forked from istio/istio
/
port_forwarder.go
126 lines (109 loc) · 3.54 KB
/
port_forwarder.go
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// Copyright 2018 Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package kube
import (
"bytes"
"fmt"
"io"
"net/http"
"os"
"regexp"
v1 "k8s.io/api/core/v1"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/portforward"
"k8s.io/client-go/transport/spdy"
)
var (
outputBufferSize = 4096
// Used to extract the first match from the regexes below. If the indexes of the two regexes ever diverge
// we'l need an index per type.
addressMatchIndex = 1
forwardRegexIPv4 = regexp.MustCompile(`Forwarding from (127.0.0.1:[0-9]+) -> ([0-9]+)`)
forwardRegexIPv6 = regexp.MustCompile(`Forwarding from (\[::1]:[0-9]+) -> ([0-9]+)`)
)
// PortForwarder manages the forwarding of a single port.
type PortForwarder interface {
io.Closer
// Start the forwarder.
Start() error
// Address returns the local forwarded address. Only valid while the forwarder is running.
Address() string
}
type defaultPortForwarder struct {
forwarder *portforward.PortForwarder
stopCh chan struct{}
readyCh <-chan struct{}
address string
output *bytes.Buffer
}
func (f *defaultPortForwarder) Start() error {
errCh := make(chan error)
go func() {
errCh <- f.forwarder.ForwardPorts()
}()
select {
case err := <-errCh:
return fmt.Errorf("failure running port forward process: %v", err)
case <-f.readyCh:
address, err := parseAddress(f.output.String())
if err != nil {
return err
}
f.address = address
return nil
}
}
func (f *defaultPortForwarder) Address() string {
return f.address
}
func (f *defaultPortForwarder) Close() error {
close(f.stopCh)
f.forwarder.Close()
return nil
}
func newPortForwarder(restConfig *rest.Config, pod v1.Pod, localPort, remotePort uint16) (PortForwarder, error) {
restClient, err := rest.RESTClientFor(restConfig)
if err != nil {
return nil, err
}
req := restClient.Post().Resource("pods").Namespace(pod.Namespace).Name(pod.Name).SubResource("portforward")
serverURL := req.URL()
roundTripper, upgrader, err := spdy.RoundTripperFor(restConfig)
if err != nil {
return nil, fmt.Errorf("failure creating roundtripper: %v", err)
}
dialer := spdy.NewDialer(upgrader, &http.Client{Transport: roundTripper}, http.MethodPost, serverURL)
stopCh := make(chan struct{})
readyCh := make(chan struct{})
output := bytes.NewBuffer(make([]byte, 0, outputBufferSize))
fw, err := portforward.New(dialer, []string{fmt.Sprintf("%d:%d", localPort, remotePort)}, stopCh, readyCh, output, os.Stderr)
if err != nil {
return nil, fmt.Errorf("failed establishing port-forward: %v", err)
}
return &defaultPortForwarder{
forwarder: fw,
stopCh: stopCh,
readyCh: readyCh,
output: output,
}, nil
}
func parseAddress(output string) (string, error) {
// TODO: improve this when we have multi port inputs.
if matches := forwardRegexIPv4.FindStringSubmatch(output); matches != nil {
return matches[addressMatchIndex], nil
} else if matches = forwardRegexIPv6.FindStringSubmatch(output); matches != nil {
return matches[addressMatchIndex], nil
}
return "", fmt.Errorf("failed to get address from output: %s", output)
}