Fix duplicate daily wiki metrics by making the write idempotent

app/Metrics/App/WikiMetrics.php

@@ -25,6 +25,18 @@ public function saveMetrics(Wiki $wiki): void {
         $this->wiki = $wiki;
 
         $today = now()->format('Y-m-d');
+
+        // Skip expensive metrics collection if today's record already exists.
+        $recordExists = WikiDailyMetrics::where('wiki_id', $wiki->id)
+            ->where('date', $today)
+            ->exists();
+
+        if ($recordExists) {
+            Log::warning("Daily metric already exists for Wiki ID {$wiki->id} on {$today}; skipping metrics collection.");
+
+            return;
+        }
+
         $tripleCount = $this->getNumOfTriples();
         $todayPageCount = $wiki->wikiSiteStats()->first()->pages ?? 0;
         $isDeleted = (bool) $wiki->deleted_at;

tests/Jobs/UpdateWikiDailyMetricJobTest.php

@@ -8,12 +8,20 @@
 use App\WikiDb;
 use Carbon\Carbon;
 use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Queue;
 use Tests\TestCase;
+use TiMacDonald\Log\LogEntry;
+use TiMacDonald\Log\LogFake;
 
 class UpdateWikiDailyMetricJobTest extends TestCase {
     use RefreshDatabase;
 
+    protected function setUp(): void {
+        parent::setUp();
+        Log::swap(new LogFake());
+    }
+
     public function testDispatchJob() {
         Queue::fake();
 
@@ -72,4 +80,47 @@ public function testRunJobForAllWikisIncludingDeletedWikis() {
             'entity_schema_count' => 0,
         ]);
     }
+
+    public function testRunningJobTwiceForSameWikiWithChangedValuesSkipsSecondRunWhenRecordExistsForToday() {
+        $wiki = Wiki::factory()->create([
+            'domain' => 'duplicate.wikibase.cloud',
+        ]);
+
+        $manager = $this->app->make('db');
+        $job = new ProvisionWikiDbJob();
+        $job->handle($manager);
+
+        $wikiDb = WikiDb::whereDoesntHave('wiki')->first();
+        $wikiDb->update(['wiki_id' => $wiki->id]);
+
+        $wiki->wikiSiteStats()->create([
+            'pages' => 10,
+            'users' => 3,
+        ]);
+
+        $dailyMetricJob = new UpdateWikiDailyMetricJob();
+        $dailyMetricJob->handle();
+
+        $wiki->wikiSiteStats()->first()->update([
+            'pages' => 12,
+            'users' => 5,
+        ]);
+
+        $dailyMetricJob->handle();
+
+        $this->assertDatabaseCount('wiki_daily_metrics', 1)
+            ->assertDatabaseHas('wiki_daily_metrics', [
+                'wiki_id' => $wiki->id,
+                'date' => Carbon::today()->toDateString(),
+                'pages' => 10,
+            ]);
+
+        Log::assertLogged(function (LogEntry $log) use ($wiki) {
+            if ($log->level !== 'warning') {
+                return false;
+            }
+
+            return str_contains($log->message, "Daily metric already exists for Wiki ID {$wiki->id} on " . Carbon::today()->toDateString());
+        });
+    }
 }