Jenkins Platform SIG, 22 Jul 2020

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From YouTube: 2020 07 22 GSoC Git Plugin Performance Project

Description

Git plugin performance improvement project for Google Summer of Code. Topics included the structure of the repository size estimator extension point

A

A

So mark I was trying to run the benchmarks on multiple platforms to uh so I saw one of your project, which is a multi-configuration project where you use a matrix to label to run the whatever build in multiple agents.

A

So I was, I was thinking of doing the same thing, but uh so I have three branches, three benchmarks. I want to run so it's a multi-branch project, I'm not sure. If, if in a multi-branch project, I can add that configuration matrix so is there a combination? Is there a project type of a project which I can use which mixes both of them or would I have to use a configuration, multi-configuration project with a simple pipeline and add my branches and then write some shell steps to run the benchmark java command to run the benchmarks?

A

How should I do it.

B

So the the I think what you would want to do is use a declarative declare use a pipeline and we probably want to put it in as a as a declarative pipeline and, let's use the matrix operator to do it. So that way you don't have to you, don't have to wrestle with the old school thing that I'm using. I have those multi-config projects, because I want to be sure that I don't break compatibility they're, actually not the best way to do it now. The best way to do it now is declarative pipeline with matrix.

B

So so there's a there's a much better way to do it thanks to declarative pipeline, and you can find you can find documentation about it on jenkins.io.

A

And I'll do that: okay, okay! uh So the second thing I think which we should discuss is the estimator class I've. I've raised a pr for that. Fran and omkar have reviewed it they've, given an initial review to it. So um so would you guys like me to discuss the design uh of the class or is it something you would for? You would first want to review the pr and discover it yourself, or would it help you guys if I discuss what I've done and what I've thought about it? The experience for the class.

B

Oh I'd like to hear the a brief design uh design description for me, your insights or your comments can be quite helpful for me as I try to understand it.

A

Okay, so um so I tried this uml diagram hang on intellij, I'm not sure. If this is going to be very helpful, but so the class, the repo estimator class size, estimator class, is it x. It can work uh in two ways. The first is uh so it has two constructors. The first requires a git scm source object uh which will be used to uh analyze. If it has a cache dot get directory or not. If it does, it would calculate the size. If it doesn't, it would switch it would.

A

uh It would try to find an extension which has which has implemented the extension point. We've provided uh the second constructor I've added is so the first constructor limits us to multi branch uh projects. That is, that is the only place where we uh use a cache dot get directory.

A

We can find a cache directory, so the second constructor would just ask for a repo for the repository url and would try to find the in the x the implementation of the extension point we have created and if it does exist, we would provide the recommendation uh on what git implementation the uh plugin should use for that project. So the input can be two things: it can be, uh the git sem source object or repo url.

A

The output will always be uh a string which would either be, which would either be get jet or I've chosen. None. If I don't want to recommend anything and want to use the default.

A

Default git tool resolved by the plugin, how that is working, I'm going to explain it more detail, but this is the basic uh input and output of the class expectations.

A

So um so I think I should directly uh show the code a little bit and then uh one of the major problems right now we have which uh fran has pointed out clearly, and that is something I need to work upon.

A

After this discussion, so so the first constructor it asks for the gate sem source, so once it, but it's initialized the class it will uh so how it calculates the size is. Is that it I'll show you the method? The method would uh try. So we are not locking the cache we're just getting the entry, then we're. uh Then we check if the cache directory, if it exists.

A

If we check that, if it, if it has a dot, get directory or not, if it does, we would um calculate the size by size of directory api and store it in a class member and and if it, if this doesn't happen, if we don't have a cache, the second option we have is to use an api.

A

So for that I have created the extension point. The extension point I would like to show to you guys is: where is the extension point yeah here?

A

The extension point right now is uh so uh when I was looking at the documentation of how to create an extension point, I saw two ways of making it. One is through the singleton pattern and the second is the descriptor describable pattern.

A

So, um to be very honest, I am not 100 sure on how the descriptor describable pattern is working single intel pattern. I could understand what it was, uh how I could design. I could how I could design the extension point through it and uh I'm not sure if the decision of using it was uh and not using that pattern is wrong here. But what this this extension point is expecting is is that I provide you, the url of the repository.

A

I assume that the implementer has the credentials for the user, and how did I uh reach to this assumption or to this analysis, is that I looked at the get github plugin brand source plugin, and I was looking at how I could initialize a client, a github client. How are they, uh how have they how they have wrapped the github apis java apis? So I was looking that they either they need the user id password or they can use a token.

A

So initially I was thinking of passing the credentials from here as well, but then I realized that the client there would uh they would have the user credentials for the particular if they, if the, if the, if the project is using that plugin, they would also have the credentials. So for me, I think the only information I need to send to them is the repository url and they would just need to.

A

uh They would just need to send a get request on the repository url to get the size through a json response from the uh api. So this is the only method. The second method is uh is where I have right the issues right now. So, as I was looking at extension points, what I could see was extension points in any plug-in are made to extend the plug-ins functionality to other plug-ins as well.

A

So we basically like I so my reference point was the listener extension point we have in uh in the git plugin within the git. uh If, if, if I want to be precise, it's within git status, we have, we have an extension point. An extension point called listener, so I kind of modeled the extension point in a similar way, and I can see that this pla, this extension point, is meant to provide uh the capability of listening to some updates now. My extension point is very is different. Is actually opposite to this thing.

A

What we want is that we are not extending. What we want is that we want other plugins output in our uh class. We don't want we're, not sending them we're, not extending any capability to them, we're actually using their capability to get something for our need.

A

So the issue with this this need is which fran has pointed out that what I am doing right now is that I am using the extension list, and so I I expect that whatever plugin has implemented the repository size api, I would call the method for the repo url. I have and get the size of the repo.

A

Now. The issue with this is that this is a list I was while I was designing uh it's it's actually a very it's a huge mistake.

A

While I was designing uh the extension point, I I I was only thinking about the github brand source plugin and I never I actually it's a very the mistake is that I didn't think about other plugins which might also implement it, and we we would have a list of implementations and I don't have any method right now to distinguish which implementation I want to use so fran was uh suggesting uh suggested he in the pr that there we might uh want to find a way where we can use the url to find out what kind of extension class we would want to use.

A

So uh so what I understood from his comment- and he he may clear me right now, fran you can clear me right clean um here. I was what I, as what I uh got to know was that if I have a github url I would uh I would extract. Maybe the word get up from it and look for the class. If, through the list, I would look for the class. uh Actually, as I'm discussing this, I uh this might not be possible.

A

So the the part where I'm confused right now is how do I, how do I clearly get to know which uh plugin classes are implementing this api?

A

What I could find from yeah, yes mark.

B

Actually friend friend has much deeper experience here, so fran. If you were going to say anything, I will defer to you.

C

You know what I, what I wanted to say is: okay, reach up a thinking station extension just like in a class that is annotated in an especially in a specific way and in the moment that the plugin is installed or in the moment that the jenkins instance is it's been started.

C

It's loaded and it's available uh for any other component. Let's say component in the jenkins instance, so you are calculating the size of the ripple two ways. The first one is just using the ticket cache, okay, but the other one, but the other one is just using the api.

C

That api is gonna, be a totally dependent on the key system that you have behind you. It's not the same api for github, that for kid lab and for bit bucket or whatever else so a what I would like you to think about is the way that you say: okay, uh who's, going to provide that api and the way to um a to calculate a site using the api.

C

Each plugin is plugin that is depending on git plugging. So what we have to do is just to, as you have said, a provide an abstract class that will be extended by the other plugins.

C

Those classes in those plugins can be annotated with extension class. So we can at any point in jenkins.

C

We can always uh read from them in our case, because we are going to to say: okay, give me the full list of reported the repository size, api classes and we need uh uh mechanisms to decide uh of the full list, because if, in our genki system we have the github plugin, the gitlab bit packet and so on, and all of them are just sending and giving and providing us the mechanisms to to discover the the size of the repository using the api that list. It will contain all those extensions.

C

So we need a mechanism to say a this git repo, it's a github repo, so I'm going to filter by the I'm going to filter that list, so I can get or or alright, this cut the rest of the of the extension point and then getting only the one that is going to give me the api for this, a gig github api, the same for gitlab and so on.

C

So what do? What you have doing here is just to creating a point, something where the rest of the, where the providers- and we can also they can have just an um generic way to calculate that. I don't know if it's possible or not- maybe it's just doing a clone in a temporary file just as a default implementation.

C

But what I mean is that you know what is the the url where you want to connect- and I said the url, because it's probably the easiest uh field that we have just to the to determine to determine which is our kit system?

C

Okay, but if we have another another way, it's totally fine, so we have to determine we have to specif to discover, which is the git system that we have behind our api just to filter in that list of first in that station list, which is the extension which will provide us the correct method to calculate that size.

C

I don't know if I might myself from the zoo.

A

It's clear to me.

D

A

Yes, yes, please justin.

D

One other thing, I'd say too, is that uh you also have to remember that uh people can locally install like a git lab or github enterprise, uh so you'll have arbitrary urls as well, so those plugins may need to provide what are registered urls, potentially um or somehow. You need to understand like for this repo which plug-in is configured to to handle this, which I'm not sure, if that second thing is possible, but perhaps the other plug-in is going to need to tell you what urls are configured for that plugin.

A

Okay, yes, mark guess: what are you saying.

B

Would could we delegate the responsibility to decide if a particular url can be handled or not to the extension implementer and make part of the contract be that if they can't implement it, they return a negative one or they return a nonsense value like zero right? Then then, you don't have the responsibility to decide show like. Shall I call you you rather tell them. I promise I'm going to call you a lot. You need to exit quickly if you can't handle this thing and you need to accept that you may get.

B

You will receive things that you cannot handle. So I solemnly promise to send the github url to the bitbucken bitbucket endpoint, to the bitbucket extension and to the giddy extension and to the gitlab extension they're all going to get it and they must all return a negative one. If they don't intend to process it could would that work so that you don't have to put any logic at this layer to to decide, um should should the callers handle this should I call them.

D

Yeah, it's almost a matcher pattern.

C

B

C

Just to add to other new or yes, a new method in your abstract class that has to be implemented by the paint implementers.

C

So I think that marcus has pointed the the easiest ways to to feel that mechanism of deciding which is the implementer of the of the api, which you know.

A

So if we implement so if we uh add that method in our contract, that means that I would only get from the list, I would only get the valid implementation and nothing else, so I would normally have english so would uh still would I have to keep a check uh to uh to see if any other implementation has not? um No, so that wouldn't happen right. So, if so, my so that, even if we have that contract and they return uh a minus one, let's say uh what issue we might have.

A

Is that so we use the extension list to get the extensions which are instantiated in the jenkins environment. So, if any, if any provider- let's say five providers have implemented the extension point.

A

If I call the, if I could call the get extension list function api, it would give me the list okay, but I would have since I have a method which, uh which might be a boolean or might be. Let's say it returns a boolean false if the url is not um if the url is github, but it's it's been implemented by buildbucket, which it says I cannot implement this. So, let's just return false or minus one: zero, whatever we're returning for the size, so I would just keep it.

A

I would just uh before calling for the size for the method which is uh trying to find out the size. I can just keep a check. Okay, uh if it's, if this, if, uh if the let's say whatever the contract, the method is, if it's false or if it's minus one, I would not call for the size for that particular instance.

A

uh Taken from the list.

A

Is that what we would do.

B

That that feels more complicated than what all I was envisioning was you call every implementation, ask their get size of repository with the repo url. If they return you a minus one, you know to ignore them and and they're responsible to decide in their get size of repository, url or git size of repository method.

B

Should they actually ask the remote system or do they look at the url or they look at some other some other thing they know and say. This is nothing I can process.

B

Okay, I I I I I may be off. It just seems like it's. It's a place where we can ask the question and rely on and tell the tell them as part of the contract you're going to get asked questions for things that aren't yours. Your responsibility is to return minus one as quickly as you reasonably can.

A

Yeah, that's that's. uh I think that that can that's easier for employee to implement for us.

B

Maybe minus one may be a poor choice. Does I don't think that java has a concept of an unsigned long? So I guess minus one is fine, but a repository size of either zero or less than zero. Both of those are nonsense right. Neither of those are useful to a repository size estimation.

A

Yes, okay, okay, so I'll highlight that to our contract and I'll update that okay, okay, so that's how we're going to do it! uh The last thing I think for this class is once so: how do we decide what implementation we have to use? I just have a simple um constant which right now I have so. I assume that every size I'm going to get is in kbs.

A

So that is also something I am. I might need to specify not sure how do I specify that in the extension point, except writing a javadoc? I am not sure yes,.

B

Why why kbs you've got a long? It's a 64-bit quantity there. There isn't a file that I know of that's ever going to overrun and I I hope nobody tries to do a terabyte size, get git repository.

A

So the reason for kv's mark is that, first, that the file the the api I use to estimate the cache it returns the size in kb. Oh okay,.

B

Good good choice, then,.

A

Yeah and the second is the uh the apis, github or git lab, so I've tested it with github. They also provided in kb.

A

That is, I yeah, so it's 5 mb right now the switch is 5 mb right now uh to be more precise on what the switch might be. I might, I might run a lot of tests for this particular reason to to get closer to the point where the nature of j gates performance changes. That point which we found out in phase one through the results. So right now I've taken it as 5 mb. So what happens is if it's greater than 5mb, we recommend git and if it's not, we recommend jiggit.

A

Another thing which was which I considered was that even if I recommend gate, I don't know if get is installed in the system or not in the particular node I'm running to so I used, I borrowed the resolve. Git tool uh implement the logic which is in get util. So what I do is once I decide from my side what implementation I should use.

A

I run it through the get util dot resolve and I've done it here determine get to so so it basically uses that resolve git tool method and if it has gate, it'll recommend gate. If it doesn't it would uh so if it doesn't, it would go for the default installation.

A

So one question I had here was while I wrote a unit test for this particular um for for just uh the cash. uh So if I have a cash, would I get the right uh tool or not? So while I was doing that uh the so the the recommendation from my class should have been j gate and my the before resolving the git tool before checking. If the system has it or not, it was jet, but once I uh I I passed it through this method.

A

It returned git tool to me, so I I actually was not get get to me. Sorry, and I was not sure why is it doing that so as I I was trying to debug it it, it looks for the descriptor implementation for the particular uh tool which which we are trying to as the parameter we have passed here. So it could not find jget and hence it went for the default installation is. Why would that happen?

A

I'm not sure, because jk is something which springs is always installed in our uh would be installed because it comes within the plugin. So that's something, maybe once you look at the pr, and um so I was running the test and I was getting that so I was not sure why that was happening. So I thought I should tell you.

B

Yeah good question: I don't know the answer, I I there's some oddity in the constructor of the get of the of get scm that have surprised me in the past, so you may be exploring areas that that will we'll have to learn more.

A

D

And this this does check the system get like. It doesn't only rely on jenkins installing it right.

A

um Justin, I am actually not sure about it. I, as far as I know, it checks uh the the agent the node wherever it is, it checks if the gate installation is present or not.

D

So, there's a there's a there's, a way to install tools in jenkins. You can have jenkins manager your tools for you, you tell what binary you want. What version you want stuff like that and I'll make sure that it's installed, but I've also seen a lot of people not use that.

D

So if it's like actually doing a check on the system, then that would work. But if it's not and it's relying on people using the get tool or the installation of tools via jenkins, that's only gonna cover partial cases. So just something to look at.

A

Okay, I will look into that. The reason why I did not was that I assumed that, since uh this is being already used with the existing functionality, it is used to resolve ticket implementation. I assume that this would look out for every case, so I did not uh bend deep into how this is resolving or how it's actually finding the executable I'll look into it.

B

Yeah, I'm not sure, maybe these guys, don't I'm sorry, I I think rishabh, your your assumption is a good assumption and if, if this method is flawed, I think we handle that separately you're you. I think you made a very good assumption to think that if this method is not doing the right thing, we should solve that as a separate, separate solution.

B

That's fair yeah, because because this thing has the node, it has a string name for the proposed get tool. It has the environment variables. So it's got all the things it could. It could potentially use to answer the questions. Justin justin noted, if it fails to do that, that seems like a bug that we need to solve separately.

D

Yeah cause imagine you're using this in other places to to invoke the right kit. I think so. Yeah, okay cool! No, that's fair!.

A

Yeah, so um so I think this is what is happening with the class and the biggest problem right now. We, what we discuss is the biggest problem, and that is something I'm going to handle right now, uh apart from this, so my next concern with the class was that how do I um actually so I wanted to test it in a real case.

A

I wanted to build a real case scenario with this class and to do that, so I know that I can rely on the cash, not 100 delay on it, but I know that the cash so I've written unit tests for uh for cases where, if I, if I don't have a cache repository or if I have a cache repository how the class would work, I don't have cases that I've actually never tested the class with the extension, so uh so with respect to testing the extension function and the second heuristic uh before so I I've seen that we have uh an annotation called test execution test extension, which actually allows us to uh implement an extension just for the test.

A

So the concern the concern with that approach is, I have is that I would have to so. If I'm working the way get brand source plugin would want to work, they would so they create a github client. So I would have to add a lot of depend. The dependencies they are using the library is there. I would have to shift all of that for the test uh only or I could just use a an http client which would just uh perform a get request with credentials or without credentials. That would not have a github client.

A

It would just be an http client performing a get request uh on the particular repository url. That is how I could test it within git plugin.

A

I was actually thinking to uh try to go to get brand source plugin and implement it just for my local system and then try to work that out, install the plugin, create a project and then see if my my system is able to my implementation is able to use the extension, the implementation provided by the extension and get the size so which so uh for so my the purpose of the whole thing is that for the demo I I was thinking that I, if I could do this, I could show the uh this class working for a cat for a cash repository, how we are going to estimate the size and maybe when we go to get scm for a single pipeline when we're just checking out the project there.

A

Also, I can use this class how I, if we have an implemented api, we would not have to call the get sem source constructor. We could call. We would just use the repository url to estimate the size and give a recommendation at that level as well.

A

So so, to do that, I need to either I need to go to get trans source plugin and create an implementation. So should I work on that and actually uh see if this implementation would work or not extension, points? Sorry.

B

So I I I like very much the idea of of doing a concrete implementation in another plug-in. I think that's a that's a very healthy thing to do. However, you did describe that the extension point test inside may help you diagnose more quickly than using a second plug-in um back to your. So so, yes, I think it's great to use the separate plug-in as a as a that's that's where the real implementation has to be anyway.

B

So that makes makes a lot of sense, but in your suggestion on how to test inside this plug-in, the test doesn't have to actually make a call to anything right. The extension point you implement in the test could just do something like given a particular url, always return this size or given this other url, because it's inside your test, you can, you can do all sorts of things that avoid any calls to the outside.

B

That keep things very, very, very simple and say: if I see it, if I see a repository that ends with the number five I'll always return. Five, if I see her those kinds of tricks, because it's a.

A

Test, yes mark sorry,.

A

I was just saying that fran suggested that I I can mock the http response. Whatever response, I need from the api- and I can test it like that, so I so yeah that will be the quickest way I'm going to do that. First to uh after I uh improve update the contract, the implementation and the extension pointer and uh for the demo, I'm I'm thinking that I can. um I can make a quick implementation there. I I actually.

A

uh I started a discussion thread on the jenkins dev group to to just know from where I can start where what would the best place to uh implement the extension point I'm providing, because that would be a that'll be easier for me to figure out where I could uh do that. So, if I, if I get the response there, then it's good. If I don't then should I is this: is it okay? If I uh contact the the repository maintainers, I I saw that I'm actually not sure of the name, I've.

A

I have seen the github handle bit wise man.

B

Yes, liam liam newman, you can certainly you can certainly ask liam questions. He's very, very willing. uh He'll he'll respond as time allows.

A

So so I'll ask him where I could do this, and so that will be quicker for me to actually implement it and then use it for our demo purposes and actually for our further analysis.

A

Yes, so um so I think this is it for uh the class. I actually have a lot more things to share, but I think the time has ended either we could do it on friday on friday I would have so. I have the some new benchmark results. Omkar was very helpful with creating different repositories with different kind of parameters we needed and we have some results from those analysis.

A

uh I also wanted a result from different platforms. I was looking at your instance and I was thinking to run that, but I could not. I could not do it, so I I don't have that right now. So, if you guys are comfortable, we could um share. There is a. I could share the results right now. Whatever I have.

E

A

So this is concern.

E

Of one thing like uh did you check, but it was failing on windows, european.

A

If you could see when you raised the concern the next commit, I I committed uh so it was failing, because I was I was expecting something wrong from the assertion. Okay, I was not. The windows returns, get dot, exe exe and I was expecting git, so I changed that. That is why it was happening. I'm sorry, I did not directly answer your question there. I'm sorry.

E

Okay, I'm not too good. I missed it. Okay,.

A

So if you guys want, I can share the results right now. If you'd like, I could share them on friday. What would you guys prefer.

B

uh Let me double check my calendar good question. I think I think I may actually have other things that are colliding on my calendar.

B

Yeah, I'm I'm supposed to be in another meeting right now, so it's probably best if it's okay with you, if we were to defer it until friday,.

A

It is okay with me. I uh I actually think the results we I have. They don't not sure if we could use them right now to uh get something actionable, but nevertheless we need to discuss them. So we can discuss them on friday.

B

A

Okay and uh the last thing with fran and uh travis, so we were discussing that we uh we could uh so we could whatever the implementation. We have discussed the update on the extension. So fran, would you like me to do it first and then you would review it. Would you uh so I I inferred, I'm not sure. If I inferred correctly, what you were saying in the get getter channel was that we could do it uh together.

A

C

But I mean what I mean is that, for example, tomorrow morning, because I'm in central european times we can overlap uh several hours, so anything that you can try. We can be re, reviewing almost live, because I can jump into the into github and see okay. This is what I mean. I was thinking more about this other thing.

C

However, I've put a couple of comments during this meeting just to try to make clear what mark justin and I was saying about having the how to filter about how to filter the extension list, using a method in the contract that the other implementers have to to develop. Okay, so.

E

C

Look at that and if you have any question regarding the that approach, uh let us know in guitar and, as I say tomorrow morning is we can overlap more time, so we can just doing almost life.

A

Sure sure fran that'll be great I'll be available uh throughout the morning, and so we could do that. Yeah and I'll try to uh do whatever we've discussed today through the night and you find so that would be better for us.

C

First, I try to have a look at that thing: how to how to do it, and tomorrow we can discuss that with more when you have spend more time. Thinking about how to do it with more context. Okay,.

A

Okay, okay, that'll be great; okay, I think that's it for the meeting. Thank you. Thank you. Everyone thanks, rashad bye thanks.

C