portforward

README

A Go library for creating port forwards into pods running in a Kubernetes cluster.

This code is heavily inspired by the implementations in kubectl, fission, and helm:

• https://github.com/kubernetes/helm/blob/master/pkg/kube/tunnel.go
• https://github.com/kubernetes/kubernetes/blob/master/pkg/kubectl/cmd/portforward.go
• https://github.com/fission/fission/blob/master/fission/portforward/portforward.go

See godoc.org for full documentation.

Example

A minimal example which will forward to the

package main

import (
	"log"
	"time"
	"github.com/justinbarrick/go-k8s-portforward"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

func main() {
	pf, err := portforward.NewPortForwarder("default", metav1.LabelSelector{
		MatchLabels: map[string]string{
			"app": "nginx",
		},
	}, 80)
	if err != nil {
		log.Fatal("Error setting up port forwarder: ", err)
	}

	err = pf.Start()
	if err != nil {
		log.Fatal("Error starting port forward: ", err)
	}

	log.Printf("Started tunnel on %d\n", pf.ListenPort)
	time.Sleep(60 * time.Second)
}

Also see cmd/main.go.

Kubeconfig

By default, it will load a Kubernetes configuration file from ~/.kube/config or $KUBECONFIG.

It is possible to provide your own Kubernetes client by instantiating the PortForward struct directly instead of calling the NewPortForwarder method.

Documentation

Index

• type PortForward
  • func NewPortForwarder(namespace string, labels metav1.LabelSelector, port int) (*PortForward, error)
  • func (p *PortForward) Start(ctx context.Context) (listenPort int, err error)
  • func (p *PortForward) Stop()

Types

type PortForward

type PortForward struct {
	// The parsed Kubernetes configuration file.
	Config *rest.Config
	// The initialized Kubernetes client.
	Clientset kubernetes.Interface
	// The pod name to use, required if Labels is empty.
	Name string
	// The labels to use to find the pod.
	Labels metav1.LabelSelector
	// The port on the pod to forward traffic to.
	DestinationPort int
	// The port that the port forward should listen to, random if not set.
	ListenPort int
	// The namespace to look for the pod in.
	Namespace string
	// contains filtered or unexported fields
}

Used for creating a port forward into a Kubernetes pod in a Kubernetes cluster.

func NewPortForwarder

func NewPortForwarder(namespace string, labels metav1.LabelSelector, port int) (*PortForward, error)

Initialize a port forwarder, loads the Kubernetes configuration file and creates the client. You do not need to use this function if you have a client to use already - the PortForward struct can be created directly.

func (*PortForward) Start

func (p *PortForward) Start(ctx context.Context) (listenPort int, err error)

Start a port forward to a pod - blocks until the tunnel is ready for use.

func (*PortForward) Stop

func (p *PortForward) Stop()

Stop a port forward.