LoggerTelegramBackend

A logger backend for Telegram.

Installation

Add :logger_telegram_backend to your list of dependencies in mix.exs:

def deps do
  [
    {:logger_telegram_backend, "~> 3.0"},
    {:logger_backends, "~> 1.0"},
    {:hackney, "~> 1.18"},
  ]
end

In your c:Application.start/2 callback, add the LoggerTelegramBackend backend:

@impl true
def start(_type, _args) do
  LoggerBackends.add(LoggerTelegramBackend)

  # ...
end

Configuration

First of all you need to create a Telegram bot. Follow the instructions here to create one and get the token for the bot. Since bots are not allowed to contact users, you need to send a message first. Afterwards, retrieve your chat_id with $ curl -X GET https://api.telegram.org/botYOUR_TOKEN/getUpdates.

Then configure the telegram chat_id and bot token:

config :logger, LoggerTelegramBackend,
  chat_id: "$chatId",
  token: "$botToken"

Options

The following options are available:

• :level - the level to be logged by this backend (either :debug, :info, :warning or :error).

  Note that messages are filtered by the general :level configuration for the :logger application first.

  Default: nil (all levels are logged)

• :metadata - the metadata to be included in the telegram message. Setting :metadata to :all gets all metadata.

  Default: [:line, :function, :module, :application, :file].

• :metadata_filter - the metadata which is required in order for a message to be logged.

  Default: nil

• :client - If you need different functionality for the HTTP client, you can define your own module that implements the LoggerTelegramBackend.HTTPClient behaviour and set client to that module

  Default: LoggerTelegramBackend.HackneyClient

• :hackney_opts

  Default: [pool: :logger_telegram_backend_pool]

• :hackney_pool_max_connections

  Default: 50

• :hackney_pool_timeout

  Default: 5000

Examples

Finch client

1. Add Finch instead of :hackney to your list of dependencies:

    {:finch, "~> 0.16"}
   

2. Add a module that implements the LoggerTelegramBackend.HTTPClient behaviour:

   defmodule MyFinchClient do
     @behaviour LoggerTelegramBackend.HTTPClient
   
     @finch_pool_name MyApp.Finch
   
     @impl true
     def child_spec do
       Finch.child_spec(name: @finch_pool_name)
     end
   
     @impl true
     def request(method, url, headers, body) do
       req = Finch.build(method, url, headers, body)
   
       case Finch.request(req, @finch_pool_name) do
         {:ok, %Finch.Response{status: status, headers: headers, body: body}} ->
           {:ok, status, headers, body}
   
         {:error, reason} ->
           {:error, reason}
       end
     end
   end
   

3. Pass your client module to the :client option:

   config :logger, LoggerTelegramBackend,
     client: MyFinchClient,
     # ...
   

Metadata filter

config :logger, LoggerTelegramBackend,
  chat_id: "$chatId",
  token: "$botToken",
  level: :info,
  metadata: :all
  metadata_filter: [application: :ui]

SOCKS5 proxy

config :logger, LoggerTelegramBackend,
  chat_id: "$chatId",
  token: "$botToken",
  hackney_opts: [
    ssl: [verify: :verify_none],
    hackney: [insecure: true],
    proxy: {:socks5, ~c"127.0.0.1", 9050}
  ]

See the hackney docs for further information.