Hi Everyone
This is the second of two emails to inform the community about what has been
happening around how we are planning to handle external dependencies in the
trunk. Two weeks ago the community discussed and agreed to the use of Gradle to
help us put together a unit test framework. While trying to get this set up
while Ant remained as our build tool became very difficult. This was because
our Ant scripts:
- are massive and contain a lot of code
- are complex
- are very brittle and make it very hard to change things
- have no dependency management
- need everything to be declared
We realised very quickly that the re-factoring issues and limitations we are
facing are because of our build tool â Ant.
Ant is verbose so it needs everything to be declared. We did a brief assessment
of Maven and found it better than Ant but not a good fit for OFBiz because it
has strict requirements for the convention-over-configuration rules to work.
Instead we decided to take a closer look at Gradle.
So why Gradle?
As Taher was already looking at Gradle for unit testing, we decided to look at
what we would need to do to totally replace Ant with Gradle. We received some
great support and feedback from David, who is already using Gradle with Moqui.
After some preliminary tests we found that Gradle has some very good features
such as:
- a much shorter code base (e.g. one single file of around 250 lines of code
replaces all the build.xml files and thousands of lines of code)
- Programming is DSL based and links in well with Groovy (e.g. the script
is short because despite heavy custom requirements for OFBiz, two small
functions took care of the complex directory structure)
- It handles all the external jar files by downloading any dependencies
directly via internet
- Jars can be upgraded by simply changing a string
- It has matured a lot and has a high level of support in tools,IDEs, books,
documentation
- It also has a lot of plugins which means that it works with pretty much
all build systems, supports multiple programming languages, and many other
features (e.g. OSGi)
We understand that it can help us make OFBiz more modular and also setting up a
framework for managing addons would be a lot easier.
So what's been done?
Taher has been working very hard on a patch for the trunk that completely
replaces Ant with Gradle. (Huge thanks to David for providing some example
scripts to help us get started!) The patch is now ready to be applied to the
trunk and includes the following:
- java -jar ofbiz.jar is now replaced with -> gradlew 'ofbiz
--whatever-options-here'
- In addition to gradlew 'ofbiz' we also have gradlew 'ofbizDebug
--whatever'. What does that mean? It means we can run debug on ALL ofbiz
commands, not just start
- If we decide to change the source directory structure in components say
from /src to /src/main, it would literally be a change of 5 characters in the
build script
- We can immediately move all jar files if we want to a unified location in
/lib for example
- We can delete most of the jars and declare them as dependencies saving
space and resources
- We can automate the creation of the .classpath file so when we update
libraries no need to do this manually (under development)
- We can ignore components that are not define in the xml files for loading
(under development)
- We can introduce unit tests with about 10 minutes of work
We are finding that the flexibility and control we are getting with Gradle is
truly amazing. We know that Gradle will be a major change to the project but we
think that it will significantly improve the project by removing a lot of build
complexity and take care of that essential dependency management that we need
to comply with.
Our next steps will be to apply the patch to the trunk and then continue the
re-factoring work. We will need to organise some knowledge transfer so that all
our committers understand what the changes are and how they would need to work
in the future.
The PMC are very, very excited about having Gradle as part of future of OFBiz
and we hope that the community will think so too. As always, feedback welcome.
Thanks
Sharan
