logger モジュール

voluntas

モチベーション

そろそろ lager から卒業して、公式の logger に移行したので、その記録。

ドキュメント

ユーザズガイド

リファレンスモジュール

voluntas

動かす

erl -kernel logger_level info
Erlang/OTP 25 [RELEASE CANDIDATE 1] [erts-13.0] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit]

=PROGRESS REPORT==== 3-Mar-2022::19:22:21.731352 ===
    application: kernel
    started_at: nonode@nohost

=PROGRESS REPORT==== 3-Mar-2022::19:22:21.737612 ===
    application: stdlib
    started_at: nonode@nohost

=PROGRESS REPORT==== 3-Mar-2022::19:22:21.743016 ===
    supervisor: {local,kernel_safe_sup}
    started: [{pid,<0.78.0>},
              {id,disk_log_sup},
              {mfargs,{disk_log_sup,start_link,[]}},
              {restart_type,permanent},
              {significant,false},
              {shutdown,1000},
              {child_type,supervisor}]

=PROGRESS REPORT==== 3-Mar-2022::19:22:21.743096 ===
    supervisor: {local,kernel_safe_sup}
    started: [{pid,<0.79.0>},
              {id,disk_log_server},
              {mfargs,{disk_log_server,start_link,[]}},
              {restart_type,permanent},
              {significant,false},
              {shutdown,2000},
              {child_type,worker}]

Eshell V13.0  (abort with ^G)
1>

voluntas

ログの時間を UTC にする

2> logger:set_handler_config(default, formatter, {logger_formatter, #{}}).
ok
3> logger:error("Oh noes, another error").
2022-03-03T19:27:53.213144+09:00 error: Oh noes, another error
ok
4> logger:set_handler_config(default, formatter, {logger_formatter, #{time_offset => "Z"}}).
ok
5> logger:error("Oh noes, another error").
2022-03-03T10:27:57.570802Z error: Oh noes, another error

logger_formatter で time_offset を "Z" に指定する。

voluntas

logger の handlers を見る

Eshell V13.0  (abort with ^G)
1> logger:i(handlers).
Handler configuration:
    Id: default
        Module: logger_std_h
        Level:  all
        Formatter:
            Module: logger_formatter
            Config:
                legacy_header: true
                single_line: false
        Filter Default: stop
        Filters:
            Id: remote_gl
                Fun: fun logger_filters:remote_gl/2
                Arg: stop
            Id: domain
                Fun: fun logger_filters:domain/2
                Arg: {log,super,[otp,sasl]}
            Id: no_domain
                Fun: fun logger_filters:domain/2
                Arg: {log,undefined,[]}
        Handler Config:
            burst_limit_enable: true
            burst_limit_max_count: 500
            burst_limit_window_time: 1000
            drop_mode_qlen: 200
            filesync_repeat_interval: no_repeat
            flush_qlen: 1000
            overload_kill_enable: false
            overload_kill_mem_size: 3000000
            overload_kill_qlen: 20000
            overload_kill_restart_after: 5000
            sync_mode_qlen: 10
            type: standard_io
ok

voluntas

独自フォーマッターを作る

OTP でいくつか独自フォーマッターを定義しているので、参考にする。

voluntas

metadata を設定

template で指定できるフォーマット。

template() =
    [metakey() |
     {metakey(), template(), template()} |
     unicode:chardata()]

1> logger:set_handler_config(default, formatter, {logger_formatter, #{template => [{pid, ["pid=", pid], []}, "\n"], single_line => true, time_offset => "Z"}}).
ok
2> logger:error("Oh noes, another error", [], #{pid => pid_to_list(self())}).
pid=<0.84.0>
ok

11> logger:set_process_metadata(#{a => 10}).
ok
12> logger:error("Oh noes, another error", [], #{}).
pid=<0.84.0>10
ok