This is the second article around automating deployments of Azure Functions. The first article can be found here.
This article focuses on deploying from Azure DevOps (formerly VSTS). It will address the second and third requirements discussed in the previous post, to recap:
- The Function App should be created and maintained by the release pipeline.
- The Function app must stay online whilst code is being deployed. Strangely this requirement took a considerable amount of research to resolve, maybe this was because Azure Functions were still in preview as I was researching.
Create your Azure DevOps Release pipeline
In Azure Develops (formerly VSTS) go to your release pipeline. I assume you are already familiar with the basics of Azure DevOps, but if not, you will need an artifact to release which should be created from a build pipeline. For the sake of brevity, I have only included the most important properties, if in doubt assume the default is fine or consult the documentation.
Incrementally deploy the ARM template
Add an Azure Resource Group Deployment task with the following settings:
- Version:
2.0* - Display Name:
ARM Template Deployment - Azure Subscription:
Azure Resource Manager - Action:
Create or update resource group - Resource Group:
$(ResourceGroup) - Location:
$(Location) - Template Location:
Linked artifact - Template:
$(System.DefaultWorkingDirectory)/$(Release.PrimaryArtifactSourceAlias)/FunctionApp.json. Your template json file will need to match this path. - Template Parameters:
$(System.DefaultWorkingDirectory)/$(Release.PrimaryArtifactSourceAlias)/$(ReleaseEnvironment).parameters.jsonYour template json file will need to match this path. - Override template parameters:
- Deployment Mode:
Incremental - Enable prerequisites:
None
This task will incrementally create or update the Function app for each release based on your supplied ARM template and parameter.
Stop the staging slot
Add an Azure App Service Manage task with the following settings:
- Version:
0.* - Display Name:
Stop Staging slot - Azure Subscription:
Azure Resource Manager - Action:
Stop App Service - App Service name:
$(AppName) - Specify Slot or App Service Environment:
true - Resource group:
$(ResourceGroup) - Slot name:
$(SlotName)
This step is optional, but in my experience, it helps to have the app service in a known state before publishing code.
Deploy Function App code
Add an AAzure App Service Deploy task with the following settings:
- Version:
3.* - Display Name:
Code Deployment - Azure Subscription:
Azure Resource Manager - App type:
Function App - App Service name:
$(AppName) - Deplot to slot:
true - Resource group:
$(ResourceGroup) - Slot Name:
$(SlotName). Suggested name ‘staging’. - Package or folder:
$(System.DefaultWorkingDirectory)/
This step takes the package or folder and deploys it to the staging slot.
Start the staging slot
Add an Azure App Service Manage task with the following settings:
- Version:
0.* - Display Name:
Start Staging slot - Azure Subscription:
Azure Resource Manager - Action:
Start App Service - App Service name:
$(AppName) - Specify Slot or App Service Environment:
true - Resource group:
$(ResourceGroup) - Slot name:
$(SlotName)
This step ensures the staging slot is started.
Swap slots
Add an Azure App Service Manage task with the following settings:
- Version:
0.* - Display Name:
Swap slots - Azure Subscription:
Azure Resource Manager - Action:
Swap Slots - App Service name:
$(AppName) - Specify Slot or App Service Environment:
true - Resource group:
$(ResourceGroup) - Slot name:
$(SlotName)
This task will swap the contents of the Staging slot with that of Production. More information on this and what specifically gets swapped can be found on docs.microsoft.com.