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fix: resolve database hostname to IP before .env template rendering #17

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Merged
konradmichalik merged 2 commits into from
Feb 18, 2026
Merged

fix: resolve database hostname to IP before .env template rendering #17

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75fca1f
fix: resolve database hostname to IP before .env template rendering
konradmichalik Feb 18, 2026
cb451de
fix: remove filter_var usage to avoid ext-filter dependency
konradmichalik Feb 18, 2026
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43 changes: 38 additions & 5 deletions src/Database/Manager/MittwaldApi.php
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Original file line number Diff line number Diff line change
Expand Up @@ -83,8 +83,8 @@ public function create(): void
// Additionally, even after the user is "ready", the DNS entry for the database host
// (e.g. mysql-xyz.pg-s-xxx.db.project.host) may not be resolvable yet and can flap
// intermittently for several minutes. The TCP connectivity check below catches the
// initial delay; the DNS-to-IP resolution in feature_sync.php::resolveDatabaseHostToIp()
// handles the ongoing flapping by eliminating DNS dependency entirely.
// initial delay, and the immediate hostname-to-IP resolution eliminates DNS dependency
// for all subsequent operations (template rendering, db_sync_tool, TYPO3 CLI, etc.).
$ready = $this->checkForDatabaseReadyStatus(
$responseBody->getUserId(),
(int) get('mittwald_database_wait', 30),
Expand All @@ -108,9 +108,15 @@ public function create(): void
);
}

// Resolve hostname to IP immediately while DNS is known to be working.
// Mittwald DNS entries flap intermittently for several minutes after database creation.
// By resolving now, the .env template will contain the IP address, eliminating DNS
// dependency for db_sync_tool, TYPO3 CLI, and all subsequent remote commands.
$databaseHost = $this->resolveHostnameToIp($database->getHostName());

$user = $this->getDatabaseUser($responseBody->getUserId());

$this->initDatabaseConfiguration($database, $user);
$this->initDatabaseConfiguration($database, $user, $databaseHost);
}

/**
Expand Down Expand Up @@ -229,14 +235,41 @@ private function getDatabaseUser(string $id): MysqlUser
return $response->getBody();
}

private function initDatabaseConfiguration(MySqlDatabase $database, MySqlUser $user): void
private function initDatabaseConfiguration(MySqlDatabase $database, MySqlUser $user, string $databaseHost): void
{
set('database_user', $user->getName());
set('database_name', $database->getName());
set('database_host', $database->getHostName());
set('database_host', $databaseHost);
set('database_password', VarUtility::getDatabasePassword());
}

/**
* Resolves a database hostname to its IP address on the remote server.
*
* This is called immediately after the TCP connectivity check passes, when DNS is
* known to be working. The resolved IP is used in the .env template instead of the
* hostname, bypassing Mittwald's intermittent DNS flapping for all subsequent commands.
*
* Falls back to the original hostname if resolution fails.
*/
private function resolveHostnameToIp(string $hostname): string
{
try {
$resolveCmd = sprintf('echo gethostbyname("%s");', addslashes($hostname));
$ip = trim(run("php -r " . escapeshellarg($resolveCmd)));

if ($ip !== $hostname) {
info("Resolved database host {$hostname} to {$ip}");
return $ip;
}
} catch (\Throwable $e) {
debug("Could not resolve {$hostname} to IP: " . $e->getMessage());
}

debug("Could not resolve {$hostname} to IP, using hostname as fallback.");
return $hostname;
}
Comment on lines 255 to 271
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@coderabbitai coderabbitai bot Feb 18, 2026 •
edited
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⚠️ Potential issue | 🟡 Minor

gethostbyname() is IPv4-only — document the limitation.

The PHP docs confirm gethostbyname() "returns the IPv4 address or a string containing the unmodified hostname on failure" and only accepts IPv4 addresses, not IPv6. If Mittwald ever introduces an IPv6-only database host, the resolution will silently return the original hostname (the $ip !== $hostname + FILTER_VALIDATE_IP gate correctly handles this), but the DNS-flapping workaround won't apply. Worth noting in the docblock so future maintainers don't assume IPv6 coverage.

📝 Suggested docblock addition 
 /**
  * Resolves a database hostname to its IP address on the remote server.
  *
+ * Note: uses PHP's gethostbyname() which resolves to IPv4 only.
+ * IPv6-only hosts will fall back to the original hostname silently.
+ *
  * This is called immediately after the TCP connectivity check passes, when DNS is
🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@src/Database/Manager/MittwaldApi.php` around lines 255 - 271, Add a docblock
to the resolveHostnameToIp method explaining that it uses PHP's gethostbyname()
(invoked via the inline PHP command in $resolveCmd) which is IPv4-only and will
return the original hostname on failure (so IPv6-only hosts won't be resolved by
this method); mention the current guard ($ip !== $hostname && filter_var($ip,
FILTER_VALIDATE_IP)) handles this by falling back to the hostname and note the
limitation and potential need for a different resolver (e.g., dns_get_record or
getaddrinfo) if Mittwald introduces IPv6-only DB hosts so future maintainers
don’t assume IPv6 coverage.

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@konradmichalik konradmichalik Feb 18, 2026

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@coderabbitai Acknowledged. The existing docblock already states "Falls back to the original hostname if resolution fails", which covers this behavior. Mittwald MySQL hosts are IPv4 — adding IPv6 future-proofing notes would be speculative at this point.

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@konradmichalik Fair point — the fallback documentation is already there, and if the infrastructure is IPv4 today, explicitly calling out a hypothetical IPv6 scenario adds noise rather than value. Thanks for the context!


private function checkDatabaseHostReachable(string $hostname, int $waitingTime, int $maxRetries): bool
{
$port = (int) get('database_port', 3306);
Expand Down