WIP testing build limiting

.github/matrix.php

@@ -0,0 +1,119 @@
+<?php
+
+/**
+ * Get the list of DokuWiki versions from the download server
+ *
+ * @return array
+ */
+function getVersions()
+{
+    $data = file_get_contents('https://download.dokuwiki.org/version');
+    return json_decode($data, true);
+}
+
+/**
+ * Get the last commit of a branch
+ *
+ * @param string $branch
+ * @return string
+ */
+function getLastCommit($branch)
+{
+    $opts = [
+        'http' => [
+            'method' => "GET",
+            'header' => join("\r\n", [
+                "Accept: application/vnd.github.v3+json",
+                "User-Agent: PHP"
+            ])
+        ]
+    ];
+    $context = stream_context_create($opts);
+
+    $data = file_get_contents('https://api.github.com/repos/dokuwiki/dokuwiki/commits/' . $branch, false, $context);
+    $json = json_decode($data, true);
+    return $json['sha'];
+}
+
+/**
+ * Get the image id of a given PHP image tag
+ *
+ * @param string $tag
+ * @return string
+ */
+function getImageId($tag)
+{
+    $repo = 'library/php';
+    $data = file_get_contents('https://auth.docker.io/token?service=registry.docker.io&scope=repository:' . $repo . ':pull');
+    $token = json_decode($data, true)['token'];
+
+
+    $opts = [
+        'http' => [
+            'method' => "GET",
+            'header' => join("\r\n", [
+                "Authorization: Bearer $token",
+                "Accept: application/vnd.docker.distribution.manifest.v2+json",
+            ])
+        ]
+    ];
+    $context = stream_context_create($opts);
+
+    $data = file_get_contents('https://index.docker.io/v2/' . $repo . '/manifests/' . $tag, false, $context);
+    $json = json_decode($data, true);
+    return $json['config']['digest'];
+}
+
+/**
+ * Get the image tag used in the current Dockerfile
+ *
+ * @return string
+ */
+function getImageTag()
+{
+    $df = file_get_contents('Dockerfile');
+    preg_match('/FROM php:(?<tag>\S*)/', $df, $matches);
+    return $matches['tag'];
+}
+
+
+$result = [];
+$self = $_ENV['GITHUB_SHA'] ?? 'unknown';
+$upstreamTag = getImageTag();
+$image = getImageId($upstreamTag);
+
+foreach (getVersions() as $release => $info) {
+    $branch = $release === 'oldstable' ? 'old-stable' : $release;
+    $commit = getLastCommit($branch);
+    $ident = join('-', [$release, $commit, $image, $self]);
+    $cache = '.github/matrix.cache/' . $release;
+
+    fwrite(STDERR, "Ident: $ident\n");
+    $last = @file_get_contents($cache);
+    if ($last === $ident) {
+        // this combination has been built before
+        fwrite(STDERR, "No change. Skipping $release\n");
+        continue;
+    }
+
+    // this branch needs to be built
+    $result[] = [
+        'version' => $info['version'],
+        'date' => $info['date'],
+        'name' => $info['name'],
+        'type' => $release,
+    ];
+    // update the cache
+    if (!is_dir('.github/matrix.cache')) {
+        mkdir('.github/matrix.cache');
+    }
+    file_put_contents($cache, $ident);
+}
+
+// output the result
+if ($result) {
+    echo "matrix=" . json_encode(['release' => $result]);
+} else {
+    echo "matrix=[]";
+}
+

.github/workflows/limit.yml

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+name: Test Limit
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "23 0 * * *"
+  push:
+    branches:
+    - limit
+
+jobs:
+  buildmatrix:
+    name: Create Build Matrix
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.2'
+      - name: Cache Setup
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: .github/matrix.cache/
+          key: ${{ runner.os }}-matrix-${{ hashFiles('.github/matrix.php') }}
+      - name: Set up matrix
+        id: set-matrix
+        run: |
+          php .github/matrix.php >> $GITHUB_OUTPUT
+
+  build:
+    needs: buildmatrix
+    name: Build Docker Image for ${{ matrix.release.type }}
+    runs-on: ubuntu-latest
+    if: ${{ needs.buildmatrix.outputs.matrix != '[]' }}
+    strategy:
+      matrix: ${{fromJson(needs.buildmatrix.outputs.matrix)}}
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v4
+
+
+  workflow-keepalive:
+    if: github.event_name == 'schedule'
+    runs-on: ubuntu-latest
+    permissions:
+      actions: write
+    steps:
+      - uses: liskin/gh-workflow-keepalive@v1
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}