Hello and welcome back.
So let's talk about Italy just clammed up when to use it and the building blocks of the several less
applications so someone should I use an enabling slander.
This is an ideal compute platform for many applications in areas.
So here is what you need to do to use the database lambda.
You need to write your own code so you are responsible for your own code in a language that is supported
by lambda and you said that is not jazz.
Java C sharp and Python.
The second thing is you should be able to run your code or be able to build the code that runs within
database lambda standard runtime environment and resources provided by Lambda as well.
Let's look at there are several applications.
A little bit.
So a typical several this application what would it consist of.
It would consist of one or more lambda functions.
So this is the code that you write one or more functions that are uploaded or deployed to Lambda.
The these codes or these functions will be triggered by events events such as words such as object uploads
to an S3 an Amazon S.A. notification an API actions.
Is this a conclusive list long.
There are many more services that can trigger a Lambda Lambda function and there are also manual you
can write your own code to call API I's and to trigger a lambda function.
You can do scheduled events for that as well.
OK so several this application is one or more lambda functions and means to trigger them to run these
functions or to trigger the functions to run the code and of course the code would be to serve the purpose
of the application.
Okay so the whole point about server lists or lambda based applications is you don't have to p provision
and infrastructure and administer it and run it by yourself in order to run your code and applications.
You can have lambda run that for you when needed by a trigger and the trigger is either as we mentioned
it could be an established service could be an alarm the function triggering another lambda function
and it could be as we mentioned a custom code or custom application that you you run could be in while
application and computer based application that runs does API calls.
This how we invoke the lambda functions so the lambda functions can stand alone or leverage other resources
such as dynamic tables or Amazon S three buckets.
The example that we just saw now the user was launching an object to an S3 bucket.
There's three bucket triggered S3 and S3 based on the unification and configuration and it knew exactly
which lambda function to trigger and that's how it worked.
So S3 you were used for that.
Now the action itself and the lambda function runs it can generate something else that will be stored
in a dynamic DV table or it will be stored in another S3 Buckets so that that's possible as well.
So the functions when they run they can stand alone so they could have the whole thing or leverage other
resources from IT areas such as dynamic DB tables or is 3 buckets.
The most basic server this application is a lambda function that's the most basic one that does not
depend on anything around it a code that learning trans that it.
Let's look at the building blocks of lambda application or lambda based application.
So the first thing and the cool component is the lambda function.
So what is the lambda function.
It is code.
So it is comprised of your custom code and any independent libraries required for this code.
So it's the foundation of the lambda service.
The second one is the event source I need to trigger that code.
I need an event or a reason or a timing or something happens that goes and triggers the code because
otherwise if you are not dependent on an event what will happen.
That means either you will not have a computer at all or you will have compute all the time sitting
idle waiting for the processing.
Right.
So now we are back to the easy to instance side when if we launch an easy to instance and it is running
you're paying for it even if it's not you.
So an Italy a service such as Amazon S.A. or custom service that could be an application that triggers
that trigger your function and executes its logic.
The third component is the downstream resources now an intelligence service such as dynamic DV S3 bucket
that lambda function calls once it is triggered.
So it could be writing information in a diamond table or saving the output into as an object into an
S3 bucket.
The fourth component of the lambda based applications or the several applications is the log streams.
So what are the log streams we're talking about.
This is when the lambda service will automatically monitor your function or function invocations or
functions invocations and report metrics to cloud watch.
Oh nice.
So that means I can through the logs streams I can monitor and know what's going on with my functions
their invocations who had requested the invocation and so on and so forth.
And you can embed some function code within some functions or subpart part of the code in order to do
custom logging statements as well.
OK so it content an execution of the code at some point when everything has been done properly then
it will say that this function was was executed at such and such read the time date and put that exactly
that allows you to analyze the execution flow and performance of your lambda function to ensure it is
working properly.
So not only are launching code but your code if it is intelligent and it has same kind of functions
you can even see the performance.
How long did it take for that step to happen how long that step waited until the next one was executed
and so on and so forth.
The last one is the model itself the framework around which the several applications in enabling is
run and this is called the several lists application model or a WSM.
This is a model of to define several applications that we assume is natively supported by Italy s cloud
formation and define simplified syntax for expressing several lists resources.
OK so let's take a quick break and I will see you again and to discuss lambda function configurations
and implications.
I'll see you shortly.