How to Set Custom Properties with Context in Azure Functions

Select Language:

If you’re working with Azure Functions and need to pass custom data or properties during execution, you’ll find that the built-in context parameter doesn’t support adding arbitrary properties directly. Instead, there are simple and effective ways to handle this situation.

One common method is to use environment variables. You can set your custom values as environment variables and then access them inside your function. For example, if you’re coding in Node.js, you can retrieve an environment variable like this:

javascript
const myCustomValue = process.env.MY_CUSTOM_PROPERTY;
console.log(‘Custom Property:’, myCustomValue);

This makes it easy to change the value without modifying your code, especially useful across different deployment environments.

Another approach is to pass custom data directly into your function through triggers or bindings. For instance, if your function is triggered by an HTTP request or a queue message, you can include the necessary data in the payload itself. This way, your function can process the data as part of its execution without needing additional context properties.

If you’re using output bindings to send data elsewhere, you can also include custom properties as part of those messages, ensuring the additional information travels with each piece of data your function handles.

Here’s a quick example showing how to access an environment variable in a Node.js Azure Function:

javascript
module.exports = async function (context, req) {
const myCustomValue = process.env.MY_CUSTOM_PROPERTY;
context.log(‘Custom Property:’, myCustomValue);
context.res = { body: “Success!” };
};

Using these methods, you can effectively pass and manage custom data within your Azure Functions without relying on unsupported modifications to the context object. Hope this helps you implement your solution smoothly!