# Stump
[](https://travis-ci.org/bbc/stump)
Stump is an Elixir log wrapper that allows you to pass Maps/Structs into the built in Logger function, returning them in a JSON format and outputting to a file in Production mode.
Providing you with the ability to write more descriptive log messages and send logs to services expecting logs in the json/map format.
The library is not limited to maps, it can also take in strings and create JSON formatted log messages.
Please note, from Version 1.1 Stump will be using Jason as its JSON encoder. This will effect the ordering of logged items.
It is strongly advised that you use version 1.4 of Stump and above, version 1.3 could cause an error to be thrown when trying to encode log messages.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `stump` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:stump, "~> 1.5.0"}
]
end
```
Documentation can be found at [https://hexdocs.pm/stump/Stump.html](https://hexdocs.pm/stump/Stump.html).
## Usage
Once the package has been installed into your project, the following usage is recommended:
```elixir
def foo do
Stump.log(:error, %{message: "Error Logged"})
end
```
Providing you with output in this format:
```elixir
{"message":"Error Logged","level":"error","datetime":"2019-03-06T12:18:24.179731Z"}
:ok
```
You can also pass in strings if you would prefer not to use maps:
```elixir
Stump.log(:error, "Error Logged")
{"message":"Error Logged","level":"error","datetime":"2019-03-06T12:21:52.661587Z"}
```
It can also be nicely used in conjuction with libraries such as [HTTPoison](https://github.com/edgurgel/httpoison)
```elixir
def process(_, {:error, %HTTPoison.Error{reason: reason}}) do
Stump.log(:error, %{message: "Failed to process HTTP request, reason: #{reason}", event: "HTTPoison.Error"})
{:error, reason}
end
```
## Configuration
The default configuration for this will simply log to the console, if you would like to configure it you can simply edit your `config.exs` file.
It is worth noting that you must keep the format as `format: "$message\n"` with whichever logging backend you choose to use otherwise you will get duplication of information.
If for example you would like to Log to a file the following configuration would be recommended:
- First edit your `mix.exs` and add the LoggerFileBackend
```elixir
defp deps do
[
{:logger_file_backend, "~> 0.0.10"}
]
end
```
- Run mix deps.get
- Edit your `config.exs`
```elixir
config :logger,
backends: [{LoggerFileBackend, :file}]
config :logger, :file,
path: "/var/log/my_app/error.log",
format: "$message\n",
level: :debug
```
