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‫So let's have a look at CloudWatch Logs.

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‫And for this, on the left hand side

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‫let's go into Log groups.

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‫So as you can see

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‫we already have one log group available to us, which is,

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‫AWS lambda, demo-lambda.

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‫Well that's because before we created a lambda function

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‫that we ran and that automatically

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‫created some log into CloudWatch logs.

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‫So if we click on this function,

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‫and this is what it was doing, he was running this code.

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‫And so if we go into CloudWatch logs

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‫and click on this log group,

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‫we can see we have one or more log streams.

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‫So here's my log stream.

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‫And within log stream, as you can see,

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‫this represents all the log lines that were logged by

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‫my lambda function. So we have the request ID,

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‫the loading function. Then we get some values,

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‫so value one... and so on,

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‫then end of the request ID and end of the reports and we can

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‫play with it. So that means that

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‫any log line logged by my lambda is going to appear here.

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‫So for example, I can change my lambda function,

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‫and say, "print an extra log line",

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‫and then we're going to deploy this and then I'm going to

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‫test my changes.

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‫So we're going to test it with this test events and then

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‫create, and then demo events perfect

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‫and create now tests.

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‫So now my function is running.

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‫And so what should happen is that

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‫if we go back into CloudWatch logs,

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‫go to my log groups and then within log group,

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‫we have a new log stream. This log stream right here,

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‫contains the log line and extra log line. Okay.

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‫So this is excellent. And this is good for just monitoring,

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‫obviously information about your lambda functions,

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‫but also what happens if there's an exception.

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‫So in this case, what I'm going to do is

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‫I'm going to put a hash sign

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‫in front of this line to comment it.

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‫And now we're going to remove the hash sign

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‫from the line 13,

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‫to have this raise exception, something went wrong.

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‫We're going to deploy the changes again

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‫and test our function.

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‫So now something went wrong and what's going to happen is

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00:01:57,890 --> 00:02:00,700
‫that if I go into my Lambda,

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‫there's a new log stream, click on this log stream.

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00:02:04,180 --> 00:02:07,030
‫And in here, I'm able to see that exception right here,

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‫and we can look at why our function went wrong.

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00:02:10,260 --> 00:02:11,470
‫So this is very handy.

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00:02:11,470 --> 00:02:13,920
‫That means that every time a Lambda function is going to run

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‫the logs are going to appear in CloudWatch logs.

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‫But this is not just true for lambda functions.

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‫Obviously this is true for any kind of logs that you want to

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‫appear in CloudWatch logs.

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00:02:22,490 --> 00:02:24,710
‫So CloudWatch logs is very handy because you can

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‫troubleshoot maybe errors in your programs

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‫or applications and so on by just looking at the log lines,

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‫within your log groups,

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‫for your services or for your applications directly within

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‫CloudWatch Logs.

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‫And then you can do some login analytics, similar things,

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‫some monitoring and so on. Okay.

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‫And this is super cool again,

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‫and something to definitely go deeper into when you are a

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‫DevOps in a company. So that's it for this lecture.

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‫I hope you liked it. And I will see you in the next lecture.