Honeybadger for Elixir

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Getting Started

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1. Install the package

Prerequisites: minimum of Elixir 1.0 and Erlang 18.0

Add the Honeybadger package to deps/0 and application/0 in your application's mix.exs file and run mix do deps.get, deps.compile

defp application do
 [applications: [:honeybadger, :logger]]
end

defp deps do
  [{:honeybadger, "~> 0.7"}]
end

2. Set your API key and environment name

By default the environment variable HONEYBADGER_API_KEY will be used to find your API key to the Honeybadger API. If you would like to specify your key or any other configuration options a different way, you can do so in config.exs:

config :honeybadger,
  api_key: "sup3rs3cr3tk3y"

We also need to set the name of the environment for each environment. This ensures that we can accurately report the environment that an error occurs in. You can add something like the following to each of your #{env}.exs files:

config :honeybadger,
  environment_name: :dev

If environment_name is not set we will fall back to the value of Mix.env(). Mix.env() uses the atomized value of the MIX_ENV environment variable and defaults to :dev when the environment variable is not set. This should be good for most setups. If you want to have an environment_name which is different than the Mix.env(), you should set environment_name in your config.exs files for each environment. This ensures that we can give you accurate environment information even during compile time. Explicitly setting the environment_name config takes higher precedence over the Mix.env() value.

3. Enable error reporting

The Honeybadger package can be used as a Plug alongside your Phoenix applications, as a logger backend, or as a standalone client for sprinkling in exception notifications where they are needed.

Phoenix and Plug

The Honeybadger Plug adds a Plug.ErrorHandler to your pipeline. Simply use the Honeybadger.Plug module inside of a Plug or Phoenix.Router and any crashes will be automatically reported to Honeybadger. It's best to use Honeybadger.Plug after the Router plugs so that exceptions due to non-matching routes are not reported to Honeybadger.

Phoenix app
defmodule MyPhoenixApp.Router do
  use Crywolf.Web, :router
  use Honeybadger.Plug

  pipeline :browser do
    [...]
  end
end
Plug app
defmodule MyPlugApp do
  use Plug.Router
  use Honeybadger.Plug

  [... the rest of your plug ...]
end

Logger

Just set the use_logger option to true in your application's config.exs and you're good to go! Any SASL compliant processes that crash will send an error report to the Honeybadger.Logger. After the error reaches the logger we take care of notifying Honeybadger for you!

Manual reporting

You can manually report rescued exceptions with the Honeybadger.notify function.

try do
  File.read! "this_file_really_should_exist_dang_it.txt"
rescue
  exception ->
    Honeybadger.notify(exception)
end

Configuration

You can set configuration options in config.exs. It looks like this:

config :honeybadger,
  api_key: "sup3rs3cr3tk3y",
  environment_name: :prod

Here are all of the options you can pass in the keyword list:

Name Description Default
app Name of your app's OTP Application as an atom Mix.Project.config[:app]
api_key Your application's Honeybadger API key System.get_env("HONEYBADGER_API_KEY"))
environment_name (required) The name of the environment your app is running in. nil
exclude_envs Environments that you want to disable Honeybadger notifications [:dev, :test]
hostname Hostname of the system your application is running on :inet.gethostname
origin URL for the Honeybadger API "https://api.honeybadger.io"
project_root Directory root for where your application is running System.cwd/0
filter Module implementing Honeybadger.Filter to filter data before sending to Honeybadger.io Honeybadger.Filter.Default
filter_keys A list of keywords (atoms) to filter. Only valid if filter is Honeybadger.Filter.Default [:password, :credit_card]
filter_args If true, will remove function arguments in backtraces true
filter_disable_url If true, will remove the request url false
filter_disable_session If true, will remove the request session false
filter_disable_params If true, will remove the request params false
notice_filter Module implementing Honeybadger.NoticeFilter. If nil, no filtering is done. Honeybadger.NoticeFilter.Default
use_logger Enable the Honeybadger Logger for handling errors outside of web requests true

Public Interface

Honeybadger.notify: Send an exception to Honeybadger.

Use the Honeybadger.notify/2 function to send exception information to the collector API. The first parameter is the exception and the second parameter is the context/metadata. There is also a Honeybadger.notify/1 which doesn't require the second parameter.

Examples:

try do
  File.read! "this_file_really_should_exist_dang_it.txt"
rescue
  exception ->
    context = %{user_id: 5, account_name: "Foo"}
    Honeybadger.notify(exception, context)
end


Honeybadger.context/1: Set metadata to be sent if an error occurs

Honeybadger.context/1 is provided for adding extra data to the notification that gets sent to Honeybadger. You can make use of this in places such as a Plug in your Phoenix Router or Controller to ensure useful debugging data is sent along.

Examples:

def MyPhoenixApp.Controller
  use MyPhoenixApp.Web, :controller

  plug :set_honeybadger_context

  def set_honeybadger_context(conn, _opts) do
    user = get_user(conn)
    Honeybadger.context(user_id: user.id, account: user.account.name)
    conn
  end
end

Honeybadger.context/1 stores the context data in the process dictionary, so it will be sent with errors/notifications on the same process. The following Honeybadger.notify/1 call will not see the context data set in the previous line.

Honeybadger.context(user_id: 5)
Task.start(fn ->
  # this notify does not see the context set earlier
  # as this runs in a different elixir/erlang process.
  Honeybadger.notify(%RuntimeError{message: "critical error"})
end)


Sample Application

If you'd like to see the module in action before you integrate it with your apps, check out our sample Phoenix application.

You can deploy the sample app to your Heroku account by clicking this button:

Deploy

Don't forget to destroy the Heroku app after you're done so that you aren't charged for usage.

The code for the sample app is available on Github, in case you'd like to read through it, or run it locally.