label_sync/main.go
func (ru RepoUpdates) DoUpdates(org string, gc client) error {
	var numUpdates int
	for _, updates := range ru {
		numUpdates += len(updates)
	}

	updateChan := make(chan repoUpdate, numUpdates)
	for repo, updates := range ru {
		logrus.WithField("org", org).WithField("repo", repo).Infof("Applying %d changes", len(updates))
		for _, item := range updates {
			updateChan <- repoUpdate{repo: repo, update: item}
		}
	}
	close(updateChan)

	wg := sync.WaitGroup{}
	wg.Add(maxConcurrentWorkers)
	errChan := make(chan error, numUpdates)
	for i := 0; i < maxConcurrentWorkers; i++ {
		go func(updates <-chan repoUpdate) {
			defer wg.Done()
			for item := range updates {
				repo := item.repo
				update := item.update
				logrus.WithField("org", org).WithField("repo", repo).WithField("why", update.Why).Debug("running update")
				switch update.Why {
				case "missing":
					err := gc.AddRepoLabel(org, repo, update.Wanted.Name, update.Wanted.Description, update.Wanted.Color)
					if err != nil {
						errChan <- err
					}
				case "change", "rename":
					err := gc.UpdateRepoLabel(org, repo, update.Current.Name, update.Wanted.Name, update.Wanted.Description, update.Wanted.Color)
					if err != nil {
						errChan <- err
					}
				case "dead":
					err := gc.DeleteRepoLabel(org, repo, update.Current.Name)
					if err != nil {
						errChan <- err
					}
				case "migrate":
					issues, err := gc.FindIssues(fmt.Sprintf("is:open repo:%s/%s label:\"%s\" -label:\"%s\"", org, repo, update.Current.Name, update.Wanted.Name), "", false)
					if err != nil {
						errChan <- err
					}
					if len(issues) == 0 {
						if err = gc.DeleteRepoLabel(org, repo, update.Current.Name); err != nil {
							errChan <- err
						}
					}
					for _, i := range issues {
						if err = gc.AddLabel(org, repo, i.Number, update.Wanted.Name); err != nil {
							errChan <- err
							continue
						}
						if err = gc.RemoveLabel(org, repo, i.Number, update.Current.Name); err != nil {
							errChan <- err
						}
					}
				default:
					errChan <- errors.New("unknown label operation: " + update.Why)
				}
			}
		}(updateChan)
	}

	wg.Wait()
	close(errChan)

	var overallErr error
	if len(errChan) > 0 {
		var updateErrs []error
		for updateErr := range errChan {
			updateErrs = append(updateErrs, updateErr)
		}
		overallErr = fmt.Errorf("failed to list labels: %v", updateErrs)
	}

	return overallErr
}
func (ru RepoUpdates) DoUpdates(org string, gc client) error {
	var numUpdates int
	for _, updates := range ru {
		numUpdates += len(updates)
	}

	updateChan := make(chan repoUpdate, numUpdates)
	for repo, updates := range ru {
		logrus.WithField("org", org).WithField("repo", repo).Infof("Applying %d changes", len(updates))
		for _, item := range updates {
			updateChan <- repoUpdate{repo: repo, update: item}
		}
	}
	close(updateChan)

	wg := sync.WaitGroup{}
	wg.Add(maxConcurrentWorkers)
	errChan := make(chan error, numUpdates)
	for i := 0; i < maxConcurrentWorkers; i++ {
		go func(updates <-chan repoUpdate) {
			defer wg.Done()
			for item := range updates {
				repo := item.repo
				update := item.update
				logrus.WithField("org", org).WithField("repo", repo).WithField("why", update.Why).Debug("running update")
				switch update.Why {
				case "missing":
					err := gc.AddRepoLabel(org, repo, update.Wanted.Name, update.Wanted.Description, update.Wanted.Color)
					if err != nil {
						errChan <- err
					}
				case "change", "rename":
					err := gc.UpdateRepoLabel(org, repo, update.Current.Name, update.Wanted.Name, update.Wanted.Description, update.Wanted.Color)
					if err != nil {
						errChan <- err
					}
				case "dead":
					err := gc.DeleteRepoLabel(org, repo, update.Current.Name)
					if err != nil {
						errChan <- err
					}
				case "migrate":
					issues, err := gc.FindIssues(fmt.Sprintf("is:open repo:%s/%s label:\"%s\" -label:\"%s\"", org, repo, update.Current.Name, update.Wanted.Name), "", false)
					if err != nil {
						errChan <- err
					}
					if len(issues) == 0 {
						if err = gc.DeleteRepoLabel(org, repo, update.Current.Name); err != nil {
							errChan <- err
						}
					}
					for _, i := range issues {
						if err = gc.AddLabel(org, repo, i.Number, update.Wanted.Name); err != nil {
							errChan <- err
							continue
						}
						if err = gc.RemoveLabel(org, repo, i.Number, update.Current.Name); err != nil {
							errChan <- err
						}
					}
				default:
					errChan <- errors.New("unknown label operation: " + update.Why)
				}
			}
		}(updateChan)
	}

	wg.Wait()
	close(errChan)

	var overallErr error
	if len(errChan) > 0 {
		var updateErrs []error
		for updateErr := range errChan {
			updateErrs = append(updateErrs, updateErr)
		}
		overallErr = fmt.Errorf("failed to list labels: %v", updateErrs)
	}

	return overallErr
}
// DoUpdates iterates generated update data and adds and/or modifies labels on repositories
// Uses AddLabel GH API to add missing labels
// And UpdateLabel GH API to update color or name (name only when case differs)