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In this video, we are going to see how a lambda invoke asynchronously using commands so we can see

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the image on the slide that shows client invoking a lambda function asynchronously.

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Edible is lambda cues the events before sending them to the function.

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For asynchronous invocation, Lambda plays the event in a queue and returns a success response without

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additional information.

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A separate process reads the events from the queue and sent them to our lambda function in order to

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invoke a function asynchronously.

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We should set the invocation type parameter to the event.

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You can see the image on the slide.

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Here is an example in location, a invocation to a lambda click command.

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You can see that the invocation type is event.

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So here you can find the location type event and there's a response says code 202.

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So the output file, which is the response, JSON doesn't contain any information, but still it is

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created when you run this command.

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If Lambda isn't able to add the event to the queue, the error message appears in the command output

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a lambda minutes, the function asynchronous event queue and attempts to retry on errors if the function

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returns an error a dubious lambda attempts to run it two more times with one minute wait between the

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

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Function errors include error returned by the function code and the error is returned by the functions

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runtime such as timeout and so on.

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So during the course so far we only invoke our lambda functions with synchronously using the Sing Invocation

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Command.

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Now let's try to invoke Lambda Functions asynchronously with providing the invocation type as an event

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for that purpose.

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Please open the Visual Studio code and create an EVE lecture folder.

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And as you remember that in the last video we have created the calculator lambda function and this is

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the or imagine object I have created in my case object as we described in the last video.

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Now I am going to invoke this function again, synchronously and asynchronously with two types.

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So if you come back to command text, if you scroll down, let's sync invocation.

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This function, if you copy this line of code and paste in here, let me create.

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And paste again.

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So we will invoke our collocated function with giving the payload event, JSON, and we don't specify

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any information about the invocation site.

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So that means this will be invoke or function synchronously and this will be create response station

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including the response calculated value of the function hit enter and see what's happened.

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So this will be returned such 200 and generate the response JSON file.

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And if you open the JSON file, you can see the response of the function.

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So this is the synchronous invocation that returns the value of the function response from the this

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event JSON object.

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Okay, so we have all these know how we can invoke synchronously, but this time let me focus on the

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asynchronous invocation.

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So if you open the command text file and scroll down, we have also invoked this lambda function asynchronously

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for that purpose.

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We have only include this property which is the invocation type event to invoke these function asynchronously.

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Please copy this line of code and come here.

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And before proceeding these command in our command line, I would like to remove this response JSON

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file.

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Okay, now paste this select command and hit enter.

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Make sure that your invocation type should be event this time.

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As you can see, that is called return 202.

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And if you check the response JSON file, you don't see any response because we are invoking this lambda

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function asynchronously.

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See response object is null.

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As you can see that the output file which is the response JSON doesn't contain any information but still

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created when we run and invoke this command.

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If Lambda isn't able to add event to the queue, the error message appear in the command output in the

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response json.

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So let's verify from the OR invocations from the message console.

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Please go to monitor and view cloud logs for the calculator project.

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And if you open the latest log stream, you can see the incoming events is the same and we are returning.

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The result is ten for synchronous invocation.

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And if you scroll down and see again we are invoking this function as the same input event object,

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but this time we don't have return any result into the object because this is executed asynchronously.

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We don't see this result into the response JSON file, but we can see the result log into the our cloud

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watch logs.

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As you can see that we have successfully invoke our lambda function synchronous and asynchronous way

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using the ACL commands before proceeding to course, we should not forget to remove and clear a resources

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for that purpose.

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Please clean up your resources what we have created in this lecture and section.

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For that purpose, I'm going to go to the Lambda functions.

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And we have only one calculator project select these calculator project actions, delete and write.

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Delete message and click the delete button.

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This will be delayed our lambda functions and we don't create any other resource during this section.

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So now we can proceed the next section.