Hacking Maven Linux day 2017
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The document discusses hacking Maven to make it more powerful. It describes embedding Maven to use it programmatically and adding decorators to add behaviors before and after compilation, such as syncing with a Git repository. A key challenge is accessing objects from Maven's internal classloaders. The solution is to use a "Charon" object to move live objects from Maven's classloaders to an external classloader, allowing these objects to be used. This makes Maven more flexible, extensible, and able to return live object models rather than just files.
![InseHacking Maven
18
We use a “Charon” object to enable the connection
between outside (our API) and inside Maven (the executed plugin),
in this way we are capable to read as a []bytes the live obejcts and move
from the internal classloader to our external classloader and use for our
needs.
In our implementation “Charon” works as a part of Maven
Trojans Horse https://it.wikipedia.org/wiki/Giandomenico_Tiepolo](https://image.slidesharecdn.com/linuxday2017hackingmaven-171028104534/85/Hacking-Maven-Linux-day-2017-18-320.jpg)
Hacking Maven Linux day 2017
- 1. Hacking Maven how to add steroids on Maven di Massimiliano Dessì
- 2. InseHacking Maven 2 Abstract 30 minutes to illustrate from 30000 ft the ideas applied to turn Maven from a “static” producer to a “rich” compiler enabled to reads objects usually unacessible
- 3. InseHacking Maven 3 Speaker @desmax74 Massimiliano Dessì has more than 17 years of experience in programming. Manager of GDG Sardegna, co-founder of Jug Sardegna. Author of Spring 2.5 AOP. He works as a Senior Software Engineer for Red Hat in the Business Systems and Intelligence Group (aka KIE - Knowledge Is Everything), he lives in Cagliari, Sardinia, Italy.
- 4. InseHacking Maven 4 https://maven.apache.org/what-is-maven.html Starting point: Maven’s Objectives
- 6. InseHacking Maven 6 Basically Maven produces artifacts on filesystem using plugins, Jar,War, Ear, documentation, but basically is a “box” to product other files, from Java multimodule projects. In our group we using a plugin and a pipeline to process rules and other projects managed by Drools/Optaplanner/JBPM to produce files , but are “dead” files, not a complete representation of a runtime objects. Context
- 7. InseHacking Maven 7 Maven, the visible (and hated) part
- 8. InseHacking Maven 8 Embedding Our first goal is to use Maven like a normal API, Maven could be embedded in two ways using two libraries: Maven Invoker, open a new process separated from the caller https://maven.apache.org/plugins/maven-invoker-plugin/index.html Maven Embedder, Works in the same process of the caller https://maven.apache.org/ref/3.5.2/maven-embedder/index.html this was our starting point
- 9. InseHacking Maven 9 Cloud Openshift/Kubernetes Containers Fast as possible between builds Live objects :) Our New Requirements
- 10. InseHacking Maven 10 http://takari.io/ Let’s go to do something challenging but first we want to optimize the time in front of Maven enabling the incremental compiler called Takari Every time a new project is discovered https://github.com/takari
- 11. InseHacking Maven 11 In our initial design we want to ask to Maven: Result of the build Output Log Classloaders Live objects Live objects generated on the fly (no .class file) then we will add other useful features Request-Response behaviour
- 13. InseHacking Maven 13 How to reach some of our goals ? Since we want to add objects to the Maven “embedded” result (a int to signal success or failure) we use a pipeline of decorators to add behaviour before and after compilation (we could add additional decorators to add behaviours) Before to sync the project with the git origin repo because our project coming from git and the changes are commited to be visible to other users After to add the KieObjects readed from inside Maven, or to add the Maven output if requested in the CompileRequest
- 14. InseHacking Maven 14 The hardest part Maven is designed to be extensible with plugins for the processing not for changes in its internals But we are highly motivated :)
- 15. InseHacking Maven 15 Maven Internal component Maven for its job use Plexus/Eclipse Sisu and ClassWorlds Plexus/Eclipse Sisu is a IoC container Classworlds is used to manage the different classloaders required
- 16. InseHacking Maven 16 Classloading ● System Classloader ● Core Classloader ● Plugin Classloaders ● Custom Classloaders https://maven.apache.org/guides/mini/guide-maven-classloading.html Classworlds is used to create this hierarchy of classloader
- 17. InseHacking Maven 17 Classloading This means that we need to find a way to move the objects from an unaccessible (from outside) plugin classloader We need a Charon/Caronte, something able to move from one “world” to “another” https://en.wikipedia.org/wiki/Charon_(mythology)
- 18. InseHacking Maven 18 We use a “Charon” object to enable the connection between outside (our API) and inside Maven (the executed plugin), in this way we are capable to read as a []bytes the live obejcts and move from the internal classloader to our external classloader and use for our needs. In our implementation “Charon” works as a part of Maven Trojans Horse https://it.wikipedia.org/wiki/Giandomenico_Tiepolo
- 19. InseHacking Maven 19 The implementation at the end is ● Flexible ● Extensible ● Open to the changes ● Could be changed on every request ● Stateless ● Ready for update Maven versions the only informations retained are the links between builders and projects associated
- 21. InseHacking Maven 21 Q & A
- 22. InseHacking Maven 22 Have fun ! and thanks for your attention ! Happy hacking