Unable to connect to MySQL from Ballerina.io on Mac OS X - mysql

Question

I want to build a simple app that connects to remote MySQL server. However, I can't make it work.
import ballerina/io;
import ballerina/jdbc;
import ballerina/mysql;
endpoint jdbc:Client jiraDB {
host: "jdbc:mysql://DB-SERVER:3306/jira",
username: "jira",
password: "PWD",
poolOptions: { maximumPoolSize: 5 }
};
type Domain record {
string domain,
string jira,
};
function main(string... args) {
var ret = jiraDB->select("SELECT * FROM `domains`", ());
table domainTable;
match ret {
table tableReturned => domainTable = tableReturned;
error e => io:println("Select data from domains table failed: " + e.message);
}
while(domainTable.hasNext()) {
var domain = <Domain>domainTable.getNext();
match domain {
Domain d => io:println("Domain: " + d.domain);
error e => io:println("Error in get employee from table: "
+ e.message);
}
}
}
The structure of MySQL is not really important. I think it has to do with missing / wrongly used JDBC/MySQL library.
Do you please have any ideas how to make it work on Mac OS X ?
$ ballerina run hello.bal
error: ballerina/runtime:CallFailedException, message: call failed
at ..<stop>(hello.bal:5)
caused by error
at ballerina/jdbc:stop(endpoint.bal:66)
I'm using latest Mac OS X with:
$ ballerina --version
Ballerina 0.980.1

Answer 1

First, the latest ballerina version is 0.981.0. It would be great if you could use the latest version since it would include latest bug fixes and improvements.
In Ballerina, there is a generic jdbc client which can be used to connect to any database which has a jdbc driver. In addition, for mysql and h2 there are two clients implemented specifically for those two databases.
When connecting to mysql, you could either use the generic jdbc client or the mysql specific client. The recommendation is to use the mysql specific client.
In your code snippet, I can see you are using jdbc client. As Anoukh mentioned above, the endpoint configuration is incorrect.
Following is a sample configuration for generic jdbc client endpoint.
endpoint jdbc:Client testDB {
url: "jdbc:mysql://localhost:3306/testdb",
username: "user1",
password: "pass1",
poolOptions: { maximumPoolSize: 5 }
};
And following is a sample configuration of mysql client endpoint.
endpoint mysql:Client testDB {
host: "localhost",
port: 3306,
name: "testDB",
username: "user1",
password: "pass1",
poolOptions: { maximumPoolSize: 5 }
};
In order to use either of the clients, you need to copy the mysql jdbc driver to ${BALLERINA_HOME}/bre/lib.
Even after correcting your configuration and copying the driver, if you still face the issue, please check whether file named ballerina-internal.log is created where you are running your bal file and share. Also please share the mysql database and driver version you are using.

Answer 2

Have you copied the MySQL JDBC driver to the BALLERINA_HOME/bre/lib folder?
You can find the ballerina home using which ballerina command.
You can download the mysql jdbc driver from http://central.maven.org/maven2/mysql/mysql-connector-java/5.1.6/mysql-connector-java-5.1.6.jar

Answer 3

The issue might be in the jiraDB endpoint configurations. As per the API docs, the config for the URL of the database is to be given as url instead of host.

Answer 4

I was not able to connect to Mysql and I faced a driver instance error. I solved it! I'm not sure to post my answer at the good place but I think it will be a good resource to fix some problems with Mysql connections issues in Ballerina.
In my terminal : echo $BALLERINA_HOME
/Library/Ballerina/ballerina-0.990.2
Copy the good jar in the right place !
Go to : http://central.maven.org/maven2/mysql/mysql-connector-java/
I have downloaded the latest stable version (at the time of writing 8.0.15).
Copy the jar in $BALLERINA_HOME/bre/lib/
I had an error with a prior version.
Be careful that your jar have the right extension (the .jar not the repository with the same name).
Also be sure to have fulfilled the recommandations (see the doc of Oracle when installing a jar, i.e setting the classpath)
In your terminal, set the class path :
export CLASSPATH=$CLASSPATH:/Library/Ballerina/ballerina-0.990.2/bre/lib/mysql-connector-java-8.0.15
Then it will work !