[](code_of_conduct.md)
# hackney_telemetry
`hackney_telemetry` will automatically compute and translate [hackney](https://github.com/benoitc/hackney) metrics to something that [telemetry](https://github.com/beam-telemetry/telemetry) understands.
## Telemetry metrics
The following metrics are exported by this library to telemetry. They will represent the last known value of the metric. They are based on [hackney's metrics](https://github.com/benoitc/hackney#metrics).
|Metric | Tags | Meaning |
|-|-|-|
|`hackney.nb_requests` | - | Current number of requests
|`hackney.finished_requests` | - | Total number of finished requests
|`hackney.total_requests` | - |Total number of requests
|`hackney_pool.free_count`| pool | Number of free sockets in a connection pool
|`hackney_pool.in_use_count`| pool | Number of busy sockets in a connection pool
|`hackney_pool.no_socket`| pool | Count of new connections
|`hackney_pool.queue_count`| pool | Number of requests waiting for a connection in a pool
|`hackney_pool.take_rate`| pool | Rate at which a connection is retrieved from the pool
*Note: metrics for hosts are still not supported*.
## Installation
Install it from [Hex](hex.pm/TheRealReal/hackney_telemetry) or [Github](github.com/TheRealReal/hackney_telemetry).
## Usage
### Configuring Telemetry
You'll likely use `telemetry` together with a reporting library.
**Elixir**
Use it with [Telemetry.Metrics](https://hex.pm/packages/telemetry_metrics) library.
```elixir
defmodule YourApplcation.Telemetry do
import Telemetry.Metrics
def metrics do
[
# other metrics
last_value("hackney.nb_requests"),
last_value("hackney.finished_requests"),
last_value("hackney.total_requests"),
last_value("hackney_pool.free_count", tags: [:pool]),
last_value("hackney_pool.in_use_count", tags: [:pool]),
last_value("hackney_pool.no_socket", tags: [:pool]),
last_value("hackney_pool.queue_count", tags: [:pool]),
last_value("hackney_pool.take_rate", tags: [:pool])
]
end
end
```
### Configuring Hackney
In your application config you need to set hackney's `mod_metrics`:
**Erlang**
```erlang
{hackney, [{mod_metrics, hackney_telemetry}]}
```
**Elixir**
```elixir
config :hackney, mod_metrics: :hackney_telemetry
```
### Options
#### Report interval
By default, workers will report data to telemetry every 1000 milliseconds. You
can change that by setting the `report_interval` option:
**Erlang**
```erlang
{hackney_telemetry, [{report_interval, 2_000}]}
```
**Elixir**
```elixir
config :hackney_telemetry, report_interval: 2_000
```
## Building
To build the source code locally you'll need [rebar3](https://github.com/erlang/rebar3):
```
rebar3 compile
```
## Code of Conduct
This project Contributor Covenant version 2.1. Check [CODE_OF_CONDUCT.md](/CODE_OF_CONDUCT.md) file for more information.
## License
`hackney_telemetry` source code is released under Apache License 2.0.
Check [NOTICE](/NOTICE) and [LICENSE](/LICENSE) files for more information.
