docker/cli · error

error reading content from

Error message

error reading content from %q: %v

What it means

Returned by runCreate() for `docker config create` when readConfigData() fails to read the data source (cli/command/config/create.go:71-74). readConfigData handles stdin ('-'), empty path, and a file path; this top-level wrapper reports the user-supplied file argument verbatim. The underlying cause is the inner error from readConfigData (file open failure, read failure, or empty-data error for the named file).

Solutions

1. Verify the path exists and is readable: ls -l <file>.
2. Ensure the file is non-empty (see errors 270) and is a regular file, not a directory.
3. Expand shell variables/tildes before passing the argument, or use an absolute path.
4. Use '-' to stream data via stdin if the source is a pipe.

Example fix

# before
docker config create mycfg ~/missing.txt   # ~ not expanded / file missing
# after
docker config create mycfg "$HOME/config.txt"

// Pre-flight check for the config file argument.
func validateConfigSource(path string) error {
    if path == "" { return errors.New("config file is required") }
    if path == "-" { return nil }
    fi, err := os.Stat(path)
    if err != nil { return err }
    if fi.IsDir() { return fmt.Errorf("%s is a directory", path) }
    if fi.Size() == 0 { return fmt.Errorf("%s is empty", path) }
    return nil
}

When it happens

Trigger: Running `docker config create NAME <file>` where the file cannot be opened, read, or is empty. The error is propagated from readConfigData and re-wrapped with the original %q file argument the user passed.

Common situations: Wrong path / typo, file does not exist, permission denied, file is a directory, or an empty file. Also when a tilde or shell variable did not expand (literal passed to the CLI).

Related errors

• error reading from : data is empty
• error reading from STDIN: data is empty
• config file is required
• cannot supply extra formatting options to the pretty…
• source is required

AI-assisted analysis of docker/cli@4f84911bfe (2026-08-07). Data as JSON: /api/errors/4f3810529093bf8c. Report an issue: GitHub.

Appendix: source

Thrown at cli/command/config/create.go:73

			}
		},
		DisableFlagsInUseLine: true,
	}
	flags := cmd.Flags()
	flags.VarP(&createOpts.labels, "label", "l", "Config labels")
	flags.StringVar(&createOpts.templateDriver, "template-driver", "", "Template driver")
	_ = flags.SetAnnotation("template-driver", "version", []string{"1.37"})

	return cmd
}

// runCreate creates a config with the given options.
func runCreate(ctx context.Context, dockerCLI command.Cli, options createOptions) error {
	apiClient := dockerCLI.Client()

	configData, err := readConfigData(dockerCLI.In(), options.file)
	if err != nil {
		return fmt.Errorf("error reading content from %q: %v", options.file, err)
	}

	spec := swarm.ConfigSpec{
		Annotations: swarm.Annotations{
			Name:   options.name,
			Labels: opts.ConvertKVStringsToMap(options.labels.GetSlice()),
		},
		Data: configData,
	}
	if options.templateDriver != "" {
		spec.Templating = &swarm.Driver{
			Name: options.templateDriver,
		}
	}
	r, err := apiClient.ConfigCreate(ctx, client.ConfigCreateOptions{
		Spec: spec,
	})
	if err != nil {

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