I am new to neo4j and I want to develop a plugin that registers changes in database to a log, for now i only want log transaction data. I am using maven with java 17 to build the jar and Docker to deploy neo4j with the latest image (5.10.0).
The plugin looks like this:
Class to handle logging events:
public class Neo4jTriggersPlugin implements TransactionEventListener<Object> {
private final Log log;
public Neo4jTriggersPlugin(DatabaseManagementService dbms, LogService lgsvc) {
this.log = lgsvc.getUserLog(Neo4jTriggersPlugin.class);
}
@Override
public Object beforeCommit(TransactionData transactionData, Transaction transaction, GraphDatabaseService graphDatabaseService) throws Exception {
return null;
}
@Override
public void afterCommit(TransactionData transactionData, Object o, GraphDatabaseService graphDatabaseService) {
log.info("Transaction committed" + transactionData.toString());
}
@Override
public void afterRollback(TransactionData transactionData, Object o, GraphDatabaseService graphDatabaseService) {
}
public class LifecycleManagement extends ExtensionFactory<LifecycleManagement.Dependencies> {
private Log logger;
@Override
public Lifecycle newInstance(ExtensionContext extensionContext, final Dependencies dependencies) {
return new LifecycleAdapter() {
LogService logService = dependencies.log();
private Neo4jTriggersPlugin triggersPlugin;
@Override
public void start() {
System.out.println("STARTING trigger watcher");
triggersPlugin = new Neo4jTriggersPlugin(dependencies.getGraphDatabaseService(), logService);
dependencies.getGraphDatabaseService().registerTransactionEventListener("neo4j", triggersPlugin);
}
@Override
public void shutdown() {
System.out.println("STOPPING trigger watcher");
dependencies.getGraphDatabaseService().unregisterTransactionEventListener("neo4j",triggersPlugin);
}
};
}
interface Dependencies {
DatabaseManagementService getGraphDatabaseService();
LogService log();
}
public LifecycleManagement(Log log) {
super(ExtensionType.DATABASE, "registerTransactionEventHandler");
this.logger = null;
}
I found example here. I went through neo4j documentation about logging, procedures, extensions etc.
After I compile and build the .jar of the above plugin, I copy it into var/lib/neo4j/plugins/ directory and restart the container. Then I run some cypher queries and I do not see any info written in a log. Also I have mounted the /logs and /data/database as volumes.
I would appreciate if someone could explain how this is done corretly or point me to a good source of information. Thanks.
