Add single-pipeline run entrypoint

internal/app/source_select.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"gitea.maximumdirect.net/eric/distributor/internal/bundle"
@@ -9,6 +10,19 @@ import (
 	"gitea.maximumdirect.net/eric/distributor/internal/storage"
 )
 
+type PipelineNotFoundError struct {
+	ID string
+}
+
+func (e PipelineNotFoundError) Error() string {
+	return fmt.Sprintf("pipeline %q not found", e.ID)
+}
+
+func IsPipelineNotFound(err error) bool {
+	var notFound PipelineNotFoundError
+	return errors.As(err, &notFound)
+}
+
 type sourceCommandOptions struct {
 	CommandName string
 	Path        string
@@ -70,7 +84,7 @@ func selectSourceBundlesFromConfig(ctx context.Context, cfg config.Config, optio
 	}
 	pipeline, ok := findPipeline(cfg, options.PipelineID)
 	if !ok {
-		return sourceSelection{}, fmt.Errorf("pipeline %q not found", options.PipelineID)
+		return sourceSelection{}, PipelineNotFoundError{ID: options.PipelineID}
 	}
 	backends := provider(secretLoad.Environment)
 	sourceBackend, err := backends.openSource(ctx, pipeline.Source)