Add extend ability to query external service for autoscaler

docs/api-references/docs.md

@@ -2329,6 +2329,21 @@ the auto-scaling would be performed.
 If not set, the default value is 5.</p>
 </td>
 </tr>
+<tr>
+<td>
+<code>externalEndpoint</code></br>
+<em>
+<a href="#externalendpoint">
+ExternalEndpoint
+</a>
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>ExternalEndpoint makes the auto-scaler controller able to query the external service
+to fetch the recommended replicas for TiKV/TiDB</p>
+</td>
+</tr>
 </tbody>
 </table>
 <h3 id="basicautoscalerstatus">BasicAutoScalerStatus</h3>
@@ -3096,6 +3111,62 @@ imported from TiDB v3.1.0</p>
 </tr>
 </tbody>
 </table>
+<h3 id="externalendpoint">ExternalEndpoint</h3>
+<p>
+(<em>Appears on:</em>
+<a href="#basicautoscalerspec">BasicAutoScalerSpec</a>)
+</p>
+<p>
+<p>ExternalEndpoint describes the external service endpoint
+which provides the ability to get the tikv/tidb auto-scaling recommended replicas</p>
+</p>
+<table>
+<thead>
+<tr>
+<th>Field</th>
+<th>Description</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td>
+<code>host</code></br>
+<em>
+string
+</em>
+</td>
+<td>
+<p>Host indicates the external service&rsquo;s host</p>
+</td>
+</tr>
+<tr>
+<td>
+<code>port</code></br>
+<em>
+int32
+</em>
+</td>
+<td>
+<p>Port indicates the external service&rsquo;s port</p>
+</td>
+</tr>
+<tr>
+<td>
+<code>tlsSecret</code></br>
+<em>
+<a href="#secretref">
+SecretRef
+</a>
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>TLSSecret indicates the Secret which stores the TLS configuration. If set, the operator will use https
+to communicate to the external service</p>
+</td>
+</tr>
+</tbody>
+</table>
 <h3 id="filelogconfig">FileLogConfig</h3>
 <p>
 (<em>Appears on:</em>
@@ -7287,6 +7358,44 @@ string
 <p>
 <p>S3StorageProviderType represents the specific storage provider that implements the S3 interface</p>
 </p>
+<h3 id="secretref">SecretRef</h3>
+<p>
+(<em>Appears on:</em>
+<a href="#externalendpoint">ExternalEndpoint</a>)
+</p>
+<p>
+<p>SecretRef indicates to secret ref</p>
+</p>
+<table>
+<thead>
+<tr>
+<th>Field</th>
+<th>Description</th>
+</tr>
+</thead>
+<tbody>
+<tr>
+<td>
+<code>name</code></br>
+<em>
+string
+</em>
+</td>
+<td>
+</td>
+</tr>
+<tr>
+<td>
+<code>namespace</code></br>
+<em>
+string
+</em>
+</td>
+<td>
+</td>
+</tr>
+</tbody>
+</table>
 <h3 id="security">Security</h3>
 <p>
 (<em>Appears on:</em>

manifests/crd.yaml

@@ -10653,6 +10653,37 @@ spec:
             tidb:
               description: TidbAutoScalerSpec describes the spec for tidb auto-scaling
               properties:
+                externalEndpoint:
+                  description: ExternalEndpoint describes the external service endpoint
+                    which provides the ability to get the tikv/tidb auto-scaling recommended
+                    replicas
+                  properties:
+                    host:
+                      description: Host indicates the external service's host
+                      type: string
+                    path:
+                      description: Path indicates the external service's path
+                      type: string
+                    port:
+                      description: Port indicates the external service's port
+                      format: int32
+                      type: integer
+                    tlsSecret:
+                      description: SecretRef indicates to secret ref
+                      properties:
+                        name:
+                          type: string
+                        namespace:
+                          type: string
+                      required:
+                      - name
+                      - namespace
+                      type: object
+                  required:
+                  - host
+                  - port
+                  - path
+                  type: object
                 maxReplicas:
                   description: maxReplicas is the upper limit for the number of replicas
                     to which the autoscaler can scale out. It cannot be less than
@@ -10713,6 +10744,37 @@ spec:
             tikv:
               description: TikvAutoScalerSpec describes the spec for tikv auto-scaling
               properties:
+                externalEndpoint:
+                  description: ExternalEndpoint describes the external service endpoint
+                    which provides the ability to get the tikv/tidb auto-scaling recommended
+                    replicas
+                  properties:
+                    host:
+                      description: Host indicates the external service's host
+                      type: string
+                    path:
+                      description: Path indicates the external service's path
+                      type: string
+                    port:
+                      description: Port indicates the external service's port
+                      format: int32
+                      type: integer
+                    tlsSecret:
+                      description: SecretRef indicates to secret ref
+                      properties:
+                        name:
+                          type: string
+                        namespace:
+                          type: string
+                      required:
+                      - name
+                      - namespace
+                      type: object
+                  required:
+                  - host
+                  - port
+                  - path
+                  type: object
                 maxReplicas:
                   description: maxReplicas is the upper limit for the number of replicas
                     to which the autoscaler can scale out. It cannot be less than