OpAMP Agent Extension (open-telemetry#16594)

See [design
document](https://docs.google.com/document/d/1KtH5atZQUs9Achbce6LiOaJxLbksNJenvgvyKLsJrkc/edit#heading=h.ioikt02qpy5f).

Depends on:

- [Implement ability for extensions to be notified about effective
configuration opentelemetry-collector#6596](open-telemetry/opentelemetry-collector#6596)
- [Make service.instance.id and other telemetry attributes available to
extensions opentelemetry-collector#6599](open-telemetry/opentelemetry-collector#6599)

Closes
open-telemetry#16618

---------

Signed-off-by: Sean Porter <[email protected]>
Co-authored-by: Daniel Jaglowski <[email protected]>
Co-authored-by: Tigran Najaryan <[email protected]>

Author: 3 people

.chloggen/add-opamp-agent-extension.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: extension/opampextension
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a new extension that implements an OpAMP agent for reporting the collector's health and effective configuration.
+
+# One or more tracking issues related to the change
+issues: [16462]
+
+# (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:

.github/CODEOWNERS

@@ -108,6 +108,7 @@ extension/observer/ecstaskobserver/                                     @open-te
 extension/observer/hostobserver/                                        @open-telemetry/collector-contrib-approvers @MovieStoreGuy
 extension/observer/k8sobserver/                                         @open-telemetry/collector-contrib-approvers @rmfitzpatrick @dmitryax
 extension/oidcauthextension/                                            @open-telemetry/collector-contrib-approvers @jpkrohling
+extension/opampextension/                                               @open-telemetry/collector-contrib-approvers @portertech @evan-bradley @tigrannajaryan
 extension/pprofextension/                                               @open-telemetry/collector-contrib-approvers @MovieStoreGuy
 extension/sigv4authextension/                                           @open-telemetry/collector-contrib-approvers @Aneurysm9 @erichsueh3
 extension/storage/                                                      @open-telemetry/collector-contrib-approvers @dmitryax @atoulme @djaglowski

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -100,6 +100,7 @@ body:
       - extension/observer/hostobserver
       - extension/observer/k8sobserver
       - extension/oidcauth
+      - extension/opamp
       - extension/pprof
       - extension/sigv4auth
       - extension/storage

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -94,6 +94,7 @@ body:
       - extension/observer/hostobserver
       - extension/observer/k8sobserver
       - extension/oidcauth
+      - extension/opamp
       - extension/pprof
       - extension/sigv4auth
       - extension/storage

.github/ISSUE_TEMPLATE/other.yaml

@@ -94,6 +94,7 @@ body:
       - extension/observer/hostobserver
       - extension/observer/k8sobserver
       - extension/oidcauth
+      - extension/opamp
       - extension/pprof
       - extension/sigv4auth
       - extension/storage

.github/dependabot.yml

@@ -8,7 +8,12 @@ updates:
       interval: "weekly"
       day: "wednesday"
   - package-ecosystem: "gomod"
-    directory: "/cmd/githubgen"
+    directory: "/cmd/otelcontribcol"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/cmd/oteltestbedcol"
     schedule:
       interval: "weekly"
       day: "wednesday"
@@ -302,11 +307,6 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/extension/encoding/jaegerencodingextension"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/extension/headerssetterextension"
     schedule:
@@ -1012,11 +1012,6 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/receiver/splunkenterprisereceiver"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/receiver/splunkhecreceiver"
     schedule:
@@ -1067,6 +1062,11 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/receiver/webhookeventreceiver"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/receiver/windowseventlogreceiver"
     schedule:

extension/opampextension/Makefile

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

extension/opampextension/README.md

@@ -0,0 +1,46 @@
+# OpAMP Agent Extension
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [development]  |
+| Distributions | [] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aextension%2Fopamp%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aextension%2Fopamp) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aextension%2Fopamp%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aextension%2Fopamp) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@portertech](https://www.github.com/portertech), [@evan-bradley](https://www.github.com/evan-bradley), [@tigrannajaryan](https://www.github.com/tigrannajaryan) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector#development
+<!-- end autogenerated section -->
+
+## Configuration
+
+The following settings are required:
+
+- `server`: The OpAMP server connection settings.
+  - `ws`: The OpAMP websocket transport settings.
+    - `endpoint` (no default): The OpAMP server websocket endpoint (URL).
+
+The following settings are optional:
+
+- `server`: The OpAMP server connection settings.
+  - `ws`: The OpAMP websocket transport settings.
+    - `tls`: TLS settings.
+    - `headers`: HTTP headers to set.
+- `instance_uid`: A ULID formatted as a 26 character string in canonical
+  representation. Auto-generated on start if missing. Setting this ensures the
+  instance UID remains constant across process restarts.
+
+### Example
+
+``` yaml
+extensions:
+  opamp:
+    server:
+      ws:
+        endpoint: wss://127.0.0.1:4320/v1/opamp
+```
+
+## Status
+
+This OpenTelemetry OpAMP agent extension is intended to support the [OpAMP
+Supervisor][supervisor].
+
+[supervisor]: https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/cmd/opampsupervisor

extension/opampextension/config.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package opampextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/opampextension"
+
+import (
+	"errors"
+
+	"github.com/oklog/ulid/v2"
+	"go.opentelemetry.io/collector/config/configopaque"
+	"go.opentelemetry.io/collector/config/configtls"
+)
+
+// Config contains the configuration for the opamp extension. Trying to mirror
+// the OpAMP supervisor config for some consistency.
+type Config struct {
+	Server *OpAMPServer `mapstructure:"server"`
+
+	// InstanceUID is a ULID formatted as a 26 character string in canonical
+	// representation. Auto-generated on start if missing.
+	InstanceUID string `mapstructure:"instance_uid"`
+}
+
+// OpAMPServer contains the OpAMP transport configuration.
+type OpAMPServer struct {
+	WS *OpAMPWebsocket `mapstructure:"ws"`
+}
+
+// OpAMPWebsocket contains the OpAMP websocket transport configuration.
+type OpAMPWebsocket struct {
+	Endpoint   string                         `mapstructure:"endpoint"`
+	TLSSetting configtls.TLSClientSetting     `mapstructure:"tls,omitempty"`
+	Headers    map[string]configopaque.String `mapstructure:"headers,omitempty"`
+}
+
+// Validate checks if the extension configuration is valid
+func (cfg *Config) Validate() error {
+	if cfg.Server.WS.Endpoint == "" {
+		return errors.New("opamp server websocket endpoint must be provided")
+	}
+
+	if cfg.InstanceUID != "" {
+		_, err := ulid.ParseStrict(cfg.InstanceUID)
+		if err != nil {
+			return errors.New("opamp instance_uid is invalid")
+		}
+	}
+
+	return nil
+}

extension/opampextension/config_test.go

@@ -0,0 +1,57 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+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/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{
+			Server: &OpAMPServer{
+				WS: &OpAMPWebsocket{
+					Endpoint: "wss://127.0.0.1:4320/v1/opamp",
+				},
+			},
+			InstanceUID: "01BX5ZZKBKACTAV9WEVGEMMVRZ",
+		}, cfg)
+}
+
+func TestConfigValidate(t *testing.T) {
+	cfg := &Config{
+		Server: &OpAMPServer{
+			WS: &OpAMPWebsocket{},
+		},
+	}
+	err := cfg.Validate()
+	assert.Equal(t, "opamp server websocket endpoint must be provided", err.Error())
+	cfg.Server.WS.Endpoint = "wss://127.0.0.1:4320/v1/opamp"
+	assert.NoError(t, cfg.Validate())
+	cfg.InstanceUID = "01BX5ZZKBKACTAV9WEVGEMMVRZFAIL"
+	err = cfg.Validate()
+	require.Error(t, err)
+	assert.Equal(t, "opamp instance_uid is invalid", err.Error())
+	cfg.InstanceUID = "01BX5ZZKBKACTAV9WEVGEMMVRZ"
+	require.NoError(t, cfg.Validate())
+}