# `Honeybadger`
[🔗](https://github.com/honeybadger-io/honeybadger-elixir/blob/v0.30.1/lib/honeybadger.ex#L1)

This module contains the notify macro and context function you can use in
your applications.

### Configuring

By default the `HONEYBADGER_API_KEY` environment variable is used to find
your API key for Honeybadger. You can also manually set your API key by
configuring the `:honeybadger` application. You can see the default
configuration in the `default_config/0` private function at the bottom of
this file.

    config :honeybadger,
      api_key: "mysupersecretkey",
      environment_name: :prod,
      app: :my_app_name,
      exclude_envs: [:dev, :test],
      breadcrumbs_enabled: true,
      ecto_repos: [MyAppName.Ecto.Repo],
      hostname: "myserver.domain.com",
      origin: "https://api.honeybadger.io",
      sasl_logging_only: false,
      proxy: "http://proxy.net:PORT",
      proxy_auth: {"Username", "Password"},
      project_root: "/home/skynet",
      revision: System.get_env("GIT_REVISION"),
      use_logger: true,
      notice_filter: Honeybadger.NoticeFilter.Default,
      filter: Honeybadger.Filter.Default,
      filter_keys: [:password, :credit_card],
      exclude_errors: []

### Notifying

If you use `Honeybadger.Plug` and `Honeybadger.Logger` included in this
library you won't need to use `Honeybadger.notify/2` for manual reporting
very often. However, if you need to send custom notifications you can do so:

    try do
      raise RunTimeError, message: "Oops"
    rescue
      exception ->
        context = %{user_id: 1, account: "A Very Important Customer"}

        Honeybadger.notify(
          exception,
          metadata: context,
          stacktrace: __STACKTRACE__,
          fingerprint: "user-1"
        )
    end

Note that `notify` may be used outside of `try`, but it will use a different
mechanism for getting the current stacktrace. The resulting stacktrace may be
noisier and less accurate.

### Setting Context

You can add an arbitrary map of context that will get sent to the Honeybadger
API when/if an exception occurs in that process. Do keep in mind the process
dictionary is used for retrieving this context so try not to put large data
structures in the context.

    Honeybadger.context(user_id: 1, account: "My Favorite Customer")
    Honeybadger.context(%{user_id: 2, account: "That Needy Customer"})

### Using the Plug

If you're using Phoenix, or any Plug-based Elixir web framework, you can
`use` the `Honeybadger.Plug` module in your Router and all exceptions in web
requests will automatically be reported to Honeybadger.

    defmodule MoneyPrinter.Router do
      use MoneyPrinter.Web, :router
      use Honeybadger.Plug
    end

You can also automatically set useful context on every request by defining
a Plug compatible function:

    defmodule MoneyPrinter.Router do
      use MoneyPrinter.Web, :router
      use Honeybadger.Plug

      plug :set_honeybadger_context

      # your routes

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

### Using the Error Logger

By default the logger is enabled. The logger will automatically receive any
error reports for SASL compliant processes such as `GenServers`, `GenEvents`,
`Agents`, `Tasks` and any process spawned using `proc_lib`. You can disable the
logger by setting `use_logger` to false in your Honeybadger config.

### Using a Notification Filter

Before data is sent to Honeybadger, it is run through a filter which can
remove sensitive fields or do other processing on the data. For basic
filtering the default configuration is equivalent to:

    config :honeybadger,
      filter: Honeybadger.Filter.Default,
      filter_keys: [:password, :credit_card]

This will remove any entries in the context, session, cgi_data and
params that match one of the filter keys. The check is case insensitive
and matches atoms or strings.

If the `Filter.Default` does not suit your needs, you can implement your
own filter. A simple filter looks like:

    defmodule MyApp.MyFilter do
      use Honeybadger.Filter.Mixin

      # drop password fields out of the context Map
      def filter_context(context), do: Map.drop(context, [:password])

      # remove secrets from an error message
      def filter_error_message(message),
        do: Regex.replace(~r/Secret: w+/, message, "Secret: ***")
    end

See `Honeybadger.Filter` for details on implementing your own filter.

### Breadcrumbs

Breadcrumbs allow you to record events along a processes execution path. If
an error is thrown, the set of breadcrumb events will be sent along with the
notice. These breadcrumbs can contain useful hints while debugging.

Breadcrumbs are stored in the logger context, referenced by the calling
process. If you are sending messages between processes, breadcrumbs will not
transfer automatically. Since a typical system might have many processes, it
is advised that you be conservative when storing breadcrumbs as each
breadcrumb consumes memory.

See `Honeybadger.add_breadcrumb` for info on how to add custom breadcrumbs.

### Automatic Breadcrumbs

We leverage the `telemetry` library to automatically create breadcrumbs from
specific events.

#### Phoenix

If you are using `phoenix` (>= v1.4.7) we add a breadcrumb from the router
start event.

#### Ecto

We can create breadcrumbs from Ecto SQL calls if you are using `ecto_sql` (>=
v3.1.0). You also must specify in the config which ecto adapters you want to
be instrumented:

    config :honeybadger,
      ecto_repos: [MyApp.Repo]

#### Insights

# `notify_options`

```elixir
@type notify_options() ::
  {:metadata, map()}
  | {:stacktrace, Exception.stacktrace()}
  | {:fingerprint, String.t()}
```

# `add_breadcrumb`

```elixir
@spec add_breadcrumb(String.t(), Honeybadger.Breadcrumbs.Breadcrumb.opts()) :: :ok
```

Stores a breadcrumb item.

Appends a breadcrumb to the notice. Use this when you want to add some custom
data to your breadcrumb trace in effort to help debugging. If a notice is
reported to Honeybadger, all breadcrumbs within the execution path will be
appended to the notice. You will be able to view the breadcrumb trace in the
Honeybadger interface to see what events led up to the notice.

## Breadcrumb with metadata

    Honeybadger.add_breadcrumb("email sent", metadata: %{
      user: user.id, message: message
    })
    => :ok

## Breadcrumb with specified category. This will display a query icon in the interface

    Honeybadger.add_breadcrumb("ETS Lookup", category: "query", metadata: %{
      key: key,
      value: value
    })
    => :ok

# `clear_context`

```elixir
@spec clear_context() :: :ok
```

Clears the context.

Note that because context is stored as logger metadata, clearing the context will clear _all_
metadata.

# `clear_event_context`

```elixir
@spec clear_event_context() :: map()
```

Clears the current event context.

# `context`

```elixir
@spec context() :: map()
```

Retrieves the context that will be sent to the Honeybadger API when an exception occurs in the
current process.

Context is stored as Logger metadata, and is in fact an alias for `Logger.metadata/0`.

# `context`

```elixir
@spec context(map() | keyword()) :: map()
```

Store additional context in the process metadata.

This function will merge the given map or keyword list into the existing metadata, with the
exception of setting a key to `nil`, which will remove that key from the metadata.

Context is stored as Logger metadata.

# `event`

```elixir
@spec event(map()) :: :ok
```

# `event`

```elixir
@spec event(String.t(), map()) :: :ok
```

# `event_context`

```elixir
@spec event_context() :: map()
```

Retrieves the current event context.

# `event_context`

```elixir
@spec event_context(map() | keyword()) :: map()
```

Merges the given map or keyword list into the current event context.

# `get_all_env`

```elixir
@spec get_all_env() :: [{atom(), any()}]
```

Fetch all configuration specific to the :honeybadger application.

This resolves values the same way that `get_env/1` does, so it resolves
:system tuple variables correctly.

## Example

    Honeybadger.get_all_env()
    #=> [api_key: "12345", environment_name: "dev", ...]

# `get_env`

```elixir
@spec get_env(atom()) :: any() | no_return()
```

Fetch configuration specific to the :honeybadger application.

## Example

    Honeybadger.get_env(:exclude_envs)
    #=> [:dev, :test]

# `inherit_event_context`

```elixir
@spec inherit_event_context() :: :already_initialized | :inherited | :not_found
```

Inherits the current event context from a parent process.

# `notify`

```elixir
@spec notify(Honeybadger.Notice.noticeable()) :: :ok
```

Send an exception notification, if reporting is enabled.

This is the primary way to do manual error reporting and it is also used
internally to deliver logged errors.

## Stacktrace

Accessing the stacktrace outside of a rescue/catch is deprecated. Notifications should happen
inside of a rescue/catch block so that the stacktrace can be provided with `__STACKTRACE__`.
Stacktraces _must_ be provided and won't be automatically extracted from the current process.

## Example

    try do
      do_something_risky()
    rescue
      exception ->
        Honeybadger.notify(exception, metadata: %{}, stacktrace: __STACKTRACE__)
    end

Send a notification directly from a string, which will be sent as a
`RuntimeError`:

    iex> Honeybadger.notify("custom error message")
    :ok

Send a notification as a `class` and `message`:

    iex> Honeybadger.notify(%{class: "SpecialError", message: "custom message"})
    :ok

Send a notification as a `badarg` atom:

    iex> Honeybadger.notify(:badarg)
    :ok

If desired additional metadata can be provided as well:

    iex> Honeybadger.notify(%RuntimeError{}, metadata: %{culprit_id: 123})
    :ok

If desired fingerprint can be provided as well:

    iex> Honeybadger.notify(%RuntimeError{}, fingerprint: "culprit_id-123")
    :ok

# `notify`

```elixir
@spec notify(Honeybadger.Notice.noticeable(), [notify_options()] | map()) :: :ok
```

# `notify`

> This function is deprecated. Use Honeybadger.notify/2 instead.

```elixir
@spec notify(Honeybadger.Notice.noticeable(), map(), Exception.stacktrace()) :: :ok
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*