# GRPCClientPool Elixir
[](https://hex.pm/packages/grpc_client_pool)
A connection pooling library to be used along with [grpc](https://github.com/elixir-grpc/grpc) to create a connection pool of gRPC clients
## Installation
The package can be installed with:
```elixir
def deps do
[
{:grpc_client_pool, "~> 0.0.1-beta"}
]
end
```
## Usage
1. Follow [grpc](https://github.com/elixir-grpc/grpc) instructions on how to generate the elixir code
2. Create a module in your app that will act as a client and make it use the connection pool:
```elixir
defmodule MyApp.GRPCClient do
use GRPCClientPool,
otp_app: :my_app
end
```
3. Configure the client:
```elixir
config :my_app, MyApp.GRPCClient,
size: 2,
max_overflow: 10,
url: "localhost:50051",
connect_opts: []
```
4. Add client requests within your new module:
```elixir
defmodule MyApp.GRPCClient do
use GRPCClientPool,
otp_app: :my_app
alias GeneratedProto.ApiInput
alias GeneratedProto.ApiService.Stub
def remote_function(%ApiInput{} = params) do
with_channel(fn channel ->
Stub.remote_function(channel, params)
end)
end
end
```
## Options
The available configuration parameters are:
| Name | Default | Required | Description |
|---------------------|-----------|------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| size | 2 | false | Poolboy size parameter |
| max_overflow | 10 | false | Poolboy max_overflow parameter |
| url | nil | true | The url to be used as first argument of `GRPC.Stub.connect/2`. Can be either a string or {:system, "ENV"} or {:system, "ENV", "default"} to load the value from an env variable |
| connect_opts | [] | false | The second argument passed to `GRPC.Stub.connect/2` |
| reconnect_interval | 5000 | false | If the initial connection doesn't succeed, retry after `reconnect_interval` ms |
## TODO
- [ ] Better naming logic for poolboy's pool
- [ ] Tests
- [ ] Configurable checkout timeout
- [ ] Better way of getting channel
- [x] Handle connection errors
- [ ] Module docs
