Shim extension for containerd

Rust crate to ease runtime v2 shim implementation.

It replicates same shim.Run API offered by containerd's shim v2 runtime implementation written in Go.

Look and feel

The API is very similar to the one offered by Go version:

```rust struct Service { exit: shim::ExitSignal, }

impl shim::Shim for Service { fn new( _id: &str, _namespace: &str, _publisher: shim::RemotePublisher, _config: &mut shim::Config, exit: shim::ExitSignal, ) -> Self { Service { exit } }

fn start_shim(&mut self, _opts: shim::StartOpts) -> Result<String, Box<dyn Error>> {
    let address = shim::spawn(opts)?;
    Ok(address)
}

}

impl shim::Task for Service { fn create( &self, _ctx: &TtrpcContext, _req: api::CreateTaskRequest, ) -> TtrpcResult { // New task nere... Ok(api::CreateTaskResponse::default()) }

fn connect(
    &self,
    _ctx: &TtrpcContext,
    _req: api::ConnectRequest,
) -> TtrpcResult<api::ConnectResponse> {
    info!("Connect request");
    Ok(api::ConnectResponse {
        version: String::from("example"),
        ..Default::default()
    })
}

fn shutdown(&self, _ctx: &TtrpcContext, _req: api::ShutdownRequest) -> TtrpcResult<api::Empty> {
    info!("Shutdown request");
    self.exit.signal(); // Signal to shutdown shim server
    Ok(api::Empty::default())
}

}

fn main() { shim::run::("io.containerd.empty.v1") }

```

How to use with containerd

Note: All operations are in the root directory of rust-extensions.

With shim v2 runtime:

bash $ cargo build --example empty_shim $ sudo cp ./target/debug/examples/empty_shim /usr/local/bin/containerd-shim-empty-v1 $ sudo ctr run --rm --runtime io.containerd.empty.v1 -t docker.io/library/hello-world:latest hello

Or if on 1.6+

bash $ cargo build --example empty_shim $ sudo ctr run --rm --runtime ./target/debug/examples/empty_shim docker.io/library/hello-world:latest hello

Or manually:

``` $ touch log

Run containerd in background

$ sudo TTRPCADDRESS="/var/run/containerd/containerd.sock.ttrpc" \ cargo run --example emptyshim -- \ -namespace default \ -id 1234 \ -address /var/run/containerd/containerd.sock \ -publish-binary ./bin/containerd \ start unix:///var/run/containerd/eb8e7d1c48c2a1ec.sock

$ cargo build --example shim-proto-connect $ sudo ./target/debug/examples/shim-proto-connect unix:///var/run/containerd/eb8e7d1c48c2a1ec.sock Connecting to unix:///var/run/containerd/eb8e7d1c48c2a1ec.sock... Sending Connect request... Connect response: version: "example" Sending Shutdown request... Shutdown response: ""

$ cat log [INFO] server listen started [INFO] server started [INFO] Shim successfully started, waiting for exit signal... [INFO] Connect request [INFO] Shutdown request [INFO] Shutting down shim instance [INFO] close monitor [INFO] listener shutdown for quit flag [INFO] ttrpc server listener stopped [INFO] listener thread stopped [INFO] begin to shutdown connection [INFO] connections closed [INFO] reaper thread exited [INFO] reaper thread stopped ```

Supported Platforms

Currently following OSs and hardware architectures are supported, and more efforts are needed to enable and validate other OSs and architectures. - Linux - Mac OS - x86_64