Support UserAssigned MSI for CosmosDB (#10306)

* Support UserAssigned MSI for CosmosDB

* add examples

* Prettify

* Prettier Fix

Author: xujin-zhang

specification/cosmos-db/resource-manager/Microsoft.DocumentDB/preview/2020-06-01-preview/cosmos-db.json

@@ -5663,6 +5663,9 @@
         "properties": {
           "x-ms-client-flatten": true,
           "$ref": "#/definitions/DatabaseAccountUpdateProperties"
+        },
+        "identity": {
+          "$ref": "#/definitions/ManagedServiceIdentity"
         }
       }
     },
@@ -7024,17 +7027,36 @@
         },
         "type": {
           "type": "string",
-          "description": "The type of identity used for the resource. The type 'SystemAssigned, UserAssigned' includes both an implicitly created identity and a set of user assigned identities. The type 'None' will remove any identities from the service.",
+          "description": "The type of identity used for the resource. The type 'SystemAssigned,UserAssigned' includes both an implicitly created identity and a set of user assigned identities. The type 'None' will remove any identities from the service.",
           "enum": [
             "SystemAssigned",
             "UserAssigned",
-            "SystemAssigned, UserAssigned",
+            "SystemAssigned,UserAssigned",
             "None"
           ],
           "x-ms-enum": {
             "name": "ResourceIdentityType",
             "modelAsString": false
           }
+        },
+        "userAssignedIdentities": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "object",
+            "properties": {
+              "principalId": {
+                "readOnly": true,
+                "type": "string",
+                "description": "The principal id of user assigned identity."
+              },
+              "clientId": {
+                "readOnly": true,
+                "type": "string",
+                "description": "The client id of user assigned identity."
+              }
+            }
+          },
+          "description": "The list of user identities associated with resource. The user identity dictionary key references will be ARM resource ids in the form: '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.ManagedIdentity/userAssignedIdentities/{identityName}'."
         }
       },
       "description": "Identity for the resource."

specification/cosmos-db/resource-manager/Microsoft.DocumentDB/preview/2020-06-01-preview/examples/CosmosDBDatabaseAccountCreateMax.json

@@ -8,6 +8,12 @@
       "location": "westus",
       "tags": {},
       "kind": "MongoDB",
+      "identity": {
+        "type": "SystemAssigned,UserAssigned",
+        "userAssignedIdentities": {
+          "/subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/eu2cgroup/providers/Microsoft.ManagedIdentity/userAssignedIdentities/id1": {}
+        }
+      },
       "properties": {
         "databaseAccountOfferType": "Standard",
         "ipRules": [
@@ -73,6 +79,15 @@
         "type": "Microsoft.DocumentDB/databaseAccounts",
         "kind": "MongoDB",
         "tags": {},
+        "identity": {
+          "type": "SystemAssigned,UserAssigned",
+          "userAssignedIdentities": {
+            "/subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/eu2cgroup/providers/Microsoft.ManagedIdentity/userAssignedIdentities/id1": {
+              "clientId": "fbe75b66-01c5-4f87-a220-233af3270436",
+              "principalId": "075a0ca6-43f6-4434-9abf-c9b1b79f9219"
+            }
+          }
+        },
         "properties": {
           "provisioningState": "Initializing",
           "isVirtualNetworkFilterEnabled": true,

specification/cosmos-db/resource-manager/Microsoft.DocumentDB/preview/2020-06-01-preview/examples/CosmosDBDatabaseAccountPatch.json

@@ -9,6 +9,12 @@
       "tags": {
         "dept": "finance"
       },
+      "identity": {
+        "type": "SystemAssigned,UserAssigned",
+        "userAssignedIdentities": {
+          "/subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/eu2cgroup/providers/Microsoft.ManagedIdentity/userAssignedIdentities/id1": {}
+        }
+      },
       "properties": {
         "ipRules": [
           {
@@ -53,6 +59,15 @@
         "tags": {
           "dept": "finance"
         },
+        "identity": {
+          "type": "SystemAssigned,UserAssigned",
+          "userAssignedIdentities": {
+            "/subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/eu2cgroup/providers/Microsoft.ManagedIdentity/userAssignedIdentities/id1": {
+              "clientId": "fbe75b66-01c5-4f87-a220-233af3270436",
+              "principalId": "075a0ca6-43f6-4434-9abf-c9b1b79f9219"
+            }
+          }
+        },
         "properties": {
           "provisioningState": "Succeeded",
           "documentEndpoint": "https://ddb1.documents.azure.com:443/",