GoogleContainerTools/jib · error · GradleException

container.appRoot is not an absolute Unix-style path: ${inva

Error message

container.appRoot is not an absolute Unix-style path: ${invalidPathValue}

What it means

The Jib Gradle plugin validates that container.appRoot is an absolute Unix-style path (e.g. /app) because it is used as the destination directory for application files inside the image. InvalidAppRootException is thrown when the value is relative, Windows-style, or otherwise not an absolute Unix path, and the task rethrows it as this GradleException.

Source

Thrown at jib-gradle-plugin/src/main/java/com/google/cloud/tools/jib/gradle/BuildImageTask.java:125

      if (Strings.isNullOrEmpty(jibExtension.getTo().getImage())) {
        throw new GradleException(
            HelpfulSuggestions.forToNotConfigured(
                "Missing target image parameter",
                "'jib.to.image'",
                "build.gradle",
                "gradle jib --image <your image name>"));
      }

      PluginConfigurationProcessor.createJibBuildRunnerForRegistryImage(
              new GradleRawConfiguration(jibExtension),
              ignored -> Optional.empty(),
              projectProperties,
              globalConfig,
              new GradleHelpfulSuggestions(HELPFUL_SUGGESTIONS_PREFIX))
          .runBuild();

    } catch (InvalidAppRootException ex) {
      throw new GradleException(
          "container.appRoot is not an absolute Unix-style path: " + ex.getInvalidPathValue(), ex);

    } catch (InvalidContainerizingModeException ex) {
      throw new GradleException(
          "invalid value for containerizingMode: " + ex.getInvalidContainerizingMode(), ex);

    } catch (InvalidWorkingDirectoryException ex) {
      throw new GradleException(
          "container.workingDirectory is not an absolute Unix-style path: "
              + ex.getInvalidPathValue(),
          ex);
    } catch (InvalidPlatformException ex) {
      throw new GradleException(
          "from.platforms contains a platform configuration that is missing required values or has invalid values: "
              + ex.getMessage()
              + ": "
              + ex.getInvalidPlatform(),
          ex);

View on GitHub (pinned to fb949e2676)

Solutions

Prefix the value with a forward slash, e.g. appRoot = '/app'.
Remove any Windows-style path (drive letter, backslashes) and use a Unix path.
If unsure, remove appRoot entirely to use Jib's default.

Example fix

// before
jib {
  container { appRoot = 'app' }
}
// after
jib {
  container { appRoot = '/app' }
}

Defensive patterns

Strategy: validation

Validate before calling

def appRoot = jib.container.appRoot
if (appRoot != null && !(appRoot ==~ '^/[A-Za-z0-9._/-]+$')) {
  throw new GradleException("container.appRoot must be an absolute Unix path, got: $appRoot")
}

Try / catch

try {
  tasks.named('jib').get().execute()
} catch (GradleException e) {
  if (e.message?.startsWith('container.appRoot is not')) {
    logger.error("Fix appRoot (must start with '/'): ${e.message}")
  }
  throw e
}

Prevention

Always include the leading slash in appRoot.
Never use Windows drive letters or backslashes in image paths.
Centralize the appRoot value in one convention plugin to avoid divergence.

When it happens

Trigger: Setting jib.container.appRoot to a relative path like 'app' or 'C:\\app' (or a Windows drive path) and running any jib build task.

Common situations: Developers on Windows copying example config with backslashes; forgetting the leading slash ('app' instead of '/app'); migrating from another plugin where appRoot was relative; setting appRoot for WAR-style layouts to a path with a trailing filename expectation.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of GoogleContainerTools/jib@fb949e2676 (2026-09-06). Data as JSON: /api/errors/b052f8effd8e8299. Report an issue: GitHub.