internal/gensupport/resumable.go - google-api-go-client - Git at Google

 // 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.

 package gensupport

 import (
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"sync"
 	"time"

 	gax "github.com/googleapis/gax-go/v2"
 )

 // Backoff is an interface around gax.Backoff's Pause method, allowing tests to provide their
 // own implementation.
 type Backoff interface {
 	Pause() time.Duration
 }

 // These are declared as global variables so that tests can overwrite them.
 var (
 	retryDeadline = 32 * time.Second
 	backoff       = func() Backoff {
 		return &gax.Backoff{Initial: 100 * time.Millisecond}
 	}
 	// isRetryable is a platform-specific hook, specified in retryable_linux.go
 	syscallRetryable func(error) bool = func(err error) bool { return false }
 )

 const (
 	// statusTooManyRequests is returned by the storage API if the
 	// per-project limits have been temporarily exceeded. The request
 	// should be retried.
 	// https://cloud.google.com/storage/docs/json_api/v1/status-codes#standardcodes
 	statusTooManyRequests = 429
 )

 // ResumableUpload is used by the generated APIs to provide resumable uploads.
 // It is not used by developers directly.
 type ResumableUpload struct {
 	Client *http.Client
 	// URI is the resumable resource destination provided by the server after specifying "&uploadType=resumable".
 	URI       string
 	UserAgent string // User-Agent for header of the request
 	// Media is the object being uploaded.
 	Media *MediaBuffer
 	// MediaType defines the media type, e.g. "image/jpeg".
 	MediaType string

 	mu       sync.Mutex // guards progress
 	progress int64      // number of bytes uploaded so far

 	// Callback is an optional function that will be periodically called with the cumulative number of bytes uploaded.
 	Callback func(int64)
 }

 // Progress returns the number of bytes uploaded at this point.
 func (rx *ResumableUpload) Progress() int64 {
 	rx.mu.Lock()
 	defer rx.mu.Unlock()
 	return rx.progress
 }

 // doUploadRequest performs a single HTTP request to upload data.
 // off specifies the offset in rx.Media from which data is drawn.
 // size is the number of bytes in data.
 // final specifies whether data is the final chunk to be uploaded.
 func (rx *ResumableUpload) doUploadRequest(ctx context.Context, data io.Reader, off, size int64, final bool) (*http.Response, error) {
 	req, err := http.NewRequest("POST", rx.URI, data)
 	if err != nil {
 		return nil, err
 	}

 	req.ContentLength = size
 	var contentRange string
 	if final {
 		if size == 0 {
 			contentRange = fmt.Sprintf("bytes */%v", off)
 		} else {
 			contentRange = fmt.Sprintf("bytes %v-%v/%v", off, off+size-1, off+size)
 		}
 	} else {
 		contentRange = fmt.Sprintf("bytes %v-%v/*", off, off+size-1)
 	}
 	req.Header.Set("Content-Range", contentRange)
 	req.Header.Set("Content-Type", rx.MediaType)
 	req.Header.Set("User-Agent", rx.UserAgent)

 	// Google's upload endpoint uses status code 308 for a
 	// different purpose than the "308 Permanent Redirect"
 	// since-standardized in RFC 7238. Because of the conflict in
 	// semantics, Google added this new request header which
 	// causes it to not use "308" and instead reply with 200 OK
 	// and sets the upload-specific "X-HTTP-Status-Code-Override:
 	// 308" response header.
 	req.Header.Set("X-GUploader-No-308", "yes")

 	return SendRequest(ctx, rx.Client, req)
 }

 func statusResumeIncomplete(resp *http.Response) bool {
 	// This is how the server signals "status resume incomplete"
 	// when X-GUploader-No-308 is set to "yes":
 	return resp != nil && resp.Header.Get("X-Http-Status-Code-Override") == "308"
 }

 // reportProgress calls a user-supplied callback to report upload progress.
 // If old==updated, the callback is not called.
 func (rx *ResumableUpload) reportProgress(old, updated int64) {
 	if updated-old == 0 {
 		return
 	}
 	rx.mu.Lock()
 	rx.progress = updated
 	rx.mu.Unlock()
 	if rx.Callback != nil {
 		rx.Callback(updated)
 	}
 }

 // transferChunk performs a single HTTP request to upload a single chunk from rx.Media.
 func (rx *ResumableUpload) transferChunk(ctx context.Context) (*http.Response, error) {
 	chunk, off, size, err := rx.Media.Chunk()

 	done := err == io.EOF
 	if !done && err != nil {
 		return nil, err
 	}

 	res, err := rx.doUploadRequest(ctx, chunk, off, int64(size), done)
 	if err != nil {
 		return res, err
 	}

 	// We sent "X-GUploader-No-308: yes" (see comment elsewhere in
 	// this file), so we don't expect to get a 308.
 	if res.StatusCode == 308 {
 		return nil, errors.New("unexpected 308 response status code")
 	}

 	if res.StatusCode == http.StatusOK {
 		rx.reportProgress(off, off+int64(size))
 	}

 	if statusResumeIncomplete(res) {
 		rx.Media.Next()
 	}
 	return res, nil
 }

 // Upload starts the process of a resumable upload with a cancellable context.
 // It retries using the provided back off strategy until cancelled or the
 // strategy indicates to stop retrying.
 // It is called from the auto-generated API code and is not visible to the user.
 // Before sending an HTTP request, Upload calls any registered hook functions,
 // and calls the returned functions after the request returns (see send.go).
 // rx is private to the auto-generated API code.
 // Exactly one of resp or err will be nil.  If resp is non-nil, the caller must call resp.Body.Close.
 func (rx *ResumableUpload) Upload(ctx context.Context) (resp *http.Response, err error) {

 	// There are a couple of cases where it's possible for err and resp to both
 	// be non-nil. However, we expose a simpler contract to our callers: exactly
 	// one of resp and err will be non-nil. This means that any response body
 	// must be closed here before returning a non-nil error.
 	var prepareReturn = func(resp *http.Response, err error) (*http.Response, error) {
 		if err != nil {
 			if resp != nil && resp.Body != nil {
 				resp.Body.Close()
 			}
 			return nil, err
 		}
 		return resp, nil
 	}

 	// Send all chunks.
 	for {
 		var pause time.Duration

 		// Each chunk gets its own initialized-at-zero retry.
 		bo := backoff()
 		quitAfter := time.After(retryDeadline)

 		// Retry loop for a single chunk.
 		for {
 			select {
 			case <-ctx.Done():
 				if err == nil {
 					err = ctx.Err()
 				}
 				return prepareReturn(resp, err)
 			case <-time.After(pause):
 			case <-quitAfter:
 				return prepareReturn(resp, err)
 			}

 			resp, err = rx.transferChunk(ctx)

 			var status int
 			if resp != nil {
 				status = resp.StatusCode
 			}

 			// Check if we should retry the request.
 			if !shouldRetry(status, err) {
 				break
 			}

 			pause = bo.Pause()
 			if resp != nil && resp.Body != nil {
 				resp.Body.Close()
 			}
 		}

 		// If the chunk was uploaded successfully, but there's still
 		// more to go, upload the next chunk without any delay.
 		if statusResumeIncomplete(resp) {
 			resp.Body.Close()
 			continue
 		}

 		return prepareReturn(resp, err)
 	}
 }

 // shouldRetry indicates whether an error is retryable for the purposes of this
 // package, following guidance from
 // https://cloud.google.com/storage/docs/exponential-backoff .
 func shouldRetry(status int, err error) bool {
 	if 500 <= status && status <= 599 {
 		return true
 	}
 	if status == statusTooManyRequests {
 		return true
 	}
 	if err == io.ErrUnexpectedEOF {
 		return true
 	}
 	// Transient network errors should be retried.
 	if syscallRetryable(err) {
 		return true
 	}
 	if err, ok := err.(interface{ Temporary() bool }); ok {
 		if err.Temporary() {
 			return true
 		}
 	}
 	// If Go 1.13 error unwrapping is available, use this to examine wrapped
 	// errors.
 	if err, ok := err.(interface{ Unwrap() error }); ok {
 		return shouldRetry(status, err.Unwrap())
 	}
 	return false
 }
	// 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.

	package gensupport

	import (
	"context"
	"errors"
	"fmt"
	"io"
	"net/http"
	"sync"
	"time"

	gax "github.com/googleapis/gax-go/v2"
	)

	// Backoff is an interface around gax.Backoff's Pause method, allowing tests to provide their
	// own implementation.
	type Backoff interface {
	Pause() time.Duration
	}

	// These are declared as global variables so that tests can overwrite them.
	var (
	retryDeadline = 32 * time.Second
	backoff = func() Backoff {
	return &gax.Backoff{Initial: 100 * time.Millisecond}
	}
	// isRetryable is a platform-specific hook, specified in retryable_linux.go
	syscallRetryable func(error) bool = func(err error) bool { return false }
	)

	const (
	// statusTooManyRequests is returned by the storage API if the
	// per-project limits have been temporarily exceeded. The request
	// should be retried.
	// https://cloud.google.com/storage/docs/json_api/v1/status-codes#standardcodes
	statusTooManyRequests = 429
	)

	// ResumableUpload is used by the generated APIs to provide resumable uploads.
	// It is not used by developers directly.
	type ResumableUpload struct {
	Client *http.Client
	// URI is the resumable resource destination provided by the server after specifying "&uploadType=resumable".
	URI string
	UserAgent string // User-Agent for header of the request
	// Media is the object being uploaded.
	Media *MediaBuffer
	// MediaType defines the media type, e.g. "image/jpeg".
	MediaType string

	mu sync.Mutex // guards progress
	progress int64 // number of bytes uploaded so far

	// Callback is an optional function that will be periodically called with the cumulative number of bytes uploaded.
	Callback func(int64)
	}

	// Progress returns the number of bytes uploaded at this point.
	func (rx *ResumableUpload) Progress() int64 {
	rx.mu.Lock()
	defer rx.mu.Unlock()
	return rx.progress
	}

	// doUploadRequest performs a single HTTP request to upload data.
	// off specifies the offset in rx.Media from which data is drawn.
	// size is the number of bytes in data.
	// final specifies whether data is the final chunk to be uploaded.
	func (rx ResumableUpload) doUploadRequest(ctx context.Context, data io.Reader, off, size int64, final bool) (http.Response, error) {
	req, err := http.NewRequest("POST", rx.URI, data)
	if err != nil {
	return nil, err
	}

	req.ContentLength = size
	var contentRange string
	if final {
	if size == 0 {
	contentRange = fmt.Sprintf("bytes */%v", off)
	} else {
	contentRange = fmt.Sprintf("bytes %v-%v/%v", off, off+size-1, off+size)
	}
	} else {
	contentRange = fmt.Sprintf("bytes %v-%v/*", off, off+size-1)
	}
	req.Header.Set("Content-Range", contentRange)
	req.Header.Set("Content-Type", rx.MediaType)
	req.Header.Set("User-Agent", rx.UserAgent)

	// Google's upload endpoint uses status code 308 for a
	// different purpose than the "308 Permanent Redirect"
	// since-standardized in RFC 7238. Because of the conflict in
	// semantics, Google added this new request header which
	// causes it to not use "308" and instead reply with 200 OK
	// and sets the upload-specific "X-HTTP-Status-Code-Override:
	// 308" response header.
	req.Header.Set("X-GUploader-No-308", "yes")

	return SendRequest(ctx, rx.Client, req)
	}

	func statusResumeIncomplete(resp *http.Response) bool {
	// This is how the server signals "status resume incomplete"
	// when X-GUploader-No-308 is set to "yes":
	return resp != nil && resp.Header.Get("X-Http-Status-Code-Override") == "308"
	}

	// reportProgress calls a user-supplied callback to report upload progress.
	// If old==updated, the callback is not called.
	func (rx *ResumableUpload) reportProgress(old, updated int64) {
	if updated-old == 0 {
	return
	}
	rx.mu.Lock()
	rx.progress = updated
	rx.mu.Unlock()
	if rx.Callback != nil {
	rx.Callback(updated)
	}
	}

	// transferChunk performs a single HTTP request to upload a single chunk from rx.Media.
	func (rx ResumableUpload) transferChunk(ctx context.Context) (http.Response, error) {
	chunk, off, size, err := rx.Media.Chunk()

	done := err == io.EOF
	if !done && err != nil {
	return nil, err
	}

	res, err := rx.doUploadRequest(ctx, chunk, off, int64(size), done)
	if err != nil {
	return res, err
	}

	// We sent "X-GUploader-No-308: yes" (see comment elsewhere in
	// this file), so we don't expect to get a 308.
	if res.StatusCode == 308 {
	return nil, errors.New("unexpected 308 response status code")
	}

	if res.StatusCode == http.StatusOK {
	rx.reportProgress(off, off+int64(size))
	}

	if statusResumeIncomplete(res) {
	rx.Media.Next()
	}
	return res, nil
	}

	// Upload starts the process of a resumable upload with a cancellable context.
	// It retries using the provided back off strategy until cancelled or the
	// strategy indicates to stop retrying.
	// It is called from the auto-generated API code and is not visible to the user.
	// Before sending an HTTP request, Upload calls any registered hook functions,
	// and calls the returned functions after the request returns (see send.go).
	// rx is private to the auto-generated API code.
	// Exactly one of resp or err will be nil. If resp is non-nil, the caller must call resp.Body.Close.
	func (rx ResumableUpload) Upload(ctx context.Context) (resp http.Response, err error) {

	// There are a couple of cases where it's possible for err and resp to both
	// be non-nil. However, we expose a simpler contract to our callers: exactly
	// one of resp and err will be non-nil. This means that any response body
	// must be closed here before returning a non-nil error.
	var prepareReturn = func(resp http.Response, err error) (http.Response, error) {
	if err != nil {
	if resp != nil && resp.Body != nil {
	resp.Body.Close()
	}
	return nil, err
	}
	return resp, nil
	}

	// Send all chunks.
	for {
	var pause time.Duration

	// Each chunk gets its own initialized-at-zero retry.
	bo := backoff()
	quitAfter := time.After(retryDeadline)

	// Retry loop for a single chunk.
	for {
	select {
	case <-ctx.Done():
	if err == nil {
	err = ctx.Err()
	}
	return prepareReturn(resp, err)
	case <-time.After(pause):
	case <-quitAfter:
	return prepareReturn(resp, err)
	}

	resp, err = rx.transferChunk(ctx)

	var status int
	if resp != nil {
	status = resp.StatusCode
	}

	// Check if we should retry the request.
	if !shouldRetry(status, err) {
	break
	}

	pause = bo.Pause()
	if resp != nil && resp.Body != nil {
	resp.Body.Close()
	}
	}

	// If the chunk was uploaded successfully, but there's still
	// more to go, upload the next chunk without any delay.
	if statusResumeIncomplete(resp) {
	resp.Body.Close()
	continue
	}

	return prepareReturn(resp, err)
	}
	}

	// shouldRetry indicates whether an error is retryable for the purposes of this
	// package, following guidance from
	// https://cloud.google.com/storage/docs/exponential-backoff .
	func shouldRetry(status int, err error) bool {
	if 500 <= status && status <= 599 {
	return true
	}
	if status == statusTooManyRequests {
	return true
	}
	if err == io.ErrUnexpectedEOF {
	return true
	}
	// Transient network errors should be retried.
	if syscallRetryable(err) {
	return true
	}
	if err, ok := err.(interface{ Temporary() bool }); ok {
	if err.Temporary() {
	return true
	}
	}
	// If Go 1.13 error unwrapping is available, use this to examine wrapped
	// errors.
	if err, ok := err.(interface{ Unwrap() error }); ok {
	return shouldRetry(status, err.Unwrap())
	}
	return false
	}