Allow custom SSH user in UI for built-in SSH server (#2617) (#2678)

* Allow custom SSH user in UI for built-in SSH server (#2617)

* Some fixes

* Did make fmt

* Updated according to review

- Renamed config to BUILTIN_SSH_SERVER_USER
- Removed unnecessary default string value for config item

* Updated according to review

* Fixed some minor issues

conf/app.ini

 DISABLE_SSH = false
 ; Whether use builtin SSH server or not.
 START_SSH_SERVER = false
+; Username to use for builtin SSH server. If blank, then it is the value of RUN_USER.
+BUILTIN_SSH_SERVER_USER =
 ; Domain name to be exposed in clone URL
 SSH_DOMAIN = %(DOMAIN)s
 ; Network interface builtin SSH server listens on

models/repo.go

 		repoName += ".wiki"
 	}
 
+	sshUser := setting.RunUser
+	if setting.SSH.StartBuiltinServer {
+		sshUser = setting.SSH.BuiltinServerUser
+	}
+
 	repo.Owner = repo.MustOwner()
 	cl := new(CloneLink)
 	if setting.SSH.Port != 22 {
-		cl.SSH = fmt.Sprintf("ssh://%s@%s:%d/%s/%s.git", setting.RunUser, setting.SSH.Domain, setting.SSH.Port, repo.Owner.Name, repoName)
+		cl.SSH = fmt.Sprintf("ssh://%s@%s:%d/%s/%s.git", sshUser, setting.SSH.Domain, setting.SSH.Port, repo.Owner.Name, repoName)
 	} else if setting.Repository.UseCompatSSHURI {
-		cl.SSH = fmt.Sprintf("ssh://%s@%s/%s/%s.git", setting.RunUser, setting.SSH.Domain, repo.Owner.Name, repoName)
+		cl.SSH = fmt.Sprintf("ssh://%s@%s/%s/%s.git", sshUser, setting.SSH.Domain, repo.Owner.Name, repoName)
 	} else {
-		cl.SSH = fmt.Sprintf("%s@%s:%s/%s.git", setting.RunUser, setting.SSH.Domain, repo.Owner.Name, repoName)
+		cl.SSH = fmt.Sprintf("%s@%s:%s/%s.git", sshUser, setting.SSH.Domain, repo.Owner.Name, repoName)
 	}
 	cl.HTTPS = ComposeHTTPSCloneURL(repo.Owner.Name, repoName)
 	return cl

modules/setting/setting.go

 	SSH = struct {
 		Disabled             bool           `ini:"DISABLE_SSH"`
 		StartBuiltinServer   bool           `ini:"START_SSH_SERVER"`
+		BuiltinServerUser    string         `ini:"BUILTIN_SSH_SERVER_USER"`
 		Domain               string         `ini:"SSH_DOMAIN"`
 		Port                 int            `ini:"SSH_PORT"`
 		ListenHost           string         `ini:"SSH_LISTEN_HOST"`
 		}
 	}
 
+	SSH.BuiltinServerUser = Cfg.Section("server").Key("BUILTIN_SSH_SERVER_USER").MustString(RunUser)
+
 	// Determine and create root git repository path.
 	sec = Cfg.Section("repository")
 	Repository.DisableHTTPGit = sec.Key("DISABLE_HTTP_GIT").MustBool()