docs: add apis and preheat (#712)

* docs: add apis and preheat

Signed-off-by: Gaius <gaius.qi@gmail.com>

docs/en/user-guide/preheat/preheat.md

@@ -0,0 +1,39 @@
+# Preheat
+
+P2P provides two types of preheating: `image` and `file`. Users can be preheat in the `console` or directly call `preheat api` for preheating
+
+## Console
+
+TODO
+
+## API
+
+Use preheat apis for preheating. First create a POST request for preheating, you can refer to [create preheat api document](../../api/api.md#create-preheat)
+
+```bash
+curl --request POST 'http://dragonfly-manager:8080/api/v1/preheats' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+    "type": "image",
+    "url": "https://registry-1.docker.io/v2/library/busybox/manifests/latest",
+    "scheduler_cluster_id": 1
+}'
+```
+
+If the output of command above has content like
+
+```bash
+{"id":"group_28439e0b-d4c3-43bf-945e-482b54c49dc5","status":"PENDING","create_at":"2021-10-09T11:54:50.6182794Z"}
+```
+
+Polling the preheating status with id. if status is `SUCCESS`, preheating is successful, you can refer to [get preheat api document](../../api/api.md#get-preheat)
+
+```bash
+curl --request GET 'http://manager-domain:8080/api/v1/preheats/group_28439e0b-d4c3-43bf-945e-482b54c49dc5'
+```
+
+If the status is `SUCCESS`, the preheating is successful.
+
+```bash
+{"id":"group_28439e0b-d4c3-43bf-945e-482b54c49dc5","status":"SUCCESS","create_at":"2021-10-09T11:54:50.5712334Z"}
+```

docs/en/user-guide/quick-start.md

@@ -23,3 +23,4 @@ This table describes some container runtimes version and documents.
 - Container Runtimes
     - [cri-o mirror](../user-guide/registry-mirror/cri-o.md) - make Dragonfly as Registry Mirror for CRIO daemon
     - [cri-containerd mirror](../user-guide/registry-mirror/cri-containerd.md) - make Dragonfly as Registry Mirror for containerd daemon
+- [preheat](../user-guide/preheat/preheat.md) - preheat feature

docs/zh-CN/user-guide/preheat/preheat.md

@@ -0,0 +1,40 @@
+# 预热
+
+P2P 加速可预热两种类型数据 `image` 和 `file`, 用户可以在控制台操作或者直接调用 api 进行预热。
+
+## Console
+
+TODO
+
+## API
+
+用户使用 api 进行预热。首先发送 POST 请求创建预热任务，具体 api 可以参考文档 [create preheat api document](../../api/api.md#create-preheat)。
+
+```bash
+curl --request POST 'http://dragonfly-manager:8080/api/v1/preheats' \
+--header 'Content-Type: application/json' \
+--data-raw '{
+    "type": "image",
+    "url": "https://registry-1.docker.io/v2/library/busybox/manifests/latest",
+    "scheduler_cluster_id": 1
+}'
+```
+
+命令行日志返回预热任务 ID。
+
+```bash
+{"id":"group_28439e0b-d4c3-43bf-945e-482b54c49dc5","status":"PENDING","create_at":"2021-10-09T11:54:50.6182794Z"}
+```
+
+使用预热任务 ID 轮训查询任务是否成功，具体 api 可以参考文档 [get preheat api document](../../api/api.md#get-preheat)。
+
+
+```bash
+curl --request GET 'http://manager-domain:8080/api/v1/preheats/group_28439e0b-d4c3-43bf-945e-482b54c49dc5'
+```
+
+如果返回预热任务状态为 `SUCCESS`，表示预热成功。
+
+```bash
+{"id":"group_28439e0b-d4c3-43bf-945e-482b54c49dc5","status":"SUCCESS","create_at":"2021-10-09T11:54:50.5712334Z"}
+```

docs/zh-CN/user-guide/quick-start.md

@@ -22,3 +22,4 @@
 - Container Runtimes
     - [cri-o mirror](../user-guide/registry-mirror/cri-o.md) - 使用 Dragonfly 作为 CRIO daemon 的 Registry Mirror
     - [cri-containerd mirror](../user-guide/registry-mirror/cri-containerd.md) - 使用 Dragonfly 作为 containerd daemon 的 Registry Mirror
+- [preheat](../user-guide/preheat/preheat.md) - 预热功能