Golang retry.Do函數代碼示例

// Finishes the job in the Buildkite Agent API. This call will keep on retrying
// forever until it finally gets a successfull response from the API.
func (r *JobRunner) finishJob(finishedAt time.Time, exitStatus string, failedChunkCount int) error {
	r.Job.FinishedAt = finishedAt.UTC().Format(time.RFC3339Nano)
	r.Job.ExitStatus = exitStatus
	r.Job.ChunksFailedCount = failedChunkCount

	return retry.Do(func(s *retry.Stats) error {
		response, err := r.APIClient.Jobs.Finish(r.Job)
		if err != nil {
			// If the API returns with a 422, that means that we
			// succesfully tried to finish the job, but Buildkite
			// rejected the finish for some reason. This can
			// sometimes mean that Buildkite has cancelled the job
			// before we get a chance to send the final API call
			// (maybe this agent took too long to kill the
			// process). In that case, we don't want to keep trying
			// to finish the job forever so we'll just bail out and
			// go find some more work to do.
			if response != nil && response.StatusCode == 422 {
				logger.Warn("Buildkite rejected the call to finish the job (%s)", err)
				s.Break()
			} else {
				logger.Warn("%s (%s)", err, s)
			}
		}

		return err
	}, &retry.Config{Forever: true, Interval: 1 * time.Second})
}

func (d Download) Start() error {
	return retry.Do(func(s *retry.Stats) error {
		err := d.try()
		if err != nil {
			logger.Warn("Error trying to download %s (%s) %s", d.URL, err, s)
		}
		return err
	}, &retry.Config{Maximum: d.Retries, Interval: 1 * time.Second})
}

func (a *ArtifactBatchCreator) Create() ([]*api.Artifact, error) {
	length := len(a.Artifacts)
	chunks := 30

	// Split into the artifacts into chunks so we're not uploading a ton of
	// files at once.
	for i := 0; i < length; i += chunks {
		j := i + chunks
		if length < j {
			j = length
		}

		// The artifacts that will be uploaded in this chunk
		theseArtiacts := a.Artifacts[i:j]

		// An ID is required so Buildkite can ensure this create
		// operation is idompotent (if we try and upload the same ID
		// twice, it'll just return the previous data and skip the
		// upload)
		batch := &api.ArtifactBatch{api.NewUUID(), theseArtiacts, a.UploadDestination}

		logger.Info("Creating (%d-%d)/%d artifacts", i, j, length)

		var creation *api.ArtifactBatchCreateResponse
		var resp *api.Response
		var err error

		// Retry the batch upload a couple of times
		err = retry.Do(func(s *retry.Stats) error {
			creation, resp, err = a.APIClient.Artifacts.Create(a.JobID, batch)
			if resp != nil && (resp.StatusCode == 401 || resp.StatusCode == 404 || resp.StatusCode == 500) {
				s.Break()
			}
			if err != nil {
				logger.Warn("%s (%s)", err, s)
			}

			return err
		}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})

		// Did the batch creation eventually fail?
		if err != nil {
			return nil, err
		}

		// Save the id and instructions to each artifact
		index := 0
		for _, id := range creation.ArtifactIDs {
			theseArtiacts[index].ID = id
			theseArtiacts[index].UploadInstructions = creation.UploadInstructions
			index += 1
		}
	}

	return a.Artifacts, nil
}

func (r *JobRunner) onUploadHeaderTime(cursor int, total int, times map[string]string) {
	retry.Do(func(s *retry.Stats) error {
		_, err := r.APIClient.HeaderTimes.Save(r.Job.ID, &api.HeaderTimes{Times: times})
		if err != nil {
			logger.Warn("%s (%s)", err, s)
		}

		return err
	}, &retry.Config{Maximum: 10, Interval: 5 * time.Second})
}

// Connects the agent to the Buildkite Agent API, retrying up to 30 times if it
// fails.
func (a *AgentWorker) Connect() error {
	return retry.Do(func(s *retry.Stats) error {
		_, err := a.APIClient.Agents.Connect()
		if err != nil {
			logger.Warn("%s (%s)", err, s)
		}

		return err
	}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})
}

// Connects the agent to the Buildkite Agent API, retrying up to 30 times if it
// fails.
func (a *AgentWorker) Connect() error {
	// Update the proc title
	a.UpdateProcTitle("connecting")

	return retry.Do(func(s *retry.Stats) error {
		_, err := a.APIClient.Agents.Connect()
		if err != nil {
			logger.Warn("%s (%s)", err, s)
		}

		return err
	}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})
}

// Call when a chunk is ready for upload. It retry the chunk upload with an
// interval before giving up.
func (r *JobRunner) onUploadChunk(chunk *LogStreamerChunk) error {
	return retry.Do(func(s *retry.Stats) error {
		_, err := r.APIClient.Chunks.Upload(r.Job.ID, &api.Chunk{
			Data:     chunk.Data,
			Sequence: chunk.Order,
		})
		if err != nil {
			logger.Warn("%s (%s)", err, s)
		}

		return err
	}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})
}

// Starts the job in the Buildkite Agent API. We'll retry on connection-related
// issues, but if a connection succeeds and we get an error response back from
// Buildkite, we won't bother retrying. For example, a "no such host" will
// retry, but a 422 from Buildkite won't.
func (r *JobRunner) startJob(startedAt time.Time) error {
	r.Job.StartedAt = startedAt.UTC().Format(time.RFC3339Nano)

	return retry.Do(func(s *retry.Stats) error {
		_, err := r.APIClient.Jobs.Start(r.Job)

		if err != nil {
			if api.IsRetryableError(err) {
				logger.Warn("%s (%s)", err, s)
			} else {
				logger.Warn("Buildkite rejected the call to start the job (%s)", err)
				s.Break()
			}
		}

		return err
	}, &retry.Config{Maximum: 30, Interval: 5 * time.Second})
}

// Performs a heatbeat
func (a *AgentWorker) Heartbeat() error {
	var beat *api.Heartbeat
	var err error

	// Retry the heartbeat a few times
	err = retry.Do(func(s *retry.Stats) error {
		beat, _, err = a.APIClient.Heartbeats.Beat()
		if err != nil {
			logger.Warn("%s (%s)", err, s)
		}
		return err
	}, &retry.Config{Maximum: 5, Interval: 1 * time.Second})

	if err != nil {
		return err
	}

	logger.Debug("Heartbeat sent at %s and received at %s", beat.SentAt, beat.ReceivedAt)
	return nil
}

func (b *Buildkite) WriteJobMetadata(metadata map[string]string) error {
	client := b.agentClient
	for k, v := range metadata {
		metadatum := &buildkite.MetaData{
			Key:   k,
			Value: v,
		}
		err := retry.Do(func(s *retry.Stats) error {
			resp, err := client.MetaData.Set(b.jobId, metadatum)
			if resp != nil && (resp.StatusCode == 401 || resp.StatusCode == 404) {
				s.Break()
			}

			return err
		}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})

		if err != nil {
			return fmt.Errorf("error setting metadata %s: %s", k, err)
		}
	}
	return nil
}

func (a *ArtifactBatchCreator) Create() ([]*api.Artifact, error) {
	length := len(a.Artifacts)
	chunks := 10
	uploaded := []*api.Artifact{}

	// Split into the artifacts into chunks so we're not uploading a ton of
	// files at once.
	for i := 0; i < length; i += chunks {
		j := i + chunks
		if length < j {
			j = length
		}

		artifacts := a.Artifacts[i:j]

		logger.Info("Creating (%d-%d)/%d artifacts", i, j, length)

		var u []*api.Artifact
		var err error

		// Retry the batch upload a couple of times
		err = retry.Do(func(s *retry.Stats) error {
			u, _, err = a.APIClient.Artifacts.Create(a.JobID, artifacts)
			if err != nil {
				logger.Warn("%s (%s)", err, s)
			}

			return err
		}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})
		if err != nil {
			return nil, err
		}

		uploaded = append(uploaded, u...)
	}

	return uploaded, nil
}

// Takes the agent template and returns a registered agent. The registered
// agent includes the Access Token used to communicate with the Buildkite Agent
// API
func (r *AgentPool) RegisterAgent(agent *api.Agent) (*api.Agent, error) {
	var registered *api.Agent
	var err error
	var resp *api.Response

	register := func(s *retry.Stats) error {
		registered, resp, err = r.APIClient.Agents.Register(agent)
		if err != nil {
			if resp != nil && resp.StatusCode == 401 {
				logger.Warn("Buildkite rejected the registration (%s)", err)
				s.Break()
			} else {
				logger.Warn("%s (%s)", err, s)
			}
		}

		return err
	}

	err = retry.Do(register, &retry.Config{Maximum: 30, Interval: 1 * time.Second})

	return registered, err
}

func (a *ArtifactUploader) upload(artifacts []*api.Artifact) error {
	var uploader Uploader

	// Determine what uploader to use
	if a.Destination != "" {
		if strings.HasPrefix(a.Destination, "s3://") {
			uploader = new(S3Uploader)
		} else {
			return errors.New("Unknown upload destination: " + a.Destination)
		}
	} else {
		uploader = new(FormUploader)
	}

	// Setup the uploader
	err := uploader.Setup(a.Destination, a.APIClient.DebugHTTP)
	if err != nil {
		return err
	}

	// Set the URL's of the artifacts based on the uploader
	for _, artifact := range artifacts {
		artifact.URL = uploader.URL(artifact)
	}

	// Create the artifacts on Buildkite
	batchCreator := ArtifactBatchCreator{
		APIClient:         a.APIClient,
		JobID:             a.JobID,
		Artifacts:         artifacts,
		UploadDestination: a.Destination,
	}
	artifacts, err = batchCreator.Create()
	if err != nil {
		return err
	}

	// Prepare a concurrency pool to upload the artifacts
	p := pool.New(pool.MaxConcurrencyLimit)
	errors := []error{}

	// Create a wait group so we can make sure the uploader waits for all
	// the artifact states to upload before finishing
	var stateUploaderWaitGroup sync.WaitGroup
	stateUploaderWaitGroup.Add(1)

	// A map to keep track of artifact states and how many we've uploaded
	artifactsStates := make(map[string]string)
	artifactStatesUploaded := 0

	// Spin up a gourtine that'll uploading artifact statuses every few
	// seconds in batches
	go func() {
		for artifactStatesUploaded < len(artifacts) {
			statesToUpload := make(map[string]string)

			// Grab all the states we need to upload, and remove
			// them from the tracking map
			for id, state := range artifactsStates {
				statesToUpload[id] = state
				delete(artifactsStates, id)
			}

			if len(statesToUpload) > 0 {
				artifactStatesUploaded += len(statesToUpload)
				for id, state := range statesToUpload {
					logger.Debug("Artifact `%s` has state `%s`", id, state)
				}

				// Update the states of the artifacts in bulk.
				err = retry.Do(func(s *retry.Stats) error {
					_, err = a.APIClient.Artifacts.Update(a.JobID, statesToUpload)
					if err != nil {
						logger.Warn("%s (%s)", err, s)
					}

					return err
				}, &retry.Config{Maximum: 10, Interval: 1 * time.Second})

				if err != nil {
					logger.Error("Error uploading artifact states: %s", err)

					// Track the error that was raised
					p.Lock()
					errors = append(errors, err)
					p.Unlock()
				}

				logger.Debug("Uploaded %d artfact states (%d/%d)", len(statesToUpload), artifactStatesUploaded, len(artifacts))
			}

			// Check again for states to upload in a few seconds
			time.Sleep(1 * time.Second)
		}

		stateUploaderWaitGroup.Done()
	}()

	for _, artifact := range artifacts {
		// Create new instance of the artifact for the goroutine
//.........這裏部分代碼省略.........

			}
		}

		// Create the API client
		client := agent.APIClient{
			Endpoint: cfg.Endpoint,
			Token:    cfg.AgentAccessToken,
		}.Create()

		// Generate a UUID that will identifiy this pipeline change. We
		// do this outside of the retry loop because we want this UUID
		// to be the same for each attempt at updating the pipeline.
		uuid := api.NewUUID()

		// Retry the pipeline upload a few times before giving up
		err = retry.Do(func(s *retry.Stats) error {
			_, err = client.Pipelines.Upload(cfg.Job, &api.Pipeline{UUID: uuid, Data: input, FileName: filename, Replace: cfg.Replace})
			if err != nil {
				logger.Warn("%s (%s)", err, s)
			}

			return err
		}, &retry.Config{Maximum: 5, Interval: 1 * time.Second})
		if err != nil {
			logger.Fatal("Failed to upload and process pipeline: %s", err)
		}

		logger.Info("Successfully uploaded and parsed pipeline config")
	},
}

		// Create the API client
		client := agent.APIClient{
			Endpoint: cfg.Endpoint,
			Token:    cfg.AgentAccessToken,
		}.Create()

		// Find the meta data value
		var metaData *api.MetaData
		var err error
		var resp *api.Response
		err = retry.Do(func(s *retry.Stats) error {
			metaData, resp, err = client.MetaData.Get(cfg.Job, cfg.Key)
			// Don't bother retrying if the response was one of these statuses
			if resp != nil && (resp.StatusCode == 401 || resp.StatusCode == 404 || resp.StatusCode == 400) {
				s.Break()
			}
			if err != nil {
				logger.Warn("%s (%s)", err, s)
			}

			return err
		}, &retry.Config{Maximum: 10, Interval: 5 * time.Second})
		if err != nil {
			logger.Fatal("Failed to get meta-data: %s", err)
		}

		// Output the value to STDOUT
		fmt.Print(metaData.Value)
	},
}