# Syslog Director

All received messages are written to *stdout* and/or forwarded to remote logging destinations.

![architecture](doc/syslogd.png)

Supported incoming message formats are:
- RFC5424 UDP and TCP
- RFC3164 (BSD) UDP and TCP
- GELF format UDP and TCP (also compressed on UDP)

Supported remote logging destinations are:
- Syslog (RFC5424 over UDP)
- Graylog (GELF over UDP)
- and Grafana Loki (HTTP over TCP).

This software is free to use and is licensed under the [Apache 2.0 License](https://bitbucket.org/mnellemann/syslogd/src/master/LICENSE).

## Usage Instructions

- Install the syslogd package (*.deb* or *.rpm*) from [downloads](https://bitbucket.org/mnellemann/syslogd/downloads/) or build from source.

```text
Usage: syslogd [-dhV] [--[no-]ansi] [--[no-]stdout] [--[no-]tcp] [--[no-]udp]
               [-f=<protocol>] [-p=<num>] [--to-gelf=<uri>] [--to-loki=<url>]
               [--to-syslog=<uri>]
  -d, --debug               Enable debugging [default: 'false'].
  -f, --format=<protocol>   Input format: RFC-5424, RFC-3164 or GELF [default:
                              RFC-3164].
  -h, --help                Show this help message and exit.
      --[no-]ansi           Output in ANSI colors [default: true].
      --[no-]stdout         Output messages to stdout [default: true].
      --[no-]tcp            Listen on TCP [default: true].
      --[no-]udp            Listen on UDP [default: true].
  -p, --port=<num>          Listening port [default: 1514].
      --to-gelf=<uri>       Forward to Graylog <udp://host:port>.
      --to-loki=<url>       Forward to Grafana Loki <http://host:port>.
      --to-syslog=<uri>     Forward to Syslog <udp://host:port> (RFC-5424).
  -V, --version             Print version information and exit.
```

The default syslog port (514) requires you to run syslogd as root / administrator.
Any port number above 1024 does not require privileges and can be selected with the *-p* or *--port* option.

### Examples

Listening on the default syslog port:

```
java -jar /path/to/syslogd-x.y.z-all.jar --port 514
```

or, if installed as a *deb* or *rpm* package:

```
/opt/syslogd/bin/syslogd --port 514
```

Forwarding messages on to another log-system on a non-standard port.

```
java -jar /path/to/syslogd-x.y.z-all.jar --to-syslog udp://remotehost:514
```

Forwarding messages to a Graylog server in GELF format.

```
java -jar /path/to/syslogd-x.y.z-all.jar --to-gelf udp://remotehost:12201
```

Forwarding to a Grafana Loki server.

```
java -jar /path/to/syslogd-x.y.z-all.jar --to-loki http://remotehost:3100
```

If you don't want any output locally (only forwarding), you can use the ```--no-stdout``` flag.


## Notes

### IBM AIX and VIO Servers

Syslog messages from AIX (and IBM Power Virtual I/O Servers) can be troublesome with some logging solutions. These can be received with
*syslogd* and then forwarded on to your preferred logging solution.

### Forwarding to Grafana Loki

Forwarding is currently done by making HTTP connections to the Loki API, which works fine for low volume messages, but might cause issues for large volume of messages.

## Development Notes

### Test Grafana Loki

Run Loki and Grafana in local containers to test.

```shell
docker run --rm -d --name=loki -p 3100:3100 grafana/loki
docker run --rm -d --name=grafana --link loki:loki -p 3000:3000 grafana/grafana:7.1.3
```