Syslogh NPM | npm.io

Syslogh.js

Syslogh.js is a library for logging to your system's Syslog (RFC 3164) from within Node.js. It provides simple native bindings to <syslog.h> and syslog(3). You're in luck, because it does not come with any bells and whistles. Intentionally. KISS, right?

Works with Node v0.10, v0.11, v0.12 and of course v4 (stable).
Using it in production with Monday Calendar, so will be kept up to date when new Node versions come out.

Installing

Install with: npm install syslogh

Using

Using Syslogh.js is similar to using syslog(3) from C/C++.
First use openlog with your app name (up to 255 characters), options and the facility:

var Syslogh = require("syslogh")
Syslogh.openlog("myapp", Syslogh.PID, Syslogh.LOCAL7)

Then, when logging, just pass in the severity and your message.
Just like with regular syslog(3), you can use sprintf style placeholders. Those internally use Node's built-in Util.format.

Syslogh.syslog(Syslogh.NOTICE, "Freeze-frame high-five.")
Syslogh.syslog(Syslogh.NOTICE, "Phone %d.", 5)

You can also call Syslogh.closelog to close things down, but I'm not sure why you should bother. :-) Exiting your Node.js program will most likely shut everything down, too.

The syslog(3) manpage also talks about setlogmask to filter logs before they're sent. This isn't implemented. Not yet, at least.

Options

Options to pass to openlog come from <syslog.h>.

Option	Description
CONS	Log to the system console on error.
ODELAY	Delay open until `syslog()` is called. (Often default.)
PID	Log the process ID with each message.
NDELAY	Connect to syslog daemon immediately.
NOWAIT	Don't wait for child processes.

Access them as constants. E.g. Syslogh.PID.
They form a bit mask, so to pass multiple of them to openlog, binary-OR them together with the | operator:

Syslogh.openlog("myapp", Syslogh.PID | Syslogh.NDELAY, Syslogh.LOCAL7)

Facilities

Facilities to pass to openlog come from <syslog.h> and (RFC 3164).
Some facilities might differ between systems. For your own app use, best stick to LOCAL* facilities.

Facility	Description
KERN	Kernel messages.
USER	User-level messages.
MAIL	Mail system.
DAEMON	System daemons.
AUTH	Security/authorization messages.
SYSLOG	Messages generated internally by syslogd.
LPR	Line printer subsystem.
NEWS	Network news subsystem.
UUCP	UUCP subsystem.
CRON	Clock daemon.
AUTHPRIV	Security/authorization messages.
LOCAL0	Local use 0.
LOCAL1	Local use 1.
LOCAL2	Local use 2.
LOCAL3	Local use 3.
LOCAL4	Local use 4.
LOCAL5	Local use 5.
LOCAL6	Local use 6.
LOCAL7	Local use 7.

Access them as constants. E.g. Syslogh.LOCAL7.

Severities

Severities to pass to syslog come from <syslog.h> and (RFC 3164).

Severity	Description
EMERG	System is unusable.
ALERT	Action must be taken immediately.
CRIT	Critical conditions.
ERR	Error conditions.
WARNING	Warning conditions.
NOTICE	Normal but significant.
INFO	Informational messages.
DEBUG	Debug-level messages.

Access them as constants. E.g. Syslogh.NOTICE.

License

Syslogh.js is released under a Lesser GNU Affero General Public License, which in summary means:

You can use this program for no cost.
You can use this program for both personal and commercial reasons.
You do not have to share your own program's code which uses this program.
You have to share modifications (e.g. bug-fixes) you've made to this program.

For more convoluted language, see the LICENSE file.