# KomachiHeartbeat
🚅Vital monitoring Elixir Web application.🚄
[](https://hex.pm/packages/komachi_heartbeat)
[](https://travis-ci.org/ne-sachirou/ex_komachi_heartbeat)
[](https://coveralls.io/github/ne-sachirou/ex_komachi_heartbeat)
This respects Rails's [KomachiHeartbeat](https://rubygems.org/gems/komachi_heartbeat).
## Usage
Mount KomachiHeartbeat at any path. We mount it for example at `/ops` below.
In Plug app. [example][plug example]
```elixir
defmodule Example.Router do
use Plug.Router
plug(:match)
plug(:dispatch)
forward("/ops", to: KomachiHeartbeat)
end
```
In Phoenix app. [example][phoenix example]
```elixir
defmodule ExampleWeb.Router do
use ExampleWeb, :router
forward("/ops", KomachiHeartbeat)
end
```
KomachiHeartbeat provides 2 endpoints.
- `GET /MOUNT_PATH/heartbeat` : Monitor the server is OK. Response `200 "heartbeat:ok"` or `503 "heartbeat:NG"`.
- `GET /MOUNT_PATH/stats` : Monitor the server statistics. Response `200 JSON` or `503 JSON`.
## Extend KomachiHeartbeat
You can extend KomachiHeartbeat to write vital plugins. Vital plugins should implement `KomachiHeartbeat.Vital`.
```elixir
defmodule ExampleVital do
alias KomachiHeartbeat.Vital
@behaviour Vital
@impl Vital
def init, do: nil
@impl Vital
def stats, do: {:ok, %{example: 42}}
@impl Vital
def vital, do: :ok
end
```
Add this at config. In Plug app :
```elixir
forward("/ops", to: KomachiHeartbeat, init_opts: [vitals: []])
```
In Phoenix app :
```elixir
forward("/ops", KomachiHeartbeat, vitals: [])
```
Now `GET /MOUNT_PATH/heartbeat` calls `ExampleVital.vital/0` & response `heartbeat:ok`.
`GET /MOUNT_PATH/stats` calls `ExampleVital.stats/0` & response `{"example": 42}`.
## BeamVital
We have a vital to observe BEAM VM. It's `BeamVital`.
To config this, in Plug app :
```elixir
forward("/ops", to: KomachiHeartbeat, init_opts: [vitals: [KomachiHeartbeat.BeamVital]])
```
In Phoenix app :
```elixir
forward("/ops", KomachiHeartbeat, vitals: [KomachiHeartbeat.BeamVital])
```
Then `GET /MOUNT_PATH/stats` responses JSON like this.
```json
{
"context_switches": 118,
"gc": {
"count": 28,
"words_reclaimed": 10385
},
"io": {
"in": 204,
"out": 228
},
"memory": {
"atom": 804813,
"binary": 587056,
"code": 14787824,
"ets": 8421128,
"processes": 13062992
},
"port_count": 7,
"process_count": 272,
"reductions": 6719,
"run_queue": 1,
"scheduler_usage": {
"1": 1.5975716910296348e-5,
"2": 1.4977518744364708e-5,
"3": 6.3936000063936e-5,
"4": 1.7984155958600475e-5,
"5": 0.0011898428149764476,
"6": 1.6977538716278364e-5,
"7": 2.197613391856444e-5,
"8": 2.1967882955119614e-5,
"9": 3.09616385298615e-5,
"10": 1.9971879593532307e-5,
"11": 1.8977985536777338e-5,
"12": 1.797169458103487e-5,
"13": 1.697179288023305e-5,
"14": 2.49564759060199e-5,
"15": 1.6969421103172084e-5,
"16": 1.3974343106057279e-5
}
}
```
## Installation
Add `:komachi_heartbeat` at `mix.exs`.
```elixir
def deps do
[
{:komachi_heartbeat, "~> 0.5"}
]
end
```
[plug example]: https://github.com/ne-sachirou/ex_komachi_heartbeat/tree/master/examples/plug_example
[phoenix example]: https://github.com/ne-sachirou/ex_komachi_heartbeat/tree/master/examples/phx_example
