feat: adds support to modify the config after it is being parsed.

service/collector.go

@@ -34,6 +34,7 @@ import (
 	"go.uber.org/zap"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/config/configcheck"
 	"go.opentelemetry.io/collector/config/configtelemetry"
 	"go.opentelemetry.io/collector/config/configunmarshaler"
@@ -236,6 +237,13 @@ func (col *Collector) runAndWaitForShutdownEvent() {
 	col.stateChannel <- Closing
 }
 
+// ConfigPostProcessor allows to intercept the final config and do changes in the factories or
+// pipelines. For further information refer to the issue:
+// https://github.com/open-telemetry/opentelemetry-collector/issues/3023
+type ConfigPostProcessor interface {
+	Process(c *config.Config)
+}
+
 // setupConfigurationComponents loads the config and starts the components. If all the steps succeeds it
 // sets the col.service with the service currently running.
 func (col *Collector) setupConfigurationComponents(ctx context.Context) error {
@@ -255,6 +263,11 @@ func (col *Collector) setupConfigurationComponents(ctx context.Context) error {
 		return fmt.Errorf("invalid configuration: %w", err)
 	}
 
+	if postProcessor, ok := col.parserProvider.(ConfigPostProcessor); ok {
+		// Here we modify the config to be able to manipulate processors and pipelines
+		postProcessor.Process(cfg)
+	}
+
 	col.logger.Info("Applying configuration...")
 
 	service, err := newService(&svcSettings{