Better cold classes management #175

a-peyrard · 2015-03-15T20:42:37Z

This PR permits to manage several new things about cold classes.

It permits to add inherited classes of cold components (components being loaded in the main factory, such as AutoStartable ones) in cold classes list.
It adds a way to declare cold classes using a property: restx.cold.classes. The property value is a list of fqcn separated by :.
It adds a way to declare cold classes using a resource file: META-INF/cold-classes.list. Resources will be loaded from the classloader, and every classes listed will be added to the cold classes list. The file must contains a list of fqcn, one per line.
It provides a way to fulfil the resource file using an annotation: @Cold. So every classes annotated with @Cold will be added to the resource file (thanks to a new annotation processor).

This method recursively analyse a class to get all its super classes, and all its interfaces

Instead of just adding the component class, also adds its inherited classes.

This property contains a string with all FQCN of cold classes, separated by ':'. This property might be specified using System.properties like that: ``` System.setProperty("restx.cold.classes", "foo.ColdClass1:bar.ColdClass2"); ``` It meant that `foo.ColdClass1` and `bar.ColdClass2` must be ignored by hot-reload mechanism. As cold classes are supposed to be used by components, they must be loaded with the same classloader as the one used for components, that's why the classloader used to initialize the factory's components is kept, and re-used to transform cold classes FQCN into real classes.

Currently only one method is defined, a method to extract cold classes from a string. The string needs to contain fqcn separated by the ':' character.

Using a resource `META-INF/cold-classes.list` permits to declare a list of cold classes. The file must contain a fqcn per line. Mind that this file will be read only once, so new cold classes declaration will requires a restart of the application.

This annotation permits to declare the class as cold. Once declared the class will not be part of the hot-reloading mechanism.

In factory annotation processor a class was used to generate the machine service file. This process use from now on the abstract class ResourceDeclaration defined in RestxAbstractProcessor. Like this other processors having the same need, might also use the ResourceDeclaration class.

@Cold

This annotation processor will produces a "cold-classes.list" file, containing the list of all classes annotated with @Cold.

xhanin · 2015-03-16T07:36:08Z

Sounds good to me. One question: is there any reason you use : as separator? I usually prefer using a comma to list values (when it's not conflicting with the values), I think it's more readable, especially if you trim the values you can have a very readable list.

a-peyrard · 2015-03-16T13:12:45Z

No reason, I just use to much ux systems :)

So I will change to , soon.

a-peyrard · 2015-03-29T22:17:02Z

Separator changed, if it's okay for you I will merge this tomorrow.

xhanin · 2015-03-30T16:35:50Z

Fine for me

fcamblor · 2015-03-31T22:14:59Z

👍 with some delay (sorry)

As a trim is done of tokens of the splitted string, property might be defined like that: restx.cold.classes="foo.bar.MyFxirColdClass, foo.bar.MySecondColdClass,or.whithout.Spaces"

a-peyrard · 2015-04-01T09:21:50Z

I changed the trim, according to Xavier's remark (thanks to "push -f" :)).

Better cold classes management. fix #160

fcamblor · 2015-10-23T15:07:53Z

@a-peyrard Just 1 simple question about @Cold annotation : will it work on only @Component-annotated classes or will it work under all circumstances ?

I'm facing some weird classloader issue and tried to fix it with @Cold annotation but it didn't worked (my classloader issue concerns a "standard" class, not a @Component)

a-peyrard · 2015-10-23T15:25:50Z

I just checked the code, and it should work for any classes, not only
@component. If you set the log level to "debug" for
RestxMainRouterFactory it should log the cold classes like this: "cold
classes: ..."

If it's not working you can try to add the property "restx.cold.classes" to
your JVM options, the value is a list of FQCN separated by commas.

On Fri, Oct 23, 2015 at 5:07 PM Frédéric Camblor notifications@github.com
wrote:

@a-peyrard https://github.com/a-peyrard Just 1 simple question about
@Cold annotation : will it work on only @Component-annotated classes or
will it work under all circumstances ?

I'm facing some weird classloader issue and tried to fix it with @Cold
annotation but it didn't worked (my classloader issue concerns a "standard"
class, not a @component)

—
Reply to this email directly or view it on GitHub
#175 (comment).

fcamblor · 2015-10-23T15:27:29Z

Yep, tried with the restx.cold.classes property as well and it didn't worked for my particular case

But no worries, my problem may not be related to hot reload (I only tried to fix it with cold classes but it didn't helped)

xhanin · 2015-10-23T20:50:06Z

Fred, I think it would be interesting to diagnose your issue more closely to see if it's not a problem with the new cold classes approach. I will try to check that with you next week or more probably the week after, since I won't be at the office next week.

fcamblor · 2015-10-24T00:42:56Z

I just created this repo reproducing my case (needs current restx version to compile well as it requires @Cold annotation)

if you run AppServer from it in dev mode, and go to http://127.0.0.1:8080/api/servletRootRealPath, you will see you have a null path returned whereas the ContainerListener has been initialized (and the App enum singleton initialized as well)

If you retry it in prod mode, everything will go well.

a-peyrard · 2015-10-24T10:27:06Z

I just cloned your repo, and I will try to explain what I understood.

The App.class is loaded a first time by the main classloader (being AppClassLoader), and after that the RestxMainRouterFactory initialize and create a first HotCompile classloader. Unfortunately this is this first HotCompile classloader which is used to load cold classes.
Then the request is made, and another HotReload classloader is created for the request. It finds the cold class (App), but the one loaded in the first HotReload classloader.

I manage to make it work by commenting the line:

mainFactoryClassLoader = hotReloadingClassLoader;

I don't know why I used this classloader to load the cold classes, I don't know what would be the impact, to use the original classloader instead of the one creating the main restx factory.

HTH

a-peyrard added 8 commits March 8, 2015 17:05

Adds method to get inherited classes

b54562c

This method recursively analyse a class to get all its super classes, and all its interfaces

adds full inheritance tree in cold classes

cb500af

Instead of just adding the component class, also adds its inherited classes.

introduces ColdClasses helper class

b3c86ce

Currently only one method is defined, a method to extract cold classes from a string. The string needs to contain fqcn separated by the ':' character.

introduces @Cold annotation

e22c813

This annotation permits to declare the class as cold. Once declared the class will not be part of the hot-reloading mechanism.

introduces annotation processor for @Cold

96653b3

This annotation processor will produces a "cold-classes.list" file, containing the list of all classes annotated with @Cold.

a-peyrard mentioned this pull request Mar 15, 2015

Better management of cold classes for HotCompile #160

Closed

change cold classes separator from ':' to ','

5f66923

As a trim is done of tokens of the splitted string, property might be defined like that: restx.cold.classes="foo.bar.MyFxirColdClass, foo.bar.MySecondColdClass,or.whithout.Spaces"

a-peyrard force-pushed the better-cold-classes branch from 8653257 to 5f66923 Compare April 1, 2015 09:16

a-peyrard added a commit that referenced this pull request Apr 1, 2015

Merge pull request #175 from a-peyrard/better-cold-classes

88e1be3

Better cold classes management. fix #160

a-peyrard merged commit 88e1be3 into restx:master Apr 1, 2015

This was referenced Apr 1, 2015

HotCompile issue #157

Closed

Fix HotReload issue with Autostartables #163

Closed

a-peyrard mentioned this pull request Nov 20, 2015

Is it possible to disable hot compile for all components except resources? #233

Open

Better cold classes management #175

Better cold classes management #175

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a-peyrard commented Mar 15, 2015

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