[cmd/opampsupervisor] Add configurable supervisor logging (open-telem…

…etry#35468)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->

Adds configurable logging for the supervisor. Lays ground work to expand
with more config options and to configure other telemetry signals. Meant
to mimic how collector telemetry/logging is configured.

**Link to tracking Issue:** <Issue number if applicable> Closes open-telemetry#35466 

**Testing:** <Describe what testing was performed and which tests were
added.>
Tested running the supervisor with default and different log levels and
outputs specified.

**Documentation:** <Describe the documentation added.>

.chloggen/configurable-supervisor-logging.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: opampsupervisor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add configurable logging for the supervisor.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [35466]
+
+# (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:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

cmd/opampsupervisor/e2e_test.go

@@ -6,9 +6,11 @@
 package main
 
 import (
+	"bufio"
 	"bytes"
 	"context"
 	"crypto/sha256"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -40,10 +42,12 @@ import (
 	"github.com/stretchr/testify/require"
 	semconv "go.opentelemetry.io/collector/semconv/v1.21.0"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 	"google.golang.org/protobuf/proto"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/config"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/telemetry"
 )
 
 var _ clientTypes.Logger = testLogger{}
@@ -1354,6 +1358,84 @@ func TestSupervisorStopsAgentProcessWithEmptyConfigMap(t *testing.T) {
 
 }
 
+type LogEntry struct {
+	Level string `json:"level"`
+}
+
+func TestSupervisorInfoLoggingLevel(t *testing.T) {
+	storageDir := t.TempDir()
+	remoteCfgFilePath := filepath.Join(storageDir, "last_recv_remote_config.dat")
+
+	collectorCfg, hash, _, _ := createSimplePipelineCollectorConf(t)
+	remoteCfgProto := &protobufs.AgentRemoteConfig{
+		Config: &protobufs.AgentConfigMap{
+			ConfigMap: map[string]*protobufs.AgentConfigFile{
+				"": {Body: collectorCfg.Bytes()},
+			},
+		},
+		ConfigHash: hash,
+	}
+	marshalledRemoteCfg, err := proto.Marshal(remoteCfgProto)
+	require.NoError(t, err)
+	require.NoError(t, os.WriteFile(remoteCfgFilePath, marshalledRemoteCfg, 0600))
+
+	connected := atomic.Bool{}
+	server := newUnstartedOpAMPServer(t, defaultConnectingHandler, server.ConnectionCallbacksStruct{
+		OnConnectedFunc: func(ctx context.Context, conn types.Connection) {
+			connected.Store(true)
+		},
+	})
+	defer server.shutdown()
+
+	supervisorLogFilePath := filepath.Join(storageDir, "supervisor_log.log")
+	cfgFile := getSupervisorConfig(t, "logging", map[string]string{
+		"url":         server.addr,
+		"storage_dir": storageDir,
+		"log_level":   "0",
+		"log_file":    supervisorLogFilePath,
+	})
+
+	cfg, err := config.Load(cfgFile.Name())
+	require.NoError(t, err)
+	logger, err := telemetry.NewLogger(cfg.Telemetry.Logs)
+	require.NoError(t, err)
+
+	s, err := supervisor.NewSupervisor(logger, cfg)
+	require.NoError(t, err)
+	require.Nil(t, s.Start())
+
+	// Start the server and wait for the supervisor to connect
+	server.start()
+	waitForSupervisorConnection(server.supervisorConnected, true)
+	require.True(t, connected.Load(), "Supervisor failed to connect")
+
+	s.Shutdown()
+
+	// Read from log file checking for Info level logs
+	logFile, err := os.Open(supervisorLogFilePath)
+	require.NoError(t, err)
+	defer logFile.Close()
+
+	scanner := bufio.NewScanner(logFile)
+	check := false
+	for scanner.Scan() {
+		if !check {
+			check = true
+		}
+
+		line := scanner.Bytes()
+		var log LogEntry
+		err := json.Unmarshal(line, &log)
+		require.NoError(t, err)
+
+		level, err := zapcore.ParseLevel(log.Level)
+		require.NoError(t, err)
+		require.GreaterOrEqual(t, level, zapcore.InfoLevel)
+	}
+	// verify at least 1 log was read
+	require.True(t, check)
+}
+
 func findRandomPort() (int, error) {
 	l, err := net.Listen("tcp", "localhost:0")
 

cmd/opampsupervisor/main.go

@@ -5,26 +5,27 @@ package main
 
 import (
 	"flag"
+	"log"
 	"os"
 	"os/signal"
 
-	"go.uber.org/zap"
-
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/config"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/telemetry"
 )
 
 func main() {
 	configFlag := flag.String("config", "", "Path to a supervisor configuration file")
 	flag.Parse()
 
-	logger, _ := zap.NewDevelopment()
-
 	cfg, err := config.Load(*configFlag)
 	if err != nil {
-		logger.Error(err.Error())
-		os.Exit(-1)
-		return
+		log.Fatal("failed to load config: %w", err)
+	}
+
+	logger, err := telemetry.NewLogger(cfg.Telemetry.Logs)
+	if err != nil {
+		log.Fatal("failed to create logger: %w", err)
 	}
 
 	supervisor, err := supervisor.NewSupervisor(logger, cfg)
@@ -36,9 +37,7 @@ func main() {
 
 	err = supervisor.Start()
 	if err != nil {
-		logger.Error(err.Error())
-		os.Exit(-1)
-		return
+		log.Fatal("failed to start supervisor: %w", err)
 	}
 
 	interrupt := make(chan os.Signal, 1)

cmd/opampsupervisor/supervisor/config/config.go

@@ -18,6 +18,7 @@ import (
 	"github.com/knadh/koanf/v2"
 	"github.com/open-telemetry/opamp-go/protobufs"
 	"go.opentelemetry.io/collector/config/configtls"
+	"go.uber.org/zap/zapcore"
 )
 
 // Supervisor is the Supervisor config file format.
@@ -26,6 +27,7 @@ type Supervisor struct {
 	Agent        Agent
 	Capabilities Capabilities `mapstructure:"capabilities"`
 	Storage      Storage      `mapstructure:"storage"`
+	Telemetry    Telemetry    `mapstructure:"telemetry"`
 }
 
 // Load loads the Supervisor config from a file.
@@ -185,6 +187,17 @@ type AgentDescription struct {
 	NonIdentifyingAttributes map[string]string `mapstructure:"non_identifying_attributes"`
 }
 
+type Telemetry struct {
+	// TODO: Add more telemetry options
+	// Issue here: https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/35582
+	Logs Logs `mapstructure:"logs"`
+}
+
+type Logs struct {
+	Level       zapcore.Level `mapstructure:"level"`
+	OutputPaths []string      `mapstructure:"output_paths"`
+}
+
 // DefaultSupervisor returns the default supervisor config
 func DefaultSupervisor() Supervisor {
 	defaultStorageDir := "/var/lib/otelcol/supervisor"
@@ -217,5 +230,11 @@ func DefaultSupervisor() Supervisor {
 			OrphanDetectionInterval: 5 * time.Second,
 			BootstrapTimeout:        3 * time.Second,
 		},
+		Telemetry: Telemetry{
+			Logs: Logs{
+				Level:       zapcore.InfoLevel,
+				OutputPaths: []string{"stdout", "stderr"},
+			},
+		},
 	}
 }

cmd/opampsupervisor/supervisor/supervisor.go

@@ -168,7 +168,6 @@ func NewSupervisor(logger *zap.Logger, cfg config.Supervisor) (*Supervisor, erro
 	if err := cfg.Validate(); err != nil {
 		return nil, fmt.Errorf("error validating config: %w", err)
 	}
-
 	s.config = cfg
 
 	if err := os.MkdirAll(s.config.Storage.Directory, 0700); err != nil {
@@ -200,7 +199,7 @@ func (s *Supervisor) Start() error {
 
 	s.agentHealthCheckEndpoint = fmt.Sprintf("localhost:%d", healthCheckPort)
 
-	s.logger.Debug("Supervisor starting",
+	s.logger.Info("Supervisor starting",
 		zap.String("id", s.persistentState.InstanceID.String()))
 
 	err = s.loadAndWriteInitialMergedConfig()

cmd/opampsupervisor/supervisor/telemetry/logger.go

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"go.uber.org/zap"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/config"
+)
+
+func NewLogger(cfg config.Logs) (*zap.Logger, error) {
+	zapCfg := zap.NewProductionConfig()
+
+	zapCfg.Level = zap.NewAtomicLevelAt(cfg.Level)
+	zapCfg.OutputPaths = cfg.OutputPaths
+
+	logger, err := zapCfg.Build()
+	if err != nil {
+		return nil, err
+	}
+	return logger, nil
+}

cmd/opampsupervisor/testdata/supervisor/supervisor_logging.yaml

@@ -0,0 +1,21 @@
+server:
+  endpoint: ws://{{.url}}/v1/opamp
+
+capabilities:
+  reports_effective_config: true
+  reports_own_metrics: true
+  reports_health: true
+  accepts_remote_config: true
+  reports_remote_config: true
+  accepts_restart_command: true
+
+storage:
+  directory: '{{.storage_dir}}'
+
+agent:
+  executable: ../../bin/otelcontribcol_{{.goos}}_{{.goarch}}{{.extension}}
+
+telemetry:
+  logs:
+    level: {{.log_level}} # info level logs
+    output_paths: ['{{.log_file}}']