1 00:00:00,720 --> 00:00:04,920 Now finished up our first little application using Takhar we're now going to start working on our second 2 00:00:04,920 --> 00:00:09,300 application which is going to be a little bit more complicated in nature and it's going to require us 3 00:00:09,300 --> 00:00:11,850 to learn some more advanced features around docker. 4 00:00:11,850 --> 00:00:14,790 Let's first take a look at a mockup of what we're going to build. 5 00:00:16,000 --> 00:00:17,120 All right so here it is. 6 00:00:17,170 --> 00:00:20,530 This is really a classic example of docker in action. 7 00:00:20,560 --> 00:00:24,470 You're going to find a lot of other applications out there that are very similar in nature. 8 00:00:24,520 --> 00:00:29,830 So the purpose of this tiny little application is to make a dock or container that contains a web application 9 00:00:30,220 --> 00:00:32,250 that simply displays inside the browser. 10 00:00:32,260 --> 00:00:36,230 The number of times at this point that someone essentially has visited this server. 11 00:00:36,550 --> 00:00:41,470 And so you can see right now it says number visits 10 that indicates that this page has been visited 12 00:00:41,500 --> 00:00:43,010 10 times. 13 00:00:43,120 --> 00:00:47,680 Now in order to build this we're going to need two separate components. 14 00:00:48,080 --> 00:00:53,490 First off are going to need some type of web server something to actually respond to HTP requests and 15 00:00:53,490 --> 00:00:58,750 generate some H.T. mail to show inside the browser to actually store the number of times that this thing 16 00:00:58,750 --> 00:00:59,830 has been visited. 17 00:00:59,830 --> 00:01:03,130 We're going to also make use of a little red house server. 18 00:01:03,370 --> 00:01:05,650 Remember this is an in-memory data store. 19 00:01:05,650 --> 00:01:11,380 You can essentially think of it as a tiny little database that sits entirely inside of memory. 20 00:01:11,590 --> 00:01:16,240 The only purpose of the server is going to be to contain the number of times that the page has been 21 00:01:16,240 --> 00:01:17,300 visited. 22 00:01:17,320 --> 00:01:18,890 Now something to be aware of here. 23 00:01:19,030 --> 00:01:23,810 Yes we absolutely could store this number of visits inside the node application itself. 24 00:01:23,830 --> 00:01:25,210 That's totally an option. 25 00:01:25,210 --> 00:01:29,080 However just to make the thing a little bit more kind of sufficiently complicated we are going to be 26 00:01:29,080 --> 00:01:31,340 making use of redness. 27 00:01:31,390 --> 00:01:37,300 Now I want to think a little bit about how we're going to generally architecture the sap using Dr. In 28 00:01:37,370 --> 00:01:39,120 your first kind of impression here. 29 00:01:39,120 --> 00:01:43,920 Maybe your first guess might be that we're going to make a single container inside that single container 30 00:01:44,160 --> 00:01:47,870 we can run both our node application and a read is server. 31 00:01:48,120 --> 00:01:53,040 Now don't get me wrong this is totally possible you could take this approach right here. 32 00:01:53,040 --> 00:01:58,350 However if this application ever got popular to any degree it would start to have some issues. 33 00:01:58,350 --> 00:02:00,550 Let me tell you what the issue would be. 34 00:02:00,760 --> 00:02:05,510 Let's imagine that you start getting a lot of traffic to this little somewhat useless web site that 35 00:02:05,520 --> 00:02:08,370 you've put together as you start to get more and more traffic. 36 00:02:08,380 --> 00:02:16,030 You're probably going to want to introduce more web application servers to respond to incoming HTP requests. 37 00:02:16,060 --> 00:02:21,100 And so in order to make additional servers you might create additional instances of your doctor container 38 00:02:21,160 --> 00:02:27,490 that contains both the node application and an instance of red is the issue with this approach is that 39 00:02:27,520 --> 00:02:33,530 every one of these different registers will be completely disconnected from each other. 40 00:02:33,640 --> 00:02:39,100 And so one server one read this instance over here inside this Takhar container might think that the 41 00:02:39,100 --> 00:02:45,220 page has been visited 99 times but then some other rattus instance in another container might think 42 00:02:45,220 --> 00:02:47,800 that its only been visited three times. 43 00:02:48,250 --> 00:02:53,920 So in general we would definitely not want to create multiple instances of a red instance for a single 44 00:02:53,920 --> 00:02:54,450 app. 45 00:02:54,610 --> 00:02:59,380 Instead we would want to have one single instance and then if we need to scale up the web application 46 00:02:59,380 --> 00:03:05,230 itself we could just scale the node server and make additional instances of the notes server. 47 00:03:05,230 --> 00:03:09,490 So essentially what we're going to do is be something that looks older and more like this. 48 00:03:09,490 --> 00:03:15,750 We are going to have separate docker containers for both the node application and the red is server. 49 00:03:15,820 --> 00:03:21,730 Each of the docker containers that holds the node app will connect somehow over to the rattus instance 50 00:03:21,790 --> 00:03:29,850 in a separate container and store the current counter current visit variable inside of a server instead. 51 00:03:31,080 --> 00:03:35,370 Now for the first iteration of this project we're not going to worry about scaling just yet. 52 00:03:35,370 --> 00:03:40,060 So we're really going to be setting up something that looks like this right here. 53 00:03:40,260 --> 00:03:45,050 We've got one docker container that contains our node up and then a second container that has just the 54 00:03:45,060 --> 00:03:46,980 red a server inside of it. 55 00:03:46,980 --> 00:03:49,520 So with that in mind let's take a quick break right here. 56 00:03:49,530 --> 00:03:50,760 We're going come back the next section. 57 00:03:50,790 --> 00:03:54,270 We're going to start writing out the code for our node application. 58 00:03:54,310 --> 00:03:56,070 So quick break and I'll see you in just a minute.