feat(goes/esgallery): add Debug option

goes/esgallery/processor.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	stdimage "image"
 	"io"
+	"log"
 	"net/http"
 	"strings"
 	"sync"
@@ -343,6 +344,12 @@ func NewPostProcessor[
 // RunProcessorOption is an option for [*PostProcessor.Run].
 type RunProcessorOption func(*runProcessorConfig)
 
+type runProcessorConfig struct {
+	workers        int
+	discardResults bool
+	debug          bool
+}
+
 // Workers returns a [RunProcessorOption] that sets the number of workers for
 // [PostProcessor.Run]. Defaults to 1.
 func Workers(workers int) RunProcessorOption {
@@ -363,9 +370,11 @@ func DiscardResults(discard bool) RunProcessorOption {
 	}
 }
 
-type runProcessorConfig struct {
-	workers        int
-	discardResults bool
+// Debug returns a [RunProcessorOption] that enables debug logs.
+func Debug(debug bool) RunProcessorOption {
+	return func(cfg *runProcessorConfig) {
+		cfg.debug = debug
+	}
 }
 
 // Run runs the post-processor in the background and returns a channel of
@@ -382,6 +391,13 @@ func (pp *PostProcessor[Gallery, StackID, ImageID]) Run(ctx context.Context, pip
 		opt(&cfg)
 	}
 
+	cfg.debugLog(
+		"starting post-processor with options:\n\tWorkers:\t%d\n\tDiscard results:\t%v",
+		cfg.workers, cfg.discardResults,
+	)
+
+	cfg.debugLog("subscribing to %v events ...", ProcessorTriggerEvents)
+
 	events, errs, err := pp.bus.Subscribe(ctx, ProcessorTriggerEvents...)
 	if err != nil {
 		return nil, nil, fmt.Errorf("subscribe to %v events: %w", ProcessorTriggerEvents, err)
@@ -440,6 +456,8 @@ func (q *processorQueue[Gallery, StackID, ImageID]) work() {
 			shouldPush = true
 		)
 
+		q.cfg.debugLog("handling %q event ...", evt.Name())
+
 		switch evt.Name() {
 		case StackAdded:
 			result, err = q.stackAdded(event.Cast[gallery.Stack[StackID, ImageID]](evt))
@@ -454,31 +472,43 @@ func (q *processorQueue[Gallery, StackID, ImageID]) work() {
 
 		result.Trigger = evt
 
+		galleryID := pick.AggregateID(evt)
+
 		if q.processor.autoApply {
-			if err := q.apply(&result, pick.AggregateID(evt)); err != nil {
+			if err := q.apply(&result, galleryID); err != nil {
 				q.fail(fmt.Errorf("apply result: %w", err))
 			}
 		}
 
-		if !q.cfg.discardResults && shouldPush {
+		if q.cfg.discardResults {
+			q.cfg.debugLog("discarding processing result [galleryId=%s, stackId=%s]", galleryID, result.StackID)
+			continue
+		}
+
+		if shouldPush {
 			q.push(result)
 		}
 	}
 }
 
 func (q *processorQueue[Gallery, StackID, ImageID]) apply(result *ProcessorResult[StackID, ImageID], galleryID uuid.UUID) error {
+	q.cfg.debugLog("fetching gallery to apply result to ... [id=%s]", galleryID)
+
 	g, err := q.processor.fetchGallery(q.ctx, galleryID)
 	if err != nil {
 		return fmt.Errorf("fetch gallery: %w", err)
 	}
+
+	q.cfg.debugLog("applying processing result ... [galleryId=%s, stackId=%s]", galleryID, result.StackID)
 	if err := result.Apply(g); err != nil {
 		return err
 	}
 	result.Applied = true
 
 	if q.processor.autoSave != nil {
+		q.cfg.debugLog("auto-saving gallery ... [id=%s]", galleryID)
 		if err := q.processor.autoSave(q.ctx, g); err != nil {
-			return fmt.Errorf("autosave gallery: %w", err)
+			return fmt.Errorf("auto-save gallery: %w", err)
 		}
 		result.Saved = true
 	}
@@ -507,9 +537,15 @@ func (q *processorQueue[Gallery, StackID, ImageID]) stackAdded(evt event.Of[gall
 		return zero, fmt.Errorf("fetch gallery: %w", err)
 	}
 
-	data := evt.Data()
+	stack := evt.Data()
 
-	result, err := q.processor.processor.Process(q.ctx, q.pipeline, g, data.ID)
+	if _, ok := g.Stack(stack.ID); !ok {
+		return zero, fmt.Errorf("%w [galleryId=%s, stackId=%s]", gallery.ErrStackNotFound, galleryID, stack.ID)
+	}
+
+	q.cfg.debugLog("running processor on stack ... [galleryId=%s, stackId=%s]", galleryID, stack.ID)
+
+	result, err := q.processor.processor.Process(q.ctx, q.pipeline, g, stack.ID)
 	if err != nil {
 		return result, fmt.Errorf("run processor: %w", err)
 	}
@@ -544,6 +580,12 @@ func (q *processorQueue[Gallery, StackID, ImageID]) stackAdded(evt event.Of[gall
 // 	return result, true, nil
 // }
 
+func (cfg runProcessorConfig) debugLog(format string, args ...any) {
+	if cfg.debug {
+		log.Printf("[DEBUG] %s", fmt.Sprintf(format, args...))
+	}
+}
+
 func zeroResult[StackID, ImageID ID]() (zero ProcessorResult[StackID, ImageID]) {
 	return zero
 }