syslog4j stops logging when rsyslog restarted

Question

After a restart of the rsyslog daemon, syslog4j 0.9.46 can no longer successfully write to the syslog without restarting the java process. No exception is thrown and I see no way to check, via the API, whether logging is still working. Is there some way to get syslog4j to recover from a rsyslog restart, or at least throw an exception so that the connection can be manually restarted?

Sample code:

import java.util.Scanner;

import org.productivity.java.syslog4j.SyslogConstants;
import org.productivity.java.syslog4j.SyslogIF;
import org.productivity.java.syslog4j.impl.unix.socket.UnixSocketSyslog;
import org.productivity.java.syslog4j.impl.unix.socket.UnixSocketSyslogConfig;


public class SysLogging {

    public static void main(String[] args) {
        UnixSocketSyslogConfig cfg = new UnixSocketSyslogConfig();
        cfg.setFacility(SyslogConstants.FACILITY_LOCAL1);
        cfg.removeAllMessageModifiers();
        cfg.setIdent(null);
        cfg.setThrowExceptionOnWrite(true);
        cfg.setWriteRetries(5);
        SyslogIF log = new UnixSocketSyslog();
        log.initialize(SyslogConstants.UNIX_SOCKET, cfg);

        Scanner scanner = new Scanner(System.in);
        System.out.println("type quit to quit, anything else to log");
        String line = scanner.nextLine();
        while(!line.equals("quit")) {
            log.info(line);
            System.out.println("type quit to quit, anything else to log");
            line = scanner.nextLine();
        }
        scanner.close();
    }
}

The code above works as you'd think until rsyslog is restarted. At that point no more messages appear in the syslog although everything seems to work otherwise.

score 1 · Accepted Answer · answered Feb 11 '16 at 20:59

Hack similar to this should help:

    SyslogIF log = new UnixSocketSyslog() {
        @Override
        protected void write(int level, byte[] message) throws SyslogRuntimeException {
            if (this.fd == -1)
                connect();
            if (this.fd == -1)
                return;
            ByteBuffer byteBuffer = ByteBuffer.wrap(message);
            int ret = this.libraryInstance.write(this.fd,byteBuffer,message.length);
            if (ret < 0) {
                shutdown();
                connect();
                if (this.fd == -1)
                    return;
                ret = this.libraryInstance.write(this.fd,byteBuffer,message.length);
            }
        }
    };

syslog4j stops logging when rsyslog restarted

1 Answers1