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

Inserting, fetching and pruning of metrics.

## Inserting
Inserting is called by the internal `WriteBuffer`. It can be grouped depending on the buffer configuration inside the backend struct:

- `flush_interval_ms`: Time interval before the write buffer calls the backend
- `max_buffer_size`: Maximum count of events before the write  buffer calls the backend

## Fetching
Fetching is called when rendering metrics in the view. The `filters` argument is a struct with predefined fields: `to`, `from`, `event_name` and `compare`.

## Pruning
Pruning is implemented to keep the datastore clean. Keeping data forever will increase the size of the storage and affect performance.
- `pruner_threshold`: *Example:* `[months: -1]`. Delete events older than a month.
- `pruner_interval_ms`: *Example:* 84_000. Time interval for the pruner process to run. The process simply calls `#prune_events!/2`.

# `t`

```elixir
@type t() :: term()
```

All the types that implement this protocol.

# `insert_event`

# `metric_data`

# `prune_events!`

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