ExSyslogger is custom backend for Elixir Logger that logs to syslog by wrapping erlang-syslog.
This project is a fork of exsyslog.
- Elixir ~> 1.3
- Logs to syslog
- Allows adding multiple backends with different configurations (e.g. each backend logs to a different facility with different log level)
- Custom log formatter
- Built-in JSON formatter(
jasondependency is set to optional and you should explicitly add it to your dependency list)
Add :ex_syslogger as a dependency in your mix.exs file
defp deps do
[
{:ex_syslogger, "~> 1.5"}
]
enddefp deps do
[
{:ex_syslogger, "~> 1.3"}
]
endAdd :ex_syslogger to your list of included_applications:
def application do
[included_applications: [:ex_syslogger]]
endIf you going to use JsonFormatter please we sure that jason is added as dependency in your application. For older Elixir versions it might be needed to add it to the list of applications as above.
ExSyslogger is a Logger custom backend, as such, it relies on Logger application.
On your config.exs file tell Logger that it should add ExSyslogger backend
config :logger,
backends: [
{ExSyslogger, :ex_syslogger_error},
{ExSyslogger, :ex_syslogger_debug},
{ExSyslogger, :ex_syslogger_json}
]
With the configuration above, Logger application will add three ExSyslogger backend with the name {ExSyslogger, :ex_syslogger_error}, {ExSyslogger, :ex_syslogger_debug} and {ExSyslogger, :ex_syslogger_json}.
You might notice that instead of just passing the Module name, we're passing a tuple with {Module name, backend configuration name}. This allow us to have multiple backends with different configuration. Let's configure the backends:
config :logger, :ex_syslogger_error,
level: :error,
format: "$date $time [$level] $levelpad$node $metadata $message",
metadata: [:module, :line, :function],
ident: "MyApplication",
facility: :local0,
option: [:pid, :cons]
config :logger, :ex_syslogger_debug,
level: :debug,
format: "$date $time [$level] $message",
ident: "MyApplication",
facility: :local1,
option: [:pid, :perror]
config :logger, :ex_syslogger_json,
level: :debug,
format: "$message",
formatter: ExSyslogger.JsonFormatter,
metadata: [:module, :line, :function],
ident: "MyApplication",
facility: :local1,
option: :pid
- level (optional): the logging level. It defaults to
:info - format (optional): Same as
:consolebackend (Logger.Formatter). It defaults to"\n$date $time [$level] $levelpad$node $metadata $message\n" - formatter (optional): Formatter that will be used to format the log. It default to Logger.Formatter
- metadata (optional): Same as
:consolebackend Logger.Formatter. It defaults to[] - ident (optional): A string that's prepended to every message, and is typically set to the app name. It defaults to
"Elixir" - facility (optional): syslog facility to be used. It defaults to
:local0. More documentation on erlang-syslog - option (optional): syslog option to be used. It defaults to
:ndelay. More documentation on erlang-syslog
ExSyslogger by default uses Logger.Formatter. However, it comes with a JSON formatter that formats a given log entry to a JSON string. NOTE: ExSyslogger.JsonFormatter can be use as an example if one wants to build his own formatter.
To build a custom formatter the formatter needs to implement the following functions:
compile(str)
Compiles a format string
compile(binary | nil) :: [Logger.Formatter.pattern | binary]
compile({atom, atom}) :: {atom, atom}
format(format, level, msg, timestamp, metadata, config_metadata)
Takes a compiled format and transforms it on a string that will be pass to syslog
format({atom, atom} | [Logger.Formatter.pattern | binary], Logger.level, Logger.message, Logger.Formatter.time, Keyword.t, [atom]) :: IO.chardata
To add the custom formatter you will need to set the formatter property on the configuration as exemplified above with ExSyslogger.JsonFormatter
In another shell:
$ tail -f /var/log/syslog
(Mac users)
$ tail -f /var/log/system.log
NOTE Mac has a funny syslog. Your info logs might not show up. You'll need to configure your Mac syslog.
Clone the project, go to examples/examples1 and run the project ($ iex -S mix).
Erlang/OTP 18 [erts-7.0.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
Interactive Elixir (1.0.5) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> Example1.run
2015-09-11 15:26:18.850 [error] nonode@nohost module=Elixir.Example1 function=run/0 line=5 Hello ExSyslogger
:ok
You should see on the tail -f something similar to:
exsyslog_error backend
Sep 11 16:26:18 bt.local MyApplication[12833]: 2015-09-11 15:26:18.850 [error] nonode@nohost module=Elixir.Example1 function=run/0 line=5 Hello ExSyslogger
exsyslog_debug backend
Sep 11 16:26:18 bt.local MyApplication[12833]: 2015-09-11 15:26:18.850 [error] Hello ExSyslogger
exsyslog_json backend
Sep 11 16:26:18 bt.local MyApplication[12833]: {"node":"nonode@nohost","module":"Elixir.Example1","message":"Hello ExSyslogger","line":5,"level":"error","function":"run/0"}
The source code is released under the MIT License. Check LICENSE for more information.
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