NOTE This file was generated by Descript 1 00:00:00,250 --> 00:00:01,799 Hi guys and welcome back. 2 00:00:01,830 --> 00:00:06,420 In this section, we're going to be deploying our Microblog app to Heroku, 3 00:00:06,450 --> 00:00:09,960 which is going to make it accessible to anyone who has an internet connection. 4 00:00:10,290 --> 00:00:12,750 So we can share our app with our users. 5 00:00:13,055 --> 00:00:16,815 There are a few things that we have to do in order to get our app on Heroku 6 00:00:16,835 --> 00:00:18,935 though, so let's get started with that. 7 00:00:19,385 --> 00:00:22,865 The first thing that we need is to be able to tell Heroku what 8 00:00:22,915 --> 00:00:28,055 dependencies our app has, so what packages we need to install from pip. 9 00:00:29,165 --> 00:00:36,275 In order to do that, we normally create a file called requirements.txt in our 10 00:00:36,275 --> 00:00:41,375 folder, and in here, we're going to write out all the dependencies of our app. 11 00:00:41,871 --> 00:00:46,491 As you can see, in here, I have activated my virtual environment and 12 00:00:46,491 --> 00:00:51,111 we have already installed dependencies using pip in previous videos. 13 00:00:51,471 --> 00:00:54,381 So if you can't remember exactly what dependencies, your application 14 00:00:54,701 --> 00:00:57,091 needs, you can do pip freeze. 15 00:00:57,451 --> 00:01:00,881 And that is going to tell you all the dependencies that we have installed. 16 00:01:01,866 --> 00:01:05,616 So by running this, you can see, we get a few different ones and 17 00:01:05,646 --> 00:01:08,676 not all of these are dependencies that we've installed manually. 18 00:01:08,676 --> 00:01:11,916 Some of these are dependencies of other dependencies. 19 00:01:12,096 --> 00:01:16,716 For example, when we install flask, it installs Jinj2 for us. 20 00:01:16,926 --> 00:01:21,366 So both of these appear in pip freeze, but we don't have to put all of 21 00:01:21,366 --> 00:01:23,916 these in our requirements.txt file. 22 00:01:24,621 --> 00:01:27,381 Instead, what we have to do here is put the stuff that we 23 00:01:27,381 --> 00:01:28,761 actually installed manually. 24 00:01:28,761 --> 00:01:31,751 So that's flask and pymongo[srv]. 25 00:01:33,561 --> 00:01:37,281 These are the two libraries that we installed, and when we install these, 26 00:01:37,671 --> 00:01:39,651 that we'll install all of these. 27 00:01:40,341 --> 00:01:44,901 You can, if you want, grab all of this, copy it and paste it in here. 28 00:01:45,141 --> 00:01:45,981 And that's totally fine. 29 00:01:45,981 --> 00:01:50,331 And what that will ensure is that you install exactly these versions of 30 00:01:50,331 --> 00:01:51,861 the libraries that we have right now. 31 00:01:52,558 --> 00:01:57,028 Installing specific versions of a library can be helpful because libraries 32 00:01:57,058 --> 00:01:59,068 change when a new version gets released. 33 00:01:59,308 --> 00:02:03,478 So by installing the exact versions that you used when you were coding 34 00:02:03,478 --> 00:02:07,438 your app, that can make sure that the app doesn't break later on when new 35 00:02:07,448 --> 00:02:08,908 versions of the libraries come out. 36 00:02:09,418 --> 00:02:14,298 If we don't write the version, for example, equal, equal 1.1.2. 37 00:02:14,938 --> 00:02:19,768 If we don't write this, then we will install the latest version of flask. 38 00:02:19,818 --> 00:02:23,215 And like I say, over time, flask will get updates and those 39 00:02:23,215 --> 00:02:25,825 updates may break past apps. 40 00:02:25,975 --> 00:02:29,605 So by installing the latest version of flask, every time it may come a 41 00:02:29,605 --> 00:02:33,205 point later down the line where our app will not work, because something that 42 00:02:33,205 --> 00:02:35,245 used to work in flask no longer works. 43 00:02:36,550 --> 00:02:39,070 However, I'm not particularly worried about that just now. 44 00:02:39,100 --> 00:02:43,150 So I'm going to leave it as is, but later on, when you're making more production 45 00:02:43,150 --> 00:02:47,920 ready applications, you may want to stay safe and ensure that specific 46 00:02:47,920 --> 00:02:49,300 versions of a library are installed. 47 00:02:49,750 --> 00:02:51,790 But again, for now, we don't really care about that. 48 00:02:52,000 --> 00:02:54,760 And we want the latest versions of apps so that we get any 49 00:02:54,760 --> 00:02:56,590 improvements that come with those. 50 00:02:57,290 --> 00:03:01,130 In the future, if something does break unexpectedly when you release 51 00:03:01,220 --> 00:03:04,610 your app or you deploy your app, just check, make sure that it isn't 52 00:03:04,640 --> 00:03:07,970 a breaking change in one of your dependencies, because that can happen. 53 00:03:08,666 --> 00:03:12,056 Now that we've got the requirements.txt file, we can use 54 00:03:12,056 --> 00:03:13,946 it to install our requirements. 55 00:03:14,456 --> 00:03:19,676 Normally you do that with pip install -r requirements.txt. 56 00:03:20,006 --> 00:03:22,466 Obviously we already have the requirements installed, so we don't 57 00:03:22,466 --> 00:03:25,796 have to run this, but this is how you would install everything that 58 00:03:25,796 --> 00:03:28,256 is in requirements.txt using pip. 59 00:03:28,496 --> 00:03:29,906 But we don't have to run it at this point. 60 00:03:30,176 --> 00:03:34,706 However, Heroku our deployment mechanism that I'll cover in a later video 61 00:03:34,926 --> 00:03:38,281 will run that, so it will install everything that is in this file. 62 00:03:39,481 --> 00:03:40,741 All right, that's everything for this video. 63 00:03:40,741 --> 00:03:44,251 I just wanted to guide you through requirements.txt and how it works. 64 00:03:44,401 --> 00:03:47,101 In the next few videos, we're going to be using these and a few 65 00:03:47,101 --> 00:03:49,291 other files to deploy to Heroku. 66 00:03:49,501 --> 00:03:50,491 So I'll see you in the next one.