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

7 files changed, 195 insertions, 1 deletions

diff --git a/custom/conf/app.ini.sample b/custom/conf/app.ini.sample
index 34c3ee9db5..599498a4b6 100644
--- a/custom/conf/app.ini.sample
+++ b/custom/conf/app.ini.sample
@@ -892,3 +892,9 @@ QUEUE_LENGTH = 1000
 ; Task queue connection string, available only when `QUEUE_TYPE` is `redis`.
 ; If there is a password of redis, use `addrs=127.0.0.1:6379 password=123 db=0`.
 QUEUE_CONN_STR = "addrs=127.0.0.1:6379 db=0"
+
+[migrations]
+; Max attempts per http/https request on migrations.
+MAX_ATTEMPTS = 3
+; Backoff time per http/https request retry (seconds)
+RETRY_BACKOFF = 3
\ No newline at end of file
diff --git a/docs/content/doc/advanced/config-cheat-sheet.en-us.md b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
index ab353f9d5a..f56ed34e43 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -585,6 +585,11 @@ Two special environment variables are passed to the render command:
 - `QUEUE_LENGTH`: **1000**: Task queue length, available only when `QUEUE_TYPE` is `channel`.
 - `QUEUE_CONN_STR`: **addrs=127.0.0.1:6379 db=0**: Task queue connection string, available only when `QUEUE_TYPE` is `redis`. If there redis needs a password, use `addrs=127.0.0.1:6379 password=123 db=0`.
 
+## Migrations (`migrations`)
+
+- `MAX_ATTEMPTS`: **3**: Max attempts per http/https request on migrations.
+- `RETRY_BACKOFF`: **3**: Backoff time per http/https request retry (seconds)
+
 ## Other (`other`)
 
 - `SHOW_FOOTER_BRANDING`: **false**: Show Gitea branding in the footer.
diff --git a/docs/content/doc/advanced/config-cheat-sheet.zh-cn.md b/docs/content/doc/advanced/config-cheat-sheet.zh-cn.md
index b545d9a99d..22e47f810f 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.zh-cn.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.zh-cn.md
@@ -272,6 +272,11 @@ IS_INPUT_FILE = false
 - `QUEUE_LENGTH`: **1000**: 任务队列长度，当 `QUEUE_TYPE` 为 `channel` 时有效。
 - `QUEUE_CONN_STR`: **addrs=127.0.0.1:6379 db=0**: 任务队列连接字符串，当 `QUEUE_TYPE` 为 `redis` 时有效。如果redis有密码，则可以 `addrs=127.0.0.1:6379 password=123 db=0`。
 
+## Migrations (`migrations`)
+
+- `MAX_ATTEMPTS`: **3**: 在迁移过程中的 http/https 请求重试次数。
+- `RETRY_BACKOFF`: **3**: 等待下一次重试的时间，单位秒。
+
 ## Other (`other`)
 
 - `SHOW_FOOTER_BRANDING`: 为真则在页面底部显示Gitea的字样。
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)
diff --git a/modules/setting/migrations.go b/modules/setting/migrations.go
new file mode 100644
index 0000000000..51d6bbcf11
--- /dev/null
+++ b/modules/setting/migrations.go
@@ -0,0 +1,22 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package setting
+
+var (
+	// Migrations settings
+	Migrations = struct {
+		MaxAttempts  int
+		RetryBackoff int
+	}{
+		MaxAttempts:  3,
+		RetryBackoff: 3,
+	}
+)
+
+func newMigrationsService() {
+	sec := Cfg.Section("migrations")
+	Migrations.MaxAttempts = sec.Key("MAX_ATTEMPTS").MustInt(Migrations.MaxAttempts)
+	Migrations.RetryBackoff = sec.Key("RETRY_BACKOFF").MustInt(Migrations.RetryBackoff)
+}
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index c0b9b99e3c..6a45797cf2 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -1062,6 +1062,7 @@ func NewServices() {
 	newRegisterMailService()
 	newNotifyMailService()
 	newWebhookService()
+	newMigrationsService()
 	newIndexerService()
 	newTaskService()
 }