[DeploymentScripts] Add tail query string (Azure#8539)

* Update swagger for missing properties

* Revert "Update swagger for missing properties"

This reverts commit dc74330.

* Add tail query string to log route

* Add example and update description

* Update description one more time

* Fix tail type in the example

specification/resources/resource-manager/Microsoft.Resources/preview/2019-10-01-preview/deploymentScripts.json

@@ -314,6 +314,9 @@
         "x-ms-examples": {
           "DeploymentScriptsGetLogs": {
             "$ref": "./examples/DeploymentScripts_GetLogsDefault.json"
+          },
+          "DeploymentScriptsGetLogsWithTail": {
+            "$ref": "./examples/DeploymentScripts_GetLogsDefaultWithTail.json"
           }
         },
         "parameters": [
@@ -328,6 +331,12 @@
           },
           {
             "$ref": "#/parameters/ApiVersionParameter"
+          },
+          {
+            "name": "tail",
+            "in": "query",
+            "description": "The number of lines to show from the tail of the deployment script log. Valid value is a positive number up to 1000. If 'tail' is not provided, all available logs are shown up to container instance log capacity of 4mb.",
+            "type": "integer"
           }
         ],
         "responses": {

specification/resources/resource-manager/Microsoft.Resources/preview/2019-10-01-preview/examples/DeploymentScripts_GetLogsDefaultWithTail.json

@@ -0,0 +1,18 @@
+{
+  "parameters": {
+    "api-version": "2019-10-01-preview",
+    "subscriptionId": "00000000-0000-0000-0000-000000000000",
+    "resourceGroupName": "script-rg",
+    "scriptName": "MyDeploymentScript",
+    "tail": 5
+  },
+  "responses": {
+    "200": {
+      "body": {
+        "properties": {
+          "log": "script execution stdout/stderr logs"
+        }
+      }
+    }
+  }
+}