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fix: use alpine with docker-cli for cert-dumper sidecar #17

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Merged
weby-homelab merged 1 commit into from
May 21, 2026
Merged

fix: use alpine with docker-cli for cert-dumper sidecar #17

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4 changes: 2 additions & 2 deletions secure-stack/docker-compose.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -82,9 +82,9 @@ services:
restart: unless-stopped

cert-dumper:
image: ldez/traefik-certs-dumper:latest
image: alpine:3.18
container_name: dms-cert-dumper
command: file --version v2 --watch --source /traefik/acme.json --dest /ssl --post-hook "docker exec dms-core postfix reload && docker exec dms-core dovecot reload"
entrypoint: /bin/sh -c 'apk add --no-cache docker-cli curl && curl -L https://github.com/ldez/traefik-certs-dumper/releases/download/v2.10.0/traefik-certs-dumper_v2.10.0_linux_amd64.tar.gz | tar xz && mv traefik-certs-dumper /usr/bin/ && traefik-certs-dumper file --version v2 --watch --source /traefik/acme.json --dest /ssl --post-hook "docker exec dms-core postfix reload && docker exec dms-core dovecot reload"'
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@gemini-code-assist gemini-code-assist Bot May 21, 2026

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high

The current entrypoint implementation introduces several issues:

  1. Security & Reliability: Downloading a binary at runtime without checksum verification is a security risk. It also makes container startup dependent on external network and repository availability.
  2. Architecture Lock-in: Hardcoding the amd64 binary URL breaks support for other architectures (e.g., ARM64). The original image was multi-arch.
  3. Signal Handling: The final command should use exec so that traefik-certs-dumper runs as PID 1 and correctly handles termination signals (SIGTERM).

Recommendation: Use a Dockerfile to build a custom image. This is the standard way to add dependencies like docker-cli while maintaining immutability and security. If you must use this inline approach, at least add exec to the final command to ensure proper signal propagation.

    entrypoint: /bin/sh -c 'apk add --no-cache docker-cli curl && curl -L https://github.com/ldez/traefik-certs-dumper/releases/download/v2.10.0/traefik-certs-dumper_v2.10.0_linux_amd64.tar.gz | tar xz && mv traefik-certs-dumper /usr/bin/ && exec traefik-certs-dumper file --version v2 --watch --source /traefik/acme.json --dest /ssl --post-hook "docker exec dms-core postfix reload && docker exec dms-core dovecot reload"'

volumes:
- ./traefik-data:/traefik:ro
- ./dms/ssl:/ssl
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