Docker setup: Wait for genesis file to exist before starting nodes

[mediremi-antithesis]

Description

The Docker image entrypoint docker/local/polygon-edge.sh had a race condition where if the init container took too long to generate the genesis.json genesis file, nodes would fail with Error: open /genesis/genesis.json: no such file or directory.

This fix ensures that nodes wait for this file to exist (by polling for its existence in a loop) prior to starting up.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

Manual tests

Manually tested by running docker-compose up

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[mediremi-antithesis]

I have read the CLA Document and I hereby sign the CLA

[epikichi]

Thanks for the identifying this behavior and adding a remediation! This change looks good functionally.

I want to see your thoughts on implementing the depends_on long syntax condition to handle this race scenario on the compose level for better init feedback. We should be able to set the dependency to wait for the service_completed_successfully condition to avoid premature node starts and uncaught init exceptions.

This approach does bring up an inevitable downstream condition where if the genesis.json already exists in the defined volumes (make run-local; make stop-local; make run-local to simply reproduce), then the init service will exit with status code 1 and fail the condition. Adding a catch for this scenario in the polygon-edge.sh file should be sufficient for that case.

[vcastellm]

LGTM

[mediremi-antithesis]

I didn't know about the depends_on long syntax but that definitely sounds like a cleaner way of implementing this.

Unfortunately I use podman-compose instead of docker-compose, which doesn't support the long syntax version of depends_on, so I'm unable to test it. So please feel free to make that change and push to this branch.

I have made the change you suggested regarding the init command, which will now only attempt to generate the genesis file if it does not already exist.

[epikichi]

I didn't know about the depends_on long syntax but that definitely sounds like a cleaner way of implementing this.

Unfortunately I use podman-compose instead of docker-compose, which doesn't support the long syntax version of depends_on, so I'm unable to test it. So please feel free to make that change and push to this branch.

I have made the change you suggested regarding the init command, which will now only attempt to generate the genesis file if it does not already exist.

Thanks for the amendments! Made a quick https://github.com/mediremi-antithesis/polygon-edge/pull/1 to add in the changes as suggested.

[epikichi]

Tested and worked with the mentioned above changes regarding docker compose conditions. LGTM!

[codecov]

Codecov Report

Merging #949 (0360f1a) into develop (f80b615) will increase coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #949      +/-   ##
===========================================
+ Coverage    52.89%   52.91%   +0.01%     
===========================================
  Files          129      129              
  Lines        17113    17113              
===========================================
+ Hits          9052     9055       +3     
+ Misses        7413     7411       -2     
+ Partials       648      647       -1     

Impacted Files	Coverage Δ
syncer/client.go	63.20% <0.00%> (+1.41%)	⬆️

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[ZeljkoBenovic]

LGTM 🏅