1 00:00:00,210 --> 00:00:04,080 In this video, we are going to create a lambda function. 2 00:00:04,470 --> 00:00:08,790 It is lambda is one competing rather than an imperative model. 3 00:00:08,790 --> 00:00:11,640 So events will compete in response to events. 4 00:00:11,640 --> 00:00:14,910 When the event source happens, it triggers the lambda function. 5 00:00:15,300 --> 00:00:21,000 The event source will be the API gateway in this case, and the source could be the request of End Point, 6 00:00:21,000 --> 00:00:27,690 which will go through later the API gateway and then the execute to incoming event and interacting with 7 00:00:27,690 --> 00:00:30,480 Dynamo DB to perform CRUD operations. 8 00:00:30,750 --> 00:00:34,320 So we create a lambda function for the back end of our API. 9 00:00:34,380 --> 00:00:39,030 This lambda function creates reads, updates and deletes items from dynamic DB. 10 00:00:39,060 --> 00:00:44,340 The function uses events from the API gateway to determine how to interact with the Dynamo DB. 11 00:00:44,550 --> 00:00:52,380 So in order to create lambda function, please open the mission console, go to a lambda and choose 12 00:00:52,380 --> 00:00:54,270 create function button. 13 00:00:54,810 --> 00:00:58,230 After that we will create a function from scratch. 14 00:00:58,320 --> 00:01:03,750 To do that, I'm going to give the name as a function, as a product function, because we are using 15 00:01:03,750 --> 00:01:07,140 the implementing product microservices. 16 00:01:07,140 --> 00:01:14,160 So if you scroll down, the runtime will be Node.js and leave as it is the other complications. 17 00:01:14,160 --> 00:01:21,510 But if you expand the permissions, so under the permissions type this time we will change default execution 18 00:01:21,510 --> 00:01:28,380 role and we can select the create a new role from a policy template. 19 00:01:29,500 --> 00:01:34,300 So let me select this new role with a WS post template. 20 00:01:34,330 --> 00:01:40,120 After that, if you scroll down, it is requiring a role information role name. 21 00:01:40,120 --> 00:01:43,230 So I'm going to provide the role name as a product role. 22 00:01:43,240 --> 00:01:50,230 And for policy templates, we can choose simple Microsoft's permission, because if you expand this 23 00:01:50,230 --> 00:01:55,210 one here, you can see the different policy templates that manage by the yes. 24 00:01:55,210 --> 00:01:58,360 So we are going to select simple Microsoft's permission. 25 00:01:58,360 --> 00:02:01,510 If you select this one, you can see that it is regarding to Dynamo. 26 00:02:01,510 --> 00:02:08,530 DB So that means this policy grants the Lambda function permissions to interact with Dynamo DB in order 27 00:02:08,530 --> 00:02:10,030 to perform perturbations. 28 00:02:10,030 --> 00:02:15,670 If you scroll down, you can see that we have added a simple Microsoft permission to create role name, 29 00:02:15,670 --> 00:02:22,150 which is the product role, and we use a manage policy for simplicity as a best practice. 30 00:02:22,240 --> 00:02:27,940 We should create our own IAM policy to grant the minimum permissions required, but this time it is 31 00:02:27,940 --> 00:02:34,240 good to use managed policy in a yes by the one creating this lambda function. 32 00:02:34,240 --> 00:02:39,670 Because if you look at the architecture lambda function, interact with the Dynamo DB and it is requiring 33 00:02:39,670 --> 00:02:42,190 the permissions and it is managed by the A. 34 00:02:42,580 --> 00:02:42,750 S. 35 00:02:42,760 --> 00:02:48,610 So that's why when we are creating lambda function, we can create a new role with assigning these dynamo 36 00:02:48,610 --> 00:02:51,160 DB policies, performing the cross operations. 37 00:02:51,990 --> 00:02:54,690 Look, let's create a function. 38 00:02:55,590 --> 00:02:58,430 A lambda function is created successfully. 39 00:02:58,440 --> 00:03:01,200 So now I am going to develop our lambda function. 40 00:03:01,200 --> 00:03:07,980 But this time I'm going to copy, paste this function and let me show how we can best please go to the 41 00:03:08,230 --> 00:03:14,850 pseudocode and go to the Section 17 and lecture 143 and open indexes. 42 00:03:15,090 --> 00:03:23,040 Let's right click copy this code and paste into our Lambda Function code. 43 00:03:23,130 --> 00:03:24,780 So click the deploy button. 44 00:03:25,680 --> 00:03:30,450 So please don't consider how we can write this function in this stage, because we will write these 45 00:03:30,450 --> 00:03:33,600 code step by step and be together in the upcoming lectures. 46 00:03:33,600 --> 00:03:38,130 For now, please download and copy from the video resources and paste into here. 47 00:03:38,220 --> 00:03:44,640 So basically if we explain a little bit, so the handle method is the method that will be executed, 48 00:03:44,640 --> 00:03:47,550 the lambda function and the function takes to object. 49 00:03:47,550 --> 00:03:53,460 As you remember that the event object contains all of the data sent from the event source and the context 50 00:03:53,460 --> 00:03:59,400 object provides several methods and properties and we have copied the snippet code and paste into the 51 00:03:59,400 --> 00:04:02,880 indexes by using the event HTTP method. 52 00:04:02,880 --> 00:04:10,290 You can see in here we want that method to differentiate the HTTP request which comes from the API gateway 53 00:04:10,290 --> 00:04:16,350 and we can basically perform, create, update, delete and retrieve operations with dynamic DB using 54 00:04:16,350 --> 00:04:17,940 the SDK package. 55 00:04:18,210 --> 00:04:24,120 And I will explain these codes and develop with the latest libraries in the upcoming videos. 56 00:04:24,120 --> 00:04:30,810 But this time I'm going to copy and paste to accommodate the incoming request from the API gateway and 57 00:04:30,810 --> 00:04:35,700 you can think that we are using the dynamic DB async package to perform CRUD operations.