Add retry for migration http/https requests (#9019)

* Add retry for migration http/https requests

* give the more suitable name for retry configuraion items

* fix docs and lint

* Only use retryDownloader when setting > 1

2 files changed, 156 insertions, 1 deletions

diff --git a/modules/migrations/base/downloader.go b/modules/migrations/base/downloader.go
index 69c2adb9e9..b853ec3020 100644
--- a/modules/migrations/base/downloader.go
+++ b/modules/migrations/base/downloader.go
@@ -5,7 +5,11 @@
 
 package base
 
-import "code.gitea.io/gitea/modules/structs"
+import (
+	"time"
+
+	"code.gitea.io/gitea/modules/structs"
+)
 
 // Downloader downloads the site repo informations
 type Downloader interface {
@@ -25,3 +29,148 @@ type DownloaderFactory interface {
 	New(opts MigrateOptions) (Downloader, error)
 	GitServiceType() structs.GitServiceType
 }
+
+// RetryDownloader retry the downloads
+type RetryDownloader struct {
+	Downloader
+	RetryTimes int // the total execute times
+	RetryDelay int // time to delay seconds
+}
+
+// NewRetryDownloader creates a retry downloader
+func NewRetryDownloader(downloader Downloader, retryTimes, retryDelay int) *RetryDownloader {
+	return &RetryDownloader{
+		Downloader: downloader,
+		RetryTimes: retryTimes,
+		RetryDelay: retryDelay,
+	}
+}
+
+// GetRepoInfo returns a repository information with retry
+func (d *RetryDownloader) GetRepoInfo() (*Repository, error) {
+	var (
+		times = d.RetryTimes
+		repo  *Repository
+		err   error
+	)
+	for ; times > 0; times-- {
+		if repo, err = d.Downloader.GetRepoInfo(); err == nil {
+			return repo, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetTopics returns a repository's topics with retry
+func (d *RetryDownloader) GetTopics() ([]string, error) {
+	var (
+		times  = d.RetryTimes
+		topics []string
+		err    error
+	)
+	for ; times > 0; times-- {
+		if topics, err = d.Downloader.GetTopics(); err == nil {
+			return topics, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetMilestones returns a repository's milestones with retry
+func (d *RetryDownloader) GetMilestones() ([]*Milestone, error) {
+	var (
+		times      = d.RetryTimes
+		milestones []*Milestone
+		err        error
+	)
+	for ; times > 0; times-- {
+		if milestones, err = d.Downloader.GetMilestones(); err == nil {
+			return milestones, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetReleases returns a repository's releases with retry
+func (d *RetryDownloader) GetReleases() ([]*Release, error) {
+	var (
+		times    = d.RetryTimes
+		releases []*Release
+		err      error
+	)
+	for ; times > 0; times-- {
+		if releases, err = d.Downloader.GetReleases(); err == nil {
+			return releases, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetLabels returns a repository's labels with retry
+func (d *RetryDownloader) GetLabels() ([]*Label, error) {
+	var (
+		times  = d.RetryTimes
+		labels []*Label
+		err    error
+	)
+	for ; times > 0; times-- {
+		if labels, err = d.Downloader.GetLabels(); err == nil {
+			return labels, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetIssues returns a repository's issues with retry
+func (d *RetryDownloader) GetIssues(page, perPage int) ([]*Issue, bool, error) {
+	var (
+		times  = d.RetryTimes
+		issues []*Issue
+		isEnd  bool
+		err    error
+	)
+	for ; times > 0; times-- {
+		if issues, isEnd, err = d.Downloader.GetIssues(page, perPage); err == nil {
+			return issues, isEnd, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, false, err
+}
+
+// GetComments returns a repository's comments with retry
+func (d *RetryDownloader) GetComments(issueNumber int64) ([]*Comment, error) {
+	var (
+		times    = d.RetryTimes
+		comments []*Comment
+		err      error
+	)
+	for ; times > 0; times-- {
+		if comments, err = d.Downloader.GetComments(issueNumber); err == nil {
+			return comments, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
+
+// GetPullRequests returns a repository's pull requests with retry
+func (d *RetryDownloader) GetPullRequests(page, perPage int) ([]*PullRequest, error) {
+	var (
+		times = d.RetryTimes
+		prs   []*PullRequest
+		err   error
+	)
+	for ; times > 0; times-- {
+		if prs, err = d.Downloader.GetPullRequests(page, perPage); err == nil {
+			return prs, nil
+		}
+		time.Sleep(time.Second * time.Duration(d.RetryDelay))
+	}
+	return nil, err
+}
diff --git a/modules/migrations/migrate.go b/modules/migrations/migrate.go
index 7a5071e125..cfaedf78e3 100644
--- a/modules/migrations/migrate.go
+++ b/modules/migrations/migrate.go
@@ -11,6 +11,7 @@ import (
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/migrations/base"
+	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/structs"
 )
 
@@ -63,6 +64,11 @@ func MigrateRepository(doer *models.User, ownerName string, opts base.MigrateOpt
 	}
 
 	uploader.gitServiceType = opts.GitServiceType
+
+	if setting.Migrations.MaxAttempts > 1 {
+		downloader = base.NewRetryDownloader(downloader, setting.Migrations.MaxAttempts, setting.Migrations.RetryBackoff)
+	}
+
 	if err := migrateRepository(downloader, uploader, opts); err != nil {
 		if err1 := uploader.Rollback(); err1 != nil {
 			log.Error("rollback failed: %v", err1)