.CreateMetricsReceiver(
+		context.Background(),
+		receivertest.NewNopCreateSettings(),
+		f.CreateDefaultConfig(),
+		consumertest.NewNop(),
+	)
+	require.NoError(t, err)
+}

receiver/filereceiver/go.mod

@@ -0,0 +1,40 @@
+module github.com/open-telemetry/opentelemetry-collector-contrib/receiver/filereceiver
+
+go 1.18
+
+require (
+	github.com/stretchr/testify v1.8.1
+	go.opentelemetry.io/collector v0.70.0
+	go.opentelemetry.io/collector/component v0.70.0
+	go.opentelemetry.io/collector/confmap v0.70.0
+	go.opentelemetry.io/collector/consumer v0.70.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/knadh/koanf v1.5.0 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/collector/featuregate v0.70.0 // indirect
+	go.opentelemetry.io/collector/pdata v1.0.0-rc4 // indirect
+	go.opentelemetry.io/otel v1.11.2 // indirect
+	go.opentelemetry.io/otel/metric v0.34.0 // indirect
+	go.opentelemetry.io/otel/trace v1.11.2 // indirect
+	go.uber.org/atomic v1.10.0 // indirect
+	go.uber.org/multierr v1.9.0 // indirect
+	go.uber.org/zap v1.24.0 // indirect
+	golang.org/x/net v0.5.0 // indirect
+	golang.org/x/sys v0.4.0 // indirect
+	golang.org/x/text v0.6.0 // indirect
+	google.golang.org/genproto v0.0.0-20221118155620-16455021b5e6 // indirect
+	google.golang.org/grpc v1.52.0 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)