fix: serve the whole results service from the cache server (#1141)

`ACTIONS_RESULTS_URL` names one origin serving every `github.actions.results.api.v1` service. Gitea serves the artifact half and this runner the cache half, so announcing `ACTIONS_CACHE_SERVICE_V2` while that URL pointed at Gitea was a promise the environment could not keep, and `docker buildx` posted its cache calls at Gitea and got a 404.

The cache server now forwards the artifact half to the instance each job registers with, so it is the whole results service and jobs are pointed at it. The announcement follows, and the bundle patch follows the cache URL instead.

Also fixes three things no JavaScript client reached: camelCase in the v2 responses where the Go clients read proto names, the missing `x-ms-request-id` on blob uploads that panics buildkit, and `cache.external_server` passed through without the trailing slash the v1 client concatenates onto.

Tests run the real actions against the services they look for: `actions/cache` over both API versions, the artifact actions up and back down through the forwarding, and `setup-node`. The regression itself is covered by asserting that whatever a job is handed as `ACTIONS_RESULTS_URL` answers a cache service call.

Fixes https://gitea.com/gitea/runner/issues/1139

Reviewed-on: https://gitea.com/gitea/runner/pulls/1141
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <2021+silverwind@noreply.gitea.com>

act/artifactcache/handler_v2.go

@@ -23,6 +23,9 @@ import (
 // endpoints, and uploads the archive to the returned URL with the Azure blob protocol.
 // Both API versions are served from the same store, so a repository keeps its cache
 // when a workflow moves between action versions.
+//
+// Responses carry the proto field names, which is what Gitea's own results API emits and the only
+// spelling the Go clients parse. The JavaScript toolkit accepts either.
 const (
 	cacheServiceV2Path = "/twirp/github.actions.results.api.v1.CacheService"
 
@@ -93,8 +96,8 @@ func (h *Handler) v2CreateCacheEntry(w http.ResponseWriter, r *http.Request, _ h
 	}
 
 	h.responseJSON(w, r, http.StatusOK, map[string]any{
-		"ok":              true,
-		"signedUploadUrl": h.signedURL(blobPath, blobUploadPurpose, cache.ID, time.Now().Add(blobUploadURLTTL)),
+		"ok":                true,
+		"signed_upload_url": h.signedURL(blobPath, blobUploadPurpose, cache.ID, time.Now().Add(blobUploadURLTTL)),
 	})
 }
 
@@ -134,7 +137,7 @@ func (h *Handler) v2FinalizeCacheEntryUpload(w http.ResponseWriter, r *http.Requ
 	h.responseJSON(w, r, http.StatusOK, map[string]any{
 		"ok": true,
 		// int64 fields travel as strings in the proto JSON mapping.
-		"entryId": strconv.FormatUint(cache.ID, 10),
+		"entry_id": strconv.FormatUint(cache.ID, 10),
 	})
 }
 
@@ -164,9 +167,9 @@ func (h *Handler) v2GetCacheEntryDownloadURL(w http.ResponseWriter, r *http.Requ
 	}
 
 	h.responseJSON(w, r, http.StatusOK, map[string]any{
-		"ok":                true,
-		"signedDownloadUrl": h.signedArtifactURL(cache.ID, time.Now().Add(artifactURLTTL)),
-		"matchedKey":        cache.Key,
+		"ok":                  true,
+		"signed_download_url": h.signedArtifactURL(cache.ID, time.Now().Add(artifactURLTTL)),
+		"matched_key":         cache.Key,
 	})
 }
 
@@ -209,6 +212,8 @@ func (h *Handler) v2UploadBlob(w http.ResponseWriter, r *http.Request, params ht
 		return
 	}
 
+	// The Azure SDK client dereferences this without checking, so its absence panics the caller.
+	w.Header().Set("x-ms-request-id", strconv.FormatInt(time.Now().UnixNano(), 10))
 	w.WriteHeader(http.StatusCreated)
 }