Save RUN --mount=type=cache
caches on GitHub Actions or other CI platforms
The BuildKit Cache Dance allows saving RUN --mount=type=cache
caches on GitHub Actions or other CI platforms by extracting the cache from the previous build and injecting it into the current build.
Use cases:
- apt-get (
/var/cache/apt
,/var/lib/apt
) - Go (
/root/.cache/go-build
) - etc.
This reproducible-containers/buildkit-cache-dance
action was forked from
overmindtech/buildkit-cache-dance
(archived on September 2023).
This action be used for "non-reproducible" containers too.
Dockerfile:
FROM ubuntu:22.04
ENV DEBIAN_FRONTEND=noninteractive
RUN \
--mount=type=cache,target=/var/cache/apt,sharing=locked \
--mount=type=cache,target=/var/lib/apt,sharing=locked \
rm -f /etc/apt/apt.conf.d/docker-clean && \
echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' >/etc/apt/apt.conf.d/keep-cache && \
apt-get update && \
apt-get install -y gcc
Action:
---
name: Build
on:
push:
jobs:
Build:
runs-on: ubuntu-22.04
steps:
- uses: actions/checkout@v4
- uses: docker/setup-buildx-action@v3
- uses: docker/metadata-action@v5
id: meta
with:
images: Build
- name: Cache
uses: actions/cache@v3
id: cache
with:
path: |
var-cache-apt
var-lib-apt
key: cache-${{ hashFiles('.github/workflows/test/Dockerfile') }}
- name: inject cache into docker
uses: reproducible-containers/[email protected]
with:
cache-map: |
{
"var-cache-apt": "/var/cache/apt",
"var-lib-apt": "/var/lib/apt"
}
skip-extraction: ${{ steps.cache.outputs.cache-hit }}
- name: Build and push
uses: docker/build-push-action@v5
with:
context: .
cache-from: type=gha
cache-to: type=gha,mode=max
file: Dockerfile
push: ${{ github.event_name != 'pull_request' }}
tags: ${{ steps.meta.outputs.tags }}
labels: ${{ steps.meta.outputs.labels }}
Real-world examples:
- https://github.com/rootless-containers/slirp4netns/blob/v1.2.2/.github/workflows/release.yaml#L18-L36
- https://github.com/containers/fuse-overlayfs/blob/40e0f3c/.github/workflows/release.yaml#L17-L36
Optionally, instead of a single string for the target
, you can provide an object with additional options that should be passed to --mount=type=cache
in the values cache-map
JSON. The target
path must be present in the object as a property.
- name: inject cache into docker
uses: reproducible-containers/[email protected]
with:
cache-map: |
{
"var-cache-apt": {
"target": "/var/cache/apt",
"id": "1"
},
"var-lib-apt": "/var/lib/apt"
}
skip-extraction: ${{ steps.cache.outputs.cache-hit }}
In other CI systems, you can run the script directly via node
:
curl -LJO https://github.com/reproducible-containers/buildkit-cache-dance/archive/refs/tags/v3.1.0.tar.gz
tar xvf buildkit-cache-dance-3.1.0.tar.gz
During injection:
node ./buildkit-cache-dance-3.1.0/dist/index.js --cache-map '{"var-cache-apt": "/var/cache/apt", "var-lib-apt": "/var/lib/apt"}'
After build during extraction:
node ./buildkit-cache-dance-3.1.0/dist/index.js --extract --cache-map '{"var-cache-apt": "/var/cache/apt", "var-lib-apt": "/var/lib/apt"}'
Here are the available options:
build-cache-dance [options]
Save 'RUN --mount=type=cache' caches on GitHub Actions or other CI platforms
Options:
--extract Extract the cache from the docker container (extract step). Otherwise, inject the cache (main step)
--cache-map The map of actions source to container destination paths for the cache paths
--scratch-dir Where the action is stores some temporary files for its processing. Default: 'scratch'
--skip-extraction Skip the extraction of the cache from the docker container
--help Show this help
v1 follows the original design of overmindtech/buildkit-cache-dance
.
v1 is composed of two actions:
reproducible-containers/buildkit-cache-dance/[email protected]
reproducible-containers/buildkit-cache-dance/[email protected]
See the releases/v1
branch.
v2 is composed of the single reproducible-containers/buildkit-cache-dance
action.
Rewrote the action in TypeScript and adds support for cache-map
that gets a string of files that need to be injected as a JSON string. This makes it possible to inject multiple directories in one call and simplifies the usage.
This release also makes it possible to run the script outside GitHub Actions in other CI platforms or locally using command line arguments.
- Thanks to Alexander Pravdin for the basic idea in this comment.
- Thanks to the authors of the original
overmindtech/buildkit-cache-dance
.