# `TelemetryUI`
[🔗](https://github.com/mirego/telemetry_ui/blob/v5.4.0/lib/telemetry_ui.ex#L1)

Main entry point to start all the processes as part of your application.

# Usage
```
use Application

def start(_type, _args) do
  children = [
    Shopcast.Repo,
    MyAppWeb.Endpoint,
    {TelemetryUI, my_config()}
  ]
```
The reporter, write buffer and pruner processes will be part of your supervision tree, ensuring that everything runs smoothly.

The config is a data structure representing all settings used by TelemetryUI.

## Config example

```
  [
    metrics: [
      {"System", [last_value("vm.memory.total", unit: {:byte, :megabyte})]}
    ],
    theme: %{title: "Metrics"},
    backend:
      %TelemetryUI.Backend.EctoPostgres{
        repo: MyApp.Repo,
        pruner_threshold: [months: -1],
        pruner_interval_ms: 3_600_000,
        max_buffer_size: 1_000,
        flush_interval_ms: 10_000
      }
  ]
```

This config will show a basic "last value" chart for the memory usage reported by the VM.
The title of the page will be "Metrics" and the backend used to store and query metrics will be PostgreSQL.
See `TelemetryUI.Config` for a list of all options.

## Metrics list

Every kind of metrics exposed by `TelemetryMetrics` is supported by `TelemetryUI`:
- `last_value`
- `summary`
- `sum`
- `counter`
- `distribution`

`TelemetryUI` also exposes its own set of metrics:
- `average`
- `average_over_time`
- `count_over_time`
- `median`
- `median_over_time`

## The Web
Finally, when the configuration is done and we actually want to see our metrics, we need to add the `TelemetryUI.Web` module in our router:

*Phoenix*
```
scope "/" do
  pipe_through([:browser])
  get("/metrics", TelemetryUI.Web, [], [assigns: %{telemetry_ui_allowed: true}])
end
```

The metrics page is protected by default. It needs to have the `telemetry_ui_allowed` assign to true to render.
We can imagine having a `:admin_protected` plug that ensure a user is an admin and also assign `telemetry_ui_allowed` to true.

```
scope "/" do
  pipe_through([:browser, :admin_protected])
  get("/metrics", TelemetryUI.Web, [])
end
```

That’s it! The `/metrics` page will show the metrics as they are recorded. Checkout the Guides to dive into more complex configuration and awesome features :)

# `backend`

# `child_spec`

Returns a specification to start this module under a supervisor.

See `Supervisor`.

# `config_name`

# `insert_metric_data`

# `metric_by_id`

# `metric_data`

# `page_by_id`

# `page_by_title`

# `pages`

# `reload`

# `start_link`

# `theme`

# `valid_share_key?`

# `valid_share_url?`

# `writer_buffer_name`

---

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