[extension/subprocess] Create subprocess extension (#6467)

extension/subprocess/Makefile

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+include ../../Makefile.Common

extension/subprocess/README.md

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+# Subprocess Extension
+
+The `subprocess` extension facilitates running a subprocess of the collector.
+
+You can provide the configuration to the subprocess via the command line arguments. 
+
+You can also specify the working directory of the command.
+
+## Configuration
+
+The executable path is required:
+
+- `executable_path`: The path of the command to run. If `executable_path` is relative, then it is evaluated relative to the working directory.
+
+The following settings can be optionally configured:
+
+- `args`: The command line arguments to use.
+- `working_directory`: Defines the working directory of the command. If it is not configured, the `subprocess` extension runs the command in the calling process's current directory.
+
+## Example Config
+
+```yaml
+extensions:
+  health_check:
+  sub_process:
+    executable_path: bin/cmd
+    args:
+      - --port
+      - 5989
+    working_directory: /usr/local/
+
+receivers:
+# {...}
+service:
+
+  extensions: [sub_process]
+```

extension/subprocess/config.go

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+// 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 subprocess
+
+import (
+	"go.opentelemetry.io/collector/config"
+)
+
+// Config has the configuration for the extension.
+type Config struct {
+	config.ExtensionSettings `mapstructure:",squash"`
+
+	// The path to the executable.
+	ExecutablePath string `mapstructure:"executable_path"`
+
+	// Command line arguments.
+	Args []string `mapstructure:"args"`
+
+	// Working directory.
+	WorkingDirectory string `mapstructure:"working_directory"`
+}

extension/subprocess/config_test.go

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+// 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 subprocess
+
+import (
+	"path"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/config/configtest"
+)
+
+func TestLoadConfig(t *testing.T) {
+	t.Parallel()
+	factories, err := componenttest.NopFactories()
+	require.NoError(t, err)
+
+	factory := NewFactory()
+	factories.Extensions[typeStr] = factory
+	cfg, err := configtest.LoadConfigAndValidate(path.Join(".", "testdata", "config.yaml"), factories)
+
+	require.Nil(t, err)
+	require.NotNil(t, cfg)
+
+	ext0 := cfg.Extensions[config.NewComponentID(typeStr)]
+	assert.Equal(t, factory.CreateDefaultConfig(), ext0)
+
+	ext1 := cfg.Extensions[config.NewComponentIDWithName(typeStr, "1")]
+	assert.Equal(t,
+		&Config{
+			ExtensionSettings: config.NewExtensionSettings(config.NewComponentIDWithName(typeStr, "1")),
+			ExecutablePath:    "bin/cmd",
+			Args:              []string{"arg1", "arg2"},
+			WorkingDirectory:  "/usr/local",
+		},
+		ext1)
+
+	assert.Equal(t, 1, len(cfg.Service.Extensions))
+	assert.Equal(t, config.NewComponentIDWithName(typeStr, "1"), cfg.Service.Extensions[0])
+}

extension/subprocess/factory.go

@@ -0,0 +1,47 @@
+// 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 subprocess
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/extension/extensionhelper"
+)
+
+const (
+	// The value of extension "type" in configuration.
+	typeStr = "sub_process"
+)
+
+// NewFactory creates a factory for SubProcess extension.
+func NewFactory() component.ExtensionFactory {
+	return extensionhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		createExtension)
+}
+
+func createDefaultConfig() config.Extension {
+	return &Config{
+		ExtensionSettings: config.NewExtensionSettings(config.NewComponentID(typeStr)),
+	}
+}
+
+func createExtension(_ context.Context, params component.ExtensionCreateSettings, cfg config.Extension) (component.Extension, error) {
+	config := cfg.(*Config)
+	return newProcessManager(config, params.Logger), nil
+}

extension/subprocess/factory_test.go

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+// 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 subprocess
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/config/configtest"
+)
+
+func TestFactory_CreateDefaultConfig(t *testing.T) {
+	cfg := createDefaultConfig()
+	assert.Equal(t, &Config{
+		ExtensionSettings: config.NewExtensionSettings(config.NewComponentID(typeStr)),
+	}, cfg)
+
+	assert.NoError(t, configtest.CheckConfigStruct(cfg))
+	ext, err := createExtension(context.Background(), componenttest.NewNopExtensionCreateSettings(), cfg)
+	require.NoError(t, err)
+	require.NotNil(t, ext)
+}
+
+func TestFactory_CreateExtension(t *testing.T) {
+	cfg := createDefaultConfig().(*Config)
+	ext, err := createExtension(context.Background(), componenttest.NewNopExtensionCreateSettings(), cfg)
+	require.NoError(t, err)
+	require.NotNil(t, ext)
+}

extension/subprocess/go.mod

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+module github.com/open-telemetry/opentelemetry-collector-contrib/extension/subprocess
+
+go 1.17
+
+require (
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/collector v0.40.0
+	go.uber.org/zap v1.19.1
+
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/benbjohnson/clock v1.2.0 // indirect
+	github.com/fsnotify/fsnotify v1.4.9 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/knadh/koanf v1.3.2 // indirect
+	github.com/kr/pretty v0.3.0 // indirect
+	github.com/magiconair/properties v1.8.5 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/mapstructure v1.4.2 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/pelletier/go-toml v1.9.3 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/spf13/cast v1.4.1 // indirect
+	go.opentelemetry.io/collector/model v0.40.0 // indirect
+	go.opentelemetry.io/otel v1.2.0 // indirect
+	go.opentelemetry.io/otel/metric v0.25.0 // indirect
+	go.opentelemetry.io/otel/trace v1.2.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.7.0 // indirect
+	golang.org/x/sys v0.0.0-20211013075003-97ac67df715c // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+)