1 00:00:00,360 --> 00:00:05,460 In this video, we are going to develop Hands on labs, which is the calculator project. 2 00:00:05,760 --> 00:00:07,620 You can see the image on the slide. 3 00:00:07,650 --> 00:00:12,380 This is very similar with the previous hands on loop, but this time we are going to create a lambda 4 00:00:12,390 --> 00:00:19,290 and develop calculator function and this will be invoked synchronously from the CLI commands and using 5 00:00:19,290 --> 00:00:20,580 the event JSON object. 6 00:00:20,580 --> 00:00:26,670 And in the event object, we should start with the designing event first and after that we will develop 7 00:00:26,670 --> 00:00:29,840 our lambda function according to these JSON object. 8 00:00:29,850 --> 00:00:31,530 So let's get started. 9 00:00:33,090 --> 00:00:40,050 Please open the Ouija board window and you can see that these are the steps, what we are going to do 10 00:00:40,050 --> 00:00:41,860 for this calculator project. 11 00:00:41,880 --> 00:00:45,630 First of all, this time we will start with the design of the event. 12 00:00:45,660 --> 00:00:52,590 This is the best practice to follow with creating event object before developing lambda function to 13 00:00:52,590 --> 00:00:58,750 understand how our lambda function and how we should develop our function according to incoming events. 14 00:00:58,860 --> 00:00:59,280 Object. 15 00:00:59,280 --> 00:01:03,230 So that's why I have put the first place designing lambda event. 16 00:01:03,240 --> 00:01:06,080 So basically this is the calculator project. 17 00:01:06,090 --> 00:01:13,620 For that purpose we are going to create a JSON file into a lecture folder and put these JSON format 18 00:01:13,620 --> 00:01:14,340 in here. 19 00:01:14,370 --> 00:01:21,450 You can find these lecture 63 calculator project and if you go to the event object or if you create 20 00:01:21,450 --> 00:01:26,180 these this object, you can create these kind of incoming images object. 21 00:01:26,190 --> 00:01:32,910 So we set that we have A and B attributes that could be represent number one and number two. 22 00:01:32,910 --> 00:01:41,610 And we have operated we expect opt attribute and the operator we can expect a calculator processes in 23 00:01:41,610 --> 00:01:43,730 this in this attribute value. 24 00:01:43,740 --> 00:01:50,940 So basically we will perform some operation with these numbers and it is can be configurable to change 25 00:01:50,940 --> 00:01:51,720 the operation. 26 00:01:51,720 --> 00:01:57,360 For example, we can multiply these numbers or we can divide these numbers, but this time I would like 27 00:01:57,360 --> 00:01:59,490 to stay at some operation. 28 00:01:59,490 --> 00:02:05,940 So the idea is that we are expecting this event JSON when invoking our calculated lambda functions after 29 00:02:05,940 --> 00:02:13,760 designing these lambda event JSON file object, now we can develop our lambda function for that purpose. 30 00:02:13,770 --> 00:02:19,860 Please go to the command section and see that now we are in the first step, which is the lambda function 31 00:02:19,860 --> 00:02:20,370 code. 32 00:02:20,400 --> 00:02:26,130 For that purpose we are going to create an index JS file and in the index case file here you can find 33 00:02:26,130 --> 00:02:28,800 the basic implementation of handle method. 34 00:02:28,830 --> 00:02:34,620 We are getting the event object which will be the our events object and in the event object in the first 35 00:02:34,620 --> 00:02:40,230 place, we are going to lock these incoming event into the Amazon Cloud Showcase and after that we will 36 00:02:40,230 --> 00:02:42,210 perform the calculator operation. 37 00:02:42,210 --> 00:02:46,260 So please start with coding in the validation. 38 00:02:46,260 --> 00:02:53,760 I would like to put a validation before we start because it is very important to get event A and even 39 00:02:53,760 --> 00:02:54,840 be an operator. 40 00:02:54,840 --> 00:03:01,170 Otherwise if there is undefined, we should return an exception for that purpose. 41 00:03:01,170 --> 00:03:09,090 I'm going to develop this block with throwing an exception if any of the parameters are undefined. 42 00:03:09,150 --> 00:03:15,510 So you can see these if statement this is validation, we can check a, B and or attributes in the event 43 00:03:15,510 --> 00:03:21,390 incoming event JSON object if one of them is undefined, we are throwing a new exception which is the 44 00:03:21,420 --> 00:03:23,850 event should exist these attributes. 45 00:03:24,000 --> 00:03:24,340 Okay. 46 00:03:24,390 --> 00:03:30,900 After the validation we can perform the actual business logic which is the or calculated project for 47 00:03:30,900 --> 00:03:31,470 that purpose. 48 00:03:31,470 --> 00:03:34,890 I'm going to create an. 49 00:03:35,990 --> 00:03:42,370 Object, which is the result object that will be load up to the perform the calculation. 50 00:03:42,380 --> 00:03:50,960 So after that I'm going to root use switch statement see which should be the event that operator operation 51 00:03:50,960 --> 00:03:58,550 and the value should be check operator will be plus the or multiply. 52 00:03:58,580 --> 00:04:08,780 For that reason I'm going to write this case and if there is a plus sign I'm going to calculate result 53 00:04:08,780 --> 00:04:12,500 a cool event dot a plus event dot b. 54 00:04:13,750 --> 00:04:19,150 Look, now we have finished the same operation and is the same way. 55 00:04:19,150 --> 00:04:22,480 I'm going to develop other calculated operations. 56 00:04:25,270 --> 00:04:30,460 So now this is the operation we are deducting. 57 00:04:32,000 --> 00:04:42,770 A and even B, and if you copy this case, this time I'm going to perform multiply operation so put 58 00:04:42,770 --> 00:04:48,380 to multiply and this time we are multiplying the incoming A and B numbers. 59 00:04:48,380 --> 00:04:51,560 And the last case will be the divide. 60 00:04:53,840 --> 00:05:01,490 For that purpose, I'm going to divide you A and event b oc. 61 00:05:01,520 --> 00:05:06,890 I can remove the default block because we have put the if statement. 62 00:05:06,890 --> 00:05:12,950 So these operators and the numbers should be exist in our incoming event JSON and this is our switch 63 00:05:12,950 --> 00:05:21,080 statement that we are performing the calculator operation and after that I'm going to lock this result 64 00:05:21,080 --> 00:05:22,220 for that purpose. 65 00:05:22,250 --> 00:05:29,480 We can look to the watch, look the result calculated result operation. 66 00:05:29,480 --> 00:05:33,110 We can see this line of code and after that I'm going to turn. 67 00:05:33,110 --> 00:05:41,510 The result here is very simple calculator lambda function that we are going to publish and deploy the 68 00:05:41,960 --> 00:05:43,040 lambda function. 69 00:05:43,070 --> 00:05:46,970 After we have finished the development, we can go to the next step. 70 00:05:46,970 --> 00:05:51,530 If you follow the command text, you can see that the next step is zip file. 71 00:05:51,560 --> 00:05:53,690 So please open a new terminal. 72 00:05:57,070 --> 00:05:59,860 And go to a related lecture. 73 00:06:00,910 --> 00:06:01,630 Calculator. 74 00:06:01,780 --> 00:06:02,280 Okay. 75 00:06:02,320 --> 00:06:10,570 Now I'm going to follow the second command since we have one index case file, it is created function 76 00:06:10,570 --> 00:06:11,290 zip file. 77 00:06:11,380 --> 00:06:16,570 And I am following the third step which is the create lambda function for that purpose. 78 00:06:16,570 --> 00:06:20,260 I have already get the A run before, which is the lambda execution role. 79 00:06:20,440 --> 00:06:26,560 Now I'm going to run directly this lambda create function select command hit enter. 80 00:06:26,560 --> 00:06:31,090 The function name should be the calculator and function is created successfully. 81 00:06:31,180 --> 00:06:39,400 And if you scroll down we have last step is invoke this function as you remember that we have created 82 00:06:39,670 --> 00:06:43,960 JSON file so now I'm going to invoke this file with. 83 00:06:45,100 --> 00:06:51,700 Give them even an object so you can copy and paste this output and hit enter. 84 00:06:51,850 --> 00:06:56,380 If you hit enter you can see this code is to 100 successfully executed. 85 00:06:56,380 --> 00:07:00,880 And if you go to response, Jason, you can see the response is seven. 86 00:07:00,880 --> 00:07:08,020 So that means we have performed this A and B operation and some these numbers very good. 87 00:07:08,020 --> 00:07:12,040 So after that, we can also change these events. 88 00:07:12,040 --> 00:07:16,300 JSON file, for example, as you can see that now the response is seven. 89 00:07:16,300 --> 00:07:22,660 But what if I change this operation as a multiply if you save this event JSON file and if you run the 90 00:07:22,690 --> 00:07:29,110 invoke again hit the enter and this time if you check the response, Jason, the response coming ten 91 00:07:29,110 --> 00:07:33,940 so that means we have multiply these two numbers A and B, very good. 92 00:07:33,940 --> 00:07:39,430 So now let's check these operations, these Lambda functions from the A management console. 93 00:07:40,000 --> 00:07:46,150 Please open the A management console, go to functions and see that we have calculated function go to 94 00:07:46,150 --> 00:07:52,510 function page and as you can see that our codes coming in index case as expected. 95 00:07:52,510 --> 00:07:57,700 So now before checking the cloud shows I would like to test again in here. 96 00:07:57,700 --> 00:08:05,410 If you click the test section and create a test operation and if you send a random head over this evaluation 97 00:08:05,410 --> 00:08:12,490 file, let's say this operation and click the test button and see what's happened this time the execution 98 00:08:12,490 --> 00:08:16,630 result is failed and we can see that the error is returning. 99 00:08:16,630 --> 00:08:19,630 The error type and error message is even should exist. 100 00:08:19,630 --> 00:08:23,350 AB and operator attributes in the incoming evaluation. 101 00:08:23,350 --> 00:08:27,370 So we also test the worse scenario with throwing an exception. 102 00:08:27,370 --> 00:08:32,530 Now if you would like to check the Amazon cloud looks, we should see three in location. 103 00:08:32,530 --> 00:08:39,490 And in these three location we should see that this function is invoked by the this incoming event. 104 00:08:39,490 --> 00:08:47,850 First we are some these two and five and return to the seven and after that we change the incoming event 105 00:08:47,860 --> 00:08:52,540 JSON file and we are multiply these numbers and return back to the ten. 106 00:08:53,080 --> 00:09:00,010 And lastly, we are sending a random invitation and we solve that it is returning an exception regarding 107 00:09:00,010 --> 00:09:04,840 these incoming payload should be a, b and operator attributes. 108 00:09:05,290 --> 00:09:06,520 Okay, very good. 109 00:09:06,850 --> 00:09:12,790 As you can see that we have successfully developed our hands on love, which is the calculator project.