Docker credential helper: route all helper output to stdout#2061
Merged
Conversation
Align the whole helper with the docker credential-helper protocol (docker-credential-helpers `Serve`): clients read only the helper's stdout, so every message - not just the not-found sentinel (#2059) - belongs there. Moves the remaining diagnostics (invalid operation/store request, missing server URL, missing OCTOPUS_CREDENTIAL_PASSWORD/DOCKER_CONFIG, and the catch-all) off stderr, where docker's cmd.Output() discarded them and the client reported an unhelpful `out: ``. Drops the now-vestigial error TextWriter from the protocol, matching Serve's single output stream. Non-behavioural for the already-fixed not-found path; this improves failure diagnosability in the deployment log. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
zentron
approved these changes
Jul 7, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Follow-up to #2059 (which moved the "credentials not found" error to stdout)
The docker credential-helper
protocolexample code (docker-credential-helpersServe) only emits to stdout, not stderr.Our
docker-credential-octopuswrote some messages to stderr, where docker'scmd.Output()discards them and the client surfaces it as:error getting credentials - err: exit status 1, out: \``.Relates to OctopusDeploy/Issues#10128.
Results
This PR changes the rest to stdout.