# PlugLoggerJson
[](https://hex.pm/packages/plug_logger_json)
[](https://travis-ci.org/bleacherreport/plug_logger_json)
[](https://github.com/bleacherreport/plug_logger_json/blob/master/LICENSE)
A comprehenisve JSON logger Plug.
## Dependencies
* Plug
* Poison
## Elixir & Erlang Support
* The support policy is to support the last 2 major versions of Erlang and the three last minor versions of Elixir.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed as:
1. Add plug_logger_json to your list of dependencies in `mix.exs`:
def deps do
[{:plug_logger_json, "~> 0.5.0"}]
end
2. Ensure plug_logger_json is started before your application:
def application do
[applications: [:plug_logger_json]]
end
3. Replace `Plug.Logger` with `Plug.LoggerJSON, log: Logger.level` in your plug pipeline (endpoint.ex for phoenix apps)
or for extra attributes (see extra attributes section)
3. Replace `Plug.Logger` with `Plug.LoggerJSON, log: Logger.level, extra_attributes_fn: &MyPlug.extra_attributes/1` in your plug pipeline (endpoint.ex for phoenix apps)
## Recommended Setup
* Configure this application
* Add to your `config/config.exs` or `config/env_name.exs` ONLY if you want to filter params or headers:
config :plug_logger_json,
filtered_keys: ["password", "authorization"],
* Configure the logger (console)
* Add to your `config/config.exs` or `config/env_name.exs`:
config :logger, :console,
format: "$message\n",
level: :info, #You may want to make this an env variable to change verbosity of the logs
metadata: [:request_id]
* Configure the logger (file)
* Add `{:logger_file_backend, "~> 0.0.7"}` to your mix.exs
* Run `mix deps.get`
* Add to your `config/config.exs` or `config/env_name.exs`:
config :logger, format: "$message\n", backends: [{LoggerFileBackend, :log_file}, :console]
config :logger, :log_file,
format: "$message\n",
level: :info,
metadata: [:request_id],
path: "log/my_pipeline.log"
* Ensure you are using Plug.Parsers (Phoenix adds this to endpoint.ex by default) to parse params & req bodies
plug Plug.Parsers,
parsers: [:urlencoded, :multipart, :json],
pass: ["*/*"],
json_decoder: Poison
## Error Logging
* In router.ex of your phoenix project or your plug pipeline
* Add `require Logger`
* Add `use Plug.ErrorHandler`
* Add the following two private functions:
defp handle_errors(%Plug.Conn{status: 500} = conn, %{kind: kind, reason: reason, stack: stacktrace}) do
Plug.LoggerJSON.log_error(kind, reason, stacktrace)
send_resp(conn, 500, Poison.encode!(%{errors: %{detail: "Internal server error"}}))
end
defp handle_errors(_, _), do: nil
## Extra Attributes
* Additional data can be logged alongside the request by specifying a function
to call which returns a map:
def extra_attributes(conn) do
map = %{
"user_id" => get_in(conn.assigns, [:user, :user_id]),
"other_id" => get_in(conn.private, [:private_resource, :id]),
"should_not_appear" => conn.private[:does_not_exist]
}
map
|> Enum.filter(&(&1 !== nil))
|> Enum.into(%{})
end
plug Plug.LoggerJSON, log: Logger.level,
extra_attributes_fn: &MyPlug.extra_attributes/1
* In this example, the `:user_id` is retrieved from `conn.assigns.user.user_id`
and added to the log if it exists. In the example, any values that are `nil`
are filtered from the map. It is a requirement that the value is
serialiazable as JSON by the Poison library, otherwise an error will be raised
when attempting to encode the value.
## Log Verbosity
* Plug Logger JSON supports two levels of logging.
* Info / Error will log api_version, date_time, duration, log_type, method, path, request_id, & status.
* Warn / Debug log levels will include everything from info plus client_id, client_version, and params / request bodies.
## Contributing
Before submitting your pull request, please run:
* `mix credo --strict`
* `mix coveralls`
* `mix dialyzer`
* Update Changelog
Please squash your pull request's commits into a single commit with a message and
detailed description explaining the commit.
