1 00:00:00,090 --> 00:00:04,890 In this video we are going to develop order acknowledgements microservices. 2 00:00:05,310 --> 00:00:11,220 So before we start, we should understand the business logic of the order, acknowledge and microservices. 3 00:00:11,220 --> 00:00:18,510 Basically the client application will be sent a http post request when any order created this will be 4 00:00:18,510 --> 00:00:25,750 order placed event and this will be sent to post request to the API gateway an API gateway redirect 5 00:00:25,750 --> 00:00:31,740 to request to the order acknowledge microservice lambda function and this will be synchronous invocation. 6 00:00:31,740 --> 00:00:37,170 That means it will require required to return back to synchronous response to the client application. 7 00:00:37,380 --> 00:00:42,750 And inside of this lambda function code in the microservice, the business logic should perform several 8 00:00:42,750 --> 00:00:43,260 things. 9 00:00:43,260 --> 00:00:50,100 For example, this will be create a new item into order dynamically v table and also publish a message 10 00:00:50,100 --> 00:00:56,370 to the Amazon sass to redirect the request to the excuse and downstream services. 11 00:00:56,550 --> 00:01:01,980 So that means we will do several things when we are creating a new item in the order table. 12 00:01:02,010 --> 00:01:09,660 We should generate a new UID so that means we also have generate UID and create any item in order table. 13 00:01:09,660 --> 00:01:11,490 And after that we will publish message. 14 00:01:11,490 --> 00:01:18,480 So that means order equals microservice interact with the dynamic db or and amazon sass to publish message 15 00:01:18,480 --> 00:01:21,420 and accommodate the incoming request from API Gateway. 16 00:01:21,450 --> 00:01:27,330 This will be the synchronous invocation and response baked in synchronous invocation to the API Gateway 17 00:01:27,330 --> 00:01:28,710 and the client application. 18 00:01:28,980 --> 00:01:30,930 Okay, let's get start to the development. 19 00:01:30,930 --> 00:01:37,200 If you open the visual code I have, create a separate folder for the order acknowledgements microservices. 20 00:01:37,200 --> 00:01:41,760 I will develop all codes in this lecture folder and we will follow these steps. 21 00:01:41,760 --> 00:01:45,600 If you open the command text, you can see that we have created index case file. 22 00:01:45,600 --> 00:01:52,230 This will be our lambda function code and I'm going to create a package JSON file and we will make these 23 00:01:52,230 --> 00:01:57,390 folder as Node.js application and we will install the required package in our application. 24 00:01:57,390 --> 00:02:02,760 So according to our business case, we can see that these are the required packages that we are going 25 00:02:02,760 --> 00:02:04,770 to install one by one. 26 00:02:04,770 --> 00:02:11,130 The first package is the UUID for generating new ID before inserting a dynamic DB table. 27 00:02:11,160 --> 00:02:18,180 The second one and the third one is Dynamo DB related SDK package, which is a Dynamo DB client and 28 00:02:18,180 --> 00:02:19,350 Util Dynamo DB. 29 00:02:19,380 --> 00:02:23,790 These are the SDK packages when we interact and perform current operations on Dynamo DB. 30 00:02:23,820 --> 00:02:30,900 And the last one is the SNS client SDK package to publish message to the SNS from the Lambda function. 31 00:02:30,900 --> 00:02:36,360 For that purpose we will run these NPM install commands and after that we will develop our lambda function 32 00:02:36,360 --> 00:02:36,780 code. 33 00:02:36,810 --> 00:02:42,060 Here you can see the several steps that we are going to perform when we are implementing business logic 34 00:02:42,060 --> 00:02:48,420 in the order acknowledges microservices and here you can see the expected payload that comes from the 35 00:02:48,420 --> 00:02:54,420 API gateway client application and we will test these expected payload with publishing sans topic. 36 00:02:54,540 --> 00:02:55,410 Okay, very good. 37 00:02:55,410 --> 00:02:56,490 Let's get started. 38 00:02:56,490 --> 00:03:01,590 In order to that, I I'm going to start with creating index JS file. 39 00:03:01,620 --> 00:03:09,140 If you come back to our index file, we'll put copy and paste a basic implementation of the Lambda 100 40 00:03:09,150 --> 00:03:12,360 method that we will modify during this video. 41 00:03:12,360 --> 00:03:18,270 So if you come back to a command section, the second step is creating package JSON file with this command. 42 00:03:18,300 --> 00:03:23,280 In order to do that, I'm going to open a terminal and locate the correct section folder. 43 00:03:23,280 --> 00:03:25,770 So this will be create a package JSON. 44 00:03:25,770 --> 00:03:32,520 So that means this will be make this lecture folder as a Node.js application that we will deploy to 45 00:03:32,520 --> 00:03:33,510 Lambda function. 46 00:03:33,510 --> 00:03:41,490 For that purpose, I'm going to copy and paste NPM in command, hit enter and this is created our package 47 00:03:41,490 --> 00:03:42,150 JSON file. 48 00:03:42,150 --> 00:03:45,780 And the first thing we should do that we should add a type statement. 49 00:03:45,780 --> 00:03:52,140 We can come here and set the type as a module in order to gain schema script six standards. 50 00:03:52,140 --> 00:03:52,740 Okay. 51 00:03:52,860 --> 00:03:57,420 After adding this type attribute, we should start to install required package. 52 00:03:57,420 --> 00:04:00,210 If you come back to our package JSON file, scroll down. 53 00:04:00,210 --> 00:04:02,610 You can see that I'm going to install one by one. 54 00:04:02,610 --> 00:04:06,450 The first package is the UID. 55 00:04:06,480 --> 00:04:12,000 You can think that we will generate any ID before inserting an item to dynamo db. 56 00:04:12,000 --> 00:04:14,880 So that's why I have installed this uid. 57 00:04:15,060 --> 00:04:21,660 And after that we will install this client as an aspect package and also dynamo DB package. 58 00:04:21,690 --> 00:04:22,740 Think about that. 59 00:04:22,740 --> 00:04:25,560 Interactions into order microservices. 60 00:04:25,560 --> 00:04:31,800 Basically we need to generate ID with the UUID library and we need to save into Dynamo DB table. 61 00:04:31,800 --> 00:04:35,550 And after that we will publish message to Psns to perform these actions. 62 00:04:35,550 --> 00:04:37,890 I am installing required package. 63 00:04:37,890 --> 00:04:41,310 This is the SNS SDK package for JavaScript version three. 64 00:04:43,910 --> 00:04:47,750 And I'm following the dynamite DB package after that. 65 00:04:47,750 --> 00:04:53,400 So let's wait for a while since these SMS package is installed successfully. 66 00:04:53,420 --> 00:05:00,770 Yes, it is installed if you come here and copy from the NPM install client dynamo tb hit enter. 67 00:05:00,800 --> 00:05:04,280 This will be installed required package for dynamic DB package. 68 00:05:04,280 --> 00:05:07,100 And also I'm going to install util dynamo db. 69 00:05:07,130 --> 00:05:13,010 You have already familiar with the dynamo db sdk package, but this time we will do several things in 70 00:05:13,010 --> 00:05:14,340 the lambda function. 71 00:05:14,500 --> 00:05:14,800 Okay. 72 00:05:14,810 --> 00:05:20,210 If you go back to package JSON file and see the dependencies, we can see that. 73 00:05:20,210 --> 00:05:26,030 Make sure that you have four dependencies for our application uid dynamo, adb, util, dynamo, adb 74 00:05:26,030 --> 00:05:27,110 and SNS. 75 00:05:27,460 --> 00:05:29,780 Okay, now it is time to develop our lambda function code. 76 00:05:29,780 --> 00:05:32,810 We should plan our development for our order. 77 00:05:32,820 --> 00:05:34,460 Acknowledge microservices. 78 00:05:34,460 --> 00:05:41,180 So that means you should check the architecture and make sure that and plan your to do things with code. 79 00:05:41,210 --> 00:05:44,810 I'm going to open our index JS file. 80 00:05:44,840 --> 00:05:52,070 The first thing I would like to change the our method buddy, you can come here and change the exports 81 00:05:52,070 --> 00:05:55,040 handler to the export code code standard. 82 00:05:55,070 --> 00:06:00,940 That means we will use Postscript six standard and after that we will implement these to do logic. 83 00:06:00,950 --> 00:06:08,210 So as you remember that we when we get the request from synchronously, we should have back to response 84 00:06:08,210 --> 00:06:09,950 synchronized to API gateway. 85 00:06:09,950 --> 00:06:17,360 So that's why this should be stay in our method and after that when the request comes to order acknowledge 86 00:06:17,450 --> 00:06:18,410 microservices. 87 00:06:18,410 --> 00:06:25,040 The first thing we should do that will let the incoming event and also we will perform the get request 88 00:06:25,040 --> 00:06:27,140 but the payload information. 89 00:06:27,140 --> 00:06:29,510 So basically let them write for the zero. 90 00:06:29,990 --> 00:06:32,270 What the incoming event. 91 00:06:33,660 --> 00:06:36,500 And after that we will get the request by the payload. 92 00:06:36,510 --> 00:06:43,740 We will get the request but the payload that means or order acknowledge microservice triggered from 93 00:06:43,740 --> 00:06:50,010 the API gateway and we will get the event JSON object and get the body information to reach the incoming 94 00:06:50,010 --> 00:06:52,650 payload of the post HTTP post operation. 95 00:06:53,160 --> 00:06:59,340 After that, when we get the incoming payload is you remember that if you open the command text, we 96 00:06:59,340 --> 00:07:01,280 will expect this kind of payload. 97 00:07:01,290 --> 00:07:07,740 And when we got this kind of payload, we will start our operations, which means we will generate the 98 00:07:07,740 --> 00:07:13,410 ID with using UID library and prepare the payload with including the ID information. 99 00:07:13,410 --> 00:07:21,690 And after that we will publish message to the SNS with using SNS SDK package and after publishing the 100 00:07:21,690 --> 00:07:29,190 message we will save the order item into Dynamo DB table with using Dynamo DB SDK package and the last 101 00:07:29,190 --> 00:07:31,950 item we will return back the synchronous response. 102 00:07:32,310 --> 00:07:38,880 You can come here and say that return back synchronous order payload which generated ID to the API gateway. 103 00:07:39,100 --> 00:07:39,410 Okay. 104 00:07:39,420 --> 00:07:46,970 These are the archetypes that we are going to implement in this lambda function for our order solutions 105 00:07:47,040 --> 00:07:47,850 microservices. 106 00:07:47,880 --> 00:07:48,020 Okay. 107 00:07:48,060 --> 00:07:53,730 Now we can start the implementation part for that purpose, open the pseudocode and go to index case 108 00:07:53,740 --> 00:07:54,270 file. 109 00:07:54,300 --> 00:07:57,870 So I'm going to start with the cache below. 110 00:07:58,170 --> 00:08:03,870 So let me come here and cover we to try to look in the tribal look. 111 00:08:03,870 --> 00:08:06,210 We will perform these actions one by one. 112 00:08:06,300 --> 00:08:11,670 I will start with the first action which is the world date incoming event. 113 00:08:11,670 --> 00:08:17,880 So we will check the event, the HTTP method, and after that we will throw an exception. 114 00:08:17,880 --> 00:08:24,390 So that means we have only accept the HTTP post request when creating a new order item. 115 00:08:24,390 --> 00:08:29,150 And the first thing we have checked that the incoming event async method should be paused. 116 00:08:29,160 --> 00:08:31,500 Which event comes from the API gateway? 117 00:08:31,530 --> 00:08:37,230 If it comes from the HTTP get put or other methods, we will throw an exception. 118 00:08:37,230 --> 00:08:40,500 This is the first step and we will validate the incoming event. 119 00:08:40,650 --> 00:08:46,890 And after that the another step is the get request payload. 120 00:08:46,920 --> 00:08:54,360 We will get request payload from the incoming event, but the operation, you can see that we basically 121 00:08:54,360 --> 00:08:59,430 get the event that the information maybe you remember in the API gateway triggered the lambda function. 122 00:08:59,430 --> 00:09:04,110 We have a body information and we can pass this information, get the odd request. 123 00:09:04,110 --> 00:09:10,710 So this is the this is the JSON object that we are sending from the our payload of the HTTP post operation. 124 00:09:10,710 --> 00:09:17,820 So I have also put a validation when we get the order request, basically this order occurs should not 125 00:09:17,820 --> 00:09:20,340 be null and the type also should not be null. 126 00:09:20,340 --> 00:09:21,960 If one of the item is null. 127 00:09:21,990 --> 00:09:26,370 I have throw an exception because type is important for our action. 128 00:09:26,370 --> 00:09:31,470 So as you remember that in the command text we will send this kind of JSON object. 129 00:09:31,470 --> 00:09:37,470 So we will check the whole object and also we will check the type and we will see the shipment requirement 130 00:09:37,470 --> 00:09:41,490 for the upcoming videos putting some business logic in the type attribute. 131 00:09:41,520 --> 00:09:44,550 That's why I have checked these two attributes. 132 00:09:44,670 --> 00:09:50,850 Okay, we will finish the first step and now we are going to focus on the second step, which is the 133 00:09:50,850 --> 00:09:53,730 generate ID with using UUID library. 134 00:09:53,730 --> 00:10:00,480 So before we start, we should go to the import statement because when we are using UUID library, we 135 00:10:00,480 --> 00:10:05,580 basically put a required import statement for using UID version for. 136 00:10:05,580 --> 00:10:12,750 So please add this import statement after come back to our second step so we will generate ID. 137 00:10:12,750 --> 00:10:16,650 So in order to generate the ID, this is the steps that we are going to do. 138 00:10:16,650 --> 00:10:25,320 We basically use uid v for method and get to order ID and set the order request id as order id. 139 00:10:25,440 --> 00:10:29,580 Maybe you remember we have a partition k for all the table, which is the id. 140 00:10:29,580 --> 00:10:35,550 So that's why I have defined any attribute as ID and pasting these needed generated order id. 141 00:10:35,850 --> 00:10:36,220 Okay. 142 00:10:36,240 --> 00:10:36,840 Very good. 143 00:10:36,840 --> 00:10:42,900 So after that we will perform our actual business logic in the third and fourth step, which is to publish, 144 00:10:42,900 --> 00:10:45,480 to source and save into dynamic DV table. 145 00:10:45,630 --> 00:10:53,550 I am skipping this three and four part and focus on the another part, which is the five step. 146 00:10:53,790 --> 00:10:57,150 And if you come back to fifth one. 147 00:10:58,360 --> 00:11:03,310 We basically turned back to sync order payload which generated ID to the API gateway. 148 00:11:03,460 --> 00:11:10,030 In order to do that, I'm going to prepare any return statement in here, which is a success return 149 00:11:10,030 --> 00:11:10,690 statement. 150 00:11:10,690 --> 00:11:14,800 So this code is 200 body is a successful message. 151 00:11:14,800 --> 00:11:20,650 And also I'm passing the data that will come from the are this three and four operation. 152 00:11:20,740 --> 00:11:28,270 And if you scroll down now, we can remove these response of the method because we will return back 153 00:11:28,270 --> 00:11:31,450 the success response after finished all these steps. 154 00:11:31,450 --> 00:11:39,720 And in the case we look, we have to handle the error and also implement the error return statement 155 00:11:39,730 --> 00:11:41,770 if you come here and. 156 00:11:42,580 --> 00:11:43,780 Write down this method. 157 00:11:43,780 --> 00:11:49,990 This will be basically logging the error if this happened in the error in the tribal log and after that 158 00:11:49,990 --> 00:11:56,080 return back to API Gateway which scored 500 and the message with error details. 159 00:11:56,110 --> 00:11:57,670 Okay, very good. 160 00:11:57,820 --> 00:12:05,200 As you can see that we have developed our function without implementing third and the fourth step. 161 00:12:05,200 --> 00:12:07,570 But you understand the idea now. 162 00:12:07,570 --> 00:12:11,590 We will continue with the third and fourth step in the next video.