Hi Geoff,
RESTEasy services are singletons, so we simply created an `AtomicReference`
field and used `compareAndSet()`,
something like this:
private final AtomicReference<WarmUpStatus> warmUpStatus = new
AtomicReference<>(WarmUpStatus.EMPTY);
@Override
public Response warmUp()
{
if (warmUpStatus.compareAndSet(WarmUpStatus.EMPTY,
WarmUpStatus.IN_PROGRESS))
{
Regards,
Dmitry
On Tue, Nov 30, 2021 at 1:41 AM JumpStart <
geoff.callender.jumpst...@gmail.com> wrote:
> Hi Dmitry,
>
> That is spectacularly helpful!
>
> We’re about to write a headless smoke test anyway that will visit every
> page. Do you see any downside to using that to do the warmup?
>
> Where do you keep your shared “warmup in progress” flag so that it is
> rapidly accessible on every health check request?
>
> Cheers,
>
> Geoff
>
> > On 30 Nov 2021, at 6:35 am, Dmitry Gusev <dmitry.gu...@gmail.com> wrote:
> >
> > Hi Geoff,
> >
> > I don't think there's a simpler way, we're doing something similar.
> >
> > We created a REST endpoint with tynamo-resteasy which is effectively a
> load
> > balancer health check.
> > On the first hit it starts the warmup process on the same request,
> > following requests return an error instantly if the initial warmup
> routine
> > is still in progress.
> >
> > Our warmup logic is heavily based on tapestry internals & reflection, in
> > conjunction with eager loading services as described here:
> > https://gist.github.com/dmitrygusev/5562739
> >
> > Warmup logic is a bit complicated, it's trying to:
> > - "touch" each page using ComponentClassResolver.getPageNames()
> > - recursively for each component with mixins on a page starting from root
> > component,
> >> find imported assets via reflection (fields with names starting as
> > `importedAssets_`)
> >> stream each asset via `StreamableResourceSource` into no-op consumer
> > - find JS modules with `ModuleManager` and stream through no-op consumer
> > - every JS stack returned from `JavaScriptStackSource` assemble with
> > `JavaScriptStackAssembler` and stream through no-op consumer
> > - repeat above for each locale/axis
> >
> > Entire process usually takes 3-5 minute in our setup.
> > After it's done we return 200 to the load balancer and the first real
> > request is handled with hot caches.
> >
> > Hope this helps,
> > Dmitry
> >
> > On Mon, Nov 29, 2021 at 9:53 PM JumpStart <
> > geoff.callender.jumpst...@gmail.com> wrote:
> >
> >> Any suggestions on best ways to write a “health check” page to be called
> >> by load balancers?
> >>
> >> My app is getting big, and the traffic is big. If the app fails
> (hopefully
> >> never, but it’s a JVM) and the traffic is heavy enough, startup never
> seems
> >> to complete - every request times out, the app log goes quiet, and CPU
> goes
> >> to 100%. It appears to be due to race conditions possibly involving
> asset
> >> compression, minimising, and first time into the pages.
> >>
> >> I’m considering having a startup service crawl every page, in every
> >> language, in every skinning, before setting a singleton flag that the
> >> health check page will read to determine whether the app is ready to
> >> receive traffic.
> >>
> >> Is there a simpler way?
> >>
> >> Geoff
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> >>
> >>
>
>
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>
--
Dmitry Gusev
AnjLab Team
http://anjlab.com
