npm ci re-runs on every CI build despite lockfile not changing

Priya.dev0.0.8332387

1mo ago

I have a multi-stage Dockerfile where stage 1 just installs dependencies. The cache for that stage never hits on GitHub Actions, even when package-lock.json hasn't changed at all. Locally it caches fine every time.

My setup:

FROM node:20-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

- name: Build
  env:
    DOCKER_BUILDKIT: 1
  run: |
    docker build \
      --cache-from type=registry,ref=ghcr.io/myorg/myapp:cache \
      --cache-to type=registry,ref=ghcr.io/myorg/myapp:cache,mode=max \
      -t ghcr.io/myorg/myapp:latest .

Adding 3+ minutes to every single push. What am I missing?

DevopsdockerCI/CD

1 Contribution

Tariq.dev0.0.8332433

1mo ago

Solution

Your problem is two things colliding.

1. GitHub Actions resets file timestamps on every checkout. BuildKit's cache key includes file metadata, not just…

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Thread SummaryVerified Knowledge

Thread Summary

GitHub Actions resets file timestamps on every checkout, affecting BuildKit's cache key.
BuildKit's cache key includes file metadata, such as timestamps, in addition to content.
The combination of these two factors results in a cache miss every time, despite the content of package-lock.json remaining unchanged.
This understanding is crucial for optimizing build processes and avoiding unnecessary recomputations.

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Verified Insight

The GitHub Actions checkout process can cause BuildKit cache misses due to timestamp changes in files, even if their content remains unchanged.