# Thrift Pool
This library provides a simple way implement [`bb8`](https://crates.io/crates/bb8)
and/or [`r2d2`](https://crates.io/crates/r2d2) Connection Pools
for any [`TThriftClient`](https://docs.rs/thrift/0.15.0/thrift/trait.TThriftClient.html)
## Documenation
- This library is primarily documented on its
[docs.rs](https://docs.rs/thrift-pool/latest/thrift_pool/) page
- Here is a quick example
```rust
use thrift::protocol::{TCompactInputProtocol, TCompactOutputProtocol, TInputProtocol, TOutputProtocol};
use thrift::transport::{
ReadHalf, TFramedReadTransport, TFramedWriteTransport, TTcpChannel, WriteHalf,
};
use thrift_pool::{MakeThriftConnectionFromAddrs, ThriftConnectionManager, ThriftConnection, FromProtocol};
// A typical generated client
struct MyThriftClient<Ip: TInputProtocol, Op: TOutputProtocol> {
i_prot: Ip,
o_prot: Op,
}
// implement this trait so that `MakeThriftConnectionFromAddrs` can create it
impl<Ip: TInputProtocol, Op: TOutputProtocol> FromProtocol for MyThriftClient<Ip, Op> {
type InputProtocol = Ip;
type OutputProtocol = Op;
fn from_protocol(
input_protocol: Self::InputProtocol,
output_protocol: Self::OutputProtocol,
) -> Self {
MyThriftClient {
i_prot: input_protocol,
o_prot: output_protocol,
}
}
}
// implement this trait so that `ThriftConnectionManager` can manage it
impl<Ip: TInputProtocol, Op: TOutputProtocol> ThriftConnection for MyThriftClient<Ip, Op> {
type Error = thrift::Error;
fn is_valid(&mut self) -> Result<(), Self::Error> {
Ok(())
}
fn has_broken(&mut self) -> bool {
false
}
}
// the actual connection type
type Client = MyThriftClient<
TCompactInputProtocol<TFramedReadTransport<ReadHalf<TTcpChannel>>>,
TCompactOutputProtocol<TFramedWriteTransport<WriteHalf<TTcpChannel>>>,
>;
// this works because we implemented FromProtocol for the client
// AND
// because the `Protocol` and `Transport` types used here satisfy the contraints
let manager = ThriftConnectionManager::new(
MakeThriftConnectionFromAddrs::<Client, _>::new("localhost:9090")
);
// this works because we implemented ThriftConnection for the client
let pool = r2d2::Pool::builder().build(manager)?;
// this also works after enabling the `impl-bb8` feature
let pool = bb8::Pool::builder().build(manager).await?;
// the pool can be used just like in r2d2/bb8 documentation
let mut client = pool.get()?;
```
## Examples
- [hbase-thrift](https://github.com/midnightexigent/hbase-thrift-rs): the project from which this
library was extracted. implements Connection Pools for the client generated from the
[HBase Thrift Spec](https://github.com/apache/hbase/tree/master/hbase-thrift/src/main/resources/org/apache/hadoop/hbase/thrift)
- [thrift-pool-tutorial](https://github.com/midnightexigent/thrift-pool-tutorial-rs): implements
Connection Pools for the client used in the official
[thrift tutorial](https://github.com/apache/thrift/tree/master/tutorial)