Network Service Mesh Forwarder

Overview

The forwarder in Network Service Mesh is responsible for handling the connectivity between the client and the network service endpoint. The following describes what needs to be done from a forwarder-provider point-of-view, so that support for other forwarder "drivers" can be developed in future. It should be considered as a baseline that can be further extended when needed.

Configuration

• Have the following package imported -

"github.com/networkservicemesh/networkservicemesh/forwarder/pkg/common"

• This structure keeps the main forwarder configuration -

type ForwarderConfig struct {
    Name                string
    NSMBaseDir          string
    RegistrarSocket     string
    RegistrarSocketType string
    ForwarderSocket     string
    ForwarderSocketType string
}

• The forwarder instance should implement the NSMForwarder interface expected by CreateForwarder having the following methods - Init(), Close(), Request() and MonitorMechanisms().

• The forwarder is responsible for populating the following base configuration fields - Name, ForwarderSocket and ForwarderSocketType in its Init() handler. They are mandatory in order to proceed with the forwarder setup.

Forwarder example

The following is an example using VPP as a forwarder.

• The configuration will look like -

&ForwarderConfig{
    Name:                "vppagent"
    NSMBaseDir:          "/var/lib/networkservicemesh/"
    RegistrarSocket:     "/var/lib/networkservicemesh/nsm.forwarder-registrar.io.sock"
    RegistrarSocketType: "unix"
    ForwarderSocket:     "/var/lib/networkservicemesh/nsm-vppagent.forwarder.sock"
    ForwarderSocketType: "unix"
}

• This is the main -

func main() {
    // Capture signals to cleanup before exiting
    c := make(chan os.Signal, 1)
    signal.Notify(c,
        syscall.SIGHUP,
        syscall.SIGINT,
        syscall.SIGTERM,
        syscall.SIGQUIT)

    go common.BeginHealthCheck()

    vppagent := vppagent.CreateVPPAgent()

    registration := common.CreateForwarder(vppagent)

    select {
    case <-c:
        logrus.Info("Closing Forwarder Registration")
        registration.Close()
    }
}