June 23, 2017 Greg

Scheduling tasks with Azure Functions time triggers

Scheduling work is a must in app development, I’m unsure how many Windows Task Scheduler I created during my years as a software developer but I’m sure one too many is the right answer.

Often as a Dev or DevOps we must solve simple requirements based on a schedule like running maintenance script, indexing content, checking state, triggering events, etc.  Task Scheduler did the job but it lacked the finesse of an efficient execution monitoring and simple multi-environment deployment. We would almost always end up missing some tasks in lower environments or having to connect to servers to figure out why a task had stopped running or simply to see what was going on. In the end, Windows Task take less time to code then they take to maintain and that’s simply a bad omen.

In this article, I will walk you through the steps of creating an Azure function based on a time trigger with NuGet dependencies and custom app settings.

1. Creating an Azure function app

  • First let’s create an Azure function app for your new trigger function.
  • Go in Azure portal and create a Function App.
  • Notice the choice between Consumption and App Service Hosting Plan.
  • For now, select either one.
Azure Function App Creation Dialog

2. Create an Azure Trigger Function

  • Click “+” on functions and choose a Timer template with your preferred language.
Options to select in azure portal to create a azure function timer

3- Azure Function development can be achieved directly in the browser web page

  • Code & Compile directly in your browser;
  • Enjoy in browser live execution logs.
Azure Functions in browser window code editor

4- Set your desired execution schedule

  • Schedules can be set from the Integrate menu;
  • The execution schedule uses a CRON expression in UTC time zone;
  • This grants the flexibility and simplicity of configuring a schedule that will meet most business requirements;
  • Configuration settings are persisted in the function.json file.
How to set a azure function schedule with a CRON expression

5- Leverage any NuGet packages

  • You can add any code dependency using NuGet packages by creating a file name project.json and adding your dependencies there.
  • This will make the package contents download and become directly available in your browser development IDE window.
How to configure nuget packages in azure portal browser web development console

6- Configure your function using appSettings

  • In the Function Apps node, you can access the Platform features tab and set application settings to use within any of your functions.
Azure function location of application settings menu
Azure function detailed app settings menu

7- Logging in Application Insight

  • Even if Azure Function provides great logging and monitoring capabilities they are only for the Azure Function itself.
  • Chances are that your Azure Function is only a small part of a larger application.
  • In that case you might also want to log within your project Application insight instance.
Azure function code to log in application insight

Read Thing to know when working with azure functions to learn more about consumption plans and how they behave.

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