Move client/unversioned/remotecommand to client-go

Module remotecommand originally part of kubernetes/pkg/client/unversioned was moved
to client-go/tools, and will be used as authoritative in kubectl, e2e and other places.

Module remotecommand relies on util/exec module which will be copied to client-go/pkg/util

Kubernetes-commit: 2612e0c78ad18ac87bbd200d547100cf99f36089

tools/remotecommand/v2.go

@@ -0,0 +1,195 @@
+/*
+Copyright 2015 The Kubernetes 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 remotecommand
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"sync"
+
+	"k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/client-go/pkg/api"
+)
+
+// streamProtocolV2 implements version 2 of the streaming protocol for attach
+// and exec. The original streaming protocol was metav1. As a result, this
+// version is referred to as version 2, even though it is the first actual
+// numbered version.
+type streamProtocolV2 struct {
+	StreamOptions
+
+	errorStream  io.Reader
+	remoteStdin  io.ReadWriteCloser
+	remoteStdout io.Reader
+	remoteStderr io.Reader
+}
+
+var _ streamProtocolHandler = &streamProtocolV2{}
+
+func newStreamProtocolV2(options StreamOptions) streamProtocolHandler {
+	return &streamProtocolV2{
+		StreamOptions: options,
+	}
+}
+
+func (p *streamProtocolV2) createStreams(conn streamCreator) error {
+	var err error
+	headers := http.Header{}
+
+	// set up error stream
+	headers.Set(api.StreamType, api.StreamTypeError)
+	p.errorStream, err = conn.CreateStream(headers)
+	if err != nil {
+		return err
+	}
+
+	// set up stdin stream
+	if p.Stdin != nil {
+		headers.Set(api.StreamType, api.StreamTypeStdin)
+		p.remoteStdin, err = conn.CreateStream(headers)
+		if err != nil {
+			return err
+		}
+	}
+
+	// set up stdout stream
+	if p.Stdout != nil {
+		headers.Set(api.StreamType, api.StreamTypeStdout)
+		p.remoteStdout, err = conn.CreateStream(headers)
+		if err != nil {
+			return err
+		}
+	}
+
+	// set up stderr stream
+	if p.Stderr != nil && !p.Tty {
+		headers.Set(api.StreamType, api.StreamTypeStderr)
+		p.remoteStderr, err = conn.CreateStream(headers)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (p *streamProtocolV2) copyStdin() {
+	if p.Stdin != nil {
+		var once sync.Once
+
+		// copy from client's stdin to container's stdin
+		go func() {
+			defer runtime.HandleCrash()
+
+			// if p.stdin is noninteractive, p.g. `echo abc | kubectl exec -i <pod> -- cat`, make sure
+			// we close remoteStdin as soon as the copy from p.stdin to remoteStdin finishes. Otherwise
+			// the executed command will remain running.
+			defer once.Do(func() { p.remoteStdin.Close() })
+
+			if _, err := io.Copy(p.remoteStdin, p.Stdin); err != nil {
+				runtime.HandleError(err)
+			}
+		}()
+
+		// read from remoteStdin until the stream is closed. this is essential to
+		// be able to exit interactive sessions cleanly and not leak goroutines or
+		// hang the client's terminal.
+		//
+		// TODO we aren't using go-dockerclient any more; revisit this to determine if it's still
+		// required by engine-api.
+		//
+		// go-dockerclient's current hijack implementation
+		// (https://github.com/fsouza/go-dockerclient/blob/89f3d56d93788dfe85f864a44f85d9738fca0670/client.go#L564)
+		// waits for all three streams (stdin/stdout/stderr) to finish copying
+		// before returning. When hijack finishes copying stdout/stderr, it calls
+		// Close() on its side of remoteStdin, which allows this copy to complete.
+		// When that happens, we must Close() on our side of remoteStdin, to
+		// allow the copy in hijack to complete, and hijack to return.
+		go func() {
+			defer runtime.HandleCrash()
+			defer once.Do(func() { p.remoteStdin.Close() })
+
+			// this "copy" doesn't actually read anything - it's just here to wait for
+			// the server to close remoteStdin.
+			if _, err := io.Copy(ioutil.Discard, p.remoteStdin); err != nil {
+				runtime.HandleError(err)
+			}
+		}()
+	}
+}
+
+func (p *streamProtocolV2) copyStdout(wg *sync.WaitGroup) {
+	if p.Stdout == nil {
+		return
+	}
+
+	wg.Add(1)
+	go func() {
+		defer runtime.HandleCrash()
+		defer wg.Done()
+
+		if _, err := io.Copy(p.Stdout, p.remoteStdout); err != nil {
+			runtime.HandleError(err)
+		}
+	}()
+}
+
+func (p *streamProtocolV2) copyStderr(wg *sync.WaitGroup) {
+	if p.Stderr == nil || p.Tty {
+		return
+	}
+
+	wg.Add(1)
+	go func() {
+		defer runtime.HandleCrash()
+		defer wg.Done()
+
+		if _, err := io.Copy(p.Stderr, p.remoteStderr); err != nil {
+			runtime.HandleError(err)
+		}
+	}()
+}
+
+func (p *streamProtocolV2) stream(conn streamCreator) error {
+	if err := p.createStreams(conn); err != nil {
+		return err
+	}
+
+	// now that all the streams have been created, proceed with reading & copying
+
+	errorChan := watchErrorStream(p.errorStream, &errorDecoderV2{})
+
+	p.copyStdin()
+
+	var wg sync.WaitGroup
+	p.copyStdout(&wg)
+	p.copyStderr(&wg)
+
+	// we're waiting for stdout/stderr to finish copying
+	wg.Wait()
+
+	// waits for errorStream to finish reading with an error or nil
+	return <-errorChan
+}
+
+// errorDecoderV2 interprets the error channel data as plain text.
+type errorDecoderV2 struct{}
+
+func (d *errorDecoderV2) decode(message []byte) error {
+	return fmt.Errorf("error executing remote command: %s", message)
+}