如何仅在Azure Function App不存在时通过Bicep创建该资源？

以下是用户提供的Bicep文件：

主模块文件 #

module functionAppTemplate 'functionApp.bicep' = {
  name: 'functionAppTemplate'
  params: {
    name: '${functionAppName}'
    kind: functionAppKind
    location: location
    servicePlanName: servicePlanName
    secretSettings: union(appSettings, productionSettings)
  }
  dependsOn: [
    servicePlanTemplate
  ]
}

module functionAppSlotTemplate 'functionAppSlot.bicep' = {
  name: 'functionAppSlotTemplate'
  params: {
    name: '${functionAppName}/staging'
    kind: functionAppKind
    location: location
    servicePlanName: servicePlanName
    secretSettings: union(appSettings, stagingSettings)
  }
  dependsOn: [
    functionAppTemplate
  ]
}

functionApp.bicep #

resource functionApp 'Microsoft.Web/sites@2018-02-01' = {
  name: name
  location: location
  kind: kind
  properties: {
    serverFarmId: resourceId('Microsoft.Web/serverfarms', servicePlanName)
    clientAffinityEnabled: false
    httpsOnly: true
    siteConfig: {
      use32BitWorkerProcess : false
      appSettings: secretSettings
    }
  }
  identity: {
    type: 'SystemAssigned'
  }
}

functionAppSlot.bicep #

resource functionAppSlot 'Microsoft.Web/sites/slots@2018-11-01' = {
  name: name
  kind: kind
  location: location
  properties: {
    clientAffinityEnabled: true
    enabled: true
    httpsOnly: true
    serverFarmId: resourceId('Microsoft.Web/serverfarms', servicePlanName)
    siteConfig: {
      use32BitWorkerProcess : false
      appSettings: secretSettings
    }
  }
  identity: {
    type: 'SystemAssigned'
  }
}

可以实现，通过Bicep的resourceExists()函数结合条件部署即可，具体有两种方式：

方式1：在子模块functionApp.bicep内控制资源创建 #

修改functionApp.bicep，添加条件判断，仅当资源不存在时才执行创建逻辑：

param name string
param location string
param kind string
param servicePlanName string
param secretSettings array

resource functionApp 'Microsoft.Web/sites@2018-02-01' = if (!resourceExists(resourceId('Microsoft.Web/sites', name))) {
  name: name
  location: location
  kind: kind
  properties: {
    serverFarmId: resourceId('Microsoft.Web/serverfarms', servicePlanName)
    clientAffinityEnabled: false
    httpsOnly: true
    siteConfig: {
      use32BitWorkerProcess : false
      appSettings: secretSettings
    }
  }
  identity: {
    type: 'SystemAssigned'
  }
}

• resourceExists(resourceId('Microsoft.Web/sites', name))会检查指定名称的Function App是否已存在
• if (!...)表示仅当资源不存在时，才会创建该资源；若资源已存在，部署时会跳过创建操作，不会修改现有资源

方式2：在主模块中控制是否部署functionAppTemplate模块 #

修改主模块代码，给functionAppTemplate模块添加条件判断：

module functionAppTemplate 'functionApp.bicep' = if (!resourceExists(resourceId('Microsoft.Web/sites', functionAppName))) {
  name: 'functionAppTemplate'
  params: {
    name: '${functionAppName}'
    kind: functionAppKind
    location: location
    servicePlanName: servicePlanName
    secretSettings: union(appSettings, productionSettings)
  }
  dependsOn: [
    servicePlanTemplate
  ]
}

module functionAppSlotTemplate 'functionAppSlot.bicep' = {
  name: 'functionAppSlotTemplate'
  params: {
    name: '${functionAppName}/staging'
    kind: functionAppKind
    location: location
    servicePlanName: servicePlanName
    secretSettings: union(appSettings, stagingSettings)
  }
  dependsOn: [
    functionAppTemplate
  ]
}

这种方式是直接控制整个子模块的部署，仅当Function App不存在时才部署functionAppTemplate模块。

内容的提问来源于stack exchange，提问作者user989988