backend/builds: error handling fixes

backend/builds/ghactions/client.go

@@ -56,6 +56,10 @@ func (c *Client) ListWorkflowRuns(ctx context.Context, owner, repo string) (*Wor
 	}
 	defer res.Body.Close()
 
+	if res.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("Upstream fetch failed with status %d %s", res.StatusCode, res.Status)
+	}
+
 	var resData WorkflowRunsListResponse
 	if err := json.NewDecoder(res.Body).Decode(&resData); err != nil {
 		return nil, err
@@ -76,6 +80,13 @@ func (c *Client) GetWorkflowRun(ctx context.Context, owner, repo, runId string)
 	}
 	defer res.Body.Close()
 
+	if res.StatusCode != http.StatusOK {
+		if res.StatusCode == http.StatusNotFound {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("Upstream fetch failed with status %d %s", res.StatusCode, res.Status)
+	}
+
 	var resData WorkflowRunResponse
 	if err := json.NewDecoder(res.Body).Decode(&resData); err != nil {
 		return nil, err

backend/builds/service/service.go

@@ -55,6 +55,9 @@ func (s *service) GetBuild(ctx context.Context, req *buildsv1.GetBuildRequest) (
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, "Failed to fetch workflow run for %s/%s/%s, %s", owner, repo, runID, err)
 	}
+	if run == nil {
+		return nil, status.Errorf(codes.NotFound, "Workflow run %s/%s/%s not found", owner, repo, runID)
+	}
 
 	return &buildsv1.GetBuildReply{
 		Build: s.transformBuild(owner, repo, run),
@@ -108,7 +111,7 @@ func (s *service) parseBuildURI(uri string) (owner, repo, runID string, err erro
 	}
 
 	match := entityURIRegex.FindStringSubmatch(uri)
-	if err != nil {
+	if match == nil {
 		return "", "", "", fmt.Errorf("uri does not match")
 	}