I have a single Azure function app in which there is 4 blob triggers? I want to run the blob trigger sequentially?

Question

I have a single azure function app in which there is 4 blob trigger and output of one blob trigger is input to another blob trigger. Now, I want to run the blob trigger in sequence one after another by ensuring if the previous blob trigger is completed by lookup.

Answer 1

Hello @Nandan To run the blob triggers sequentially, you can use the functionChaining feature of Azure Functions. With function chaining, you can chain multiple functions together and pass output from one function as input to another function.

Here's an example of how you can use function chaining to run your blob triggers sequentially:

1. Create a new function that will act as the entry point for your function chain. This function will be triggered by the first blob trigger. In this function, you can use the context.bindings object to pass the output of the first blob trigger to the next function in the chain. For example:

module.exports = async function (context, myBlob) 
{ 
	context.bindings.blob1Output = myBlob; 
};

2. Create a second function that will be triggered by the output of the first function. In this function, you can process the output of the first blob trigger and pass the output to the next function in the chain. For example:

module.exports = async function (context) 
{ 
	const blob1Output = context.bindings.blob1Output; 
	// process blob1Output
	context.bindings.blob2Output = processedOutput; 
};

3. Repeat step 2 for each subsequent function in the chain, passing the output of the previous function as input to the next function.
4. Finally, create a function that will be triggered by the output of the last function in the chain. This function will be responsible for processing the final output of the chain. For example:

module.exports = async function (context) 
{ 
	const finalOutput = context.bindings.blob4Output; 
	// process finalOutput 
};

5. By using function chaining, you can ensure that your blob triggers are run sequentially and that the output of each trigger is passed to the next trigger in the chain.

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