# Glasgow [](https://hex.pm/packages/glasgow) [](https://hexdocs.pm/glasgow/)
An Elixir logger backend for sending logs to [`Grafana Loki`](https://github.com/grafana/loki).
## Installation
The package can be installed by adding `glasgow` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:glasgow, "~> 0.1.0"}
]
end
```
## Configuration
Example of a basic configuration for `config.exs` or `runtime.exs`:
```elixir
config :my_app, :logger, [
{:handler, :glasgow, Glasgow,
%{
config: %{
level: :info,
url: System.get_env("URL", "http://localhost:3100"),
labels: [
{"service_name", "service_1"},
{"env", "env_1"}
]
},
formatter: Logger.Formatter.new()
}}
]
```
Once defined, the handler can be explicitly attached with `add_handlers/1`.
For example, in your `Application.start/2`:
```elixir
@impl true
def start(_type, _args) do
...
:ok = Logger.add_handlers(:my_app)
...
Supervisor.start_link(children, opts)
end
```
#### Advanced Configuration
Elixir `Logger` handlers can be configured with [`filters`](https://hexdocs.pm/logger/Logger.html#module-filtering) and `metadata` to provide control and context.
```elixir
config :my_app, :logger, [
{:handler, :glasgow, Glasgow,
%{
config: %{
level: :info,
url: System.get_env("URL", "http://localhost:3100"),
labels: [
{"service_name", "service_1"},
{"env", "env_1"}
],
metadata: [:my_metadata_key]
},
formatter: Logger.Formatter.new(),
filters: [filter_name: {&MyModule.filter/2, []}]
}}
]
```
## Usage
Once the handler has been configured and attached, logs can be sent to Loki using the standard `Logger` module.
```elixir
Logger.info("Hello, world!")
```
The library also provides a `send/4` function for sending messages directly and bypass the `Logger`.
```elixir
Glasgow.send("http://localhost:3100", [{"label1","value1"}], "message", DateTime.utc_now())
```
## Requirements
The library requires the `Rust` toolchain because it depends on [`Snappyrex`](https://github.com/c2bw/snappyrex) for Snappy compression.
