moved dockerfile to main repo (#4393)

.docker/dbtest.php

@@ -0,0 +1,55 @@
+<?php
+$DB_HOST = $argv[1];
+$DB_BASE = $argv[2];
+$DB_PORT = $argv[3];
+$DB_USER = $argv[4];
+$DB_PASS = $argv[5];
+
+echo "Testing DB:";
+echo "*";
+echo "* new \PDO(mysql:host=$DB_HOST;dbname=$DB_BASE;port=$DB_PORT, $DB_USER, $DB_PASS, [ \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION ]);";
+echo "*";
+
+try {
+    $pdo = new \PDO("mysql:host=$DB_HOST;dbname=$DB_BASE;port=$DB_PORT", "$DB_USER", "$DB_PASS", [
+        \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION
+    ]);
+} catch(\Exception $ex) {
+    switch ($ex->getCode()) {
+        // we can immediately stop startup here and show the error message
+        case 1045:
+            echo 'Access denied (1045)';
+            die(1);
+        // we can immediately stop startup here and show the error message
+        case 1049:
+            echo 'Unknown database (1049)';
+            die(2);
+        // a lot of errors share the same meaningless error code zero
+        case 0:
+            // this error includes the database name, so we can only search for the static part of the error message
+            if (stripos($ex->getMessage(), 'SQLSTATE[HY000] [1049] Unknown database') !== false) {
+                echo 'Unknown database (0-1049)';
+                die(3);
+            }
+            switch ($ex->getMessage()) {
+                // eg. no response (fw) - the startup script should retry it a couple of times
+                case 'SQLSTATE[HY000] [2002] Operation timed out':
+                    echo 'Operation timed out (0-2002)';
+                    die(4);
+                // special case "localhost" with a stopped db server (should not happen in docker compose setup)
+                case 'SQLSTATE[HY000] [2002] No such file or directory':
+                    echo 'Connection could not be established (0-2002)';
+                    die(5);
+                // using IP with stopped db server - the startup script should retry it a couple of times
+                case 'SQLSTATE[HY000] [2002] Connection refused':
+                    echo 'Connection refused (0-2002)';
+                    die(5);
+            }
+            echo $ex->getMessage() . " (0)";
+            die(7);
+        default:
+            // unknown error
+            echo $ex->getMessage() . " (?)";
+            die(10);
+    }
+}