[hibernate-dev] ci.hibernate.org : announcing distributed cache for maven artifacts

[Yoann Rodiere]

> We should reconfigure those to not "install" - that's actually a bad
> habit, legacy from Maven 2 times - people nowadays recommend using
> "mvn clean verify", especially on CI environments.

I could not agree more, that would be cleaner, but that's not possible. And
believe me, I tried hard. Last time I checked, some of the plugins we use
with dynamic dependency resolution would ignore the artifacts being built,
and would always fetch the artifacts from the Maven repos (for SNAPSHOTs,
they would end up using nightlies).
I'm not talking about when we use standard maven markup to declare
dependencies, but when the plugin itself has to fetch dependencies
"dynamically", which happens when we setup a WildFly server with our own
modules in particular. See maven-dependency-plugin's "artifactItems"
configuration.



On Mon, 15 Jan 2018 at 11:29 Sanne Grinovero <sanne at hibernate.org> wrote:

> On 15 January 2018 at 08:42, Yoann Rodiere <yoann at hibernate.org> wrote:
> > Thanks Sanne !
> >
> > I have one question...
> >
> >> Please never rely on this as "storage": it's just meant as cache and
> >> we reserve the right to wipe it all out at any time.
> >
> > I gather you say that so that we don't try to "release" artifacts into
> this
> > cache? But temporary storage for the duration of one build will still be
> > safe?
> >
> > Because our builds obviously rely on the local repository for short-term
> > storage (for the duration of the build). For example the dependencies are
> > only checked and downloaded if necessary at the beginning of the build,
> and
> > then are expected to exist in the local repository until the build stops.
> > Another example: our WildFly modules are first built and installed in the
> > "modules" subproject, and later "fetched" from the local repository in
> the
> > "integrationtest/wildfly" subproject.
> >
> > If we were to clear the cache during a build, things would probably go
> > wrong. Worse, if two parallel builds were to install the same artifacts
> > (e.g. hibernate-search-engine version 5.9.0-SNAPSHOT), we would run the
> risk
> > of testing the wrong "version" of this artifact in one of the builds...
>
> SNAPSHOT being installed are indeed a problem, e.g the PR testing jobs
> could conflict with the regular master jobs.
> We should reconfigure those to not "install" - that's actually a bad
> habit, legacy from Maven 2 times - people nowadays recommend using
> "mvn clean verify", especially on CI environments.
>
> I agree about the perils of clearing the cache during in-progress builds
> too.
>
> I just meant to warn that we don't have any backup plan in place, and
> I do plan to just wipe the whole thing occasionally:
>  - when we have any direct need, e.g. currupted downloads
>  - when it gets too large
>  - if it gets too expensive
>  - regularly, just to "practice" that everything works with an empty cache
>
> Also our "disaster recovery" plan to rebuild all infrastructure will
> always assume it's ok to reboot with having this file system empty.
>
> Thanks,
> Sanne
>
> >
> >
> > On Sun, 14 Jan 2018 at 01:18 Sanne Grinovero <sanne at hibernate.org>
> wrote:
> >>
> >> Hi all,
> >>
> >> while the new build machines are fast, some of you pointed out we're
> >> now spending a relative high amount of time downloading maven
> >> dependencies, this problem being compounded by the fact we "nuke" idle
> >> slaves shortly after they become idle.
> >>
> >> I just spent the day testing a distributed file system, and it's now
> >> running in "production".
> >> It's used exclusively to store the Gradle and Maven caches. This is
> >> stateful and independent from the lifecycle of individual slave nodes.
> >>
> >> Unfortunately this solution is not viable for Docker images, so while
> >> I experimented with the idea I backed off from moving the docker
> >> storage graph to a similar device. Please don't waste time trying that
> >> w/o carefully reading the Docker documentation or talking with me :)
> >> Also, beyond correctness of storage semantics, it's likely far less
> >> efficient for Docker.
> >>
> >> To learn more about our new cache:
> >>  -
> >>
> https://github.com/hibernate/ci.hibernate.org/commit/dc6e0a4bd09fb3ae6347081243b4fb796a219f90
> >>  - https://docs.aws.amazon.com/efs/latest/ug/how-it-works.html
> >>
> >> I'd add that - because of other IO tuning in place - writes might
> >> appear out of order to other nodes, and conflicts are not handled.
> >> Shouldn't be a problem since snapshots now have timestamps, but this
> >> might be something to keep in mind.
> >>
> >> N.B.
> >> Please never rely on this as "storage": it's just meant as cache and
> >> we reserve the right to wipe it all out at any time.
> >>
> >> Thanks,
> >> Sanne
> >> _______________________________________________
> >> hibernate-dev mailing list
> >> hibernate-dev at lists.jboss.org
> >> https://lists.jboss.org/mailman/listinfo/hibernate-dev
> >
> >
> >
> > --
> > Yoann Rodiere
> > yoann at hibernate.org / yrodiere at redhat.com
> > Software Engineer
> > Hibernate NoORM team
>


-- 
Yoann Rodiere
yoann at hibernate.org / yrodiere at redhat.com
Software Engineer
Hibernate NoORM team