fix(database): normalize read/write host lists

Trim comma-separated database host values and fall back to DB_HOST or the default host when write hosts are empty. Add unit coverage for read/write host parsing.

config/database.php

@@ -3,6 +3,24 @@
 use Illuminate\Support\Str;
 use Pdo\Pgsql;
 
+$parseDatabaseHosts = function (mixed $hosts, mixed $fallback = 'coolify-db'): array {
+    $parsedHosts = array_values(array_filter(
+        array_map('trim', explode(',', (string) $hosts)),
+        'strlen',
+    ));
+
+    if ($parsedHosts !== []) {
+        return $parsedHosts;
+    }
+
+    $fallbackHosts = array_values(array_filter(
+        array_map('trim', explode(',', (string) $fallback)),
+        'strlen',
+    ));
+
+    return $fallbackHosts === [] ? ['coolify-db'] : $fallbackHosts;
+};
+
 $pgsql = [
     'driver' => 'pgsql',
     'url' => env('DATABASE_URL'),
@@ -28,13 +46,13 @@ $pgsql = [
  */
 if (env('DB_READ_HOST')) {
     $pgsql['read'] = [
-        'host' => array_map('trim', explode(',', (string) env('DB_READ_HOST'))),
+        'host' => $parseDatabaseHosts(env('DB_READ_HOST'), env('DB_HOST', 'coolify-db')),
         'port' => env('DB_READ_PORT', env('DB_PORT', '5432')),
         'username' => env('DB_READ_USERNAME', env('DB_USERNAME', 'coolify')),
         'password' => env('DB_READ_PASSWORD', env('DB_PASSWORD', '')),
     ];
     $pgsql['write'] = [
-        'host' => array_map('trim', explode(',', (string) env('DB_WRITE_HOST', env('DB_HOST', 'coolify-db')))),
+        'host' => $parseDatabaseHosts(env('DB_WRITE_HOST'), env('DB_HOST', 'coolify-db')),
         'port' => env('DB_WRITE_PORT', env('DB_PORT', '5432')),
         'username' => env('DB_WRITE_USERNAME', env('DB_USERNAME', 'coolify')),
         'password' => env('DB_WRITE_PASSWORD', env('DB_PASSWORD', '')),

tests/Unit/DatabaseReadWriteHostConfigTest.php

@@ -0,0 +1,64 @@
+<?php
+
+use Illuminate\Support\Env;
+
+function databaseConfigWithEnvironment(array $overrides): array
+{
+    $keys = [
+        'DB_HOST',
+        'DB_READ_HOST',
+        'DB_WRITE_HOST',
+    ];
+
+    $repository = Env::getRepository();
+    $original = [];
+
+    foreach ($keys as $key) {
+        $original[$key] = env($key);
+        $repository->clear($key);
+    }
+
+    try {
+        foreach ($overrides as $key => $value) {
+            $repository->set($key, (string) $value);
+        }
+
+        return require __DIR__.'/../../config/database.php';
+    } finally {
+        foreach ($keys as $key) {
+            $repository->clear($key);
+
+            if ($original[$key] !== null) {
+                $repository->set($key, (string) $original[$key]);
+            }
+        }
+    }
+}
+
+it('trims and filters read hosts from comma separated values', function () {
+    $config = databaseConfigWithEnvironment([
+        'DB_READ_HOST' => ' read-1, read-2, ',
+    ]);
+
+    expect($config['connections']['pgsql']['read']['host'])->toBe(['read-1', 'read-2']);
+});
+
+it('falls back to db host when write host is empty', function () {
+    $config = databaseConfigWithEnvironment([
+        'DB_HOST' => 'primary-db',
+        'DB_READ_HOST' => 'read-db',
+        'DB_WRITE_HOST' => '',
+    ]);
+
+    expect($config['connections']['pgsql']['write']['host'])->toBe(['primary-db']);
+});
+
+it('falls back to the default host when write host and db host are empty', function () {
+    $config = databaseConfigWithEnvironment([
+        'DB_HOST' => '',
+        'DB_READ_HOST' => 'read-db',
+        'DB_WRITE_HOST' => '',
+    ]);
+
+    expect($config['connections']['pgsql']['write']['host'])->toBe(['coolify-db']);
+});