WEBVTT 00:00.080 --> 00:01.940 The final project is now done. 00:01.940 --> 00:06.770 We have the two Python programs, but I thought it would be nice to show you how you can launch, or 00:06.770 --> 00:10.850 how you can actually automatically launch your programs when the Raspberry Pi boots. 00:10.850 --> 00:14.240 And here in this lesson, this is actually something completely new that you're going to see. 00:14.240 --> 00:16.310 So it's not something we covered in the course. 00:16.520 --> 00:17.720 It's really a bonus step. 00:17.720 --> 00:22.490 If you want to go a bit further, we're going to learn a new functionality that's quite useful on the 00:22.490 --> 00:23.240 Raspberry Pi. 00:23.240 --> 00:30.140 So let's come back to the we have the two terminals and you see that I run my project step four and 00:30.140 --> 00:32.960 then I run my project step six. 00:32.960 --> 00:33.980 Those are the two files. 00:33.980 --> 00:35.600 And the problem with that. 00:35.600 --> 00:36.950 So it's correctly working. 00:36.950 --> 00:42.860 But every time you want to start your project you have to, well, get access to the Raspberry Pi. 00:42.860 --> 00:47.660 So you need to either like I'm doing here, login with VNC or plug a screen. 00:47.660 --> 00:54.230 Or even if you don't want to have any desktop access, you can just log in with SSH and run the program. 00:54.230 --> 00:55.850 But you will always have to do that. 00:55.850 --> 01:02.090 Now there is a way for you to start this project without even Accessing the Raspberry Pi. 01:02.120 --> 01:05.120 So the only thing you need to do is to boot the Raspberry Pi. 01:05.120 --> 01:07.850 And the project is going to start automatically. 01:07.850 --> 01:10.010 And let's learn how to do this. 01:10.010 --> 01:13.550 So I'm going to I'm just going to use one terminal. 01:14.270 --> 01:15.410 Let's clear everything. 01:15.410 --> 01:19.580 And we are going to use the functionality that's called systemd. 01:19.610 --> 01:25.100 And here for this video I really emphasize that you have to just just follow every step that I do. 01:25.130 --> 01:25.310 Okay. 01:25.340 --> 01:28.550 It's very important to follow exactly the things that I do. 01:28.550 --> 01:32.600 So you will go to slash lib okay. 01:32.630 --> 01:34.640 We start from the root of the file system. 01:34.640 --> 01:44.060 So slash lib slash system D slash system okay. 01:44.090 --> 01:44.990 That should work. 01:44.990 --> 01:51.590 And if I do ls uh, well, you see, we have a lot of files and lots of them. 01:51.590 --> 01:54.410 You can see they end with dot service. 01:54.410 --> 02:00.260 So all of those files basically are programs that are going to be run automatically, for example, 02:00.290 --> 02:00.890 on boot. 02:00.890 --> 02:03.140 And they will be run in the background. 02:03.140 --> 02:07.400 So you don't necessarily know what's happening, but everything is running in the background. 02:07.400 --> 02:10.460 And what we will do is we will simply add a new service. 02:10.460 --> 02:16.040 So actually two new services, one for the first program and one for the second program, so that we 02:16.040 --> 02:18.800 can just start them on boot. 02:18.800 --> 02:24.050 And to do that we simply need to add new files in this here in this directory. 02:24.050 --> 02:30.350 And so I'm going to add a new file with a nano directly because I'm going to write to it and note that 02:30.350 --> 02:36.590 I'm not in my home directory anymore okay I am not in slash home slash pi slash something. 02:36.590 --> 02:41.150 So because I'm the you see I'm logged in at the as the user Pi. 02:41.150 --> 02:45.560 But I'm in another directory that's not in my home directory. 02:45.560 --> 02:48.530 I will need the admin privilege. 02:48.530 --> 02:54.080 So I will need to write sudo in front of comments if I want to, for example, modify files to remove 02:54.080 --> 03:05.990 files, etc. so I will do sudo nano and then let's name this project take Photos and then that service. 03:06.020 --> 03:09.080 Okay, so you need to end with that service. 03:09.140 --> 03:10.880 I'm going to press enter. 03:10.910 --> 03:12.620 Let's make it a bit bigger. 03:16.340 --> 03:20.960 And here where you're going to need to write exactly what I'm writing. 03:20.990 --> 03:21.620 Okay. 03:21.620 --> 03:30.380 So you're going to start with brackets like that and write unit then description equal. 03:30.380 --> 03:32.240 And here you can write whatever you want okay. 03:32.270 --> 03:47.420 For example program that detects movement and then takes a photo and send it by email. 03:47.420 --> 03:49.430 So this is just a description. 03:49.430 --> 03:52.010 It's not going to be used by anything okay. 03:52.040 --> 03:52.820 It's just for you. 03:52.850 --> 03:56.780 Maybe later if you find a service again and you know what it does. 03:56.780 --> 04:02.480 But that's not really important, then you're going to write after okay with uppercase at the beginning 04:02.490 --> 04:08.250 and no space multi user dot targets. 04:08.250 --> 04:12.270 So this is basically going to say when to start the service. 04:12.300 --> 04:12.480 Okay. 04:12.510 --> 04:15.630 You have different things that are going to be executed on boot. 04:15.630 --> 04:17.850 And there is a certain order to respect. 04:17.850 --> 04:20.520 I'm not going to go much further with this okay. 04:20.550 --> 04:23.640 This is something you can explore on your own after this course. 04:23.640 --> 04:28.830 If you want to, you can explore more about systemd and learn what's the multi user target. 04:28.830 --> 04:31.410 But for now let's just write it like this okay. 04:31.440 --> 04:34.320 So multi user dot target. 04:34.500 --> 04:35.760 When I go back to a new line. 04:35.760 --> 04:46.380 And then I'm going to do service inside bracket, I will have to put working directory with a W and 04:46.380 --> 04:47.490 D uppercase. 04:48.960 --> 04:54.030 And here I'm going to put the directory where I have my files. 04:54.030 --> 04:57.210 So here slash home slash. 04:57.210 --> 05:03.000 If you are not sure you just open a new terminal Here. 05:03.060 --> 05:09.720 I'm going to my document Python programs and I do PWD. 05:10.680 --> 05:16.980 And then I can just copy this inside the file and how to copy. 05:17.010 --> 05:20.400 You can do control shift and C okay. 05:20.430 --> 05:24.450 Because just Ctrl C you see Ctrl C is sending Ctrl C to the terminal. 05:24.570 --> 05:31.380 So Ctrl shift and C and here Ctrl shift and V. 05:31.650 --> 05:32.100 All right. 05:32.100 --> 05:33.750 And this way you don't make any mistake. 05:33.750 --> 05:36.720 So that's the working directory for our script. 05:36.810 --> 05:40.740 So that we can also run this as the Pi user. 05:40.770 --> 05:42.120 That's going to be very important. 05:42.120 --> 05:50.700 Then we have exec start like this is equal to an exec start is the command we want to run. 05:50.880 --> 05:53.670 So a service is not necessarily going to run a Python script. 05:53.670 --> 05:56.490 It's going to run any command that you want. 05:56.520 --> 06:02.400 Now the command we want to run here is Python three project. 06:02.400 --> 06:04.170 Step four dot p y. 06:04.200 --> 06:06.660 But for this we are going to use the absolute path. 06:06.660 --> 06:12.390 So we're going to use the absolute path for the file name here but also for the command. 06:12.420 --> 06:15.330 And you might think what's the absolute path for Python three. 06:15.330 --> 06:18.090 It's already a it's just a comment right. 06:18.090 --> 06:21.480 But even comments have an absolute path. 06:21.480 --> 06:24.480 And you can find that with the command which. 06:24.780 --> 06:27.900 So you do which Python three. 06:27.900 --> 06:30.000 And you see that when you run Python three. 06:30.030 --> 06:35.490 Actually what's running is slash user slash bin slash Python three. 06:35.520 --> 06:35.880 All right. 06:35.880 --> 06:39.210 So this is kind of an alias for that one. 06:39.210 --> 06:46.080 So I'm going to copy again and paste it there with Ctrl shift and C and Ctrl shift and V. 06:46.260 --> 06:46.590 All right. 06:46.620 --> 06:48.270 So error in Python three. 06:48.270 --> 06:50.730 And then what. 06:50.760 --> 06:59.280 That's the same path here for the Python program that I'm going to copy here. 07:00.510 --> 07:10.680 And then slash and the name of the file is project step four dot p y. 07:10.710 --> 07:13.170 Make sure you don't make any typo. 07:13.170 --> 07:20.250 If you want, you can actually just copy that and run it inside the terminal and see if it's going to 07:20.250 --> 07:20.970 work. 07:22.050 --> 07:24.150 And you see it's working. 07:24.390 --> 07:24.630 All right. 07:24.660 --> 07:27.210 So you can be sure that you have the correct command. 07:27.240 --> 07:28.530 That's very important. 07:28.560 --> 07:29.160 Good. 07:29.190 --> 07:30.450 Now I go back to a new line. 07:30.450 --> 07:31.860 I have one more thing here. 07:31.860 --> 07:34.830 User equal pi. 07:34.860 --> 07:35.220 Okay. 07:35.250 --> 07:40.050 So pi is pi because we are here connected as the user pi. 07:40.080 --> 07:42.780 So that's the user you want to run the script as. 07:42.810 --> 07:43.170 Right. 07:43.200 --> 07:48.030 So if you used something different than pi you need to also replace the user here. 07:48.030 --> 07:49.530 And we are almost done. 07:49.530 --> 07:59.220 So finally this one last thing is going to be install like that and wanted by okay. 07:59.250 --> 08:00.630 So be uppercase. 08:00.630 --> 08:07.590 And we're going to write the same thing here multi That's user dot target. 08:07.680 --> 08:08.070 All right. 08:08.070 --> 08:09.720 So it's quite a lot of new things. 08:09.720 --> 08:11.670 Once again I'm not going to explain everything. 08:11.670 --> 08:15.000 That's something you can search on your own after the course. 08:15.000 --> 08:17.220 But now the file is finished. 08:17.220 --> 08:21.810 So I'm going to do Ctrl S and then Ctrl x. 08:21.810 --> 08:26.220 And I have my new file that's going to be saved inside inside here. 08:26.220 --> 08:31.320 And I'm going to directly create a service for the second Python program. 08:31.320 --> 08:32.970 So that's going to be the project. 08:33.390 --> 08:34.710 Step six. 08:34.710 --> 08:36.360 Here we have run the project step four. 08:36.360 --> 08:42.660 And we want the project step six to do this is going to be much simpler because I already created a 08:42.690 --> 08:44.700 service is going to be almost the same. 08:44.700 --> 08:46.680 So I can just copy it. 08:46.770 --> 08:51.660 To copy it I'm going to also need to do sudo because I'm not in my home directory. 08:52.320 --> 08:57.960 So sudo cp project take photos service. 08:57.960 --> 09:00.270 That's the one I want to copy from. 09:00.660 --> 09:08.190 And the new file is going to be for example project Web server dot service. 09:08.190 --> 09:11.220 So that's the name for my second service. 09:11.550 --> 09:19.710 Then I do sudo nano project web server. 09:21.330 --> 09:22.380 Okay, that's the same one. 09:22.380 --> 09:27.930 And what I will do is modify the description first because it's not accurate. 09:28.440 --> 09:41.580 So this is going to be program actually uses a web server that displays last photo. 09:41.610 --> 09:42.930 It's really not important. 09:42.930 --> 09:45.000 So unit is the same description. 09:45.000 --> 09:47.520 We can change it after it's going to be the same. 09:47.520 --> 09:52.920 And then the working directory is the same because the Python file is still in that one. 09:52.920 --> 09:58.710 But the exact start is going to be different only with the file name here you're going to be project 09:58.710 --> 10:00.420 step six. 10:00.660 --> 10:01.020 Okay. 10:01.050 --> 10:04.140 So that's the only thing we need to change is the exact start. 10:04.170 --> 10:05.920 So we don't run the same script. 10:05.950 --> 10:06.340 All right. 10:06.370 --> 10:07.660 The rest is the same. 10:07.690 --> 10:11.860 Now let's do control S and X, and we have the two services. 10:11.890 --> 10:12.460 All right. 10:12.460 --> 10:19.270 So now that we have created those files we will be able to start and stop the service. 10:19.270 --> 10:22.060 So make sure that you don't have anything running. 10:22.090 --> 10:22.660 Okay. 10:22.690 --> 10:28.150 Make sure that you are not running those files anywhere else on your Raspberry Pi. 10:28.180 --> 10:31.090 Then let's go back to the home directory for example. 10:31.120 --> 10:32.140 Let's do clear. 10:32.140 --> 10:34.030 And now how to start the service. 10:34.060 --> 10:37.870 We can do sudo systemctl. 10:37.900 --> 10:38.200 Okay. 10:38.230 --> 10:44.140 So we have the systemctl command with start and then the name of the service. 10:44.140 --> 10:49.150 So for example project and then take photos. 10:49.150 --> 10:50.440 So I can press tab here. 10:50.440 --> 10:51.610 It should be found. 10:51.640 --> 10:52.030 Okay. 10:52.060 --> 10:57.850 So if it's correctly placed in the right folder with the right name and everything we should find it 10:57.850 --> 10:58.150 here. 10:58.150 --> 11:01.600 If I press enter you see that we go back to a new line. 11:01.600 --> 11:02.500 Nothing happens. 11:02.500 --> 11:06.370 But the program was actually started And you can check that. 11:06.370 --> 11:11.230 For example, the easy check is just to put your hand in front of the Pir sensor and you should see 11:11.230 --> 11:16.180 the LED should be turned on, and then you can put your hand for five seconds. 11:16.180 --> 11:20.920 And you will also see new photos in the photos. 11:20.920 --> 11:25.600 Final project okay, a new log file and you will also receive an email. 11:25.600 --> 11:37.060 I can start my second program with pseudo system CTL start project with a web server. 11:38.020 --> 11:42.280 And this is going to start the second Python program, this one. 11:42.280 --> 11:43.120 How to test it. 11:43.150 --> 11:48.760 Well you just go to the URL here and you see it's working okay. 11:48.760 --> 11:51.910 So note I didn't run any Python script directly. 11:51.910 --> 11:53.950 I just started the services. 11:53.980 --> 11:55.450 Now if you have an error. 11:55.450 --> 12:01.150 So for example if you cannot see the LED, if you cannot see new photos, if you cannot see that you 12:01.150 --> 12:05.830 can use the journal Settle. 12:05.830 --> 12:07.720 So you don't need sudo for that. 12:07.720 --> 12:12.070 And then dash u and the name of the service for example that one. 12:14.500 --> 12:20.950 I press enter and well that's actually not from today. 12:20.950 --> 12:24.160 But the last time I, I tried this I had some error. 12:24.190 --> 12:24.400 Okay. 12:24.430 --> 12:27.280 So if you have some error logs then. 12:27.310 --> 12:29.980 So I press Q here or ctrl C to exit. 12:29.980 --> 12:36.460 So if you have some errors and you are not sure what you can use this Journalctl u and then the name 12:36.460 --> 12:37.390 of the service. 12:37.840 --> 12:38.260 Okay. 12:38.260 --> 12:41.680 But if it's working fine you will not see anything in this file. 12:41.770 --> 12:43.810 It's just for you to to know. 12:43.840 --> 12:46.390 So let's, uh, clear that. 12:46.390 --> 12:51.880 And now, while those programs are running in the background as services, how to stop them, you can 12:51.880 --> 12:54.610 do sudo systemctl. 12:54.610 --> 12:55.780 And we had the start. 12:55.780 --> 13:06.730 So we have stop project take photos and then we do the same with project web server Seven and they are 13:06.730 --> 13:07.390 stopped. 13:07.750 --> 13:10.540 And you can see if I refresh this page here. 13:12.100 --> 13:13.960 Now, you see it's not working anymore. 13:13.960 --> 13:18.730 And if you put your hand in front of the Pir sensor, you will not see the LED anymore. 13:18.730 --> 13:21.640 So you can see that the scripts have been stopped. 13:21.640 --> 13:26.050 And so you can do start and stop just like that. 13:26.080 --> 13:26.620 Great. 13:26.620 --> 13:28.810 And now you might think that that's great. 13:28.810 --> 13:33.160 Instead of starting the Python script directly, we can start them with the service. 13:33.160 --> 13:35.260 But it's still the same as before. 13:35.260 --> 13:42.670 And so yes, but now what we can do is we can enable those services so that they will be started automatically 13:42.670 --> 13:43.420 on boot. 13:43.630 --> 13:45.160 So that's why we create a service. 13:45.160 --> 13:48.040 And before we enable the service there is a command you can use. 13:48.040 --> 13:57.370 So sudo systemctl it's called list dash unit dash files. 13:57.820 --> 13:59.890 Let's run that and you can see. 13:59.890 --> 14:01.390 So we will have a lot of stuff. 14:01.420 --> 14:04.450 And you can see the kind of file and then the state. 14:04.450 --> 14:05.830 So we have state and presets. 14:05.860 --> 14:12.730 What's going to be interesting for us is state and you can see some stuff is disabled, some stuff is 14:12.730 --> 14:13.750 enabled. 14:13.780 --> 14:14.440 Okay. 14:14.980 --> 14:18.400 If I press enter I can scroll here. 14:18.490 --> 14:24.340 And I'm just going to do Ctrl C and I'm going to run the command again. 14:24.340 --> 14:26.830 But this time I can just do pipe. 14:26.830 --> 14:28.930 So we've done this before in this course. 14:28.930 --> 14:34.750 If you do pipe, basically the whole content of the left is going to be on the right. 14:34.750 --> 14:38.140 And you can for example, do grep to filter the content. 14:38.560 --> 14:40.930 And I'm going to do grep project. 14:42.940 --> 14:48.190 So it's going to filter and only print the lines that correspond to this here on the right. 14:48.190 --> 14:49.180 So that's quite useful. 14:49.180 --> 14:51.070 And we can find our two services. 14:51.070 --> 14:53.470 So you see with this you can find the services. 14:53.470 --> 15:00.730 And then you see what's interesting for us is that first column here so disabled and disabled. 15:00.760 --> 15:05.020 This means that if you start the Raspberry Pi again nothing's going to happen. 15:05.020 --> 15:06.490 But now you can enable them. 15:06.490 --> 15:11.500 So sudo systemctl enable. 15:11.530 --> 15:12.970 Okay so the commands are quite simple. 15:12.970 --> 15:17.200 You have start and stop to directly start and stop them right away. 15:17.200 --> 15:23.170 And you have enabled to well, enable the service to be started on the next boot and every other boot 15:23.170 --> 15:28.030 and let's do project take photos service. 15:28.030 --> 15:30.730 You see it's going to create a symlink somewhere. 15:30.760 --> 15:38.530 And now if I do this again you see that this one is enabled okay I'm going to do the same thing. 15:38.530 --> 15:45.190 So I'm going to do enable project with web server. 15:46.210 --> 15:49.030 And now they are enabled okay. 15:49.060 --> 15:55.030 So what I recommend you is when you create a new system like that, you can use the start and stop just 15:55.030 --> 15:57.070 to make sure that everything is working. 15:57.070 --> 16:00.880 When everything is working, then you can enable them and how to test that. 16:00.910 --> 16:04.390 Well I'm going to do a sudo reboot. 16:04.390 --> 16:06.550 So let's reboot the Raspberry Pi. 16:06.550 --> 16:11.900 And well as we reboot the Raspberry Pi, we also lose the connection to VNC because I was connected 16:11.900 --> 16:19.700 with VNC and now you can already see actually if it's working because the LED should turn on if you 16:19.700 --> 16:22.100 put your hand close to the Pir sensor. 16:22.130 --> 16:22.520 Okay. 16:22.550 --> 16:26.540 We didn't even connect to the Raspberry Pi, but if you see this, it means that the program is already 16:26.540 --> 16:30.560 running on boot, so you don't need to connect to the Raspberry Pi to start it. 16:30.890 --> 16:39.440 And then also I just opened a web browser and note that I opened this web browser here on my windows 16:39.440 --> 16:40.250 computer. 16:40.250 --> 16:44.180 So this computer is connected to the same network as the Raspberry Pi. 16:44.210 --> 16:45.350 It's very important. 16:45.380 --> 16:51.230 I could have opened that also from my smartphone if I wanted to, and I just typed the IP address of 16:51.230 --> 16:57.620 the Raspberry Pi and then the port, and then slash check photos and you see we have no photo available. 16:57.620 --> 16:59.180 So it's actually working. 16:59.180 --> 17:05.930 You see, I can get access to that web page, well, basically from any web browser that's in the network. 17:05.960 --> 17:07.820 And then if I take a photo. 17:07.880 --> 17:09.680 So let's refresh. 17:10.640 --> 17:12.410 You see, we have one new photo. 17:12.410 --> 17:13.820 So I just took a photo. 17:15.350 --> 17:16.940 Well, that's just my hand. 17:16.970 --> 17:18.320 I was doing some movement. 17:18.320 --> 17:20.420 And you see also the path to the photo. 17:20.420 --> 17:21.950 So it's correctly working. 17:21.950 --> 17:25.550 And we didn't even have to access the Raspberry Pi ourselves. 17:25.550 --> 17:27.980 So this is a quite powerful functionality. 17:28.190 --> 17:30.950 You can develop your application and then you create a service. 17:30.950 --> 17:34.310 And then it's just going to run when you boot the Raspberry Pi. 17:34.340 --> 17:39.440 Now let's connect again to VNC and let's get back to the Raspberry Pi. 17:39.950 --> 17:46.640 So I am back here and I'm just going to show you one last thing is how to disable the services. 17:46.640 --> 17:52.010 Because now that you have created the services and that they are enabled, they will run every time 17:52.010 --> 17:53.330 you boot your Raspberry Pi. 17:53.360 --> 17:53.990 So that's nice. 17:53.990 --> 17:55.760 But what if you want to stop that? 17:55.790 --> 17:59.540 Well I'm just going to show you this to conclude the project here. 17:59.540 --> 18:08.630 So first of all let's do again sudo systemctl with list unit Files. 18:08.630 --> 18:13.520 And let's do pipe grep to sort and with the project. 18:13.520 --> 18:15.050 And we see that it's enabled. 18:15.050 --> 18:20.450 So I can do sudo systemctl and you probably guessed the command. 18:20.450 --> 18:25.730 So if we have enable to enable something we have disabled okay. 18:25.760 --> 18:30.080 Quite easy to disable project take photo. 18:30.440 --> 18:32.720 You see it's removing something here. 18:33.020 --> 18:37.910 And I can do the same with project web server. 18:37.940 --> 18:38.330 Okay. 18:38.360 --> 18:44.360 And now if I list again you see those two are disabled. 18:44.360 --> 18:48.800 And very important note they are disabled for the next boot okay. 18:48.830 --> 18:50.870 Which means that they are actually still running. 18:50.870 --> 18:52.220 If you check they are still running. 18:52.220 --> 18:57.200 So if you want to stop them you will need to do sudo systemctl stop okay. 18:57.230 --> 19:04.040 When you enable disable it's not starting or stopping the program, it's just enabling or disabling 19:04.040 --> 19:06.770 the run of the program for the next boot. 19:06.800 --> 19:07.100 All right. 19:07.130 --> 19:08.900 So that's a very important difference.