Feat: aria2 download and transfer in slave node (#1040)

* Feat: retrieve nodes from data table

* Feat: master node ping slave node in REST API

* Feat: master send scheduled ping request

* Feat: inactive nodes recover loop

* Modify: remove database operations from aria2 RPC caller implementation

* Feat: init aria2 client in master node

* Feat: Round Robin load balancer

* Feat: create and monitor aria2 task in master node

* Feat: salve receive and handle heartbeat

* Fix: Node ID will be 0 in download record generated in older version

* Feat: sign request headers with all `X-` prefix

* Feat: API call to slave node will carry meta data in headers

* Feat: call slave aria2 rpc method from master

* Feat: get slave aria2 task status
Feat: encode slave response data using gob

* Feat: aria2 callback to master node / cancel or select task to slave node

* Fix: use dummy aria2 client when caller initialize failed in master node

* Feat: slave aria2 status event callback / salve RPC auth

* Feat: prototype for slave driven filesystem

* Feat: retry for init aria2 client in master node

* Feat: init request client with global options

* Feat: slave receive async task from master

* Fix: competition write in request header

* Refactor: dependency initialize order

* Feat: generic message queue implementation

* Feat: message queue implementation

* Feat: master waiting slave transfer result

* Feat: slave transfer file in stateless policy

* Feat: slave transfer file in slave policy

* Feat: slave transfer file in local policy

* Feat: slave transfer file in OneDrive policy

* Fix: failed to initialize update checker http client

* Feat: list slave nodes for dashboard

* Feat: test aria2 rpc connection in slave

* Feat: add and save node

* Feat: add and delete node in node pool

* Fix: temp file cannot be removed when aria2 task fails

* Fix: delete node in admin panel

* Feat: edit node and get node info

* Modify: delete unused settings

pkg/serializer/slave.go

@@ -1,5 +1,12 @@
 package serializer
 
+import (
+	"crypto/sha1"
+	"encoding/gob"
+	"fmt"
+	model "github.com/cloudreve/Cloudreve/v3/models"
+)
+
 // RemoteDeleteRequest 远程策略删除接口请求正文
 type RemoteDeleteRequest struct {
 	Files []string `json:"files"`
@@ -10,3 +17,51 @@ type ListRequest struct {
 	Path      string `json:"path"`
 	Recursive bool   `json:"recursive"`
 }
+
+// NodePingReq 从机节点Ping请求
+type NodePingReq struct {
+	SiteURL       string      `json:"site_url"`
+	SiteID        string      `json:"site_id"`
+	IsUpdate      bool        `json:"is_update"`
+	CredentialTTL int         `json:"credential_ttl"`
+	Node          *model.Node `json:"node"`
+}
+
+// NodePingResp 从机节点Ping响应
+type NodePingResp struct {
+}
+
+// SlaveAria2Call 从机有关Aria2的请求正文
+type SlaveAria2Call struct {
+	Task         *model.Download        `json:"task"`
+	GroupOptions map[string]interface{} `json:"group_options"`
+	Files        []int                  `json:"files"`
+}
+
+// SlaveTransferReq 从机中转任务创建请求
+type SlaveTransferReq struct {
+	Src    string        `json:"src"`
+	Dst    string        `json:"dst"`
+	Policy *model.Policy `json:"policy"`
+}
+
+// Hash 返回创建请求的唯一标识，保持创建请求幂等
+func (s *SlaveTransferReq) Hash(id string) string {
+	h := sha1.New()
+	h.Write([]byte(fmt.Sprintf("transfer-%s-%s-%s-%d", id, s.Src, s.Dst, s.Policy.ID)))
+	bs := h.Sum(nil)
+	return fmt.Sprintf("%x", bs)
+}
+
+const (
+	SlaveTransferSuccess = "success"
+	SlaveTransferFailed  = "failed"
+)
+
+type SlaveTransferResult struct {
+	Error string
+}
+
+func init() {
+	gob.Register(SlaveTransferResult{})
+}