Cloud SQL Proxy no longer working in App Engine environment

[Jordan Cote]

Sometime in the past few weeks an issue with Cloud SQL started to occur with the App Engine's Cloud SQL Proxy. I get the following error in the App Engine logs:

error when connecting to db: { Error: connect ECONNREFUSED 127.0.0.1:3306

The app works on my local machine with Cloud SQL Proxy, as does the counterpart app in Compute Cluster. It used to work in App Engine, too. I double checked the App Engine user's credentials are set to Editor.  I noticed that recently the App Engine parameter vm:true has been deprecated in favor of env: flex. I tried it both ways, with the same result. The following shows how I am connecting in Node.js:

var connection;

function handleDisconnect() {

  connection = mysql.createConnection({

    user: process.env.MYSQL_USER,

    password: process.env.MYSQL_PASSWORD,

    socketPath: process.env.MYSQL_SOCKET_PATH,

    database: process.env.MYSQL_DATABASE

  });                                             // Recreate the connection, since

                                                  // the old one cannot be reused.

  connection.connect(function(err) {              // The server is either down

    if(err) {                                     // or restarting (takes a while sometimes).

      console.log('error when connecting to db:', err);

      setTimeout(handleDisconnect, 2000); // We introduce a delay before attempting to reconnect,

    }                                     // to avoid a hot loop, and to allow our node script to

  });                                     // process asynchronous requests in the meantime.

                                          // If you're also serving http, display a 503 error.

  connection.on('error', function(err) {

    console.log('db error', err);

    if(err.code === 'PROTOCOL_CONNECTION_LOST') { // Connection to the MySQL server is usually

      handleDisconnect();                         // lost due to either server restart, or a

    } else {                                      // connnection idle timeout (the wait_timeout

      throw err;                                  // server variable configures this)

    }

  });

}

handleDisconnect();

I have the connection string as follows:

  INSTANCE_CONNECTION_NAME: /cloudsql/cybers-cafe:us-east1:cybers-cafe

and under beta_settings:

  cloud_sql_instances: cybers-cafe:us-east1:cybers-cafe

I also tried restarting the SQL server. It is in us-east1 and the instances are in us-east1-b/c.

[Adam (Cloud Platform Support)]

Your app shouldn't be trying to connect to localhost in production. It should use the instance connection name (/cloudsql/[INSTANCE_CONNECTION_NAME] UNIX socket). I can reproduce your issue though with the tutorial app, because it uses nconf to check if NODE_ENV is set to "production" to conditionally parse INSTANCE_CONNECTION_NAME. This is actually related to a different issue where NODE_ENV is not being respected in app.yaml for deployed apps.

In my case, the workaround was to manually set NODE_ENV to "production" in config.json.

[Valter Negreiros]

Same error...

How to fix ?