fix(preview): atomic writes, pinned images, structured logging, and error handling

- Atomic temp-file-rename writes in PreviewStore to prevent partial writes
- Pin busybox image to 1.37 instead of latest for reproducibility
- Add zerowrap structured logging to WaitForContainer and dispatcher Handle
- Handle filepath.Match errors in matchesTagPatterns (skip malformed patterns)
- Distinguish not-found vs internal errors in preview admin HTTP handlers

commit: e2d78b5d419639d1afea9b691acf86550f4fa23a
author: brice · 7mo ago · 2026-03-19 05:27 UTC
parent: 9f0ec73
signature: unsigned

5 files · +57 -6

M internal/adapters/in/http/admin/preview_handler.go +10 -2


@@ -92,7 +92,11 @@ func (h Handler) handlePreviewAction(w http.ResponseWriter, r http.Request, pa
92	92
93	93		if err := h.previewSvc.Delete(ctx, name); err != nil {
94	94		log.Error().Err(err).Str("name", name).Msg("failed to delete preview")
95		-	h.sendError(w, http.StatusNotFound, "preview not found")
	95	+	if strings.Contains(err.Error(), "not found") {
	96	+	http.Error(w, err.Error(), http.StatusNotFound)
	97	+	} else {
	98	+	http.Error(w, err.Error(), http.StatusInternalServerError)
	99	+	}
96	100		return
97	101		}
98	102

@@ -127,7 +131,11 @@ func (h Handler) handlePreviewAction(w http.ResponseWriter, r http.Request, pa
127	131
128	132		if err := h.previewSvc.Extend(ctx, name, ttl); err != nil {
129	133		log.Error().Err(err).Str("name", name).Dur("ttl", ttl).Msg("failed to extend preview TTL")
130		-	h.sendError(w, http.StatusNotFound, "preview not found")
	134	+	if strings.Contains(err.Error(), "not found") {
	135	+	http.Error(w, err.Error(), http.StatusNotFound)
	136	+	} else {
	137	+	http.Error(w, err.Error(), http.StatusInternalServerError)
	138	+	}
131	139		return
132	140		}
133	141

 		if err := h.previewSvc.Delete(ctx, name); err != nil {
 			log.Error().Err(err).Str("name", name).Msg("failed to delete preview")
-			h.sendError(w, http.StatusNotFound, "preview not found")
+			if strings.Contains(err.Error(), "not found") {
+				http.Error(w, err.Error(), http.StatusNotFound)
+			} else {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+			}
 			return
 		}
 		if err := h.previewSvc.Extend(ctx, name, ttl); err != nil {
 			log.Error().Err(err).Str("name", name).Dur("ttl", ttl).Msg("failed to extend preview TTL")
-			h.sendError(w, http.StatusNotFound, "preview not found")
+			if strings.Contains(err.Error(), "not found") {
+				http.Error(w, err.Error(), http.StatusNotFound)
+			} else {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+			}
 			return
 		}

M internal/adapters/out/docker/runtime.go +11 -1


@@ -216,14 +216,24 @@ func (r *Runtime) StartContainer(ctx context.Context, containerID string) error
216	216
217	217		// WaitForContainer waits for a container to stop running.
218	218		func (r *Runtime) WaitForContainer(ctx context.Context, containerID string) error {
	219	+	ctx = zerowrap.CtxWithFields(ctx, map[string]any{
	220	+	zerowrap.FieldLayer: "adapter",
	221	+	zerowrap.FieldAdapter: "docker",
	222	+	zerowrap.FieldAction: "WaitForContainer",
	223	+	zerowrap.FieldEntityID: containerID,
	224	+	})
	225	+	log := zerowrap.FromCtx(ctx)
	226	+
219	227		statusCh, errCh := r.client.ContainerWait(ctx, containerID, container.WaitConditionNotRunning)
220	228		select {
221	229		case err := <-errCh:
222	230		if err != nil {
223		-	return err
	231	+	return log.WrapErr(err, "failed to wait for container")
224	232		}
225	233		case <-statusCh:
226	234		}
	235	+
	236	+	log.Debug().Msg("container wait completed")
227	237		return nil
228	238		}
229	239

 // WaitForContainer waits for a container to stop running.
 func (r *Runtime) WaitForContainer(ctx context.Context, containerID string) error {
+	ctx = zerowrap.CtxWithFields(ctx, map[string]any{
+		zerowrap.FieldLayer:    "adapter",
+		zerowrap.FieldAdapter:  "docker",
+		zerowrap.FieldAction:   "WaitForContainer",
+		zerowrap.FieldEntityID: containerID,
+	})
+	log := zerowrap.FromCtx(ctx)
 	statusCh, errCh := r.client.ContainerWait(ctx, containerID, container.WaitConditionNotRunning)
 	select {
 	case err := <-errCh:
 		if err != nil {
-			return err
+			return log.WrapErr(err, "failed to wait for container")
 		}
 	case <-statusCh:
 	}
+	log.Debug().Msg("container wait completed")
 	return nil
 }

M internal/adapters/out/filesystem/previewstore.go +25 -1


@@ -6,6 +6,7 @@ import (
6	6		"errors"
7	7		"io/fs"
8	8		"os"
	9	+	"path/filepath"
9	10		"sync"
10	11
11	12		"github.com/bnema/gordon/internal/domain"

@@ -61,5 +62,28 @@ func (s *PreviewStore) Save(_ context.Context, previews []domain.PreviewRoute) e
61	62		if err != nil {
62	63		return err
63	64		}
64		-	return os.WriteFile(s.path, data, 0o644)
	65	+
	66	+	// Atomic write: temp file → rename
	67	+	dir := filepath.Dir(s.path)
	68	+	tmp, err := os.CreateTemp(dir, ".previews-*.json.tmp")
	69	+	if err != nil {
	70	+	return err
	71	+	}
	72	+	tmpName := tmp.Name()
	73	+
	74	+	if _, err := tmp.Write(data); err != nil {
	75	+	tmp.Close()
	76	+	os.Remove(tmpName)
	77	+	return err
	78	+	}
	79	+	if err := tmp.Sync(); err != nil {
	80	+	tmp.Close()
	81	+	os.Remove(tmpName)
	82	+	return err
	83	+	}
	84	+	if err := tmp.Close(); err != nil {
	85	+	os.Remove(tmpName)
	86	+	return err
	87	+	}
	88	+	return os.Rename(tmpName, s.path)
65	89		}


@@ -6,6 +6,7 @@ import (
6		"errors"	6		"errors"
7		"io/fs"	7		"io/fs"
8		"os"	8		"os"
			9	+	"path/filepath"
9		"sync"	10		"sync"
10			11
11		"github.com/bnema/gordon/internal/domain"	12		"github.com/bnema/gordon/internal/domain"

@@ -61,5 +62,28 @@ func (s *PreviewStore) Save(_ context.Context, previews []domain.PreviewRoute) e
61		if err != nil {	62		if err != nil {
62		return err	63		return err
63		}	64		}
64	-	return os.WriteFile(s.path, data, 0o644)	65	+
			66	+	// Atomic write: temp file → rename
			67	+	dir := filepath.Dir(s.path)
			68	+	tmp, err := os.CreateTemp(dir, ".previews-*.json.tmp")
			69	+	if err != nil {
			70	+	return err
			71	+	}
			72	+	tmpName := tmp.Name()
			73	+
			74	+	if _, err := tmp.Write(data); err != nil {
			75	+	tmp.Close()
			76	+	os.Remove(tmpName)
			77	+	return err
			78	+	}
			79	+	if err := tmp.Sync(); err != nil {
			80	+	tmp.Close()
			81	+	os.Remove(tmpName)
			82	+	return err
			83	+	}
			84	+	if err := tmp.Close(); err != nil {
			85	+	os.Remove(tmpName)
			86	+	return err
			87	+	}
			88	+	return os.Rename(tmpName, s.path)
65		}	89		}

M internal/usecase/auto/dispatcher.go +10 -1


@@ -4,6 +4,8 @@ import (
4	4		"context"
5	5		"path/filepath"
6	6
	7	+	"github.com/bnema/zerowrap"
	8	+
7	9		"github.com/bnema/gordon/internal/boundaries/out"
8	10		"github.com/bnema/gordon/internal/domain"
9	11		)

@@ -38,8 +40,11 @@ func (d *ImagePushDispatcher) CanHandle(t domain.EventType) bool {
38	40		}
39	41
40	42		func (d *ImagePushDispatcher) Handle(ctx context.Context, event domain.Event) error {
	43	+	log := zerowrap.FromCtx(ctx)
	44	+
41	45		payload, ok := event.Data.(domain.ImagePushedPayload)
42	46		if !ok {
	47	+	log.Warn().Str("event_type", string(event.Type)).Msg("dispatcher received event with unexpected payload type; forwarding to route handler")
43	48		return d.routeHandler.Handle(ctx, event)
44	49		}
45	50

@@ -51,7 +56,11 @@ func (d *ImagePushDispatcher) Handle(ctx context.Context, event domain.Event) er
51	56
52	57		func (d *ImagePushDispatcher) matchesTagPatterns(reference string) bool {
53	58		for _, pattern := range d.config.GetPreviewTagPatterns() {
54		-	if matched, _ := filepath.Match(pattern, reference); matched {
	59	+	matched, err := filepath.Match(pattern, reference)
	60	+	if err != nil {
	61	+	continue // skip malformed patterns
	62	+	}
	63	+	if matched {
55	64		return true
56	65		}
57	66		}

 	"context"
 	"path/filepath"
+	"github.com/bnema/zerowrap"
 	"github.com/bnema/gordon/internal/boundaries/out"
 	"github.com/bnema/gordon/internal/domain"
 )
 }
 func (d *ImagePushDispatcher) Handle(ctx context.Context, event domain.Event) error {
+	log := zerowrap.FromCtx(ctx)
 	payload, ok := event.Data.(domain.ImagePushedPayload)
 	if !ok {
+		log.Warn().Str("event_type", string(event.Type)).Msg("dispatcher received event with unexpected payload type; forwarding to route handler")
 		return d.routeHandler.Handle(ctx, event)
 	}
 func (d *ImagePushDispatcher) matchesTagPatterns(reference string) bool {
 	for _, pattern := range d.config.GetPreviewTagPatterns() {
-		if matched, _ := filepath.Match(pattern, reference); matched {
+		matched, err := filepath.Match(pattern, reference)
+		if err != nil {
+			continue // skip malformed patterns
+		}
+		if matched {
 			return true
 		}
 	}

M internal/usecase/auto/preview/volumes.go +1 -1


@@ -48,7 +48,7 @@ func CloneVolumes(ctx context.Context, cloner VolumeCloner, previewName string,
48	48		}
49	49
50	50		helperConfig := &domain.ContainerConfig{
51		-	Image: "busybox:latest",
	51	+	Image: "busybox:1.37",
52	52		Name: "gordon-vol-copy-" + destName,
53	53		Cmd: []string{"cp", "-a", "/src/.", "/dst/"},
54	54		Volumes: map[string]string{


@@ -48,7 +48,7 @@ func CloneVolumes(ctx context.Context, cloner VolumeCloner, previewName string,
48		}	48		}
49			49
50		helperConfig := &domain.ContainerConfig{	50		helperConfig := &domain.ContainerConfig{
51	-	Image: "busybox:latest",	51	+	Image: "busybox:1.37",
52		Name: "gordon-vol-copy-" + destName,	52		Name: "gordon-vol-copy-" + destName,
53		Cmd: []string{"cp", "-a", "/src/.", "/dst/"},	53		Cmd: []string{"cp", "-a", "/src/.", "/dst/"},
54		Volumes: map[string]string{	54		Volumes: map[string]string{