Problem

Users encountering 403 Forbidden errors during astro deploy receive cryptic error messages that provide no actionable guidance. This is particularly common for new users with Docker Desktop's containerd snapshotter enabled, leading to support escalations and poor user experience. Slack Thread

Current Error Message:

unknown: unexpected status from HEAD request... 403 Forbidden
Error: failed to execute cmd: exit status 1

Solution

Enhanced error handling in the Docker image push flow to detect 403 authentication errors and provide specific, actionable troubleshooting guidance.

New Error Message:

Error: failed to push image due to authentication error (403 Forbidden).

This commonly occurs due to:
1. Invalid cached Docker credentials
2. Incompatible containerd snapshotter configuration

To resolve:
• Run 'docker logout' for each Astro registry to clear cached credentials
• Ensure containerd snapshotter is disabled (Docker Desktop users)
• Try running 'astro deploy' again

For detailed troubleshooting steps, visit:
https://support.astronomer.io/hc/en-us/articles/41427905156243-403-errors-on-image-push

Technical Changes

Core Implementation

• Enhanced Error Detection: Added is403Error() function that checks entire error chains using errors.Unwrap() to detect 403/forbidden patterns
• Stderr Capture: Modified pushWithBash() to capture and preserve Docker stderr output containing actual error details
• Error Message Constant: Added imagePush403ErrMsg constant with comprehensive troubleshooting guidance
• Proper Error Flow: Ensures 403 detection only occurs after both pushWithClient() and pushWithBash() methods fail, preserving normal fallback behavior

Key Files Modified

• airflow/docker_image.go: Core error handling and detection logic
• airflow/docker_image_test.go: Comprehensive test coverage for new functionality

Testing

Unit Tests

• Added TestIs403Error covering various error patterns and edge cases
• Added TestDockerImagePush403Error validating end-to-end error flow
• All existing tests pass, confirming no regressions

End-to-End Validation

Tested real-world scenario with Docker Desktop containerd snapshotter:

Test 1 (Containerd ON - Error Case):

• Enabled "Use containerd for pulling and storing images" in Docker Desktop
• Ran astro deploy
• Result: Enhanced 403 error message displayed correctly

Test 2 (Containerd OFF - Success Case):

• Disabled containerd snapshotter
• Ran astro deploy
• Result: Deployment succeeded normally

Regression Testing

• Verified existing deploy functionality remains unchanged
• Confirmed bash fallback mechanism works properly
• All linter checks pass

Impact Assessment

Positive Impact

• Improved User Experience: Users get immediate, actionable guidance instead of cryptic errors
• Reduced Support Load: Self-service resolution reduces support ticket volume
• Faster Onboarding: New users can resolve common issues independently

Risk Mitigation

• No Breaking Changes: Enhancement only affects error messaging, not core functionality
• Backward Compatible: Existing error handling preserved for non-403 errors
• Minimal Code Surface: Changes isolated to error detection and messaging logic

Reviewer Checklist

• Enhanced error message provides clear, actionable guidance
• Error detection correctly identifies 403 authentication issues
• Normal deploy flow remains unaffected
• Unit tests cover error detection logic comprehensively
• Code follows project conventions and passes linting
• No regressions in existing functionality

Related Issues

Addresses the 403 authentication error issue described in the Astronomer support article: https://support.astronomer.io/hc/en-us/articles/41427905156243-403-errors-on-image-push

This enhancement directly improves the user experience for the containerd snapshotter configuration issue commonly encountered by Docker Desktop users.