Functions triggers and bindings

 Triggers are what cause a function to run. A trigger defines how a function is invoked and a function must have exactly one trigger. Triggers have associated data, which is often provided as the payload of the function.

Binding to a function is a way of declaratively connecting another resource to the function; bindings may be connected as input bindings, output bindings, or both. Data from bindings are provided to the function as parameters. All triggers and bindings have a direction property in the function.json file

1. For triggers, the direction is always in
2. Input and output bindings use in and out
3. Some bindings support a special direction input. If you use input, only the Advanced editor is available via the Integrate tab in the portal

Triggers and bindings let you avoid hardcoding access to other services. 

In the above screenshot, we are copying a newly uploaded file in the blob input container to the same blob output container with help of the azure function 

If you want to learn more about the azure function then read my previous blog about Azure Function

Azure Function in Azure portal

We will create an azure function with help of the Azure portal. In this demo, we will create 2 containers inside the blob

1.       Input

2.       Output

When the user will upload any file in the input container blob it will copy to the output container blob with help of the azure function binding feature without any code.  

Need to follow the below steps

1.       Go to the Azure portal (https://portal.azure.com/)

2.       I have created an Azure Function with a consumption plan which will be hosted in djblogs storage account. If you want to learn more about the azure function, please my previous blog

about AzureStorage Account.

3.       Add new function “BlobTrigger1” in the newly created function app. We will use Azure blob trigger to invoke this function.

 

4.       Once the function is created, we can add output in function on the azure portal and click in the integration link below

5.       In this demo we will show how to copy any file which will be uploaded in blob input container with help of the azure function to the same blob output container.

6.       Once the output is added then we click on the integration link inside the azure function it will display a link this

7.       If we want to see the azure function code, then need to click on the Code +Test link

Function code as below

Run.csx

No code change in this file

Function.json

Azure function all binding defined inside function.json file, so we can see the binding which we have defined

Hope it will help you to give a little understanding of the azure function trigger and binding

Keep sharing keep learning. Cheers