1 00:00:00,180 --> 00:00:04,200 In this video we are going to create a lambda function for our product. 2 00:00:04,200 --> 00:00:11,490 Microservices is lambda is event driven computing service and event driven computing response to event. 3 00:00:11,490 --> 00:00:14,580 When the event source happens, it triggered the lambda function. 4 00:00:14,970 --> 00:00:21,470 The event source could be a request to end point, which will be go through the using the API gateway. 5 00:00:21,480 --> 00:00:24,720 So we create a lambda function for the back end of our API. 6 00:00:24,750 --> 00:00:30,720 This lambda function performs CRUD operations over the Dynamo DB and the function used events from the 7 00:00:30,720 --> 00:00:36,250 API gateway to determine how to interact with Dynamo DB in order to create a lambda function. 8 00:00:36,270 --> 00:00:39,060 Please go to the A mission console. 9 00:00:39,090 --> 00:00:41,580 Go to lambda functions and create function. 10 00:00:41,970 --> 00:00:48,300 So we will create function alter from scratch and the function name will be the product function runtime 11 00:00:48,300 --> 00:00:52,600 will be Node.js and leave as it is for the default complications. 12 00:00:52,620 --> 00:00:58,080 The only thing we should do that under the permission, please click the change default execution role 13 00:00:58,080 --> 00:01:04,440 and we are going to create a new role from the policy templates because we will interact with the Dynamo 14 00:01:04,440 --> 00:01:04,980 DB. 15 00:01:05,010 --> 00:01:10,470 So give the role name as a product role and the policy templates should be the. 16 00:01:11,340 --> 00:01:15,470 Simple microservices, simple microservice permission. 17 00:01:15,480 --> 00:01:21,150 This is important because these provide to interact with dynamic DB and give required permission to 18 00:01:21,150 --> 00:01:22,170 lambda function. 19 00:01:22,380 --> 00:01:28,470 So if you scroll down and click the create function, these will be create our function. 20 00:01:28,470 --> 00:01:34,950 But see that there is an exemption which is set that role with the name product will already exist. 21 00:01:34,950 --> 00:01:40,350 So make sure that this rule is including simple microservice permission come to iam. 22 00:01:41,400 --> 00:01:42,480 Court rules. 23 00:01:45,480 --> 00:01:49,290 And if you search with the product roll and if you open the product roll. 24 00:01:50,220 --> 00:01:56,620 You can see the permissions permissions are including Lambda Microservice execution role, which including 25 00:01:56,640 --> 00:01:57,960 the Dynamo DB interaction. 26 00:01:57,960 --> 00:02:02,220 So that means we can use this product role in our function. 27 00:02:02,220 --> 00:02:10,110 So if you come back to Lambda function, I can use an existing role so we can choose existing role as 28 00:02:10,110 --> 00:02:13,650 a product role and we can continue with this role. 29 00:02:13,650 --> 00:02:15,300 So please create function. 30 00:02:18,060 --> 00:02:22,560 As you can see that we have successfully create our product lambda function which is simple Microsoft's 31 00:02:22,560 --> 00:02:29,550 role that provide to interact crowd operations on dynamic DB table you can verify that in the configurations 32 00:02:29,550 --> 00:02:35,070 go to permissions and see the resource summary in Amazon Dynamic DB, we have five actions. 33 00:02:35,100 --> 00:02:38,250 These actions are CRUD operations on Dynamic DB. 34 00:02:38,280 --> 00:02:45,450 So our role is OC for our lambda function, which is the product role, including the simple microservice 35 00:02:45,450 --> 00:02:47,790 roles from interacting dynamic. 36 00:02:47,790 --> 00:02:52,500 DB Now we can configure our lambda function with additional configurations. 37 00:02:52,500 --> 00:02:55,680 You can click the configuration type and see the details. 38 00:02:55,680 --> 00:02:57,570 We can see the general configuration. 39 00:02:57,570 --> 00:03:03,210 This time we will follow the best practices when developing our CRUD operations on this lambda function. 40 00:03:03,210 --> 00:03:07,840 So one of the best practice is using environment variables as soon as possible. 41 00:03:07,860 --> 00:03:13,200 For that reason, I would like to define some environment variables to get dynamic DB related parameters 42 00:03:13,200 --> 00:03:17,730 as an environment variables, if you come here and click the environment variables, you can see that 43 00:03:17,730 --> 00:03:19,200 there is no environment for this. 44 00:03:19,200 --> 00:03:22,410 So click the edit button and add an environment variable. 45 00:03:22,410 --> 00:03:27,360 So I would like to add environment variable as a primary key, which is the ID. 46 00:03:27,570 --> 00:03:32,280 So this is our primary key of ID of the product table. 47 00:03:32,310 --> 00:03:34,500 ID is a partition and primary key. 48 00:03:34,500 --> 00:03:40,140 And I'm going to add additional environment which is the Dynamo DB table name and give the table name 49 00:03:40,170 --> 00:03:45,900 as a product so these parameters could be changed without changing any code on Lambda function. 50 00:03:45,900 --> 00:03:50,460 So that's why we will define as environment variable on lambda functions. 51 00:03:50,610 --> 00:03:57,870 So click the say button and after that you verify that environments very environment variables located 52 00:03:57,870 --> 00:03:58,530 in here. 53 00:03:58,530 --> 00:04:00,210 So come to code part. 54 00:04:00,210 --> 00:04:06,510 So that means we can use a mime, we can get environment variables into the code part of lambda function. 55 00:04:06,510 --> 00:04:13,380 But before implementing these actual logic, I would like to add a log path into our lambda function. 56 00:04:13,380 --> 00:04:19,830 As you remember that this is our generic code which is basically log incoming event from the API gateway 57 00:04:19,830 --> 00:04:22,020 and after that I don't implement any code. 58 00:04:22,020 --> 00:04:27,660 Now we will implement in the upcoming sections, but I'm leaving as it is for the response part and 59 00:04:27,660 --> 00:04:29,760 deploy the function. 60 00:04:31,050 --> 00:04:33,110 For now, it is enough to implement handler code. 61 00:04:33,120 --> 00:04:38,670 This is only return message with 200 success code, but we will develop this function interacting with 62 00:04:38,670 --> 00:04:42,360 product dynamic DB table in order to perform CRUD operations soon. 63 00:04:42,600 --> 00:04:48,270 And this code implementation, all this interaction with product dynamic DB table will be handled by 64 00:04:48,270 --> 00:04:51,840 using a SDK JavaScript version three. 65 00:04:51,990 --> 00:04:55,110 So I'm not going to jump at this SDK now. 66 00:04:55,140 --> 00:04:59,430 Instead of that, let's focus on the infrastructure, create operations. 67 00:04:59,580 --> 00:05:05,370 As you remember that if you check our architecture, we basically create product table and create product 68 00:05:05,370 --> 00:05:06,360 microservices. 69 00:05:06,360 --> 00:05:11,310 And we should also need to create API, Gateway Rest API.