syslogger

A syslog backend for erlang logger.

Usage

The easiest way to use syslogger is to just include it as a dependency in your rebar.config like this:

{deps, [
  {syslogger, "*", {git, "git://github.com/garazdawi/syslogger", {branch, "master"}}}
]}.

The default configuration is then used and any log messages will turn up in the local syslog.

Build Requirements

You need to have Erlang/OTP, a C compiler, rebar3 and the autoconf toolchain installed.

apt-get install build-essential autoconf libtool

Recommended Configuration

If you just want to get started with syslogger, the recommended configuration in the system's sys.config is:

[{kernel, logger, [{handler, default, undefined}]}].
[{syslogger, [
  {log_opts, [cons, pid, perror]},
  {logger, [{handler, default, syslogger,
            #{formatter => {logger_formatter, #{single_line => true}}}}]}
]}].

Configuration

The syslogger application can be used either by configuring the handlers through application variables, or by using the logger:add_handler/2 API.

For instance if you want to add two handlers that log to two different syslog facilities just add this to your sys.config.

[{syslogger, [
  {ident, "myapp"},
  {log_opts, [cons, pid, perror]},
  {logger, [{handler, user_syslogger, syslogger, #{facility => user}},
            {handler, local0_syslogger, syslogger, #{facility => local0}}]
   }
]}].

This will add two syslogger instances to the Erlang logger that use different facilities.

The same effect could have been achieved by using the logger API like this:

logger:add_handler(user_syslogger, syslogger, #{facility => user}),
logger:add_handler(local0_syslogger, syslogger, #{facility => local0}).

Each syslogger handler can be configured using a map with these configuration options:

• facility: The syslog facility to log though.
  • Default: undefined i.e. the default set by openlog or the system default.

The openlog call can get the following init at startup:

• ident: The syslog identifier that is prepended to each log message.
  • Default: The value of init:get_argument(progname).
• facility: The syslog facility to log though.
  • Default: user
• log_opts: The syslog options (as a list) to use.
  • Default: []

For more details of what each of these options do see syslog(3).

Cross Compilation

When cross compiling syslogger you need to set the correct environment variables as you normally would. The configure flags (i.e. --host=, --build= etc) should be passed through the CONFIGURE_FLAGS environment variable. You also have to make sure that the CPPFLAGS include the path to the erlang include files.

Example:

CONFIGURE_FLAGS="--build i686-pc-linux-gnu --host i586-mingw32msvc" CPPFLAGS="-I /cross/compiled/erlang/usr/include" rebar3 compile