name: Cache Go Dependencies

description: Cache Go Dependencies

inputs:

save:

description: Whether this job saves caches on pushes to the default branch.

required: false

default: 'true'

key-suffix:

description: Extra suffix for cache keys (use to distinguish matrix entries that share github.job).

required: false

default: ''

runs:

using: composite

steps:

- name: Determine Go cache paths

id: cache-paths

run: |

echo "GOCACHE=$(go env GOCACHE)" >> "$GITHUB_OUTPUT"

echo "GOARCH=$(go env GOARCH)" >> "$GITHUB_OUTPUT"

echo "TAG=${{ github.sha }}" >> "$GITHUB_OUTPUT"

suffix="${{ inputs.key-suffix }}"

echo "KEY_SUFFIX=${suffix:+-$suffix}" >> "$GITHUB_OUTPUT" # prepends dash if set

shell: bash

- name: Cache Go Build (save)

if: inputs.save == 'true' && (github.event_name == 'push' && github.ref_name == github.event.repository.default_branch)

uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # ratchet:actions/cache@v5

with:

path: ${{ steps.cache-paths.outputs.GOCACHE }}

key: go-build-v1-${{ github.job }}${{ steps.cache-paths.outputs.KEY_SUFFIX }}-${{ steps.cache-paths.outputs.GOARCH }}-${{ steps.cache-paths.outputs.TAG }}

restore-keys: go-build-v1-${{ github.job }}${{ steps.cache-paths.outputs.KEY_SUFFIX }}-${{ steps.cache-paths.outputs.GOARCH }}-

- name: Cache Go Build (restore)

if: ${{ !(inputs.save == 'true' && (github.event_name == 'push' && github.ref_name == github.event.repository.default_branch)) }}

uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae # ratchet:actions/cache/restore@v5

with:

path: ${{ steps.cache-paths.outputs.GOCACHE }}

key: go-build-v1-${{ github.job }}${{ steps.cache-paths.outputs.KEY_SUFFIX }}-${{ steps.cache-paths.outputs.GOARCH }}-${{ steps.cache-paths.outputs.TAG }}

restore-keys: go-build-v1-${{ github.job }}${{ steps.cache-paths.outputs.KEY_SUFFIX }}-${{ steps.cache-paths.outputs.GOARCH }}-

- name: Mark GOCACHE entries for stale detection

run: |

gocache="${{ steps.cache-paths.outputs.GOCACHE }}"

if [[ -d "$gocache" ]]; then

# Backdate all cache entries to year 2000. During the build/test,

# Go's markUsed() updates mtimes of accessed entries to "now"

# (it always updates when mtime is >1 hour old). The post-step

# below trims entries still at year 2000 before cache save.

timeout 120 find "$gocache" -type f -exec touch -t 200001010000 {} + || true

# Protect trim.txt: if backdated, Go's built-in Trim() sees

# "last trim was in year 2000" and deletes ALL backdated entries

# before the build starts. Setting it to now prevents this.

echo "$(date +%s)" > "$gocache/trim.txt"

echo "Marked GOCACHE entries for stale detection"

fi

shell: bash

# Registered AFTER cache steps so the post-step runs BEFORE cache save

# (GHA runs post-steps in reverse registration order).

- name: Trim stale GOCACHE entries (post-step)

uses: gacts/run-and-post-run@81b6ce503cde93862cec047c54652e45c5dca991 # v1.4.0

with:

post: >

set +e;

gocache="$(go env GOCACHE)";

[[ -d "$gocache" ]] && [[ -f "$gocache/trim.txt" ]] || { echo "Skipping GOCACHE trim"; exit 0; };

before=$(du -sm "$gocache" 2>/dev/null | cut -f1);

cutoff=$(mktemp); touch -t 200001020000 "$cutoff";

find "$gocache" -type f ! -newer "$cutoff" -delete 2>/dev/null || true;

rm -f "$cutoff";

find "$gocache" -mindepth 1 -type d -empty -delete 2>/dev/null || true;

after=$(du -sm "$gocache" 2>/dev/null | cut -f1);

echo "GOCACHE trimmed: ${before:-0}MB -> ${after:-0}MB (removed $((${before:-0} - ${after:-0}))MB)"

- name: Stabilize file mtimes for Go test cache

run: |

# Go's test cache validates inputs by (path, size, mtime) — NOT content.

# git checkout sets all mtimes to "now", which differs between CI runs,

# causing every test to miss the cache. Setting a fixed mtime makes the

# test cache hit across runs when file content hasn't changed.

#

# Risk: if a non-.go testdata file changes content but not size between

# commits, the test cache could return a stale result. This is extremely

# rare and Go's own test cache has the same inherent limitation.

git ls-files | xargs touch -t 200101010000

# Also stabilize directory mtimes — tests using os.ReadDir or

# filepath.Walk check directory mtimes too. git ls-files only

# lists files, not directories.

git ls-files | sed 's|/[^/]*$||' | sort -u | xargs touch -t 200101010000

shell: bash