logger_webhook_h

This is an OTP logger handler for Erlang that sends a Webhook message for log events.

It uses multipart/form-data, so make sure the receiver supports this.

It's been tested to work fine with Discord.

Usage

Shell example:

logger:add_handler(error_webhook, logger_webhook_h, #{
  config => #{ url => "https://discord.com/api/webhooks/023916370468945/jWxqZRTNWiP9qejPG6-P-z_UG3IVM_7nVt5nWSoir8bEsIV9iWXgIkNcLiBohTFSW" },
  level => warning,
  formatter => {logger_formatter, #{ single_line => false }}
}).

sys.config example:

[
  {kernel, [
    {logger, [
      {handler, error_webhook, logger_webhook_h,
        #{ config => #{ url => "https://discord.com/api/webhooks/12345/chyschmancyid" },
           level => warning,
           formatter => {logger_formatter, #{ single_line => false }}}}
    ]}
  ]}
].

How it looks:

11> logger:debug("this one won't be sent").
=DEBUG REPORT==== 14-Aug-2021::11:52:29.217000 ===
this one won't be sent
ok
12> logger:warning("but this one needs to be known!"). 
=WARNING REPORT==== 14-Aug-2021::11:52:40.114000 ===
but this one needs to be known!
ok
13> logger:warning("There's been a complicated error: ~p", [{#Ref<0.2049192390.542638081.248283>,{http_error,500,#{<<"error">> => <<"Internal Server Error">>,<<"message">> => <<>>,<<"status">> => 500}}}]).  
=WARNING REPORT==== 14-Aug-2021::11:53:52.840000 ===
There's been a complicated error: {#Ref<0.2049192390.542638081.248283>,
                                   {http_error,500,
                                       #{<<"error">> =>
                                             <<"Internal Server Error">>,
                                         <<"message">> => <<>>,
                                         <<"status">> => 500}}}
ok

Caveats

Logging will fail silently if httpc and inets aren't started. This is intentional as alternative behaviors are worse.

The handler will intentionally fail if a non-success response is received when sending the webhook message.