`lager_logstash`

Logstash backend for lager

Configuration

Add lager and lager_logstash to rebar.config:

{deps, [lager, lager_logstash]}.

Add configuration to sys.config:

{lager, [{ handlers
         , [{ lager_logstash_backend
            , [ {host, "logstash_host"}
              , {port, 9125}
              ]
            }]
         }]
}

Note: Logstash requires timestamps to be in UTC. However, there is no need to do anything special to get this working - lager_logstash does the conversion for you.

Configure a logstash pipeline:

input {
  udp {
    codec => "json"
    port  => 9125
  }
}

output {
  ...
}

Supported options

Option	Default	Acceptable values
`host` (required)	/	`inet:socket_address()` or `inet:hostname()`
`port` (required)	/	`inet:port_number()`
`level`	`info`	`lager:log_level()` - including syslog style comparison flags
`fields`	`[]`	`[{atom(), jsx:json_term()}]` - allows specifying a bunch of extra fields to be included

Output format

All metadata is included as fields. Code like this:

-module foo

-export([bar/0]).

bar () ->
  lager:info([{foo, bar}], "Hello ~s", ["world"]).

Would result in JSON like this:

{
  "message": "Hello world",
  "@timestamp": "2019-01-13T21:33:56.925Z",
  "fields": {
    "severity": "info",
    "foo": "bar",
    "application": "otp_application",
    "node": "some_node@localhost",
    "pid": "<0.13919.0>",
    "module": "foo",
    "function": "bar",
    "line": "6"
  }
}

License

Released under the MIT license - please see the LICENSE file.