Cannot connect to MySQL from Azure JAVA Function

[steccami]

Hi all,

I am developing a simple JAVA Time triggered Azure Function. I am trying to connect to a Azure MySQL instance but I keep getting this error:

[Information] com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

Here is the code:
String url ="jdbc:mysql://XXXX.mysql.database.azure.com:3306/DBNAME?useSSL=true&requireSSL=false";
connect = DriverManager.getConnection(url, "user@DBNAME", "passwd");

statement = connect.createStatement()

resultSet = statement.executeQuery("select * from table1");

while (resultSet.next()) {
//App logic
}

I am using the following library:

mysql mysql-connector-java 8.0.13

Notes:

• The program works fine on my local machine (i.e., after adding my IP address to the MySQL firewall, I can reach the DB from my machine);

• I've already tried different mysql libraries (8.0.13, 5.1.45, 5.1.42): nothing changes;

• Another Azure function implemented with NodeJS is able to reach the DB;

• I tried to add the Function "ADDITIONAL OUTBOUND IP ADDRESSES" to the MySQL firewall: nothing changes.

• I developed a simple C# Azure function, it works well. It seems to be a problem strictly related to the JAVA-based Azure Function env.

• I also created a fat jar file as suggested here: Access Azure SQL  #35 (comment)

Any ideas?

Thank you in advance.

[marwaadihu]

Hello, I was trying the same with the same code base but facing the same issue.

I also tried below things in four combinations i.e. true | false

System.setProperty("java.net.preferIPv4Stack", "false");
System.setProperty("java.net.preferIPv6Addresses", "false");

when both are false, it is working in local but not working after deploying to Azure functions.

do we have any timeline until when it is going to resolve?

[sureddy1]

We are actively working to fix this issue. This is specific to the java version used with functions.

Can you use this workaround for now:

1. Upload a custom JRE (lets say JRE 1.8_0_202) to D:/home/site/jre1.8.0_202 and add these application settings for your function from portal:

Key: languageWorkers:java:defaultExecutablePath
Value: D:/home/site/jre1.8.0_202/bin/java

If you are using consumption plan, please add this app setting as well:

Key: WEBSITE_USE_PLACEHOLDER
Value: 0

[fabiocav]

This is resolved with the release currently being deployed. Please use Azure/app-service-announcements#188 to track the deployment progress.

[pragnagopa]

On AppService, JAVA_HOME is set to D:\Program Files\Java\zulu8.31.0.2-jre8.0.181-win_x64 while the latest JRE on AppService is: D:\Program Files\Java\zulu8.36.0.1-jre8.0.202-win_x64. Needs to be updated.