1
00:00:01,720 --> 00:00:04,940
In this video we're going to focus on how to build out this shared library.

2
00:00:04,960 --> 00:00:09,430
We're going to first take a look at how we can somehow share code between multiple different services.

3
00:00:09,430 --> 00:00:14,020
We're going to outline three different ways to share code between the OSS service and a ticket service.

4
00:00:14,020 --> 00:00:14,820
Now just be clear.

5
00:00:14,830 --> 00:00:17,780
There are more than three ways to share code between projects.

6
00:00:17,850 --> 00:00:20,950
But we're going to be mostly focused on these three different methods.

7
00:00:20,950 --> 00:00:26,760
So meet the number one for sharing code between two projects is to just do a very direct copy paste

8
00:00:27,340 --> 00:00:32,080
so we can go into our all service we could find all those Middleware is all the custom error handling

9
00:00:32,080 --> 00:00:37,750
stuff and so on and do a direct copy paste of that code over to this new ticket service we're going

10
00:00:37,750 --> 00:00:39,200
to put together.

11
00:00:39,280 --> 00:00:42,200
There's definitely a very big downside to this approach.

12
00:00:42,400 --> 00:00:47,110
If we start to copy paste stuff over we might then go back over to our auto service and start to make

13
00:00:47,110 --> 00:00:48,510
changes to this common code.

14
00:00:48,770 --> 00:00:51,490
And so maybe we are now on version two over here.

15
00:00:51,490 --> 00:00:53,610
How would we know what files change.

16
00:00:53,680 --> 00:00:57,880
How would we somehow get those files sync over to the ticket service.

17
00:00:57,880 --> 00:01:00,370
We would have to do a direct copy paste again.

18
00:01:00,570 --> 00:01:04,480
And when we did that direct copy paste it might be really challenging for us to keep in mind exactly

19
00:01:04,480 --> 00:01:05,530
what changed.

20
00:01:05,590 --> 00:01:09,560
So it's kind of hard to document these changes over time.

21
00:01:09,590 --> 00:01:12,560
I think you can probably we don't really need to spend a lot of time on this.

22
00:01:12,560 --> 00:01:17,120
I think you can probably kind of instinctually sense that doing a direct copy paste this code between

23
00:01:17,120 --> 00:01:20,510
projects is probably not the best way to do any kind of code sharing.

24
00:01:20,510 --> 00:01:25,720
So I just want to mention it but we're not really going to consider this as a serious option met the

25
00:01:25,720 --> 00:01:31,780
number two is to use what is called a get sub module if you are familiar with get then you might have

26
00:01:31,770 --> 00:01:38,050
heard of some modules a sub module is whenever we have one get repository and we want to somehow include

27
00:01:38,110 --> 00:01:40,320
another get repository inside there.

28
00:01:40,510 --> 00:01:46,510
So we might create a get repo for our auto service and our ticket service we then create a third repo

29
00:01:46,570 --> 00:01:53,850
for all of our common code we would then add in this common repo into our off and tickets repos as a

30
00:01:53,850 --> 00:01:54,820
sub module.

31
00:01:54,960 --> 00:01:57,600
And so you can imagine that we kind of take a copy of this thing

32
00:02:00,870 --> 00:02:05,880
and put it directly in right there and right there.

33
00:02:05,990 --> 00:02:10,700
Now the upside to this approach is that we have all of these common code inside of version control and

34
00:02:10,700 --> 00:02:15,230
so we know at all times exactly what version of the common code we are running between these two different

35
00:02:15,230 --> 00:02:16,270
projects.

36
00:02:16,280 --> 00:02:20,790
We also have some really solid documentation on what gets changed between different versions.

37
00:02:20,810 --> 00:02:26,050
The downside to this approach is that using get some modules in general is just a little bit challenging.

38
00:02:26,090 --> 00:02:28,130
There's some different complicated commands.

39
00:02:28,130 --> 00:02:32,890
Whenever you create a new get rid repository setting up some modules is always a bit of a pain.

40
00:02:32,930 --> 00:02:38,130
And so this definitely is a valid option but there's just a little bit of pain associated with it.

41
00:02:38,170 --> 00:02:45,800
So third option we're gonna take a look at is publishing all this common code as an NPM package.

42
00:02:45,890 --> 00:02:47,430
This is what we are going to do.

43
00:02:47,600 --> 00:02:51,220
We're going to take all this common code we're going to move it into a new project.

44
00:02:51,320 --> 00:02:55,250
We're then going to publish this as a package to the NPM registry.

45
00:02:55,670 --> 00:03:00,200
So we might give it a name of something like get ticks stash common or something like that.

46
00:03:00,590 --> 00:03:05,630
Then inside of each of our different services that need this common code we will simply install it as

47
00:03:05,630 --> 00:03:09,160
a NPM dependency using that same kind of NPM install command.

48
00:03:09,160 --> 00:03:14,030
You are already familiar with the nice thing about this approach is that we can still version the code

49
00:03:14,060 --> 00:03:20,780
inside this common repository or this come library so our auto service might use version 0 0 1 of this

50
00:03:20,780 --> 00:03:25,370
common library and a ticket service might use say version 0 0 2.

51
00:03:25,370 --> 00:03:31,160
So if we ever start to make a change to this get ticks library no problem we can still have all of our

52
00:03:31,160 --> 00:03:36,650
other services using the older version until we eventually get around to making updates and adjusting

53
00:03:36,650 --> 00:03:42,110
them and saying okay let's now use version zeros or two over inside the out service so we're going to

54
00:03:42,110 --> 00:03:44,120
use option number three right here.

55
00:03:44,120 --> 00:03:47,920
Now this definitely solves a lot of issues but there are some really big downsides.

56
00:03:48,020 --> 00:03:51,980
This means that any time that we want to change our common code we're going to have to make our change

57
00:03:52,340 --> 00:03:57,710
push it up to the NPM registry then go over to our different services and update our version to the

58
00:03:57,770 --> 00:03:58,730
latest.

59
00:03:58,730 --> 00:04:01,130
And that's just kind of a tedious process.

60
00:04:01,130 --> 00:04:04,550
We are going to eventually write out a little script that's going to kind of automate some of stuff

61
00:04:04,550 --> 00:04:05,010
for us.

62
00:04:05,030 --> 00:04:09,440
But I just want to point out that it is a little bit tedious and there will be times where we start

63
00:04:09,440 --> 00:04:14,510
to write some code in an update to this common repository or it's come library and then we will publish

64
00:04:14,510 --> 00:04:14,840
it.

65
00:04:14,840 --> 00:04:19,730
We will update our ticket service with the newest version and then we'll say oh my gosh we just made

66
00:04:19,730 --> 00:04:20,580
a little mistake.

67
00:04:20,690 --> 00:04:26,460
So we'll have to go back over to this library make the update rebuild it push it again update ticket

68
00:04:26,460 --> 00:04:27,480
service again.

69
00:04:27,620 --> 00:04:32,420
In other words there will be times where it's a little bit of a pain but this kind of has the best of

70
00:04:32,450 --> 00:04:34,310
all different options.

71
00:04:34,340 --> 00:04:35,600
OK so that might.

72
00:04:35,600 --> 00:04:40,510
Another quick pause right here in the next video we're going to go ahead and create this common library.

73
00:04:40,550 --> 00:04:45,050
We're going to start to set it up as an NPR module and then start to move all of our common code over

74
00:04:45,050 --> 00:04:45,390
to it.