*: Change etcdserver API to support raft learner

- Added isLearner flag to MemberAddRequest in Cluster API.
- Added isLearner field to StatusResponse in Maintenance API.
- Added MemberPromote rpc to Cluster API.

Documentation/dev-guide/apispec/swagger/rpc.swagger.json

@@ -501,6 +501,33 @@
         }
       }
     },
+    "/v3/cluster/member/promote": {
+      "post": {
+        "tags": [
+          "Cluster"
+        ],
+        "summary": "MemberPromote promotes a member from raft learner (non-voting) to raft voting member.",
+        "operationId": "MemberPromote",
+        "parameters": [
+          {
+            "name": "body",
+            "in": "body",
+            "required": true,
+            "schema": {
+              "$ref": "#/definitions/etcdserverpbMemberPromoteRequest"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "A successful response.",
+            "schema": {
+              "$ref": "#/definitions/etcdserverpbMemberPromoteResponse"
+            }
+          }
+        }
+      }
+    },
     "/v3/cluster/member/remove": {
       "post": {
         "tags": [
@@ -820,7 +847,7 @@
           "200": {
             "description": "A successful response.(streaming responses)",
             "schema": {
-              "$ref": "#/definitions/etcdserverpbLeaseKeepAliveResponse"
+              "$ref": "#/x-stream-definitions/etcdserverpbLeaseKeepAliveResponse"
             }
           }
         }
@@ -1009,7 +1036,7 @@
           "200": {
             "description": "A successful response.(streaming responses)",
             "schema": {
-              "$ref": "#/definitions/etcdserverpbSnapshotResponse"
+              "$ref": "#/x-stream-definitions/etcdserverpbSnapshotResponse"
             }
           }
         }
@@ -1091,7 +1118,7 @@
           "200": {
             "description": "A successful response.(streaming responses)",
             "schema": {
-              "$ref": "#/definitions/etcdserverpbWatchResponse"
+              "$ref": "#/x-stream-definitions/etcdserverpbWatchResponse"
             }
           }
         }
@@ -1882,6 +1909,11 @@
             "type": "string"
           }
         },
+        "isLearner": {
+          "description": "isLearner indicates if the member is raft learner.",
+          "type": "boolean",
+          "format": "boolean"
+        },
         "name": {
           "description": "name is the human-readable name of the member. If the member is not started, the name will be an empty string.",
           "type": "string"
@@ -1898,6 +1930,11 @@
     "etcdserverpbMemberAddRequest": {
       "type": "object",
       "properties": {
+        "isLearner": {
+          "description": "isLearner indicates if the added member is raft learner.",
+          "type": "boolean",
+          "format": "boolean"
+        },
         "peerURLs": {
           "description": "peerURLs is the list of URLs the added member will use to communicate with the cluster.",
           "type": "array",
@@ -1944,6 +1981,31 @@
         }
       }
     },
+    "etcdserverpbMemberPromoteRequest": {
+      "type": "object",
+      "properties": {
+        "ID": {
+          "description": "ID is the member ID of the member to promote.",
+          "type": "string",
+          "format": "uint64"
+        }
+      }
+    },
+    "etcdserverpbMemberPromoteResponse": {
+      "type": "object",
+      "properties": {
+        "header": {
+          "$ref": "#/definitions/etcdserverpbResponseHeader"
+        },
+        "members": {
+          "description": "members is a list of all members after promoting the member.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/etcdserverpbMember"
+          }
+        }
+      }
+    },
     "etcdserverpbMemberRemoveRequest": {
       "type": "object",
       "properties": {
@@ -2266,6 +2328,11 @@
         "header": {
           "$ref": "#/definitions/etcdserverpbResponseHeader"
         },
+        "isLearner": {
+          "description": "isLearner indicates if the member is raft learner.",
+          "type": "boolean",
+          "format": "boolean"
+        },
         "leader": {
           "description": "leader is the member ID which the responding member believes is the current leader.",
           "type": "string",
@@ -2508,6 +2575,43 @@
           "format": "int64"
         }
       }
+    },
+    "protobufAny": {
+      "type": "object",
+      "properties": {
+        "type_url": {
+          "type": "string"
+        },
+        "value": {
+          "type": "string",
+          "format": "byte"
+        }
+      }
+    },
+    "runtimeStreamError": {
+      "type": "object",
+      "properties": {
+        "details": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/protobufAny"
+          }
+        },
+        "grpc_code": {
+          "type": "integer",
+          "format": "int32"
+        },
+        "http_code": {
+          "type": "integer",
+          "format": "int32"
+        },
+        "http_status": {
+          "type": "string"
+        },
+        "message": {
+          "type": "string"
+        }
+      }
     }
   },
   "securityDefinitions": {
@@ -2521,5 +2625,43 @@
     {
       "ApiKey": []
     }
-  ]
+  ],
+  "x-stream-definitions": {
+    "etcdserverpbLeaseKeepAliveResponse": {
+      "properties": {
+        "error": {
+          "$ref": "#/definitions/runtimeStreamError"
+        },
+        "result": {
+          "$ref": "#/definitions/etcdserverpbLeaseKeepAliveResponse"
+        }
+      },
+      "title": "Stream result of etcdserverpbLeaseKeepAliveResponse",
+      "type": "object"
+    },
+    "etcdserverpbSnapshotResponse": {
+      "properties": {
+        "error": {
+          "$ref": "#/definitions/runtimeStreamError"
+        },
+        "result": {
+          "$ref": "#/definitions/etcdserverpbSnapshotResponse"
+        }
+      },
+      "title": "Stream result of etcdserverpbSnapshotResponse",
+      "type": "object"
+    },
+    "etcdserverpbWatchResponse": {
+      "properties": {
+        "error": {
+          "$ref": "#/definitions/runtimeStreamError"
+        },
+        "result": {
+          "$ref": "#/definitions/etcdserverpbWatchResponse"
+        }
+      },
+      "title": "Stream result of etcdserverpbWatchResponse",
+      "type": "object"
+    }
+  }
 }