Support for Read Only Cache / Configurable Cache Saving #334
Description
Version
actions/cache@v2
Description
We have a repository with multiple workflows that could benefit from shared caching across all of them. We would like to avoid trying to create and conditionalize one large workflow.
e.g. caching the download of all Go Modules:
# Workflow 1
name: Code Checks
on:
push:
branches:
- master
pull_request:
paths:
- go.sum
- src/**
jobs:
go_mod_download:
name: go mod download
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
id: cache-go-pkg-mod
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
- if: steps.cache-go-pkg-mod.outputs.cache-hit != 'true' || steps.cache-go-pkg-mod.outcome == 'failure'
run: go mod download
# ... much more ...
# Workflow 2
name: CHANGELOG Checks
on:
push:
branches:
- master
pull_request:
paths:
- CHANGELOG.md
jobs:
misspell:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
- run: go install github.com/client9/misspell/cmd/misspell
- run: misspell -error -source text CHANGELOG.mdCurrently there can be race conditions between these workflows, where the first one that completes will save the cache, while other jobs will see the post-action hit on the cache key and prevent overwriting it. If the latter workflow completes first, the Go Modules download would contain only the download of the Go Modules relevant to the installed package, rather than all Go Modules for the project.
As a simple workaround, we could run the go mod download in every workflow:
jobs:
misspell:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
- run: |
go mod download
go install github.com/client9/misspell/cmd/misspell
- run: misspell -error -source text CHANGELOG.mdThis could needlessly waste time/bandwidth, fail for unrelated networking reasons, and seems easy to miss though.
As a more complex workaround, we could add the go_mod_download job to every workflow:
jobs:
go_mod_download:
name: go mod download
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
id: cache-go-pkg-mod
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
- if: steps.cache-go-pkg-mod.outputs.cache-hit != 'true' || steps.cache-go-pkg-mod.outcome == 'failure'
run: go mod download
misspell:
needs: [go_mod_download]
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
- run: go install github.com/client9/misspell/cmd/misspell
- run: misspell -error -source text CHANGELOG.mdBut this feels like a lot of overhead and maintenance for each workflow. It would be great if we could tell this action to skip the post save action, effectively making the cache best effort and read-only, while preventing it from missing contents.
Proposals
Adding a read-only input:
jobs:
misspell:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
read-only: true
- run: go install github.com/client9/misspell/cmd/misspell
- run: misspell -error -source text CHANGELOG.mdOr maybe adding a save input (see references for why this may be beneficial):
jobs:
misspell:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- uses: actions/setup-go@v2
with:
go-version: "1.14"
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-pkg-mod-${{ hashFiles('go.sum') }}
save: never # or "always", defaults to current "when missing"
- run: go install github.com/client9/misspell/cmd/misspell
- run: misspell -error -source text CHANGELOG.mdThank you for the consideration! Please reach out if I'm missing something and this is already possible or if this would be acceptable as an enhancement.
References
- Configurable save cache on failure: Configurable save cache on failure #92
- Enable caching of dependencies even if builds fail with post-if modifier: Enable caching of dependencies even if builds fail with post-if modifier. #165