WEBVTT 1 00:00.000 --> 00:04.200 So now that we know what a basic YAML document looks like, what I want to show 2 00:04.200 --> 00:04.760 you is how 3 00:04.760 --> 00:08.520 we can create something known as key value pairs within YAML. 4 00:08.520 --> 00:10.840 So with that said, let's just dive in. 5 00:10.840 --> 00:14.380 Now one of the primary purposes of having these key value pairs is that it's 6 00:14.380 --> 00:15.040 going to allow 7 00:15.040 --> 00:18.720 you to make your data much more accessible programmatically. 8 00:18.720 --> 00:21.120 Take for example this text document. 9 00:21.120 --> 00:24.880 If you wanted some type of automation system to programmatically peel out the 10 00:24.880 --> 00:25.560 data within 11 00:25.560 --> 00:29.720 this particular paragraph, it's actually quite a complicated process. 12 00:29.720 --> 00:33.430 You would have to use things such as regular expressions to really try to match WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 12 00:29.720 --> 00:33.430 You would have to use things such as regular expressions to really try to match 13 00:33.430 --> 00:33.920 out very 14 00:33.920 --> 00:36.280 particular patterns within the text. 15 00:36.280 --> 00:39.800 And the problem with this is that there can be multiple instances of those 16 00:39.800 --> 00:40.560 patterns. 17 00:40.560 --> 00:42.800 Say for example that we wanted to parse out my name. 18 00:42.800 --> 00:46.700 Now if you happen to know that my name here is John McGovern, well it does make 19 00:46.700 --> 00:47.200 the search 20 00:47.200 --> 00:49.040 pattern a lot easier to find. 21 00:49.040 --> 00:50.680 But that is if you know what you're looking for. 22 00:50.680 --> 00:54.160 Say for example you have a whole bunch of configurations whereby you have lots 23 00:54.160 --> 00:54.600 and lots 24 00:54.600 --> 00:55.920 of data to deal with. 25 00:55.920 --> 01:00.000 Quite simply this data is far too unstructured whereas if we happen to just WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 26 01:00.000 --> 01:01.360 take this information 27 01:01.360 --> 01:06.980 here and utilize these key value pairs, we can easily access the very data that 28 01:06.980 --> 01:07.680 we want 29 01:07.680 --> 01:09.200 very very precisely. 30 01:09.200 --> 01:12.990 So say for example we could create a key called name and associated with that 31 01:12.990 --> 01:13.560 key would be 32 01:13.560 --> 01:14.880 the corresponding value. 33 01:14.880 --> 01:17.080 So John McGovern in my case. 34 01:17.080 --> 01:20.800 So if for example you want to retrieve the name from your data sets, we just 35 01:20.800 --> 01:21.280 tell the 36 01:21.280 --> 01:25.500 system to look for the name key and it will return the corresponding value in 37 01:25.500 --> 01:26.120 this case 38 01:26.120 --> 01:30.900 here, John McGovern as opposed to trying to rifle through all of this text un WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 38 01:26.120 --> 01:30.900 here, John McGovern as opposed to trying to rifle through all of this text un 39 01:30.900 --> 01:31.960 structured, 40 01:31.960 --> 01:34.640 trying to find a very particular pattern match. 41 01:34.640 --> 01:37.880 Once again this still might not be quite so clear just yet. 42 01:37.880 --> 01:41.500 But once we begin getting hands on writing these Ansible Playbooks, you're 43 01:41.500 --> 01:41.800 going to 44 01:41.800 --> 01:45.320 see that having this very strict structure really does help us when we're 45 01:45.320 --> 01:46.360 trying to engage 46 01:46.360 --> 01:47.920 an automation system. 47 01:47.920 --> 01:51.680 So let's look at some of the rules that we can use to create these key value 48 01:51.680 --> 01:52.280 pairs. 49 01:52.280 --> 01:56.230 Now before we actually dig in and begin writing these yaml files, the text 50 01:56.230 --> 01:57.320 editor that I would 51 01:57.320 --> 01:59.600 suggest you use is Vim. 52 01:59.600 --> 02:03.150 The reason being is that when it sees that dot yml extension, it's going to WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 52 01:59.600 --> 02:03.150 The reason being is that when it sees that dot yml extension, it's going to 53 02:03.150 --> 02:03.760 give you some 54 02:03.760 --> 02:07.960 nice syntax highlighting and also going to help you follow the rules of the 55 02:07.960 --> 02:09.040 indentation. 56 02:09.040 --> 02:13.240 So in this case here, I'm just going to use Vim and I will just say example dot 57 02:13.240 --> 02:13.560 yml. 58 02:13.560 --> 02:14.560 Okay. 59 02:14.560 --> 02:17.460 So if I press I for insert and have my three hyphens at the top, what I'm going 60 02:17.460 --> 02:17.760 to do 61 02:17.760 --> 02:19.360 is first create my key. 62 02:19.360 --> 02:23.850 Now the way we specify a key is just by giving the key a name and then we 63 02:23.850 --> 02:25.320 specify a colon. 64 02:25.320 --> 02:27.080 Notice the coloration change here. 65 02:27.080 --> 02:29.640 The text editor knows that we have just created the key. 66 02:29.640 --> 02:33.070 Now one thing to note is that when we create these keys, we want to leave a WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 66 02:29.640 --> 02:33.070 Now one thing to note is that when we create these keys, we want to leave a 67 02:33.070 --> 02:33.880 space before 68 02:33.880 --> 02:35.800 we pass in the value. 69 02:35.800 --> 02:41.320 So if I say space and then John McGuffin, this is absolutely valid. 70 02:41.320 --> 02:46.300 However, if I happen to just move over here and I remove the space, check out 71 02:46.300 --> 02:47.080 the syntax 72 02:47.080 --> 02:48.080 highlighting. 73 02:48.080 --> 02:49.920 Suddenly it's when read again, this is no longer the key. 74 02:49.920 --> 02:52.280 We do not have the key value pair. 75 02:52.280 --> 02:53.280 So just be aware of that. 76 02:53.280 --> 02:55.000 Like I say, Vim is going to help you. 77 02:55.000 --> 02:59.080 Now when I press return, naturally, we're going to get some type of indentation 78 02:59.080 --> 02:59.280 . 79 02:59.280 --> 03:01.160 This happens to be two spaces in. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 79 02:59.280 --> 03:01.160 This happens to be two spaces in. 80 03:01.160 --> 03:04.080 But for now, I don't actually want to use this indentation. 81 03:04.080 --> 03:05.880 We'll talk about that very, very shortly. 82 03:05.880 --> 03:10.340 So all I will do is just press backspace once and notice it actually goes back 83 03:10.340 --> 03:11.000 two spaces 84 03:11.000 --> 03:13.280 to the correct level of indentation. 85 03:13.280 --> 03:19.290 So if I say age and then colon and then space, I can now pass in my age, which 86 03:19.290 --> 03:20.240 in this case 87 03:20.240 --> 03:21.880 here is actually 38. 88 03:21.880 --> 03:24.400 Once again, I hit enter, we try to automatically indent. 89 03:24.400 --> 03:26.440 We don't want to use this quite just yet. 90 03:26.440 --> 03:28.360 So I just press backspace again. 91 03:28.360 --> 03:32.420 Now roughly as a concept, what we're looking at here is that when we have a key WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 91 03:28.360 --> 03:32.420 Now roughly as a concept, what we're looking at here is that when we have a key 92 03:32.420 --> 03:32.920 , you can 93 03:32.920 --> 03:36.960 roughly imagine that as like a folder and the value is what is actually inside 94 03:36.960 --> 03:37.640 the folder. 95 03:37.640 --> 03:42.210 Now the way I say this is because the actual value kind of belongs to the key, 96 03:42.210 --> 03:43.080 so to speak, 97 03:43.080 --> 03:47.400 the same way that anything inside of a folder belongs to that particular folder 98 03:47.400 --> 03:47.680 . 99 03:47.680 --> 03:50.200 This might make more sense when we happen to see nested values. 100 03:50.200 --> 03:52.240 So say for example, look at this. 101 03:52.240 --> 03:55.160 What if I also wanted to add in my address, okay? 102 03:55.160 --> 03:58.720 Now inside of the address, I didn't just want to type in the entire address, 103 03:58.720 --> 03:59.080 such as maybe 104 03:59.080 --> 04:04.370 say one main street in Scotland, and then let's maybe say there's a postcode or WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 104 03:59.080 --> 04:04.370 say one main street in Scotland, and then let's maybe say there's a postcode or 105 04:04.370 --> 04:04.920 a zip code 106 04:04.920 --> 04:08.040 in the US, which is the 54321. 107 04:08.040 --> 04:11.770 Let's maybe say I wanted to break up all of this data into individual 108 04:11.770 --> 04:12.640 components by 109 04:12.640 --> 04:16.600 still wanting to all to be under the association of address. 110 04:16.600 --> 04:21.510 Well, the way we can do this is just create more key value pairs, but indent it 111 04:21.510 --> 04:22.040 within 112 04:22.040 --> 04:23.040 the address key. 113 04:23.040 --> 04:24.040 So look at this. 114 04:24.040 --> 04:28.060 If I actually don't give a value right here and I just press enter, we get this 115 04:28.060 --> 04:28.720 automatic 116 04:28.720 --> 04:29.720 indentation. 117 04:29.720 --> 04:32.520 And what I can just do is just create a new key. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 117 04:29.720 --> 04:32.520 And what I can just do is just create a new key. 118 04:32.520 --> 04:35.910 So I could say, for example, the street that I belong to and how do I create a 119 04:35.910 --> 04:36.200 key? 120 04:36.200 --> 04:39.200 Of course, I just say colon and now look at the highlighting we have created 121 04:39.200 --> 04:40.320 another key 122 04:40.320 --> 04:43.240 and it is indented within the address key. 123 04:43.240 --> 04:46.120 So I could just say the street is one main street. 124 04:46.120 --> 04:50.260 So the next key I create is a setting, which is going to be Glasgow in Scotland 125 04:50.260 --> 04:50.320 . 126 04:50.320 --> 04:52.760 And then I could just say, say, for example, the zip code, now it doesn't 127 04:52.760 --> 04:53.320 actually make 128 04:53.320 --> 04:54.320 sense in the UK. 129 04:54.320 --> 04:57.320 We don't actually have zip codes, but nevertheless, you kind of get the drift. 130 04:57.320 --> 05:02.040 The point here is though, is because we have actually indented all of this data WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 130 04:57.320 --> 05:02.040 The point here is though, is because we have actually indented all of this data 131 05:02.040 --> 05:02.560 here, we 132 05:02.560 --> 05:05.920 know this data is effectively a child of the address. 133 05:05.920 --> 05:10.640 Basically, all of this data here is directly related to the address. 134 05:10.640 --> 05:15.200 It just has been subdivided and separated into more key value pairs. 135 05:15.200 --> 05:18.490 So the way I happen to say this was kind of like having a folder on your 136 05:18.490 --> 05:19.160 desktop. 137 05:19.160 --> 05:20.360 Let me show you what that looks like. 138 05:20.360 --> 05:22.360 So right now here, I have three folders. 139 05:22.360 --> 05:26.580 If I go into the name folder and just double click it, we have the name John Mc 140 05:26.580 --> 05:27.680 Govern inside. 141 05:27.680 --> 05:30.720 If I go back out, I can go into age double click it. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 141 05:27.680 --> 05:30.720 If I go back out, I can go into age double click it. 142 05:30.720 --> 05:32.160 We have the value 38. 143 05:32.160 --> 05:35.520 If I go back out, if I select address. 144 05:35.520 --> 05:38.560 Inside of address, we actually have more folders. 145 05:38.560 --> 05:41.920 We have a street folder, city folder and a zip folder. 146 05:41.920 --> 05:45.760 Just in the same way here, we have a street key, city key and a zip key. 147 05:45.760 --> 05:50.280 Basically, all of this data here is contained within a greater address key. 148 05:50.280 --> 05:52.920 This is a loaner to structure and associate data accordingly. 149 05:52.920 --> 05:56.990 So if I now go into the street key or the street folder, if you wish, we see 150 05:56.990 --> 05:57.560 the value 151 05:57.560 --> 05:58.560 one main street. 152 05:58.560 --> 06:02.580 If we go back out, we go into the city key or city folder, double click it, we WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 152 05:58.560 --> 06:02.580 If we go back out, we go into the city key or city folder, double click it, we 153 06:02.580 --> 06:03.000 see the 154 06:03.000 --> 06:07.230 value is Glasgow and then finally, the zip key tells us that the zip value is 5 155 06:07.230 --> 06:08.280 4321. 156 06:08.280 --> 06:12.040 Like I said, the beauty of YAML is this human readability. 157 06:12.040 --> 06:14.000 So you just correctly eyeballing this. 158 06:14.000 --> 06:18.320 By virtue of seeing the indentation, your eyes and brain can easily interpret 159 06:18.320 --> 06:18.720 all of 160 06:18.720 --> 06:23.580 this information here as relating to and is subsequently a product of the 161 06:23.580 --> 06:24.560 address information 162 06:24.560 --> 06:26.040 that we're trying to communicate. 163 06:26.040 --> 06:29.300 So whilst this might be a very frivolous example right now, when it comes to 164 06:29.300 --> 06:30.480 creating configuration WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 164 06:29.300 --> 06:30.480 creating configuration 165 06:30.480 --> 06:33.120 files, you may have a whole bunch of nested data. 166 06:33.120 --> 06:38.480 Say, for example, a key for servers and intended within that key, you may have 167 06:38.480 --> 06:39.280 a database 168 06:39.280 --> 06:43.720 key as well as a corresponding web key and then maybe some corresponding values 169 06:43.720 --> 06:44.000 . 170 06:44.000 --> 06:49.950 Let's maybe say eight dot eight dot eight dot eight and one dot one dot one dot 171 06:49.950 --> 06:50.520 one. 172 06:50.520 --> 06:53.500 This one here could be the IP address of the web server and this one here could 173 06:53.500 --> 06:54.120 be the IP 174 06:54.120 --> 06:55.560 address of the database server. 175 06:55.560 --> 06:59.930 And again, just at a glance by virtue of the web and database keys being ind 176 06:59.930 --> 07:00.440 ented with WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 176 06:59.930 --> 07:00.440 ented with 177 07:00.440 --> 07:05.590 then the greater server key, we know here that the database in the web happens 178 07:05.590 --> 07:05.960 to be 179 07:05.960 --> 07:08.160 talking about servers explicitly. 180 07:08.160 --> 07:11.680 So the indentation and nesting allows us to correlate the data together.