Add config loading and dry-run validation

internal/app/run.go

@@ -3,10 +3,52 @@ package app
 import (
 	"context"
 	"fmt"
+	"io"
+
+	"gitea.maximumdirect.net/eric/distributor/internal/config"
 )
 
-type RunOptions struct{}
-
-func Run(context.Context, RunOptions) error {
-	return fmt.Errorf("run command: %w", ErrNotImplemented)
+type RunOptions struct {
+	ConfigPath string
+	DryRun     bool
+	Stdout     io.Writer
+}
+
+func Run(ctx context.Context, options RunOptions) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if !options.DryRun {
+		return fmt.Errorf("run command: %w", ErrNotImplemented)
+	}
+
+	configPath := options.ConfigPath
+	if configPath == "" {
+		configPath = config.DefaultConfigPath
+	}
+	cfg, err := config.LoadFile(configPath)
+	if err != nil {
+		return err
+	}
+	return writeRunSummary(options.Stdout, cfg)
+}
+
+func writeRunSummary(w io.Writer, cfg config.Config) error {
+	if w == nil {
+		return nil
+	}
+	if _, err := fmt.Fprintf(w, "Configured pipelines: %d\n", len(cfg.Pipelines)); err != nil {
+		return err
+	}
+	for _, pipeline := range cfg.Pipelines {
+		if _, err := fmt.Fprintf(w, "- %s: source=%s destinations=%d\n", pipeline.ID, pipeline.Source.Backend, len(pipeline.Destinations)); err != nil {
+			return err
+		}
+		for _, destination := range pipeline.Destinations {
+			if _, err := fmt.Fprintf(w, "  - %s: backend=%s publish_source=%t publish_html=%t\n", destination.ID, destination.Backend, destination.Publish.Source, destination.Publish.HTML); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
 }