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In this video, we are going to create Lambda function for subscribing Amazon sans topic.

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So we will create the function that process events coming from the Amazon SAS topics.

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So let's get started.

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Please open the PlayStation console, go to Lambda functions and click the create function.

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This is the name of the function should be the goal goal function.

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If you scroll down, we are going to leave as it is for the other configurations and click the create

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function button.

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So as we learned from the Lambda asynchronous invocations, Amazon Sans invoke functions asynchronously

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to process the events.

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So when we invoke a function asynchronously, we don't wait a response from the function code and we

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hand off the event to lambda and lambda handle the rest.

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We can configure how lambda handle the errors and can send the invocation recourse to the DOM setting

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resources to chain together component or application.

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So we have successfully create goal function in the lambda.

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So if you scroll down and go to configurations and if you scroll down, if you open the asynchronous

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invocation, you can see the configurations about the asynchronous invocation.

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Basically Lambda manage the function asynchronous event queue and the attempts to retry on the errors.

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Here you can see two retry attempts setting up to or asynchronous invocation.

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If the function return an error lambda attempts to run it to two times with a one minute wait between

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the first two attempts and 2 minutes between the second and the third attempts.

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Function errors include the errors returned by the function code and the error return to by function

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runtime such as the timeout.

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So if you come to the permissions.

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And scroll down.

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We can see that we have created a new role, which is the execution role for this particular lambda

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function.

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And we have only Amazon colored watch permissions.

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But when sans invoke our function asynchronously, it needs to invoke Lambda permission into resource

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based policy section.

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If you scroll down, you can see the resource based policy and we don't have any resource based policy.

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But when it comes to invoke from the Psns this should be including an SNS record can be required permissions

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setting up in here.

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So when we subscribe our lambda function to the SNS, we should give required permission to SNS.

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In our case, permission is invoke lambda function from the SNS topics.