Azure Resource Template Dependencies / Application

I have a chicken and egg problem deploying Application Insights with my web application to Azure. In the ARM template, the Application Insights module is dependent upon the web site for the application id (see dependencies in the ARM templates below). On the other hand, in order to fully instrument the web application, I need the instrumentation key from the Application Insights Module. How does one get around this?

Application Insights View From the Portal

ARM Template for Web App

ARM Template for Application Insights

The solution is to have the connection strings and app settings created as nested child resources of the web site. By using the child resource strategy, one can then make the appsettings dependent upon both the web site and application insights. This allows provisioning to occur in the following order:

Web Site
Application Insights
Web Site config / appsettings

The following two answers were helpful. The first one illustrates how to pull the instrumentation key. The second one illustrates how to nest app settings and connection strings as child resources of the web site.

How to pull the instrumentation key

How to nest app settings as child resources

Here is my final template:

{
  "$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "webSiteName": {
      "type": "string"
    },
    "aadTenant": {
      "type": "string"
    },
    "aadAudience": {
      "type": "string"
    },
    "endpoints": {
      "type": "string",
      "defaultValue": "n/a"
    },
    "apiEndpoint": {
      "type": "string",
      "defaultValue": "n/a"
    },
    "sqlConnStrName": {
      "type": "string"
    },
    "sqlConnStrValue": {
      "type": "string"
    },
    "skuName": {
      "type": "string",
      "defaultValue": "F1",
      "allowedValues": [
        "F1",
        "D1",
        "B1",
        "B2",
        "B3",
        "S1",
        "S2",
        "S3",
        "P1",
        "P2",
        "P3",
        "P4"
      ],
      "metadata": {
        "description": "Describes plan's pricing tier and instance size. Check details at https://azure.microsoft.com/en-us/pricing/details/app-service/"
      }
    },
    "skuCapacity": {
      "type": "int",
      "defaultValue": 1,
      "minValue": 1,
      "metadata": {
        "description": "Describes plan's instance count"
      }
    }
  },
  "variables": {
    "hostingPlanName": "[concat(parameters('webSiteName'), '-hostingplan')]"
  },
  "resources": [
    {
      "apiVersion": "2015-08-01",
      "name": "[variables('hostingPlanName')]",
      "type": "Microsoft.Web/serverfarms",
      "location": "[resourceGroup().location]",
      "tags": {
        "displayName": "HostingPlan"
      },
      "sku": {
        "name": "[parameters('skuName')]",
        "capacity": "[parameters('skuCapacity')]"
      },
      "properties": {
        "name": "[variables('hostingPlanName')]"
      }
    },
    {
      "apiVersion": "2015-08-01",
      "name": "[parameters('webSiteName')]",
      "type": "Microsoft.Web/sites",
      "location": "[resourceGroup().location]",
      "dependsOn": [
        "[variables('hostingPlanName')]"
      ],
      "tags": {
        "[concat('hidden-related:', resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName')))]": "empty",
        "displayName": "Website"
      },
      "properties": {
        "name": "[parameters('webSiteName')]",
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]"
      },
      "resources": [
        {
          "apiVersion": "2015-08-01",
          "name": "appsettings",
          "type": "config",
          "dependsOn": [
            "[parameters('webSiteName')]",
            "[concat('AppInsights', parameters('webSiteName'))]"
          ],
          "properties": {
            "ida:Tenant": "[parameters('aadTenant')]",
            "ida:Audience": "[parameters('aadAudience')]",
            "endpoints": "[parameters('endpoints')]",
            "apiEndpoint": "[parameters('apiEndpoint')]",
            "applicationInsightsInstrumentationKey": "[reference(resourceId('Microsoft.Insights/components', concat('AppInsights', parameters('webSiteName'))), '2014-04-01').InstrumentationKey]"
          }
        },
        {
          "apiVersion": "2015-08-01",
          "type": "config",
          "name": "connectionstrings",
          "dependsOn": [
            "[parameters('webSiteName')]"
          ],
          "properties": {
            "[parameters('sqlConnStrName')]": {
              "value": "[parameters('sqlConnStrValue')]",
              "type": "SQLServer"
            }
          }
        },
        {
          "apiVersion": "2015-08-01",
          "name": "logs",
          "type": "config",
          "dependsOn": [
            "[parameters('webSiteName')]"
          ],
          "properties": {
            "applicationLogs": {
              "fileSystem": {
                "level": "Off"
              },
              "azureTableStorage": {
                "level": "Off",
                "sasUrl": null
              },
              "azureBlobStorage": {
                "level": "Information",
                "sasUrl": "TO DO: pass in a SAS Url",
                "retentionInDays": null
              }
            },
            "httpLogs": {
              "fileSystem": {
                "retentionInMb": 40,
                "enabled": true
              }
            },
            "failedRequestsTracing": {
              "enabled": true
            },
            "detailedErrorMessages": {
              "enabled": true
            }
          }
        }
      ]
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat(variables('hostingPlanName'), '-', resourceGroup().name)]",
      "type": "Microsoft.Insights/autoscalesettings",
      "location": "[resourceGroup().location]",
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName')))]": "Resource",
        "displayName": "AutoScaleSettings"
      },
      "dependsOn": [
        "[variables('hostingPlanName')]"
      ],
      "properties": {
        "profiles": [
          {
            "name": "Default",
            "capacity": {
              "minimum": 1,
              "maximum": 2,
              "default": 1
            },
            "rules": [
              {
                "metricTrigger": {
                  "metricName": "CpuPercentage",
                  "metricResourceUri": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
                  "timeGrain": "PT1M",
                  "statistic": "Average",
                  "timeWindow": "PT10M",
                  "timeAggregation": "Average",
                  "operator": "GreaterThan",
                  "threshold": 80.0
                },
                "scaleAction": {
                  "direction": "Increase",
                  "type": "ChangeCount",
                  "value": 1,
                  "cooldown": "PT10M"
                }
              },
              {
                "metricTrigger": {
                  "metricName": "CpuPercentage",
                  "metricResourceUri": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
                  "timeGrain": "PT1M",
                  "statistic": "Average",
                  "timeWindow": "PT1H",
                  "timeAggregation": "Average",
                  "operator": "LessThan",
                  "threshold": 60.0
                },
                "scaleAction": {
                  "direction": "Decrease",
                  "type": "ChangeCount",
                  "value": 1,
                  "cooldown": "PT1H"
                }
              }
            ]
          }
        ],
        "enabled": false,
        "name": "[concat(variables('hostingPlanName'), '-', resourceGroup().name)]",
        "targetResourceUri": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]"
      }
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat('ServerErrors ', parameters('webSiteName'))]",
      "type": "Microsoft.Insights/alertrules",
      "location": "[resourceGroup().location]",
      "dependsOn": [
        "[parameters('webSiteName')]"
      ],
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/sites', parameters('webSiteName')))]": "Resource",
        "displayName": "ServerErrorsAlertRule"
      },
      "properties": {
        "name": "[concat('ServerErrors ', parameters('webSiteName'))]",
        "description": "[concat(parameters('webSiteName'), ' has some server errors, status code 5xx.')]",
        "isEnabled": true,
        "condition": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.ThresholdRuleCondition",
          "dataSource": {
            "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleMetricDataSource",
            "resourceUri": "[resourceId('Microsoft.Web/sites', parameters('webSiteName'))]",
            "metricName": "Http5xx"
          },
          "operator": "GreaterThan",
          "threshold": 5.0,
          "windowSize": "PT5M"
        },
        "action": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleEmailAction",
          "sendToServiceOwners": true,
          "customEmails": ["you@example.com"]
        }
      }
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat('ForbiddenRequests ', parameters('webSiteName'))]",
      "type": "Microsoft.Insights/alertrules",
      "location": "[resourceGroup().location]",
      "dependsOn": [
        "[parameters('webSiteName')]"
      ],
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/sites', parameters('webSiteName')))]": "Resource",
        "displayName": "ForbiddenRequestsAlertRule"
      },
      "properties": {
        "name": "[concat('ForbiddenRequests ', parameters('webSiteName'))]",
        "description": "[concat(parameters('webSiteName'), ' has some requests that are forbidden, status code 403.')]",
        "isEnabled": true,
        "condition": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.ThresholdRuleCondition",
          "dataSource": {
            "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleMetricDataSource",
            "resourceUri": "[resourceId('Microsoft.Web/sites', parameters('webSiteName'))]",
            "metricName": "Http403"
          },
          "operator": "GreaterThan",
          "threshold": 5,
          "windowSize": "PT5M"
        },
        "action": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleEmailAction",
          "sendToServiceOwners": true,
          "customEmails": [ ]
        }
      }
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat('CPUHigh ', variables('hostingPlanName'))]",
      "type": "Microsoft.Insights/alertrules",
      "location": "[resourceGroup().location]",
      "dependsOn": [
        "[variables('hostingPlanName')]"
      ],
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName')))]": "Resource",
        "displayName": "CPUHighAlertRule"
      },
      "properties": {
        "name": "[concat('CPUHigh ', variables('hostingPlanName'))]",
        "description": "[concat('The average CPU is high across all the instances of ', variables('hostingPlanName'))]",
        "isEnabled": false,
        "condition": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.ThresholdRuleCondition",
          "dataSource": {
            "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleMetricDataSource",
            "resourceUri": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
            "metricName": "CpuPercentage"
          },
          "operator": "GreaterThan",
          "threshold": 90,
          "windowSize": "PT15M"
        },
        "action": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleEmailAction",
          "sendToServiceOwners": true,
          "customEmails": [ ]
        }
      }
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat('LongHttpQueue ', variables('hostingPlanName'))]",
      "type": "Microsoft.Insights/alertrules",
      "location": "[resourceGroup().location]",
      "dependsOn": [
        "[variables('hostingPlanName')]"
      ],
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName')))]": "Resource",
        "displayName": "AutoScaleSettings"
      },
      "properties": {
        "name": "[concat('LongHttpQueue ', variables('hostingPlanName'))]",
        "description": "[concat('The HTTP queue for the instances of ', variables('hostingPlanName'), ' has a large number of pending requests.')]",
        "isEnabled": false,
        "condition": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.ThresholdRuleCondition",
          "dataSource": {
            "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleMetricDataSource",
            "resourceUri": "[concat(resourceGroup().id, '/providers/Microsoft.Web/serverfarms/', variables('hostingPlanName'))]",
            "metricName": "HttpQueueLength"
          },
          "operator": "GreaterThan",
          "threshold": 100.0,
          "windowSize": "PT5M"
        },
        "action": {
          "odata.type": "Microsoft.Azure.Management.Insights.Models.RuleEmailAction",
          "sendToServiceOwners": true,
          "customEmails": [ ]
        }
      }
    },
    {
      "apiVersion": "2014-04-01",
      "name": "[concat('AppInsights', parameters('webSiteName'))]",
      "type": "Microsoft.Insights/components",
      "location": "Central US",
      "dependsOn": [
        "[parameters('webSiteName')]"
      ],
      "tags": {
        "[concat('hidden-link:', resourceId('Microsoft.Web/sites', parameters('webSiteName')))]": "Resource",
        "displayName": "AppInsightsComponent"
      },
      "properties": {
        "ApplicationId": "[parameters('webSiteName')]"
      }
    }
  ],
  "outputs": {
    "siteUri": {
      "type": "string",
      "value": "[reference(concat('Microsoft.Web/sites/', parameters('webSiteName')), '2015-08-01').hostnames[0]]"
    }
  }

}