opamp agent extension, hello world

part of open-telemetry#16462

Signed-off-by: Sean Porter <portertech@gmail.com>

extension/opampextension/Makefile

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

extension/opampextension/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 opampextension
+
+import (
+	"errors"
+
+	"go.opentelemetry.io/collector/config"
+)
+
+// Config has the configuration for the opamp extension.
+type Config struct {
+	config.ExtensionSettings `mapstructure:",squash"` // squash ensures fields are correctly decoded in embedded struct
+
+	// Endpoint is the OpAMP server URL. Transport based on the scheme of the URL.
+	Endpoint string `mapstructure:"endpoint"`
+
+	// InstanceUID is a ULID formatted as a 36 character string in canonical
+	// representation. Auto-generated on start if missing.
+	InstanceUID string `mapstructure:"instance_uid"`
+}
+
+// Validate checks if the extension configuration is valid
+func (cfg *Config) Validate() error {
+	// no need to validate less than 0 case for uint64
+	if len(cfg.InstanceUID) > 26 {
+		return errors.New("instance_uid has more than 26 characters")
+	}
+	return nil
+}

extension/opampextension/config_test.go

@@ -0,0 +1,56 @@
+// 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 opampextension
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/confmap"
+	"go.opentelemetry.io/collector/confmap/confmaptest"
+)
+
+func TestUnmarshalDefaultConfig(t *testing.T) {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	assert.NoError(t, component.UnmarshalConfig(confmap.New(), cfg))
+	assert.Equal(t, factory.CreateDefaultConfig(), cfg)
+}
+
+func TestUnmarshalConfig(t *testing.T) {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	assert.NoError(t, component.UnmarshalConfig(cm, cfg))
+	assert.Equal(t,
+		&Config{
+			ExtensionSettings: config.NewExtensionSettings(component.NewID(typeStr)),
+			Endpoint:          "wss://127.0.0.1:4320/v1/opamp",
+			InstanceUID:       "01BX5ZZKBKACTAV9WEVGEMMVRZ",
+		}, cfg)
+}
+
+func TestConfigValidate(t *testing.T) {
+	cfg := &Config{InstanceUID: "01BX5ZZKBKACTAV9WEVGEMMVRZFAIL"}
+	err := cfg.Validate()
+	require.Error(t, err)
+	assert.Equal(t, "instance_uid has more than 26 characters", err.Error())
+}

extension/opampextension/factory.go

@@ -0,0 +1,41 @@
+// 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 opampextension
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+)
+
+const (
+	// The value of extension "type" in configuration.
+	typeStr = "opamp"
+)
+
+func NewFactory() component.ExtensionFactory {
+	return component.NewExtensionFactory(typeStr, createDefaultConfig, createExtension, component.StabilityLevelBeta)
+}
+
+func createDefaultConfig() component.ExtensionConfig {
+	return &Config{
+		ExtensionSettings: config.NewExtensionSettings(component.NewID(typeStr)),
+	}
+}
+
+func createExtension(_ context.Context, set component.ExtensionCreateSettings, cfg component.ExtensionConfig) (component.Extension, error) {
+	return newOpampAgent(cfg.(*Config), set.Logger)
+}

extension/opampextension/factory_test.go

@@ -0,0 +1,44 @@
+// 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 opampextension
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config"
+)
+
+func TestFactory_CreateDefaultConfig(t *testing.T) {
+	cfg := createDefaultConfig()
+	assert.Equal(t, &Config{ExtensionSettings: config.NewExtensionSettings(component.NewID(typeStr))}, cfg)
+
+	assert.NoError(t, componenttest.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/opampextension/go.mod

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+module github.com/open-telemetry/opentelemetry-collector-contrib/extension/opampextension
+
+go 1.18
+
+require (
+	github.com/stretchr/testify v1.8.1
+	go.opentelemetry.io/collector v0.66.1-0.20221202180633-b3e9d209d368
+	go.opentelemetry.io/collector/component v0.66.1-0.20221202180633-b3e9d209d368
+	go.uber.org/zap v1.24.0
+)
+
+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 v1.4.4 // 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/confmap v0.0.0-20221201172708-2bdff61fa52a // indirect
+	go.opentelemetry.io/collector/consumer v0.66.0 // indirect
+	go.opentelemetry.io/collector/featuregate v0.66.0 // indirect
+	go.opentelemetry.io/collector/pdata v0.66.0 // indirect
+	go.opentelemetry.io/otel v1.11.1 // indirect
+	go.opentelemetry.io/otel/metric v0.33.0 // indirect
+	go.opentelemetry.io/otel/trace v1.11.1 // indirect
+	go.uber.org/atomic v1.10.0 // indirect
+	go.uber.org/multierr v1.8.0 // indirect
+	golang.org/x/net v0.0.0-20220722155237-a158d28d115b // indirect
+	golang.org/x/sys v0.2.0 // indirect
+	golang.org/x/text v0.4.0 // indirect
+	google.golang.org/genproto v0.0.0-20211208223120-3a66f561d7aa // indirect
+	google.golang.org/grpc v1.51.0 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)