# 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, "~> 1.0"}]

## 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`.

Then add `LoggerTelegramBackend` to the `:backends` configuration, configure
the telegram `chat_id` and bot `token`:

config :logger, backends: [LoggerTelegramBackend, :console]

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

The logger configuration is read at runtime from the application environment so
that you can provide it via
[distillerys]( dynamic configuration
with environment variables.

### Options

The following options are available:

* `:level` - the level to be logged by this backend (either `:debug`,
  `:info`, `:warn` or `:error`). Note that messages are filtered by the
  general `:level` configuration for the `:logger` application first. If not
  explicitly configured all levels are logged.
* `:metadata` - the metadata to be included in the telegram message. Defaults
  to `[:line, :function, :module, :application, :file]`. Setting `:metadata`
  to `:all` gets all metadata.
* `:metadata_filter` - the metadata which is required in order for a message
  to be logged. Example: `metadata_filter: [application: :ui]`.

#### Example

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

### Multiple logger handlers

Like the
multiple logger handlers may be configured, each with different `:chat_id`s,
`:level`s etc. Each handler has to be configured as a separate logger backend:

config :logger,
  backends: [
    {LoggerTelegramBackend, :telegram_filter},
    {LoggerTelegramBackend, :telegram_level},

config :logger, :telegram_filter,
  chat_id: "$chatId",
  token: "$botToken",
  metadata_filter: [application: :ui],
  metadata: [:line, :function, :module, :pid]

config :logger, :telegram_level,
  chat_id: "$chatId",
  token: "$botToken",
  level: :warn,