1 00:00:00,660 --> 00:00:02,190 In a previous lecture. 2 00:00:02,280 --> 00:00:09,420 In this course you've learnt about how to create a group that contains multiple notes and the benefits 3 00:00:09,420 --> 00:00:10,170 of doing that. 4 00:00:10,830 --> 00:00:18,720 In this lecture, I'm going to show you a new feature that appeared with no trait version 2.0 that allows 5 00:00:18,720 --> 00:00:21,870 you to set environment variables inside a group. 6 00:00:21,960 --> 00:00:26,880 And once you do that, then those variables will be accessible from any node within this group. 7 00:00:27,630 --> 00:00:33,870 So I've got an extension of the original example that you've seen previously, and in this example I've 8 00:00:33,870 --> 00:00:40,840 got a group already created that contains several debug notes and a change note here. 9 00:00:41,610 --> 00:00:46,800 And before we have a look inside those notes list, check out the group itself, the double click to 10 00:00:46,800 --> 00:00:49,080 open up the properties window. 11 00:00:49,590 --> 00:00:56,910 And then in the environment variables tab can see here that I've got three environmental variables set 12 00:00:56,910 --> 00:00:58,140 for the group itself. 13 00:00:58,710 --> 00:01:05,790 The first one group in VAR one just sets this variable into a fixed string. 14 00:01:06,210 --> 00:01:10,620 So there's a few options here of things that you can store in set environment of. 15 00:01:10,620 --> 00:01:13,830 Our boy just took a string and typed in a bit of text. 16 00:01:14,400 --> 00:01:22,920 The other two are more interesting here because what they do is that they grab a variable and actually 17 00:01:22,920 --> 00:01:24,270 I just found a mistake. 18 00:01:24,270 --> 00:01:25,140 That should be silly. 19 00:01:25,890 --> 00:01:32,250 They just grab a variable that I have already said as an environment variable in this settings file. 20 00:01:32,880 --> 00:01:41,310 So let's switch over to the command line now and have a look at the settings file and just going to 21 00:01:41,310 --> 00:01:43,590 use the cap command for that. 22 00:01:43,860 --> 00:01:46,950 Just need to have a look at the very top of this file. 23 00:01:47,460 --> 00:01:55,830 So at the beginning of this file, outside of the existing module export segment, I have created another 24 00:01:55,830 --> 00:01:58,590 export module to export segment. 25 00:01:58,590 --> 00:02:01,620 And in it I've set a couple of variables. 26 00:02:02,040 --> 00:02:07,170 So each line contains the name for the variable followed by a colon. 27 00:02:07,170 --> 00:02:14,130 Then the words process dot, EMV followed by dot, and then the name of the variable in capitals. 28 00:02:14,490 --> 00:02:21,060 This is a name that I'm using inside node red to access the value for this particular variable. 29 00:02:21,660 --> 00:02:28,650 Let's go back into the file, the settings file and I've got the equals sign and then I'm making a reference 30 00:02:28,650 --> 00:02:35,520 to the operating system function hostname which will return the hostname for my Raspberry Pi. 31 00:02:36,000 --> 00:02:41,700 So this is just one environmental variable that just grabs a piece of information from the operating 32 00:02:41,700 --> 00:02:49,080 system of a comma because then in the next line of code, the second environment variable in this case 33 00:02:49,080 --> 00:02:50,310 it's say a city. 34 00:02:50,820 --> 00:02:55,740 It's just the name that I chose, followed by the colon process that EMV. 35 00:02:55,740 --> 00:03:01,530 And then in capital letters, the name of the environment variable that I'm going to reference from 36 00:03:01,530 --> 00:03:09,480 inside my node, the red node and after the equals sign, just a arbitrary string. 37 00:03:09,480 --> 00:03:12,120 In this case Sydney, which is my city. 38 00:03:12,690 --> 00:03:22,160 So save the updated settings to file and then restart the node red instance like this. 39 00:03:22,950 --> 00:03:29,670 And then the instance at the runtime of the node, for instance, a will pick up this environment variables 40 00:03:29,670 --> 00:03:33,930 and they will be accessible from inside your nodes like this. 41 00:03:34,140 --> 00:03:42,420 So I've got a reference to hostname and city and those are stored in group EMV via two and three respectively. 42 00:03:43,560 --> 00:03:47,250 In my debug notes. 43 00:03:47,250 --> 00:03:50,220 Let's pick up an example and have a look at this one here. 44 00:03:50,220 --> 00:03:59,640 For example, this is just presenting or printing out the value stored in group B in v var three of 45 00:03:59,640 --> 00:04:00,840 the message object. 46 00:04:01,350 --> 00:04:02,730 I've got the same thing here. 47 00:04:04,370 --> 00:04:13,310 So just to recap, before I run this example, you know, trigger it in my group level, I can create 48 00:04:13,310 --> 00:04:22,490 environment variables such as this one here, simply a string or grab values from the operating system, 49 00:04:22,760 --> 00:04:29,720 environmental variables or arbitrary environmental variables that I have set inside the settings file. 50 00:04:30,500 --> 00:04:31,010 All right. 51 00:04:31,960 --> 00:04:36,490 Also, let's check out what's happening in the inject note. 52 00:04:36,940 --> 00:04:40,210 I haven't made any changes compared to what I had in the original example. 53 00:04:40,540 --> 00:04:43,690 I just serve the payload topic which is empty. 54 00:04:44,020 --> 00:04:45,220 And then the message. 55 00:04:45,640 --> 00:04:47,890 Example message here with a bit of text in it. 56 00:04:49,040 --> 00:04:53,080 So I'm going to deploy this flow and then trigger it. 57 00:04:53,090 --> 00:05:02,780 And then you can see that the environment variables that came from the settings file city and hostname 58 00:05:03,260 --> 00:05:10,700 are printed out by the debug nodes as they were set inside the change node. 59 00:05:14,250 --> 00:05:24,090 So just to recap, you can use environment variables in the group level to share the data among all 60 00:05:24,120 --> 00:05:25,920 nodes that are included in the group. 61 00:05:26,340 --> 00:05:35,340 And those environmental variables can be fixed at the group level or the can be fetched or read from 62 00:05:35,340 --> 00:05:36,600 the settings file. 63 00:05:38,220 --> 00:05:42,720 If you want to learn more about environment variables, then have a look at this documentation page. 64 00:05:42,720 --> 00:05:46,560 You can see the URL for this page on your screen right now.