[exporter/debug] add ability to set output_paths

.chloggen/debug-exporter-output-paths.yaml

@@ -0,0 +1,29 @@
+# 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. otlpreceiver)
+component: exporter/debug
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add `output_paths` configuration option to control output destination when `use_internal_logger` is false
+
+# One or more tracking issues or pull requests related to the change
+issues: [10472]
+
+# (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: |
+  When `use_internal_logger` is set to `false`, the debug exporter now supports configuring the output destination via the `output_paths` option.
+  This allows users to send debug exporter output to `stdout`, `stderr`, or a file path.
+  The default value is `["stdout"]` to maintain backward compatibility.
+
+# 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: []
+

exporter/debugexporter/README.md

@@ -38,6 +38,7 @@ The following settings are optional:
   Refer to [Zap docs](https://godoc.org/go.uber.org/zap/zapcore#NewSampler) for more details
   on how sampling parameters impact number of messages.
 - `use_internal_logger` (default = `true`): uses the collector's internal logger for output. See [below](#using-the-collectors-internal-logger) for description.
+- `output_paths` (default = `["stdout"]`): a list of URLs or file paths to write logging output to. This option is only used when `use_internal_logger` is `false`. The URLs could only be with "file" schema or without schema. The URLs with "file" schema must be an absolute path. The URLs without schema are treated as local file paths. "stdout" and "stderr" are interpreted as os.Stdout and os.Stderr.
 - `sending_queue` (disabled by default): see [Sending Queue](../exporterhelper/README.md#sending-queue) for the full set of available options.
 
 Example configuration:
@@ -50,6 +51,16 @@ exporters:
     sampling_thereafter: 200
 ```
 
+Example configuration with custom output path:
+
+```yaml
+exporters:
+  debug:
+    use_internal_logger: false
+    output_paths:
+      - stderr
+```
+
 ## Verbosity levels
 
 The following subsections describe the output from the exporter depending on the configured verbosity level - `basic`, `normal` and `detailed`.
@@ -138,7 +149,8 @@ This comes with the following consequences:
 
 When `use_internal_logger` is set to `false`, the exporter does not use the collector's internal logger.
 Changing the values in `service::telemetry::logs` has no effect on the exporter's output.
-The exporter's output is sent to `stdout`.
+The exporter's output is sent to the paths specified in `output_paths` (default: `["stdout"]`).
+You can configure `output_paths` to send output to `stderr`, a file, or multiple destinations.
 
 [internal_telemetry]: https://opentelemetry.io/docs/collector/internal-telemetry/
 [internal_logs_config]: https://opentelemetry.io/docs/collector/internal-telemetry/#configure-internal-logs

exporter/debugexporter/config.go

@@ -33,6 +33,15 @@ type Config struct {
 	// UseInternalLogger defines whether the exporter sends the output to the collector's internal logger.
 	UseInternalLogger bool `mapstructure:"use_internal_logger"`
 
+	// OutputPaths is a list of URLs or file paths to write logging output to.
+	// This option is only used when use_internal_logger is false.
+	// The URLs could only be with "file" schema or without schema.
+	// The URLs with "file" schema must be an absolute path.
+	// The URLs without schema are treated as local file paths.
+	// "stdout" and "stderr" are interpreted as os.Stdout and os.Stderr.
+	// (default = ["stdout"])
+	OutputPaths []string `mapstructure:"output_paths"`
+
 	QueueConfig exporterhelper.QueueBatchConfig `mapstructure:"sending_queue"`
 
 	// prevent unkeyed literal initialization

exporter/debugexporter/config_test.go

@@ -37,6 +37,19 @@ func TestUnmarshalConfig(t *testing.T) {
 				Verbosity:          configtelemetry.LevelDetailed,
 				SamplingInitial:    10,
 				SamplingThereafter: 50,
+				UseInternalLogger:  false,
+				OutputPaths:        []string{"stdout"},
+				QueueConfig:        queueCfg,
+			},
+		},
+		{
+			filename: "config_output_paths.yaml",
+			cfg: &Config{
+				Verbosity:          configtelemetry.LevelBasic,
+				SamplingInitial:    2,
+				SamplingThereafter: 1,
+				UseInternalLogger:  false,
+				OutputPaths:        []string{"stderr"},
 				QueueConfig:        queueCfg,
 			},
 		},

exporter/debugexporter/exporter_test.go

@@ -124,6 +124,16 @@ func createTestCases() []testCase {
 				return cfg
 			}(),
 		},
+		{
+			name: "custom output paths",
+			config: func() *Config {
+				cfg := createDefaultConfig().(*Config)
+				cfg.QueueConfig.QueueSize = 10
+				cfg.UseInternalLogger = false
+				cfg.OutputPaths = []string{"stderr"}
+				return cfg
+			}(),
+		},
 	}
 }
 

exporter/debugexporter/factory.go

@@ -50,6 +50,7 @@ func createDefaultConfig() component.Config {
 		SamplingInitial:    defaultSamplingInitial,
 		SamplingThereafter: defaultSamplingThereafter,
 		UseInternalLogger:  true,
+		OutputPaths:        []string{"stdout"},
 		QueueConfig:        queueCfg,
 	}
 }
@@ -128,6 +129,11 @@ func createCustomLogger(exporterConfig *Config) *zap.Logger {
 	encoderConfig.LevelKey = ""
 	// Do not prefix the output with current timestamp.
 	encoderConfig.TimeKey = ""
+	outputPaths := exporterConfig.OutputPaths
+	if len(outputPaths) == 0 {
+		// Default to stdout if not specified
+		outputPaths = []string{"stdout"}
+	}
 	zapConfig := zap.Config{
 		Level:         zap.NewAtomicLevelAt(zap.InfoLevel),
 		DisableCaller: true,
@@ -137,8 +143,7 @@ func createCustomLogger(exporterConfig *Config) *zap.Logger {
 		},
 		Encoding:      "console",
 		EncoderConfig: encoderConfig,
-		// Send exporter's output to stdout. This should be made configurable.
-		OutputPaths: []string{"stdout"},
+		OutputPaths:   outputPaths,
 	}
 	return zap.Must(zapConfig.Build())
 }

exporter/debugexporter/testdata/config_output_paths.yaml

@@ -0,0 +1,4 @@
+use_internal_logger: false
+output_paths:
+  - stderr
+