GoogleContainerTools/skaffold · error

running post-renderer: %w

Error message

running post-renderer: %w

What it means

Wraps a failure from cmd.StdoutPipe() when setting up stdout piping for the post-renderer process in `skaffold filter --post-renderer`. The post-renderer is an external command whose stdout is read as rendered manifests.

Source

Thrown at cmd/skaffold/app/cmd/filter.go:78

			{Value: &postRenderer, Name: "post-renderer", DefValue: "", FlagAddMethod: "StringVar", Usage: "Any executable that accepts rendered Kubernetes manifests on STDIN and returns valid Kubernetes manifests on STDOUT"},
		}).
		NoArgs(func(ctx context.Context, out io.Writer) error {
			return doFilter(ctx, out, debuggingFilters, postRenderer, renderFromBuildOutputFile.BuildArtifacts())
		})
}

// runFilter loads the Kubernetes manifests from stdin and applies the debug transformations.
// Unlike `skaffold debug`, this filtering affects all images and not just the built artifacts.
func runFilter(ctx context.Context, out io.Writer, debuggingFilters bool, postRenderer string, buildArtifacts []graph.Artifact) error {
	return withRunner(ctx, out, func(r runner.Runner, configs []util.VersionedConfig) error {
		var manifestList manifest.ManifestList
		var err error
		if postRenderer != "" {
			cmd := exec.CommandContext(ctx, postRenderer)
			cmd.Stdin = os.Stdin
			stdoutPipe, err := cmd.StdoutPipe()
			if err != nil {
				return fmt.Errorf("running post-renderer: %w", err)
			}
			err = cmd.Start()
			if err != nil {
				return fmt.Errorf("running post-renderer: %w", err)
			}

			manifestList, err = manifest.Load(stdoutPipe)
			if err != nil {
				return fmt.Errorf("loading post-renderer result: %w", err)
			}
			stdoutPipe.Close()
		} else {
			manifestList, err = manifest.Load(os.Stdin)
		}
		if err != nil {
			return fmt.Errorf("loading manifests: %w", err)
		}
		var ass applysetters.ApplySetters

View on GitHub (pinned to a1189de023)

Solutions

1. Check the wrapped error for fd/pipe exhaustion
2. Raise the process file-descriptor limit (ulimit -n)
3. Verify the environment allows spawning processes
4. Retry the filter command once resources are freed

if err != nil {
    return fmt.Errorf("running post-renderer: %w", err)
}
// caller: log %v of the wrapped error; retry once if it is a transient resource error

When it happens

Trigger: exec.CommandContext(postRenderer) is configured with StdoutPipe() and that call returns a non-nil error (pipe creation failure), wrapped at filter.go:78.

Common situations: Extremely rare; typically process resource exhaustion (too many open file descriptors) prevents creating the pipe.

Related errors

• loading post-renderer result: %w
• starting command %v: %w
• `apply` requires at least one manifest argument
• `exec` requires exactly one action to execute
• `config-dependencies add` requires exactly one file path arg

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/b061c153c83c6690. Report an issue: GitHub.