[cmd/opampsupervisor] Add OpAMP supervisor skeleton (open-telemetry#1…

…9143)


This is a direct copy of the [supervisor example implementation](https://github.com/open-telemetry/opamp-go/tree/main/internal/examples/supervisor) in the opamp-go repository. I've made some minor changes that are largely centered around linting and making it a little less of an example. Any existing or new TODOs have a linked issue that gives some context.

**Link to tracking Issue:**

Implements open-telemetry#18461
Co-authored-by: Matej Gera <38492574+matej-g@users.noreply.github.com>

---------

Co-authored-by: Evan Bradley <evan-bradley@users.noreply.github.com>
Co-authored-by: Matej Gera <38492574+matej-g@users.noreply.github.com>

.github/CODEOWNERS

@@ -22,6 +22,7 @@
 
 cmd/configschema/                                        @open-telemetry/collector-contrib-approvers @mx-psi @dmitryax @pmcollins
 cmd/mdatagen/                                            @open-telemetry/collector-contrib-approvers @dmitryax
+cmd/opampsupervisor/                                     @open-telemetry/collector-contrib-approvers @evan-bradley @atoulme @tigrannajaryan
 cmd/otelcontribcol/                                      @open-telemetry/collector-contrib-approvers
 cmd/oteltestbedcol/                                      @open-telemetry/collector-contrib-approvers
 cmd/telemetrygen/                                        @open-telemetry/collector-contrib-approvers @mx-psi @codeboten

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -20,6 +20,7 @@ body:
       # Start Collector components list
       - cmd/configschema
       - cmd/mdatagen
+      - cmd/opampsupervisor
       - cmd/otelcontribcol
       - cmd/oteltestbedcol
       - cmd/telemetrygen

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -14,6 +14,7 @@ body:
       # Start Collector components list
       - cmd/configschema
       - cmd/mdatagen
+      - cmd/opampsupervisor
       - cmd/otelcontribcol
       - cmd/oteltestbedcol
       - cmd/telemetrygen

.github/ISSUE_TEMPLATE/other.yaml

@@ -14,6 +14,7 @@ body:
       # Start Collector components list
       - cmd/configschema
       - cmd/mdatagen
+      - cmd/opampsupervisor
       - cmd/otelcontribcol
       - cmd/oteltestbedcol
       - cmd/telemetrygen

.github/dependabot.yml

@@ -17,6 +17,11 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/cmd/opampsupervisor"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/cmd/otelcontribcol"
     schedule:
@@ -1097,8 +1102,3 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/receiver/tcplogreceiver"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"

cmd/opampsupervisor/.gitignore

@@ -0,0 +1,2 @@
+effective.yaml
+agent.log

cmd/opampsupervisor/Makefile

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

cmd/opampsupervisor/README.md

@@ -0,0 +1,24 @@
+# OpAMP Supervisor for the OpenTelemetry Collector
+
+This is an implementation of an OpAMP Supervisor that runs a Collector instance using configuration provided from an OpAMP server. This implementation
+is following a design specified [here](./specification/README.md).
+The design is still undergoing changes, and as such this implementation may change as well.
+
+## Experimenting with the supervisor
+
+The supervisor is currently undergoing heavy development and is not ready for any serious use. However, if you would like to test it, you can follow the steps below:
+
+1. Download the [opamp-go](https://github.com/open-telemetry/opamp-go) repository, and run the OpAMP example server in the `internal/examples/server` directory.
+2. From the Collector contrib repository root, build the Collector:
+
+   ```shell
+   make otelcontribcol
+   ```
+
+3. Run the supervisor, substituting `<OS>` for your platform:
+
+   ```shell
+   go run . --config testdata/supervisor_<OS>.yaml
+   ```
+
+4. The supervisor should connect to the OpAMP server and start a Collector instance.

cmd/opampsupervisor/go.mod

@@ -0,0 +1,27 @@
+module github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor
+
+go 1.19
+
+require (
+	github.com/cenkalti/backoff/v4 v4.2.0
+	github.com/knadh/koanf v1.5.0
+	github.com/oklog/ulid/v2 v2.1.0
+	github.com/open-telemetry/opamp-go v0.6.0
+	go.uber.org/zap v1.24.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fsnotify/fsnotify v1.6.0 // indirect
+	github.com/gorilla/websocket 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/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.8.2 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	go.uber.org/multierr v1.6.0 // indirect
+	golang.org/x/sys v0.5.0 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

cmd/opampsupervisor/main.go

@@ -0,0 +1,33 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+import (
+	"flag"
+	"os"
+	"os/signal"
+
+	"go.uber.org/zap"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor"
+)
+
+func main() {
+	configFlag := flag.String("config", "", "Path to a supervisor configuration file")
+	flag.Parse()
+
+	logger, _ := zap.NewDevelopment()
+
+	supervisor, err := supervisor.NewSupervisor(logger, *configFlag)
+	if err != nil {
+		logger.Error(err.Error())
+		os.Exit(-1)
+		return
+	}
+
+	interrupt := make(chan os.Signal, 1)
+	signal.Notify(interrupt, os.Interrupt)
+	<-interrupt
+	supervisor.Shutdown()
+}