Rework pacman pkg cache and enable by default

.github/workflows/action.yml

@@ -6,26 +6,7 @@ on:
     - cron: '0 0 * * 3,6'
 jobs:
 
-  save:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@v2
-    - name: build action
-      shell: bash
-      run: |
-        npm ci
-        npm run pkg
-        rm -rf node_modules
-    - name: run action
-      uses: ./
-      with:
-        cache: save
-    - shell: msys2 {0}
-      run: |
-        uname -a
-
   cache:
-    needs: [save]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
@@ -39,7 +20,7 @@ jobs:
       uses: ./
       with:
         update: true
-        cache: true
+        install: base-devel git
     - shell: msys2 {0}
       run: |
         uname -a
@@ -71,7 +52,7 @@ jobs:
         msys2 ./test.sh MINGW32
 
   cmd:
-    needs: [powershell]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
@@ -100,7 +81,7 @@ jobs:
         msys2 ./test.sh MINGW32
 
   env:
-    needs: [cmd]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
@@ -126,7 +107,7 @@ jobs:
         MSYSTEM: MINGW32
 
   shell:
-    needs: [env]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
@@ -143,7 +124,7 @@ jobs:
         uname -a
 
   msystem:
-    needs: [shell]
+    needs: [cache]
     strategy:
       matrix:
         task: [ MSYS, MINGW64, MINGW32 ]
@@ -163,7 +144,7 @@ jobs:
     - run: msys2 ./test.sh ${{ matrix.task }}
 
   update:
-    needs: [msystem]
+    needs: [cache]
     strategy:
       fail-fast: false
       max-parallel: 3
@@ -186,7 +167,7 @@ jobs:
     - run: msys2 ./test.sh ${{ matrix.msystem }}
 
   MSYS2_PATH_TYPE:
-    needs: [update]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/setup-go@v1
@@ -204,7 +185,7 @@ jobs:
         MSYS2_PATH_TYPE: inherit
 
   path-type:
-    needs: [update]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/setup-go@v1
@@ -222,7 +203,7 @@ jobs:
     - run: msys2 -c "go env"
 
   install:
-    needs: [path-type]
+    needs: [cache]
     strategy:
       fail-fast: false
       max-parallel: 3
@@ -246,7 +227,7 @@ jobs:
     - run: msys2 ./test.sh MINGW64
 
   defaultclean:
-    needs: [install]
+    needs: [cache]
     runs-on: windows-latest
     defaults:
       run:
@@ -271,7 +252,7 @@ jobs:
     - run: git describe --dirty --tags
 
   defaultdirty:
-    needs: [install]
+    needs: [cache]
     runs-on: windows-latest
     defaults:
       run:
@@ -294,7 +275,7 @@ jobs:
     - run: git describe --dirty --tags
 
   errorhandling:
-    needs: [defaultdirty]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
@@ -312,7 +293,7 @@ jobs:
         [[ "$-" =~ 'e' ]] || exit 1; # make sure "set -e" is active by default
 
   workingdir:
-    needs: [errorhandling]
+    needs: [cache]
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2

README.md

@@ -146,24 +146,6 @@ Installing additional packages after updating the system is supported through op
       install: 'git base-devel'
 ```
 
-#### cache
-
-If set to `true`, directory `/var/cache/pacman/pkg` is restored/cached in order to speed up future updates:
-
-```yaml
-  - uses: msys2/setup-msys2@v1
-    with:
-      cache: true
-```
-
-If set to `save`, the same directory is cached, but it is not restored. This can be used to force a save of a clean state.
-
-```yaml
-  - uses: msys2/setup-msys2@v1
-    with:
-      cache: save
-```
-
 ## Development
 
 The steps to publish a new release are the following:

action.yml

@@ -24,10 +24,6 @@ inputs:
     description: 'Install packages after installation through pacman'
     required: false
     default: false
-  cache:
-    description: 'Cache /var/cache/pacman/pkg to speed up future updates'
-    required: false
-    default: false
 runs:
   using: 'node12'
   main: 'index.js'

main.js

@@ -5,6 +5,7 @@ const exec = require('@actions/exec');
 const tc = require('@actions/tool-cache');
 const path = require('path');
 const fs = require('fs');
+const crypto = require('crypto');
 const { hashElement } = require('folder-hash');
 
 const inst_url = 'https://github.com/msys2/msys2-installer/releases/download/2020-07-19/msys2-base-x86_64-20200719.sfx.exe';
@@ -36,7 +37,6 @@ async function run() {
     const p_pathtype = core.getInput('path-type');
     const p_msystem = core.getInput('msystem');
     const p_install = core.getInput('install');
-    const p_cache = core.getInput('cache');
 
     let base = 'C:';
 
@@ -75,7 +75,7 @@ async function run() {
     fs.writeFileSync(cmd, wrap);
 
     core.addPath(dest);
-    const c_paths = [(p_release ? dest : 'C:') + `\\msys64\\var\\cache\\pacman\\pkg\\`];
+    const pkgCachePath = (p_release ? dest : 'C:') + `\\msys64\\var\\cache\\pacman\\pkg\\`;
 
     const msystem_allowed = ['MSYS', 'MINGW32', 'MINGW64'];
     if (!msystem_allowed.includes(p_msystem.toUpperCase())) {
@@ -84,11 +84,21 @@ async function run() {
     }
     core.exportVariable('MSYSTEM', p_msystem.toUpperCase());
 
-    if (p_cache === 'true') {
-      core.startGroup('Restoring cache...');
-      console.log('Cache ID:', await cache.restoreCache(c_paths, 'msys2', ['msys2-']));
-      core.endGroup();
-    }
+    // We want a cache key that is ideally always the same for the same kind of job.
+    // So that mingw32 and ming64 jobs, and jobs with different install packages have different caches.
+    let shasum = crypto.createHash('sha1');
+    shasum.update([p_release, p_update, p_pathtype, p_msystem, p_install].toString());
+    // We include "update" in the fallback key so that a job run with update=false never fetches
+    // a cache created with update=true. Because this would mean a newer version than needed is in the cache
+    // which would never be used but also would win during cache prunging because it is newer.
+    const baseCacheKey = 'msys2-pkgs-upd:' + p_update.toString();
+    const jobCacheKey = baseCacheKey + '-conf:' + shasum.digest('hex').slice(0, 8);
+
+    core.startGroup('Restoring cache...');
+    // We ideally want a cache matching our configuration, but every cache is OK since we prune it later anyway
+    const restoreKey = await cache.restoreCache([pkgCachePath], jobCacheKey, [jobCacheKey, baseCacheKey]);
+    console.log(`Cache restore for ${jobCacheKey}, got ${restoreKey}`);
+    core.endGroup();
 
     async function run(args, opts) {
       await exec.exec('cmd', ['/D', '/S', '/C', cmd].concat(['-c', args.join(' ')]), opts);
@@ -121,12 +131,28 @@ async function run() {
       core.endGroup();
     }
 
-    if (p_cache === 'true' || p_cache === 'save') {
-      core.startGroup('Saving cache...');
-      const key = (await hashElement(c_paths[0]))['hash'].toString() + (new Date()).getTime().toString();
-      console.log('Cache ID:', await cache.saveCache(c_paths, 'msys2-' + key), '[' + key + ']');
-      core.endGroup();
+    core.startGroup('Prune cache...');
+    // Remove all uninstalled packages
+    await run(['paccache', '-r', '-f', '-u', '-k0']);
+    // Keep the newest for all other packages
+    await run(['paccache', '-r', '-f', '-k1']);
+    core.endGroup();
+
+    core.startGroup('Saving cache...');
+    const saveKey = jobCacheKey + '-files:' + (await hashElement(pkgCachePath))['hash'].toString();
+    if (restoreKey === saveKey) {
+      console.log(`Cache unchanged, skipping save for ${saveKey}`);
+    } else {
+      try {
+        const cacheId  = await cache.saveCache([pkgCachePath], saveKey);
+        console.log(`Cache saved as ID ${cacheId} using key ${saveKey}`);
+      } catch (error) {
+        // In case something created the same cache since we restored we'll get an error here,
+        // but that's OK with us, so ignore.
+        console.log(error.message);
+      }
     }
+    core.endGroup();
   }
   catch (error) {
     core.setFailed(error.message);