WEBVTT 00:00.840 --> 00:03.060 -: Much earlier in this course, like in the first one 00:03.060 --> 00:05.610 or two sections, you saw me start up a new copy 00:05.610 --> 00:08.820 of Redis on my computer by using docker. 00:08.820 --> 00:11.820 As a reminder, Redis is an in-memory data store 00:11.820 --> 00:14.700 that's very commonly used with web applications. 00:14.700 --> 00:17.100 You saw me start up a Redis instance using docker 00:17.100 --> 00:20.100 and it seemed to be really easy and very straightforward. 00:20.100 --> 00:23.130 But I wanna show you kind of an oddity around using Redis 00:23.130 --> 00:24.900 with docker very quickly. 00:24.900 --> 00:26.820 I took the liberty of installing Redis 00:26.820 --> 00:28.710 on my local machine directly 00:28.710 --> 00:31.140 without docker being involved whatsoever. 00:31.140 --> 00:33.120 'Cause I wanna show you the normal way 00:33.120 --> 00:35.670 in which we might interact with Redis. 00:35.670 --> 00:37.200 I'm gonna first start up an instance 00:37.200 --> 00:39.450 of the Redis server by running Redis server. 00:39.450 --> 00:41.760 Now again, I am able to run this command 00:41.760 --> 00:44.160 because I installed Redis on my local machine 00:44.160 --> 00:45.780 without docker involved. 00:45.780 --> 00:48.120 Chances are you do not have Redis installed 00:48.120 --> 00:50.520 on your computer, so don't try to run this command 00:50.520 --> 00:53.280 because it's probably going to result in an error. 00:53.280 --> 00:54.720 Now when I run that command, you're gonna see 00:54.720 --> 00:57.450 that, yep, I get an instance of the Reddit server running. 00:57.450 --> 00:59.670 It's in memory, it's ready to store data 00:59.670 --> 01:01.593 or do whatever I need it to do. 01:02.640 --> 01:05.520 The one of the very common ways in which we can kind of poke 01:05.520 --> 01:07.470 into this thing or into this server 01:07.470 --> 01:08.610 and inspect the data 01:08.610 --> 01:11.910 that is inside of it, is by using a second program, 01:11.910 --> 01:13.950 called the Redis CLI. 01:13.950 --> 01:16.770 So on my computer, I've already got Redis server running. 01:16.770 --> 01:20.130 I'm gonna now start up a second program called Redis CLI. 01:20.130 --> 01:21.360 And again, the entire purpose 01:21.360 --> 01:22.950 of this thing is to kind of reach 01:22.950 --> 01:25.250 into that server and poke around inside of it. 01:26.220 --> 01:28.950 So, I'm gonna open up a second terminal window 01:28.950 --> 01:31.980 and I'll run Redis CLI 01:31.980 --> 01:33.690 and that gives me a little prompt right here 01:33.690 --> 01:35.910 that allows me to issue commands directly 01:35.910 --> 01:37.350 to the running Redis server. 01:37.350 --> 01:41.070 And so I can do something like store my number 01:41.070 --> 01:46.070 or excuse me, not store, but set my number, is five 01:46.410 --> 01:48.790 and then I can then retrieve that value 01:50.070 --> 01:51.390 and it prints out five. 01:51.390 --> 01:53.280 So this right here is the normal interaction 01:53.280 --> 01:56.130 that you would see with Redis, with Redis CLI. 01:56.130 --> 01:58.530 Clearly it's really nice to be able to run the Redis CLI 01:58.530 --> 02:00.570 and interact directly with information 02:00.570 --> 02:02.700 inside that running Redis server. 02:02.700 --> 02:03.796 All right, 02:03.796 --> 02:05.220 so now you're probably wondering where am I going with this? 02:05.220 --> 02:08.220 Well, let's try starting up Redis using docker 02:08.220 --> 02:10.020 and then you're gonna very quickly see some 02:10.020 --> 02:12.870 interesting behavior around Redis CLI. 02:12.870 --> 02:14.400 So let's give it a shot. 02:14.400 --> 02:16.510 I'm gonna stop my running stuff 02:18.240 --> 02:20.640 and then I'm going to start up an instance of Redis 02:20.640 --> 02:24.243 on my machine using Docker Run Redis. 02:25.350 --> 02:27.570 Now it's gonna start up just about instantly for me. 02:27.570 --> 02:29.490 For you it might take a second or two as it has 02:29.490 --> 02:30.570 to download the image 02:30.570 --> 02:32.940 but overall it should be pretty darn quick. 02:32.940 --> 02:35.760 When you start up Redis, you might see a couple of warnings. 02:35.760 --> 02:37.890 Those are totally fine, you can ignore them. 02:37.890 --> 02:39.270 Just make sure that the very last line 02:39.270 --> 02:40.103 that you see is something 02:40.103 --> 02:42.690 that says, ready to accept connections. 02:42.690 --> 02:45.090 So as long as you see that, you're good to go. 02:45.090 --> 02:46.140 All right, so this right here, 02:46.140 --> 02:48.750 what we are running right here is the Redis server. 02:48.750 --> 02:51.600 So I now want to start up a copy of the Redis CLI 02:51.600 --> 02:53.340 and try to work with the information 02:53.340 --> 02:56.640 that is being handled inside of the server. 02:56.640 --> 02:58.500 As you saw just a moment ago, I was able 02:58.500 --> 03:02.580 to open up a second console window and run Redis CLI. 03:02.580 --> 03:05.340 So, well maybe for docker being involved here, 03:05.340 --> 03:08.220 maybe we just have to run like Red CLI here. 03:08.220 --> 03:10.170 Oh no, that clearly doesn't do anything. 03:10.170 --> 03:12.210 Maybe we need to start up a second terminal window 03:12.210 --> 03:15.000 and try running Redis CLI there, let's try that. 03:15.000 --> 03:18.870 We'll open up a second window and then run Redis CLI. 03:18.870 --> 03:20.520 Now chances are you're gonna see a message 03:20.520 --> 03:21.353 that says something 03:21.353 --> 03:23.610 like, Command not recognized or Command not Found. 03:23.610 --> 03:26.430 I see something that says, could not connect to Redis. 03:26.430 --> 03:29.180 So what's going on here? Well, let's look at a diagram. 03:30.420 --> 03:33.660 So just a second ago, we started up a new container 03:33.660 --> 03:36.000 that is running Redis server. 03:36.000 --> 03:39.360 Now, Redis is running only inside this container. 03:39.360 --> 03:43.860 So if I tried to run Redis CLI outside the container, 03:43.860 --> 03:46.080 outside the container I have no access 03:46.080 --> 03:48.120 to anything that's going on inside there. 03:48.120 --> 03:50.370 And so, there is no Redis CLI command 03:50.370 --> 03:52.590 to run outside the container. 03:52.590 --> 03:54.780 If we want to start up the CLI, we need 03:54.780 --> 03:58.170 to somehow get into this container 03:58.170 --> 04:02.280 and execute a second command inside of it, like this. 04:02.280 --> 04:06.060 We need to start up a second program inside the container. 04:06.060 --> 04:08.100 So to figure out how to do so let's take a quick break. 04:08.100 --> 04:09.210 We'll come back to the next section 04:09.210 --> 04:12.150 and figure out how we can execute a second command 04:12.150 --> 04:14.340 inside of a running container. 04:14.340 --> 04:15.990 So I'll see you in just a minute.