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Posted to dev@maven.apache.org by or...@io7m.com on 2017/01/01 13:04:36 UTC
Using the Maven API outside of a plugin?
Apologies if this isn't an appropriate subject for this list. I tried
the user list and got no response. Perhaps it is more of a development
question...
Hello.
I'm writing a small program to analyze the dependencies of Maven
projects. There are numerous examples of how to do this from within a
Maven plugin, but I can't work out how to simply load a POM file and
derive a ProjectDependencyGraph from it outside of the context of a
plugin. How do I instantiate all of the required classes? As an
example, I believe I need to instantiate a MavenSession, but all of the
constructors of that class are deprecated...
Does anyone have any example code or documentation I can look at?
Even some pointers such as "these are the list of classes you need to
instantiate" would help.
M
Re: Using the Maven API outside of a plugin?
Posted by Stian Soiland-Reyes <st...@apache.org>.
Hi, you may want to have look at Apache Taverna's plugin system which did
something similar. War story below..
We initially (2007) used Maven dependencies directly by parsing pom.xml
dependencies and using a set of repositories, but found this very fragile
because of versioning mismatches when upgrading anything; basically we
ended pulling down both the newer and older version of dependencies of the
main application, which might not match.
Back then it was even trickier to use Maven APIs outside Maven, so we
replicated our own pom.xml parsers and our own dependency tree resolution.
(Not a good idea!) We called this Raven..
In addition to having to play catch up with Maven (e.g. property expansion
within version strings) this infrastructure also ran into problems with
third party maven repositories for plugins being unreliable, but because we
had merged to a single list of repositories this affected installation of
all plugins and slowed down every startup. (We actually added blacklisting
of repos before Maven did :-))
While our first attempt, using our own "Raven" system assumed everything
was a plugin, meaning we could ship a minimal launcher and pom files, but
it would easily take 20 minutes on first launch to download everything. So
we had to "prewarm" our local repository - a naïve copy from .m2/repository
would also work.
We introduced a distinction from the Application (the full base
application that the installer provides) and optional plugins, which then
must be compatible with the particular application version. This is more of
a Firefox+plugins style model which is probably what you need as well.
In the end we decided for a simpler OSGi based launcher where we have a
maven plugin that can generate a Taverna plugin description (it unrolls all
the transitive dependencies), which can then be installed from a single
site independent of Maven infrastructure. So now we don't use anything
Maven related at runtime, meaning you can also install plugins by dropping
a file into a folder.
Taverna Osgi has update support as well with pre-checking of compatibility,
to avoid upgrading yourself to an version-incompatible state.
We use it for a command line tool and a Swing-based workbench, with Swing
components to manage plugin install.
I'm afraid we don't have much documentation yet, see
https://taverna.incubator.apache.org/download/osgi/
and ask on dev@taverna if you (or anyone else) are interested !
https://taverna.incubator.apache.org/community/lists
On 1 Jan 2017 6:00 pm, <or...@io7m.com> wrote:
> On 2017-01-01T17:37:26 +0100
> "Robert Scholte" <rf...@apache.org> wrote:
>
> > Hi,
> >
> > doing this outside the context of Maven is probably hard to do. What you
> > at least need is the maven-artifact-resolver[1] (that's the project where
> > the development of Eclipses Aether[2] continues), though is has not been
> > released yet, so right now using Aether would be an option.
> > You'll also need a maven-aether-provider[3].
> > I would expect that with these projects you should be able to do your
> > stuff, although doing it with a custom maven-plugin is probably a lot
> > easier.
> >
> > Robert
> >
> > [1] https://maven.apache.org/components/resolver-archives/
> resolver-LATEST/
> > [2] http://www.eclipse.org/aether/
> > [3] http://maven.apache.org/ref/3.3.9/maven-aether-provider/
> >
>
> 'Ello.
>
> Thanks for these.
>
> I should elaborate what I'm trying to do.
>
> I'm writing a small game and the game is designed to support third
> party modification out of the box. What this means in practical terms
> is that the game ships with a simple launcher and a directory full of
> jar files and their associated Maven POMs. In the launcher, the user
> states that they want to run the game with any extra specified mod
> packages, and the launcher analyzes the local POM files of the packages
> to determine if all of the dependencies are met (and will fetch packages
> from our server or Maven Central if the dependencies aren't currently
> installed).
>
> So, there isn't actually a plugin as all of this is happening post
> "deployment".
>
> I'll have a go at a proof of concept with the links you've provided.
>
> M
>
Re: Using the Maven API outside of a plugin?
Posted by Robert Scholte <rf...@apache.org>.
Someone pointed me once to https://github.com/nanosai/modrun which seems
to match your requirements.
I haven't tried it.
Robert
On Sun, 01 Jan 2017 19:00:28 +0100, <or...@io7m.com> wrote:
> On 2017-01-01T17:37:26 +0100
> "Robert Scholte" <rf...@apache.org> wrote:
>
>> Hi,
>>
>> doing this outside the context of Maven is probably hard to do. What you
>> at least need is the maven-artifact-resolver[1] (that's the project
>> where
>> the development of Eclipses Aether[2] continues), though is has not been
>> released yet, so right now using Aether would be an option.
>> You'll also need a maven-aether-provider[3].
>> I would expect that with these projects you should be able to do your
>> stuff, although doing it with a custom maven-plugin is probably a lot
>> easier.
>>
>> Robert
>>
>> [1]
>> https://maven.apache.org/components/resolver-archives/resolver-LATEST/
>> [2] http://www.eclipse.org/aether/
>> [3] http://maven.apache.org/ref/3.3.9/maven-aether-provider/
>>
>
> 'Ello.
>
> Thanks for these.
>
> I should elaborate what I'm trying to do.
>
> I'm writing a small game and the game is designed to support third
> party modification out of the box. What this means in practical terms
> is that the game ships with a simple launcher and a directory full of
> jar files and their associated Maven POMs. In the launcher, the user
> states that they want to run the game with any extra specified mod
> packages, and the launcher analyzes the local POM files of the packages
> to determine if all of the dependencies are met (and will fetch packages
> from our server or Maven Central if the dependencies aren't currently
> installed).
>
> So, there isn't actually a plugin as all of this is happening post
> "deployment".
>
> I'll have a go at a proof of concept with the links you've provided.
>
> M
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Re: Using the Maven API outside of a plugin?
Posted by or...@io7m.com.
On 2017-01-01T17:37:26 +0100
"Robert Scholte" <rf...@apache.org> wrote:
> Hi,
>
> doing this outside the context of Maven is probably hard to do. What you
> at least need is the maven-artifact-resolver[1] (that's the project where
> the development of Eclipses Aether[2] continues), though is has not been
> released yet, so right now using Aether would be an option.
> You'll also need a maven-aether-provider[3].
> I would expect that with these projects you should be able to do your
> stuff, although doing it with a custom maven-plugin is probably a lot
> easier.
>
> Robert
>
> [1] https://maven.apache.org/components/resolver-archives/resolver-LATEST/
> [2] http://www.eclipse.org/aether/
> [3] http://maven.apache.org/ref/3.3.9/maven-aether-provider/
>
'Ello.
Thanks for these.
I should elaborate what I'm trying to do.
I'm writing a small game and the game is designed to support third
party modification out of the box. What this means in practical terms
is that the game ships with a simple launcher and a directory full of
jar files and their associated Maven POMs. In the launcher, the user
states that they want to run the game with any extra specified mod
packages, and the launcher analyzes the local POM files of the packages
to determine if all of the dependencies are met (and will fetch packages
from our server or Maven Central if the dependencies aren't currently
installed).
So, there isn't actually a plugin as all of this is happening post
"deployment".
I'll have a go at a proof of concept with the links you've provided.
M
Re: Using the Maven API outside of a plugin?
Posted by Robert Scholte <rf...@apache.org>.
Hi,
doing this outside the context of Maven is probably hard to do. What you
at least need is the maven-artifact-resolver[1] (that's the project where
the development of Eclipses Aether[2] continues), though is has not been
released yet, so right now using Aether would be an option.
You'll also need a maven-aether-provider[3].
I would expect that with these projects you should be able to do your
stuff, although doing it with a custom maven-plugin is probably a lot
easier.
Robert
[1] https://maven.apache.org/components/resolver-archives/resolver-LATEST/
[2] http://www.eclipse.org/aether/
[3] http://maven.apache.org/ref/3.3.9/maven-aether-provider/
On Sun, 01 Jan 2017 14:04:36 +0100, <or...@io7m.com> wrote:
> Apologies if this isn't an appropriate subject for this list. I tried
> the user list and got no response. Perhaps it is more of a development
> question...
>
> Hello.
>
> I'm writing a small program to analyze the dependencies of Maven
> projects. There are numerous examples of how to do this from within a
> Maven plugin, but I can't work out how to simply load a POM file and
> derive a ProjectDependencyGraph from it outside of the context of a
> plugin. How do I instantiate all of the required classes? As an
> example, I believe I need to instantiate a MavenSession, but all of the
> constructors of that class are deprecated...
>
> Does anyone have any example code or documentation I can look at?
>
> Even some pointers such as "these are the list of classes you need to
> instantiate" would help.
>
> M
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