Add internal upload to external storage

internal/api/api.go

@@ -66,6 +66,15 @@ func NewAPI(myURL *url.URL, version string, roundTripper *badgateway.RoundTrippe
 
 type HandleFunc func(http.ResponseWriter, *http.Request, *Response)
 
+type RemoteObjectStore struct {
+	// StoreURL is the temporary URL to which upload the first found file
+	StoreURL string
+	// ObjectID is a unique identifier of object storage upload
+	ObjectID string
+	// Timeout is a number that represents timeout in seconds for sending data to StoreURL
+	Timeout int
+}
+
 type Response struct {
 	// GL_ID is an environment variable used by gitlab-shell hooks during 'git
 	// push' and 'git pull'
@@ -83,6 +92,9 @@ type Response struct {
 	// TmpPath is the path where we should store temporary files
 	// This is set by authorization middleware
 	TempPath string
+	// ObjectStore is provided by the GitLab Rails application
+	// and defines a way to store object on remote storage
+	ObjectStore RemoteObjectStore
 	// Archive is the path where the artifacts archive is stored
 	Archive string `json:"archive"`
 	// Entry is a filename inside the archive point to file that needs to be extracted

internal/artifacts/artifacts_store.go

+package artifacts
+
+import (
+	"fmt"
+	"mime/multipart"
+	"net/http"
+	"os"
+	"time"
+
+	"golang.org/x/net/context"
+	"golang.org/x/net/context/ctxhttp"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	DefaultObjectStoreTimeoutSeconds = 360
+)
+
+var (
+	objectStorageUploadRequests = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitlab_workhorse_object_storage_upload_requests",
+			Help: "How many object storage requests have been processed",
+		},
+		[]string{"status"},
+	)
+	objectStorageUploadsOpen = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "gitlab_workhorse_object_storage_upload_open",
+			Help: "Describes many object storage requests are open now",
+		},
+	)
+	objectStorageUploadBytes = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "gitlab_workhorse_object_storage_upload_bytes",
+			Help: "How many bytes were sent to object storage",
+		},
+	)
+	objectStorageUploadTime = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Name:    "gitlab_workhorse_object_storage_upload_time",
+			Help:    "How long it took to upload objects",
+			Buckets: objectStorageUploadTimeBuckets,
+		})
+
+	objectStorageUploadRequestsFileFailed      = objectStorageUploadRequests.WithLabelValues("file-failed")
+	objectStorageUploadRequestsRequestFailed   = objectStorageUploadRequests.WithLabelValues("request-failed")
+	objectStorageUploadRequestsInvalidStatus   = objectStorageUploadRequests.WithLabelValues("invalid-status")
+	objectStorageUploadRequestsSucceeded       = objectStorageUploadRequests.WithLabelValues("succeeded")
+	objectStorageUploadRequestsMultipleUploads = objectStorageUploadRequests.WithLabelValues("multiple-uploads")
+
+	objectStorageUploadTimeBuckets = []float64{.1, .25, .5, 1, 2.5, 5, 10, 25, 50, 100}
+)
+
+func init() {
+	prometheus.MustRegister(
+		objectStorageUploadRequests,
+		objectStorageUploadsOpen,
+		objectStorageUploadBytes)
+}
+
+func (a *artifactsUploadProcessor) storeFile(formName, fileName string, writer *multipart.Writer) error {
+	if a.ObjectStore.StoreURL == "" {
+		return nil
+	}
+
+	if a.stored {
+		objectStorageUploadRequestsMultipleUploads.Inc()
+		return nil
+	}
+
+	started := time.Now()
+	defer func() {
+		objectStorageUploadTime.Observe(time.Since(started).Seconds())
+	}()
+
+	file, err := os.Open(fileName)
+	if err != nil {
+		objectStorageUploadRequestsFileFailed.Inc()
+		return err
+	}
+	defer file.Close()
+
+	fi, err := file.Stat()
+	if err != nil {
+		objectStorageUploadRequestsFileFailed.Inc()
+		return err
+	}
+
+	req, err := http.NewRequest("PUT", a.ObjectStore.StoreURL, file)
+	if err != nil {
+		objectStorageUploadRequestsRequestFailed.Inc()
+		return fmt.Errorf("PUT %q: %v", a.ObjectStore.StoreURL, err)
+	}
+	req.Header.Set("Content-Type", "application/octet-stream")
+	req.ContentLength = fi.Size()
+
+	objectStorageUploadsOpen.Inc()
+	defer objectStorageUploadsOpen.Dec()
+
+	timeout := DefaultObjectStoreTimeoutSeconds
+	if a.ObjectStore.Timeout != 0 {
+		timeout = a.ObjectStore.Timeout
+	}
+
+	ctx, cancelFn := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
+	defer cancelFn()
+
+	resp, err := ctxhttp.Do(ctx, http.DefaultClient, req)
+	if err != nil {
+		objectStorageUploadRequestsRequestFailed.Inc()
+		return fmt.Errorf("PUT request %q: %v", a.ObjectStore.StoreURL, err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		objectStorageUploadRequestsInvalidStatus.Inc()
+		return fmt.Errorf("PUT request %v returned: %d %s", a.ObjectStore.StoreURL, resp.StatusCode, resp.Status)
+	}
+
+	writer.WriteField(formName+".store_url", a.ObjectStore.StoreURL)
+	writer.WriteField(formName+".object_id", a.ObjectStore.ObjectID)
+
+	objectStorageUploadRequestsSucceeded.Inc()
+	objectStorageUploadBytes.Add(float64(fi.Size()))
+
+	// Allow to upload only once using given credentials
+	a.stored = true
+	return nil
+}

internal/artifacts/artifacts_store_test.go

+package artifacts
+
+import (
+	"archive/zip"
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/api"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/testhelper"
+)
+
+func createTestZipArchive(t *testing.T) []byte {
+	var buffer bytes.Buffer
+	archive := zip.NewWriter(&buffer)
+	fileInArchive, err := archive.Create("test.file")
+	require.NoError(t, err)
+	fmt.Fprint(fileInArchive, "test")
+	archive.Close()
+	return buffer.Bytes()
+}
+
+func createTestMultipartForm(t *testing.T, data []byte) (bytes.Buffer, string) {
+	var buffer bytes.Buffer
+	writer := multipart.NewWriter(&buffer)
+	file, err := writer.CreateFormFile("file", "my.file")
+	require.NoError(t, err)
+	file.Write(data)
+	writer.Close()
+	return buffer, writer.FormDataContentType()
+}
+
+func TestUploadHandlerSendingToExternalStorage(t *testing.T) {
+	tempPath, err := ioutil.TempDir("", "uploads")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempPath)
+
+	archiveData := createTestZipArchive(t)
+	contentBuffer, contentType := createTestMultipartForm(t, archiveData)
+
+	storeServerCalled := 0
+	storeServerMux := http.NewServeMux()
+	storeServerMux.HandleFunc("/url/put", func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "PUT", r.Method)
+
+		receivedData, err := ioutil.ReadAll(r.Body)
+		require.NoError(t, err)
+		require.Equal(t, archiveData, receivedData)
+
+		storeServerCalled++
+		w.WriteHeader(200)
+	})
+
+	responseProcessorCalled := 0
+	responseProcessor := func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "store-id", r.FormValue("file.object_id"))
+		assert.NotEmpty(t, r.FormValue("file.store_url"))
+		w.WriteHeader(200)
+		responseProcessorCalled++
+	}
+
+	storeServer := httptest.NewServer(storeServerMux)
+	defer storeServer.Close()
+
+	authResponse := api.Response{
+		TempPath: tempPath,
+		ObjectStore: api.RemoteObjectStore{
+			StoreURL: storeServer.URL + "/url/put",
+			ObjectID: "store-id",
+		},
+	}
+
+	ts := testArtifactsUploadServer(t, authResponse, responseProcessor)
+	defer ts.Close()
+
+	response := testUploadArtifacts(contentType, &contentBuffer, t, ts)
+	testhelper.AssertResponseCode(t, response, 200)
+	assert.Equal(t, 1, storeServerCalled, "store should be called only once")
+	assert.Equal(t, 1, responseProcessorCalled, "response processor should be called only once")
+}
+
+func TestUploadHandlerSendingToExternalStorageAndStorageServerUnreachable(t *testing.T) {
+	tempPath, err := ioutil.TempDir("", "uploads")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempPath)
+
+	responseProcessor := func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("it should not be called")
+	}
+
+	authResponse := api.Response{
+		TempPath: tempPath,
+		ObjectStore: api.RemoteObjectStore{
+			StoreURL: "http://localhost:12323/invalid/url",
+			ObjectID: "store-id",
+		},
+	}
+
+	ts := testArtifactsUploadServer(t, authResponse, responseProcessor)
+	defer ts.Close()
+
+	archiveData := createTestZipArchive(t)
+	contentBuffer, contentType := createTestMultipartForm(t, archiveData)
+
+	response := testUploadArtifacts(contentType, &contentBuffer, t, ts)
+	testhelper.AssertResponseCode(t, response, 500)
+}
+
+func TestUploadHandlerSendingToExternalStorageAndInvalidURLIsUsed(t *testing.T) {
+	tempPath, err := ioutil.TempDir("", "uploads")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempPath)
+
+	responseProcessor := func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("it should not be called")
+	}
+
+	authResponse := api.Response{
+		TempPath: tempPath,
+		ObjectStore: api.RemoteObjectStore{
+			StoreURL: "htt:////invalid-url",
+			ObjectID: "store-id",
+		},
+	}
+
+	ts := testArtifactsUploadServer(t, authResponse, responseProcessor)
+	defer ts.Close()
+
+	archiveData := createTestZipArchive(t)
+	contentBuffer, contentType := createTestMultipartForm(t, archiveData)
+
+	response := testUploadArtifacts(contentType, &contentBuffer, t, ts)
+	testhelper.AssertResponseCode(t, response, 500)
+}
+
+func TestUploadHandlerSendingToExternalStorageAndItReturnsAnError(t *testing.T) {
+	tempPath, err := ioutil.TempDir("", "uploads")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempPath)
+
+	putCalledTimes := 0
+
+	storeServerMux := http.NewServeMux()
+	storeServerMux.HandleFunc("/url/put", func(w http.ResponseWriter, r *http.Request) {
+		putCalledTimes++
+		assert.Equal(t, "PUT", r.Method)
+		w.WriteHeader(510)
+	})
+
+	responseProcessor := func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("it should not be called")
+	}
+
+	storeServer := httptest.NewServer(storeServerMux)
+	defer storeServer.Close()
+
+	authResponse := api.Response{
+		TempPath: tempPath,
+		ObjectStore: api.RemoteObjectStore{
+			StoreURL: storeServer.URL + "/url/put",
+			ObjectID: "store-id",
+		},
+	}
+
+	ts := testArtifactsUploadServer(t, authResponse, responseProcessor)
+	defer ts.Close()
+
+	archiveData := createTestZipArchive(t)
+	contentBuffer, contentType := createTestMultipartForm(t, archiveData)
+
+	response := testUploadArtifacts(contentType, &contentBuffer, t, ts)
+	testhelper.AssertResponseCode(t, response, 500)
+	assert.Equal(t, 1, putCalledTimes, "upload should be called only once")
+}
+
+func TestUploadHandlerSendingToExternalStorageAndSupportRequestTimeout(t *testing.T) {
+	tempPath, err := ioutil.TempDir("", "uploads")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tempPath)
+
+	putCalledTimes := 0
+
+	storeServerMux := http.NewServeMux()
+	storeServerMux.HandleFunc("/url/put", func(w http.ResponseWriter, r *http.Request) {
+		putCalledTimes++
+		assert.Equal(t, "PUT", r.Method)
+		time.Sleep(10 * time.Second)
+		w.WriteHeader(510)
+	})
+
+	responseProcessor := func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("it should not be called")
+	}
+
+	storeServer := httptest.NewServer(storeServerMux)
+	defer storeServer.Close()
+
+	authResponse := api.Response{
+		TempPath: tempPath,
+		ObjectStore: api.RemoteObjectStore{
+			StoreURL: storeServer.URL + "/url/put",
+			ObjectID: "store-id",
+			Timeout:  1,
+		},
+	}
+
+	ts := testArtifactsUploadServer(t, authResponse, responseProcessor)
+	defer ts.Close()
+
+	archiveData := createTestZipArchive(t)
+	contentBuffer, contentType := createTestMultipartForm(t, archiveData)
+
+	response := testUploadArtifacts(contentType, &contentBuffer, t, ts)
+	testhelper.AssertResponseCode(t, response, 500)
+	assert.Equal(t, 1, putCalledTimes, "upload should be called only once")
+}

internal/artifacts/artifacts_upload.go

@@ -2,6 +2,7 @@ package artifacts
 
 import (
 	"fmt"
+	"io"
 	"io/ioutil"
 	"mime/multipart"
 	"net/http"
@@ -17,7 +18,30 @@ import (
 
 type artifactsUploadProcessor struct {
 	TempPath     string
+	ObjectStore  api.RemoteObjectStore
 	metadataFile string
+	stored       bool
+}
+
+func (a *artifactsUploadProcessor) generateMetadataFromZip(fileName string, metadataFile io.Writer) (bool, error) {
+	// Generate metadata and save to file
+	zipMd := exec.Command("gitlab-zip-metadata", fileName)
+	zipMd.Stderr = os.Stderr
+	zipMd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	zipMd.Stdout = metadataFile
+
+	if err := zipMd.Start(); err != nil {
+		return false, err
+	}
+	defer helper.CleanUpProcessGroup(zipMd)
+	if err := zipMd.Wait(); err != nil {
+		if st, ok := helper.ExitStatus(err); ok && st == zipartifacts.StatusNotZip {
+			return false, nil
+		}
+		return false, err
+	}
+
+	return true, nil
 }
 
 func (a *artifactsUploadProcessor) ProcessFile(formName, fileName string, writer *multipart.Writer) error {
@@ -36,28 +60,23 @@ func (a *artifactsUploadProcessor) ProcessFile(formName, fileName string, writer
 		return err
 	}
 	defer tempFile.Close()
-	a.metadataFile = tempFile.Name()
 
-	// Generate metadata and save to file
-	zipMd := exec.Command("gitlab-zip-metadata", fileName)
-	zipMd.Stderr = os.Stderr
-	zipMd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
-	zipMd.Stdout = tempFile
+	a.metadataFile = tempFile.Name()
 
-	if err := zipMd.Start(); err != nil {
-		return err
+	generatedMetadata, err := a.generateMetadataFromZip(fileName, tempFile)
+	if err != nil {
+		return fmt.Errorf("generateMetadataFromZip: %v", err)
 	}
-	defer helper.CleanUpProcessGroup(zipMd)
-	if err := zipMd.Wait(); err != nil {
-		if st, ok := helper.ExitStatus(err); ok && st == zipartifacts.StatusNotZip {
-			return nil
-		}
-		return err
+
+	if generatedMetadata {
+		// Pass metadata file path to Rails
+		writer.WriteField("metadata.path", a.metadataFile)
+		writer.WriteField("metadata.name", "metadata.gz")
 	}
 
-	// Pass metadata file path to Rails
-	writer.WriteField("metadata.path", a.metadataFile)
-	writer.WriteField("metadata.name", "metadata.gz")
+	if err := a.storeFile(formName, fileName, writer); err != nil {
+		return fmt.Errorf("storeFile: %v", err)
+	}
 	return nil
 }
 
@@ -86,7 +105,10 @@ func UploadArtifacts(myAPI *api.API, h http.Handler) http.Handler {
 			return
 		}
 
-		mg := &artifactsUploadProcessor{TempPath: a.TempPath}
+		mg := &artifactsUploadProcessor{
+			TempPath:    a.TempPath,
+			ObjectStore: a.ObjectStore,
+		}
 		defer mg.Cleanup()
 
 		upload.HandleFileUploads(w, r, h, a.TempPath, mg)

internal/artifacts/artifacts_upload_test.go

@@ -22,7 +22,7 @@ import (
 	"gitlab.com/gitlab-org/gitlab-workhorse/internal/zipartifacts"
 )
 
-func testArtifactsUploadServer(t *testing.T, tempPath string) *httptest.Server {
+func testArtifactsUploadServer(t *testing.T, authResponse api.Response, bodyProcessor func(w http.ResponseWriter, r *http.Request)) *httptest.Server {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/url/path/authorize", func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != "POST" {
@@ -31,9 +31,7 @@ func testArtifactsUploadServer(t *testing.T, tempPath string) *httptest.Server {
 
 		w.Header().Set("Content-Type", api.ResponseContentType)
 
-		data, err := json.Marshal(&api.Response{
-			TempPath: tempPath,
-		})
+		data, err := json.Marshal(&authResponse)
 		if err != nil {
 			t.Fatal("Expected to marshal")
 		}
@@ -79,7 +77,11 @@ func testArtifactsUploadServer(t *testing.T, tempPath string) *httptest.Server {
 			return
 		}
 
-		w.WriteHeader(200)
+		if bodyProcessor != nil {
+			bodyProcessor(w, r)
+		} else {
+			w.WriteHeader(200)
+		}
 	})
 	return testhelper.TestServerWithHandler(nil, mux.ServeHTTP)
 }
@@ -107,7 +109,7 @@ func TestUploadHandlerAddingMetadata(t *testing.T) {
 	}
 	defer os.RemoveAll(tempPath)
 
-	ts := testArtifactsUploadServer(t, tempPath)
+	ts := testArtifactsUploadServer(t, api.Response{TempPath: tempPath}, nil)
 	defer ts.Close()
 
 	var buffer bytes.Buffer
@@ -138,7 +140,7 @@ func TestUploadHandlerForUnsupportedArchive(t *testing.T) {
 	}
 	defer os.RemoveAll(tempPath)
 
-	ts := testArtifactsUploadServer(t, tempPath)
+	ts := testArtifactsUploadServer(t, api.Response{TempPath: tempPath}, nil)
 	defer ts.Close()
 
 	var buffer bytes.Buffer
@@ -162,7 +164,7 @@ func TestUploadFormProcessing(t *testing.T) {
 	}
 	defer os.RemoveAll(tempPath)
 
-	ts := testArtifactsUploadServer(t, tempPath)
+	ts := testArtifactsUploadServer(t, api.Response{TempPath: tempPath}, nil)
 	defer ts.Close()
 
 	var buffer bytes.Buffer

vendor/golang.org/x/net/context/ctxhttp/ctxhttp.go

+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.7
+
+// Package ctxhttp provides helper functions for performing context-aware HTTP requests.
+package ctxhttp // import "golang.org/x/net/context/ctxhttp"
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+// Do sends an HTTP request with the provided http.Client and returns
+// an HTTP response.
+//
+// If the client is nil, http.DefaultClient is used.
+//
+// The provided ctx must be non-nil. If it is canceled or times out,
+// ctx.Err() will be returned.
+func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
+	if client == nil {
+		client = http.DefaultClient
+	}
+	resp, err := client.Do(req.WithContext(ctx))
+	// If we got an error, and the context has been canceled,
+	// the context's error is probably more useful.
+	if err != nil {
+		select {
+		case <-ctx.Done():
+			err = ctx.Err()
+		default:
+		}
+	}
+	return resp, err
+}
+
+// Get issues a GET request via the Do function.
+func Get(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Head issues a HEAD request via the Do function.
+func Head(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Post issues a POST request via the Do function.
+func Post(ctx context.Context, client *http.Client, url string, bodyType string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", bodyType)
+	return Do(ctx, client, req)
+}
+
+// PostForm issues a POST request via the Do function.
+func PostForm(ctx context.Context, client *http.Client, url string, data url.Values) (*http.Response, error) {
+	return Post(ctx, client, url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
+}

vendor/golang.org/x/net/context/ctxhttp/ctxhttp_pre17.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.7
+
+package ctxhttp // import "golang.org/x/net/context/ctxhttp"
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+func nop() {}
+
+var (
+	testHookContextDoneBeforeHeaders = nop
+	testHookDoReturned               = nop
+	testHookDidBodyClose             = nop
+)
+
+// Do sends an HTTP request with the provided http.Client and returns an HTTP response.
+// If the client is nil, http.DefaultClient is used.
+// If the context is canceled or times out, ctx.Err() will be returned.
+func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
+	if client == nil {
+		client = http.DefaultClient
+	}
+
+	// TODO(djd): Respect any existing value of req.Cancel.
+	cancel := make(chan struct{})
+	req.Cancel = cancel
+
+	type responseAndError struct {
+		resp *http.Response
+		err  error
+	}
+	result := make(chan responseAndError, 1)
+
+	// Make local copies of test hooks closed over by goroutines below.
+	// Prevents data races in tests.
+	testHookDoReturned := testHookDoReturned
+	testHookDidBodyClose := testHookDidBodyClose
+
+	go func() {
+		resp, err := client.Do(req)
+		testHookDoReturned()
+		result <- responseAndError{resp, err}
+	}()
+
+	var resp *http.Response
+
+	select {
+	case <-ctx.Done():
+		testHookContextDoneBeforeHeaders()
+		close(cancel)
+		// Clean up after the goroutine calling client.Do:
+		go func() {
+			if r := <-result; r.resp != nil {
+				testHookDidBodyClose()
+				r.resp.Body.Close()
+			}
+		}()
+		return nil, ctx.Err()
+	case r := <-result:
+		var err error
+		resp, err = r.resp, r.err
+		if err != nil {
+			return resp, err
+		}
+	}
+
+	c := make(chan struct{})
+	go func() {
+		select {
+		case <-ctx.Done():
+			close(cancel)
+		case <-c:
+			// The response's Body is closed.
+		}
+	}()
+	resp.Body = &notifyingReader{resp.Body, c}
+
+	return resp, nil
+}
+
+// Get issues a GET request via the Do function.
+func Get(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Head issues a HEAD request via the Do function.
+func Head(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Post issues a POST request via the Do function.
+func Post(ctx context.Context, client *http.Client, url string, bodyType string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", bodyType)
+	return Do(ctx, client, req)
+}
+
+// PostForm issues a POST request via the Do function.
+func PostForm(ctx context.Context, client *http.Client, url string, data url.Values) (*http.Response, error) {
+	return Post(ctx, client, url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
+}
+
+// notifyingReader is an io.ReadCloser that closes the notify channel after
+// Close is called or a Read fails on the underlying ReadCloser.
+type notifyingReader struct {
+	io.ReadCloser
+	notify chan<- struct{}
+}
+
+func (r *notifyingReader) Read(p []byte) (int, error) {
+	n, err := r.ReadCloser.Read(p)
+	if err != nil && r.notify != nil {
+		close(r.notify)
+		r.notify = nil
+	}
+	return n, err
+}
+
+func (r *notifyingReader) Close() error {
+	err := r.ReadCloser.Close()
+	if r.notify != nil {
+		close(r.notify)
+		r.notify = nil
+	}
+	return err
+}

vendor/vendor.json

@@ -148,6 +148,12 @@
 			"path": "golang.org/x/net/context",
 			"revision": "f2499483f923065a842d38eb4c7f1927e6fc6e6d"
 		},
+		{
+			"checksumSHA1": "WHc3uByvGaMcnSoI21fhzYgbOgg=",
+			"path": "golang.org/x/net/context/ctxhttp",
+			"revision": "a6577fac2d73be281a500b310739095313165611",
+			"revisionTime": "2017-03-08T20:54:49Z"
+		},
 		{
 			"checksumSHA1": "N1akwAdrHVfPPrsFOhG2ouP21VA=",
 			"path": "golang.org/x/net/http2",