docker build_error ai_generated true

WARNING: Build cache was invalidated by environment variable 'GIT_COMMIT' change.

ID: docker/build-cache-invalidation-due-to-env

Also available as: JSON · Markdown · 中文
85%Fix Rate
82%Confidence
1Evidence
2024-03-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Docker 24.0.6 active — — —
Docker 25.0.2 active — — —

Root Cause

Docker build uses --build-arg with a dynamic variable (e.g., git commit hash) that changes each build, causing all subsequent layers to be rebuilt.

generic

中文

Docker 构建使用带有动态变量（例如 git 提交哈希）的 --build-arg，该变量每次构建都会更改，导致所有后续层被重建。

Official Documentation

https://docs.docker.com/engine/reference/builder/#arg

Workarounds

  1. 85% success Place the ARG declaration after all stable layers (e.g., after apt-get install) so only final layers are rebuilt, e.g., 'ARG GIT_COMMIT' at the end of Dockerfile. 
    Place the ARG declaration after all stable layers (e.g., after apt-get install) so only final layers are rebuilt, e.g., 'ARG GIT_COMMIT' at the end of Dockerfile.
  2. 90% success Use a separate label instruction like 'LABEL git.commit=$GIT_COMMIT' after caching dependencies, keeping build-arg only for metadata. 
    Use a separate label instruction like 'LABEL git.commit=$GIT_COMMIT' after caching dependencies, keeping build-arg only for metadata.

中文步骤

  1. 将 ARG 声明放在所有稳定层之后（例如 apt-get install 之后），以便仅重建最终层，例如在 Dockerfile 末尾放置 'ARG GIT_COMMIT'。
  2. 在缓存依赖项之后使用单独的标签指令，如 'LABEL git.commit=$GIT_COMMIT'，仅将 build-arg 用于元数据。

Dead Ends

Common approaches that don't work:

  1. 60% fail

    Removing the --build-arg entirely loses the dynamic value needed for labeling or debugging.

  2. 90% fail

    Adding the ARG after RUN commands in Dockerfile still invalidates cache for those layers.