1 00:00:02,350 --> 00:00:05,370 So with that, we added these two features 2 00:00:05,370 --> 00:00:07,920 to the database, MongoDB container. 3 00:00:07,920 --> 00:00:10,330 Now, let's work on the node backend, 4 00:00:10,330 --> 00:00:14,600 and there we also wanna ensure that data persists 5 00:00:14,600 --> 00:00:18,380 in this case, the log files, this container writes, 6 00:00:18,380 --> 00:00:22,310 and we wanna have life source code updates 7 00:00:22,310 --> 00:00:24,560 so that when we change our source code 8 00:00:24,560 --> 00:00:27,180 in our local host project folder, 9 00:00:27,180 --> 00:00:31,513 the latest source code is also available in the container. 10 00:00:33,420 --> 00:00:34,700 For this, I'll first of all, 11 00:00:34,700 --> 00:00:38,130 stop my goals backend container again. 12 00:00:38,130 --> 00:00:41,320 So this node container, so that we can restart it 13 00:00:41,320 --> 00:00:43,200 with a different configuration 14 00:00:43,200 --> 00:00:45,950 because we now also wanna add a volume there, 15 00:00:45,950 --> 00:00:49,030 or actually two volumes. 16 00:00:49,030 --> 00:00:51,990 We wanna run our goal backend with docker run, 17 00:00:51,990 --> 00:00:54,020 but we need volumes. 18 00:00:54,020 --> 00:00:57,120 We need one volume for the log files. 19 00:00:57,120 --> 00:01:01,450 Now we can go for a name volume to not know 20 00:01:01,450 --> 00:01:03,400 where they are stored on the host machine, 21 00:01:03,400 --> 00:01:06,880 but to ensure that they survive container tear down, 22 00:01:06,880 --> 00:01:10,520 or we go for a bind mount so that we can also read 23 00:01:10,520 --> 00:01:14,870 the log files from inside our hosting machine. 24 00:01:14,870 --> 00:01:16,290 Now you could do either way. 25 00:01:16,290 --> 00:01:18,590 I'll go for a named module here, 26 00:01:18,590 --> 00:01:21,400 so that we don't have easy access to these files 27 00:01:21,400 --> 00:01:22,570 from the host machine, 28 00:01:22,570 --> 00:01:25,313 but just to practice using volumes again. 29 00:01:26,250 --> 00:01:28,420 And for that, I'll name this logs 30 00:01:28,420 --> 00:01:33,420 and bind this to /app/logs in the container. 31 00:01:33,720 --> 00:01:36,670 /app is our working directory 32 00:01:36,670 --> 00:01:39,180 as specified in the docker file. 33 00:01:39,180 --> 00:01:43,170 So that is where the entire application is copied to. 34 00:01:43,170 --> 00:01:45,910 And then we have the logs folder in there 35 00:01:45,910 --> 00:01:48,380 to which this application writes the logs 36 00:01:48,380 --> 00:01:53,050 and therefore, it's /app/logs internally 37 00:01:53,050 --> 00:01:55,410 in the container where logs are written to 38 00:01:55,410 --> 00:01:59,053 and that's there for the path we wanna bind to our volume. 39 00:01:59,950 --> 00:02:02,860 Now that's one volume, but we need another one, 40 00:02:02,860 --> 00:02:05,330 or to be precise, we need a bind mount 41 00:02:05,330 --> 00:02:08,600 which we also create with /v build. 42 00:02:08,600 --> 00:02:12,580 I wanna bind everything in the app folder 43 00:02:12,580 --> 00:02:17,150 to my local hosting directory here, 44 00:02:17,150 --> 00:02:19,950 simply to ensure that whenever I change something 45 00:02:19,950 --> 00:02:21,460 in my source code here, 46 00:02:21,460 --> 00:02:24,130 it's reflected inside of the container. 47 00:02:24,130 --> 00:02:26,010 Now for such a bind mount, 48 00:02:26,010 --> 00:02:29,670 you need the full path to your folder here, 49 00:02:29,670 --> 00:02:34,060 which you bind as a name to the container internal path. 50 00:02:34,060 --> 00:02:36,390 So, therefore, here, we can, for example, right-lick 51 00:02:36,390 --> 00:02:41,390 on app.js and copy the path and paste this in here. 52 00:02:41,440 --> 00:02:43,863 However, delete app.js at the end. 53 00:02:44,880 --> 00:02:48,230 So that I just paste the full path to backend 54 00:02:48,230 --> 00:02:51,023 and bind this to the internal app folder. 55 00:02:52,270 --> 00:02:55,270 Now also keep in mind what you learned about volumes 56 00:02:55,270 --> 00:02:58,590 and files overwriting each other in the container. 57 00:02:58,590 --> 00:03:02,990 Longer container internal paths have precedents 58 00:03:02,990 --> 00:03:05,550 and overwrite shorter paths. 59 00:03:05,550 --> 00:03:07,520 So in the example of logs here, 60 00:03:07,520 --> 00:03:11,400 we already do ensure that logs written by the container 61 00:03:11,400 --> 00:03:15,350 are not overwritten by the local logs folder 62 00:03:15,350 --> 00:03:17,560 in my local host project folder. 63 00:03:17,560 --> 00:03:21,490 So that's good. The logs in the container will survive. 64 00:03:21,490 --> 00:03:24,220 But we also learned that we should do something similar 65 00:03:24,220 --> 00:03:27,960 about node modules to ensure that if we didn't have 66 00:03:27,960 --> 00:03:31,420 node modules here on the local host machine, 67 00:03:31,420 --> 00:03:34,240 we don't overwrite the existing node modules 68 00:03:34,240 --> 00:03:37,430 in the container with the non-existing ones here, 69 00:03:37,430 --> 00:03:40,120 which would cause our container to crash 70 00:03:40,120 --> 00:03:42,450 because dependencies would be missing. 71 00:03:42,450 --> 00:03:44,640 So therefore we should add another volume, 72 00:03:44,640 --> 00:03:47,460 and here we can simply use an anonymous one 73 00:03:47,460 --> 00:03:50,410 and point at app node_modules 74 00:03:50,410 --> 00:03:52,330 to basically tell the container 75 00:03:52,330 --> 00:03:54,900 that the existing node modules folder 76 00:03:54,900 --> 00:03:58,030 inside of the container should stay there 77 00:03:58,030 --> 00:04:00,070 and should not be overwritten 78 00:04:00,070 --> 00:04:03,130 by the non-existing node modules folder 79 00:04:03,130 --> 00:04:07,820 in our host machine folder, which we bind to the app folder. 80 00:04:07,820 --> 00:04:11,740 And I did talk about this in the volumes course section. 81 00:04:11,740 --> 00:04:14,320 So definitely make sure you go through that again 82 00:04:14,320 --> 00:04:16,713 in case this doesn't tell you anything. 83 00:04:17,930 --> 00:04:20,540 With that though, we should be starting 84 00:04:20,540 --> 00:04:24,870 this node server here with our volumes added, 85 00:04:24,870 --> 00:04:28,410 and I'm again, going to run it in detached mode now 86 00:04:28,410 --> 00:04:30,140 and start it. 87 00:04:30,140 --> 00:04:34,380 And it is up and running. So that's looking good. 88 00:04:34,380 --> 00:04:38,620 If I reload my application, my React application here, 89 00:04:38,620 --> 00:04:41,590 it also is still able to fetch data, 90 00:04:41,590 --> 00:04:45,397 and deleting all the words and adding again all the words, 91 00:04:45,397 --> 00:04:47,760 so that also is looking good. 92 00:04:47,760 --> 00:04:50,910 All is got no errors here in the developer tools. 93 00:04:50,910 --> 00:04:54,820 And that proves that indeed our containers 94 00:04:54,820 --> 00:04:56,830 are up and running successfully. 95 00:04:56,830 --> 00:05:00,870 Now, although the node container with our bind mount 96 00:05:00,870 --> 00:05:05,050 and the upper volumes, however, we're not done yet. 97 00:05:05,050 --> 00:05:08,900 Yes, we do put our latest source code 98 00:05:08,900 --> 00:05:12,160 from the local host folder into the node container, 99 00:05:12,160 --> 00:05:14,860 but currently that doesn't do much 100 00:05:14,860 --> 00:05:16,890 because when we start the container, 101 00:05:16,890 --> 00:05:19,540 we run app.js with the node command, 102 00:05:19,540 --> 00:05:22,580 and that basically logs in the code 103 00:05:22,580 --> 00:05:25,580 at the point of time this containers starts. 104 00:05:25,580 --> 00:05:28,010 The node process loads all the code, 105 00:05:28,010 --> 00:05:31,210 and then starts that code, so to say. 106 00:05:31,210 --> 00:05:33,310 So, if the code changes their author, 107 00:05:33,310 --> 00:05:37,670 this has no impact on the already running node server. 108 00:05:37,670 --> 00:05:39,900 And that's of course not what we want here. 109 00:05:39,900 --> 00:05:42,650 We want the node server to restart 110 00:05:42,650 --> 00:05:44,890 whenever the code changes. 111 00:05:44,890 --> 00:05:47,713 Yes, we could stop and restart the container, 112 00:05:47,713 --> 00:05:51,100 that would do the trick, but even better than that, 113 00:05:51,100 --> 00:05:54,700 we can add the extra dependency to this project, 114 00:05:54,700 --> 00:05:57,230 which then actually will restart the server 115 00:05:57,230 --> 00:06:00,263 automatically for us when the code changes. 116 00:06:01,640 --> 00:06:04,060 For this, I'll delete package log JSON, 117 00:06:04,060 --> 00:06:08,457 and here in packaged.js, I'll add a new devDependencies node 118 00:06:09,540 --> 00:06:14,540 below dependencies, and add nodemon here as a dependency, 119 00:06:15,080 --> 00:06:16,463 and I'll pick version 2.0.4. 120 00:06:19,091 --> 00:06:21,150 Nodemon is an extra tool, 121 00:06:21,150 --> 00:06:24,010 which I already covered early in the course, 122 00:06:24,010 --> 00:06:27,610 which watches the project folder for file changes 123 00:06:27,610 --> 00:06:29,650 in JavaScript files, 124 00:06:29,650 --> 00:06:32,380 and if such a JavaScript file does change, 125 00:06:32,380 --> 00:06:35,100 it restarts the node server. 126 00:06:35,100 --> 00:06:38,020 We just have to ensure that to utilize nodemon, 127 00:06:38,020 --> 00:06:41,030 we can do that by adding a start script here 128 00:06:41,030 --> 00:06:42,800 to the scripts section. 129 00:06:42,800 --> 00:06:46,780 And there, I wanna run nodemon app.js 130 00:06:46,780 --> 00:06:49,310 to use nodemon to run app.js, 131 00:06:49,310 --> 00:06:52,010 and under the hood nodemon uses node, 132 00:06:52,010 --> 00:06:56,630 but it restarts the node server whenever any JavaScript file 133 00:06:56,630 --> 00:06:58,070 in the project folder, 134 00:06:58,070 --> 00:07:00,583 so in this case, in the backend folder changes. 135 00:07:02,330 --> 00:07:05,520 So these are changes we need to make to package.js, 136 00:07:05,520 --> 00:07:08,320 in the docker file of the backend project, 137 00:07:08,320 --> 00:07:11,320 we now need to run this start script, 138 00:07:11,320 --> 00:07:14,880 and can start like this to utilize nodemon. 139 00:07:15,890 --> 00:07:18,320 And that of course now means that we need to stop 140 00:07:18,320 --> 00:07:20,420 our goals backend container, 141 00:07:20,420 --> 00:07:23,960 so there's node application container we started, 142 00:07:23,960 --> 00:07:28,960 and then restart it, but based on a rebuilt image 143 00:07:29,010 --> 00:07:31,283 because we changed the docker file. 144 00:07:32,130 --> 00:07:35,193 So we built this goals node image again, 145 00:07:37,540 --> 00:07:40,280 and it installs all new dependencies ends on 146 00:07:40,280 --> 00:07:42,460 because the package.js file changed 147 00:07:43,560 --> 00:07:46,880 and thereafter, we can run this container 148 00:07:46,880 --> 00:07:49,653 with the same configuration as before. 149 00:07:50,740 --> 00:07:52,070 And if you'd run docker, PS, 150 00:07:52,070 --> 00:07:55,130 it should be up and running, and it is, 151 00:07:55,130 --> 00:07:58,370 but now it uses nodemon internally. 152 00:07:58,370 --> 00:08:02,920 And we can verify this by running docker logs goals-backend, 153 00:08:02,920 --> 00:08:04,390 which was our container name. 154 00:08:04,390 --> 00:08:07,050 Here, we see the nodemon log. 155 00:08:07,050 --> 00:08:09,913 And now if we change something in our code here, 156 00:08:11,070 --> 00:08:15,320 for example, here, when we say connected to MongoDB, 157 00:08:15,320 --> 00:08:17,300 I add two exclamation marks. 158 00:08:17,300 --> 00:08:22,040 If I save this and we log our goals back in logs again, 159 00:08:22,040 --> 00:08:24,570 we see it restarted because of changes, 160 00:08:24,570 --> 00:08:26,700 and we see that latest log 161 00:08:26,700 --> 00:08:29,360 and our application also still works. 162 00:08:29,360 --> 00:08:34,360 So now we also successfully provide life source code updates 163 00:08:34,429 --> 00:08:38,130 to our node application with help of our bind mount. 164 00:08:38,130 --> 00:08:41,059 And in this case with help of nodemon, 165 00:08:41,059 --> 00:08:45,330 which watches for file changes and restarts the node server 166 00:08:45,330 --> 00:08:49,480 without us being required to manually restart the container, 167 00:08:49,480 --> 00:08:52,663 which would be an option, but of course is less convenient. 168 00:08:54,250 --> 00:08:57,180 Now, there are two last things which I wanna tweak 169 00:08:57,180 --> 00:08:59,220 about this node application. 170 00:08:59,220 --> 00:09:01,540 One is this connection string. 171 00:09:01,540 --> 00:09:05,540 I had coded username and password into this string here, 172 00:09:05,540 --> 00:09:09,770 but of course that means that whenever I change that 173 00:09:09,770 --> 00:09:12,770 when I start my MongoDB container, 174 00:09:12,770 --> 00:09:17,300 so if I run MongoDB here with a different username 175 00:09:17,300 --> 00:09:18,950 or a different secret, 176 00:09:18,950 --> 00:09:21,790 which definitely is something that could happen, 177 00:09:21,790 --> 00:09:25,400 I need to change it in my code here, which is not horrible, 178 00:09:25,400 --> 00:09:28,170 but we could utilize environment variables here 179 00:09:28,170 --> 00:09:32,410 to inject dynamic values here and actually set 180 00:09:32,410 --> 00:09:34,660 the username and password we do use 181 00:09:34,660 --> 00:09:37,860 when we start this node container. 182 00:09:37,860 --> 00:09:39,820 And that's something I wanna do here. 183 00:09:39,820 --> 00:09:41,740 For data and the docker file, 184 00:09:41,740 --> 00:09:46,700 I'll add environment variables with the nth instruction, 185 00:09:46,700 --> 00:09:51,030 and I'll add one which will name MONGODB_USERNAME. 186 00:09:51,030 --> 00:09:52,853 The name is totally up to you here, 187 00:09:53,760 --> 00:09:57,380 and I'll set this to a default value of root, 188 00:09:57,380 --> 00:10:00,743 and add a second one, which I'll name MONGODB_PASSWORD, 189 00:10:02,910 --> 00:10:07,100 which I'll set to secret as a default value. 190 00:10:07,100 --> 00:10:10,000 Now these environment variables are available 191 00:10:10,000 --> 00:10:13,803 in the container environment and also in the running code. 192 00:10:14,700 --> 00:10:17,000 Now in app.js, we can utilize that. 193 00:10:17,000 --> 00:10:19,610 I wanna replace max with the values stored 194 00:10:19,610 --> 00:10:21,980 in the username environment variable 195 00:10:21,980 --> 00:10:24,799 and use the password environment variable to get 196 00:10:24,799 --> 00:10:28,780 to the value for the password and disconnection string. 197 00:10:28,780 --> 00:10:31,290 To conveniently add this in JavaScript, 198 00:10:31,290 --> 00:10:35,020 we can replace these single quote here with a backtick, 199 00:10:35,020 --> 00:10:37,690 which is a different character on your keyboard 200 00:10:37,690 --> 00:10:40,600 and do that all at the end of the string here. 201 00:10:40,600 --> 00:10:43,280 And that's just a special JavaScript syntax, 202 00:10:43,280 --> 00:10:45,340 has nothing to do with docker, 203 00:10:45,340 --> 00:10:49,500 which makes injecting dynamic values into a string easier. 204 00:10:49,500 --> 00:10:53,220 Now we can add dollar sign curly braces here, 205 00:10:53,220 --> 00:10:56,500 and then add a dynamically resolved value here, 206 00:10:56,500 --> 00:11:00,260 which is then combined into one long string. 207 00:11:00,260 --> 00:11:04,083 And here it's process.env, and then MONGODB_USERNAME. 208 00:11:05,520 --> 00:11:08,210 And here you should make sure that you really use 209 00:11:08,210 --> 00:11:10,700 the exact same environment variable 210 00:11:10,700 --> 00:11:13,570 as you specified in docker file, 211 00:11:13,570 --> 00:11:16,420 and do the same here for the password, 212 00:11:16,420 --> 00:11:20,560 dollar sign curly braces, which is just JavaScript syntax, 213 00:11:20,560 --> 00:11:24,083 has nothing to do with docker and then process.env, 214 00:11:25,090 --> 00:11:27,053 and then here it's MONGODB_PASSWORD, 215 00:11:27,960 --> 00:11:29,660 which I wanna access. 216 00:11:29,660 --> 00:11:32,750 And now these values will be injected dynamically, 217 00:11:32,750 --> 00:11:35,103 and we can set them when the container starts. 218 00:11:36,300 --> 00:11:41,170 So therefore here, I'll now stop my goals backend container, 219 00:11:41,170 --> 00:11:42,837 this node application container, 220 00:11:42,837 --> 00:11:46,900 and then I wanna restart it with specific values passed 221 00:11:46,900 --> 00:11:48,790 for these environment variables. 222 00:11:48,790 --> 00:11:52,690 The default values will not work because of root and secret 223 00:11:52,690 --> 00:11:55,220 are not the username and password I chose 224 00:11:55,220 --> 00:11:57,210 on my MongoDB database. 225 00:11:57,210 --> 00:12:01,290 There, I did choose max as a username, not root. 226 00:12:01,290 --> 00:12:04,940 So therefore, when I read on this container now, 227 00:12:04,940 --> 00:12:07,730 I will add an environment variable here, for example, 228 00:12:07,730 --> 00:12:12,623 with -d, and set MONGODB_USERNAME equal to max. 229 00:12:13,880 --> 00:12:17,640 We could also set MONGODB_PASSWORD to a different value, 230 00:12:17,640 --> 00:12:19,040 but here in my case, 231 00:12:19,040 --> 00:12:21,803 the default value I assigned will actually work. 232 00:12:22,680 --> 00:12:24,440 And of course I could have also used max 233 00:12:24,440 --> 00:12:25,920 as a default value here, 234 00:12:25,920 --> 00:12:28,430 and we wouldn't need to set any environment variable 235 00:12:28,430 --> 00:12:31,020 at all then, but I also want to practice again 236 00:12:31,020 --> 00:12:34,510 how we set our own environment variables. 237 00:12:34,510 --> 00:12:37,870 So with that, this should not work. 238 00:12:37,870 --> 00:12:41,750 And if we inspect the logs of this container, 239 00:12:41,750 --> 00:12:45,380 we see authentication failed. 240 00:12:45,380 --> 00:12:48,160 And the reason for that can be found in the docker file. 241 00:12:48,160 --> 00:12:50,410 We should assign a default value like this 242 00:12:50,410 --> 00:12:51,653 with an equal sign. 243 00:12:52,700 --> 00:12:53,533 My bad. 244 00:12:53,533 --> 00:12:55,790 We should add the default value like this 245 00:12:55,790 --> 00:12:57,310 with an equal sign. 246 00:12:57,310 --> 00:13:01,670 And if we do that, we can now stop the goals backend, 247 00:13:01,670 --> 00:13:03,550 so this running container, 248 00:13:03,550 --> 00:13:05,950 and since we changed the docker file, again, 249 00:13:05,950 --> 00:13:09,343 rebuild the image to pick up this latest docker file. 250 00:13:10,520 --> 00:13:13,410 So rebuild the image with docker build goals-node 251 00:13:14,380 --> 00:13:16,320 and then run the container again 252 00:13:16,320 --> 00:13:20,780 with our MONGODB_USERNAME being set, but not the password. 253 00:13:20,780 --> 00:13:22,183 And if we do this, 254 00:13:24,300 --> 00:13:26,850 we can again, look into the logs here, 255 00:13:26,850 --> 00:13:29,450 and now you see this connected. 256 00:13:29,450 --> 00:13:30,860 And hence, if I reload here, 257 00:13:30,860 --> 00:13:33,363 this application also again works. 258 00:13:34,720 --> 00:13:37,170 So that is working here, and that's how we can add 259 00:13:37,170 --> 00:13:39,540 our own environment variables. 260 00:13:39,540 --> 00:13:41,730 Now with the environment variables out of the way, 261 00:13:41,730 --> 00:13:45,230 there is one last thing I wanna take care of. 262 00:13:45,230 --> 00:13:47,910 At the moment, thanks to the stalker file, 263 00:13:47,910 --> 00:13:51,030 I copied everything from this backend folder 264 00:13:51,030 --> 00:13:53,690 into the container, after the dependencies 265 00:13:53,690 --> 00:13:55,610 have been installed in there. 266 00:13:55,610 --> 00:13:58,970 This is okay, but there are files I'm copying 267 00:13:58,970 --> 00:14:02,820 into the container, which I might not wanna copy in here. 268 00:14:02,820 --> 00:14:05,910 And for that, I'll add a .dockerignore file. 269 00:14:05,910 --> 00:14:08,823 I also covered this earlier in the course already. 270 00:14:09,670 --> 00:14:12,460 Here, I, for example, want to exclude node modules. 271 00:14:12,460 --> 00:14:14,610 If I had this folder here, 272 00:14:14,610 --> 00:14:17,320 I'll also exclude the docker file itself 273 00:14:17,320 --> 00:14:21,570 and exclude a .git folder if it should exist. 274 00:14:21,570 --> 00:14:24,910 And these are some folders which are now simply won't copy 275 00:14:24,910 --> 00:14:26,500 into the existing container, 276 00:14:26,500 --> 00:14:29,430 and the node modules folder is the most important one 277 00:14:29,430 --> 00:14:32,470 simply to ensure that I'm not unnecessarily copying 278 00:14:32,470 --> 00:14:36,410 all my dependencies again after I already did install them 279 00:14:36,410 --> 00:14:38,410 inside of the container. 280 00:14:38,410 --> 00:14:40,510 And that is now really all. 281 00:14:40,510 --> 00:14:42,340 Now, if we would rebuild the image, 282 00:14:42,340 --> 00:14:44,500 we would ensure that the image gets built 283 00:14:44,500 --> 00:14:47,630 without these redundant files being copied in. 284 00:14:47,630 --> 00:14:50,070 And we now have our node application 285 00:14:50,070 --> 00:14:51,440 where we can change the code 286 00:14:51,440 --> 00:14:53,620 and it will be picked up automatically 287 00:14:53,620 --> 00:14:56,490 and where we also use environment variables. 288 00:14:56,490 --> 00:14:59,443 So therefore, let's now move on to the React application.