Appengine Flex unable to connect on cloudSQL mysql DB

Question

I have a Java application running on GAE Flex but it's falling to connect on my private mysql instance with the error:

at com.zaxxer.hikari.pool.HikariPool.(HikariPool.java:115) at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) at com.googlecode.flyway.core.util.jdbc.JdbcUtils.openConnection(JdbcUtils.java:50) ... 33 common frames omitted Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure 2020-08-04 03:16:54 core-api[20200803t145941] The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

I've tried the following by Google recommendation:

https://cloud.google.com/appengine/docs/flexible/java/using-shared-vpc#setting_up_permissions

and also a lot of other ways without any luck:

Here are my app.yaml config:

service: core-api runtime: java env: flex runtime_config: jdk: openjdk8 env_variables: DB_URL: jdbc:mysql://10.115.0.33:3306/database?useSSL=false&requireSSL=false&autoReconnect=true DB_USER: user DB_PASSWORD: password network: instance_tag: java-app name: projects/java-app/global/networks/java-app-network subnetwork_name: java-app-subnet1 beta_settings: cloud_sql_instances: "java-app:southamerica-east1:java-app-mysql-database" manual_scaling: instances: 3 resources: cpu: 4 memory_gb: 8 disk_size_gb: 100 

I'm currently with no clue at all what may be causing suck headache and any help will be much appreciated, Thanks.

Answer 1

It could be related to this. Maybe the solution is posted here 7.1

Quote: "The Google Cloud SQL API must be enabled in your GCP project. To do that, go to the API library page of the Google Cloud Console, search for "Cloud SQL API", click the first result and enable the API. "