Add OTel collector log file

internal/collector/otel_collector_plugin_test.go

@@ -29,6 +29,8 @@ func TestCollector_New(t *testing.T) {
 
 func TestCollector_InitAndClose(t *testing.T) {
 	conf := types.OTelConfig(t)
+	conf.Collector.Log.Path = ""
+
 	collector, err := New(conf)
 	require.NoError(t, err, "NewCollector should not return an error with valid config")
 
@@ -62,6 +64,7 @@ func TestCollector_Process(t *testing.T) {
 	defer nginxPlusMock.Close()
 
 	conf := types.OTelConfig(t)
+	conf.Collector.Log.Path = ""
 
 	tests := []struct {
 		name      string

internal/collector/otelcol.tmpl

@@ -82,6 +82,19 @@ extensions:
     {{- end }}
 
 service:
+  telemetry:
+    logs:
+      level: {{ .Log.Level -}}
+      {{- if .Log.Path}}
+      output_paths: ["{{ .Log.Path -}}"]
+      {{- else }}
+      output_paths: ["stderr"]
+      {{- end }}
+      {{- if .Log.Path}}
+      error_output_paths: ["{{ .Log.Path -}}"]
+      {{- else }}
+      error_output_paths: ["stderr"]
+      {{- end }}
   extensions:
     - health_check
   pipelines:

internal/config/config.go

@@ -124,7 +124,7 @@ func registerFlags() {
 		"info",
 		`The desired verbosity level for logging messages from nginx-agent. 
 		Available options, in order of severity from highest to lowest, are: 
-		panic, fatal, error, info, debug, and trace.`,
+		panic, fatal, error, info and debug.`,
 	)
 	fs.String(
 		LogPathKey,
@@ -201,12 +201,28 @@ func registerFlags() {
 		DefInstanceHealthWatcherMonitoringFrequency,
 		"How often the NGINX Agent will check for instance health changes.",
 	)
+
 	fs.String(
 		CollectorConfigPathKey,
 		DefCollectorConfigPath,
 		"The path to the Opentelemetry Collector configuration file.",
 	)
 
+	fs.String(
+		CollectorLogLevelKey,
+		DefCollectorLogLevel,
+		`The desired verbosity level for logging messages from nginx-agent OTel collector. 
+		Available options, in order of severity from highest to lowest, are: 
+		ERROR, WARN, INFO and DEBUG.`,
+	)
+
+	fs.String(
+		CollectorLogPathKey,
+		DefCollectorLogPath,
+		`The path to output OTel collector log messages to. 
+		If the default path doesn't exist, log messages are output to stdout/stderr.`,
+	)
+
 	fs.SetNormalizeFunc(normalizeFunc)
 
 	fs.VisitAll(func(flag *flag.Flag) {
@@ -305,6 +321,7 @@ func resolveCollector(allowedDirs []string) (*Collector, error) {
 		processors  []Processor
 		receivers   Receivers
 		healthCheck ServerConfig
+		log         Log
 	)
 
 	err = errors.Join(
@@ -313,6 +330,7 @@ func resolveCollector(allowedDirs []string) (*Collector, error) {
 		resolveMapStructure(CollectorProcessorsKey, &processors),
 		resolveMapStructure(CollectorReceiversKey, &receivers),
 		resolveMapStructure(CollectorHealthKey, &healthCheck),
+		resolveMapStructure(CollectorLogKey, &log),
 	)
 	if err != nil {
 		return nil, fmt.Errorf("unmarshal collector config: %w", err)
@@ -324,6 +342,7 @@ func resolveCollector(allowedDirs []string) (*Collector, error) {
 		Processors: processors,
 		Receivers:  receivers,
 		Health:     &healthCheck,
+		Log:        &log,
 	}
 
 	err = col.Validate(allowedDirs)

internal/config/config_test.go

@@ -209,12 +209,12 @@ func TestResolveCollector(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			viperInstance = viper.NewWithOptions(viper.KeyDelimiter(KeyDelimiter))
-			viperInstance.Set(CollectorRootKey, "set")
 			viperInstance.Set(CollectorConfigPathKey, test.expected.ConfigPath)
 			viperInstance.Set(CollectorReceiversKey, test.expected.Receivers)
 			viperInstance.Set(CollectorProcessorsKey, test.expected.Processors)
 			viperInstance.Set(CollectorExportersKey, test.expected.Exporters)
 			viperInstance.Set(CollectorHealthKey, test.expected.Health)
+			viperInstance.Set(CollectorLogKey, test.expected.Log)
 
 			actual, err := resolveCollector(testDefault.AllowedDirectories)
 			if test.shouldErr {
@@ -348,6 +348,10 @@ func getAgentConfig() *Config {
 				Port: 1337,
 				Type: 0,
 			},
+			Log: &Log{
+				Level: "INFO",
+				Path:  "/var/log/nginx-agent/otelcol.log",
+			},
 		},
 		Command: &Command{
 			Server: &ServerConfig{

internal/config/defaults.go

@@ -14,6 +14,8 @@ const (
 	DefTreatErrorsAsWarnings       = true
 
 	DefCollectorConfigPath = "/var/run/nginx-agent/otelcol.yaml"
+	DefCollectorLogLevel   = "INFO"
+	DefCollectorLogPath    = "/var/log/nginx-agent/otelcol.log"
 
 	DefCommandServerHostKey    = ""
 	DefCommandServerPortKey    = 0

internal/config/flags.go

@@ -32,6 +32,9 @@ var (
 	CollectorProcessorsKey         = pre(CollectorRootKey) + "processors"
 	CollectorHealthKey             = pre(CollectorRootKey) + "health"
 	CollectorReceiversKey          = pre(CollectorRootKey) + "receivers"
+	CollectorLogKey                = pre(CollectorRootKey) + "log"
+	CollectorLogLevelKey           = pre(CollectorLogKey) + "level"
+	CollectorLogPathKey            = pre(CollectorLogKey) + "path"
 	CommandAuthKey                 = pre(CommandRootKey) + "auth"
 	CommandAuthTokenKey            = pre(CommandAuthKey) + "token"
 	CommandServerHostKey           = pre(CommandServerKey) + "host"

internal/config/types.go

@@ -78,6 +78,7 @@ type (
 
 	Collector struct {
 		ConfigPath string        `yaml:"-" mapstructure:"config_path"`
+		Log        *Log          `yaml:"-" mapstructure:"log"`
 		Exporters  []Exporter    `yaml:"-" mapstructure:"exporters"`
 		Health     *ServerConfig `yaml:"-" mapstructure:"health"`
 		Processors []Processor   `yaml:"-" mapstructure:"processors"`

test/config/collector/test-otelcol.yaml

@@ -49,6 +49,11 @@ extensions:
     endpoint: "localhost:1337"
 
 service:
+  telemetry:
+    logs:
+      level: INFO
+      output_paths: ["/var/log/nginx-agent/otelcol.log"]
+      error_output_paths: ["/var/log/nginx-agent/otelcol.log"]
   extensions:
     - health_check
   pipelines:

test/types/config.go

@@ -81,6 +81,10 @@ func AgentConfig() *config.Config {
 				Port: randomPort3,
 				Type: 0,
 			},
+			Log: &config.Log{
+				Level: "INFO",
+				Path:  "/var/log/nginx-agent/otelcol.log",
+			},
 		},
 		Command: &config.Command{
 			Server: &config.ServerConfig{