Export property in module.xml file

[sebastian.fekete]

Hi everyone,
I'm currently developing a custom Ignition module using the scripting-function Maven project as a base. In my module.xml file, I'm including third-party libraries like so:

<jar scope="DG">msal4j-1.20.1.jar</jar>

According to( The module.xml File | Ignition SDK Programmer's Guide) there's an <export> tag that can be used to make JARs available to a higher classloader

However, I'm not sure how to properly configure this in my maven-based build so that the required JARs are both:

• packaged in the .modl file, and
• included in the <export> section of the module.xml.

Are there any examples or best practices for automatically generating the <export> entries?

Thanks in advance!

[pturmel]

I still use ant to build my modules, so I can't help you with maven or gradle. But I use this in my Integration Toolkit module if you'd like an example of how it is supposed to turn out.

[PGriffith]

The current Maven module plugin doesn't have any way to set a dependency as export that I can see:

GitHub - inductiveautomation/ignition-maven-plugin: A Maven plugin for building...

[sebastian.fekete]

Sure, could you provide the module?

[pturmel]

Over here:

Automation Professionals' Integration Toolkit Module

Automation Professionals is pleased to announce the immediately availability of a major upgrade to its free Simulation Aids Integration Toolkit module. The new feature justifying the "major upgrade" language is the implementation of eleven thirty-one new expression functions which use iteration to accomplish complex transforms of datasets and lists, to or from other datasets and lists, applying filtering, ordering, and computed new columns along the way. While there are certain operations that…

[sebastian.fekete]

Thanks! may i ask a further question: it says that with the export tag the dependencies are available in a higher classloader, which classloader does this refer to and in which context are those dependencies accessible? My original goal was to make msal4j.jar available to the database classloaders, but I assume that’s not feasible using export or generally with a module, correct?

[pturmel]

@sebastian.fekete

which classloader does this refer to

Not sure. I thought it was the root classloader.

[Kevin.Herron]

@pturmel

I thought it was the root classloader.

It's a separate ClassLoader that sits between modules and the root/context ClassLoader.

@sebastian.fekete

My original goal was to make msal4j.jar available to the database classloaders, but I assume that’s not feasible using export or generally with a module, correct?

I don't think so; JDBC drivers are in their own isolated ClassLoader.

[Kevin.Herron]

Something like this I think:

[pturmel]

Then scripting must run from that modules classloader, as exported classes are directly accessible in gateway scripts.

[PGriffith]

@sebastian.fekete

My original goal was to make msal4j.jar available to the database classloaders, but I assume that’s not feasible using export or generally with a module, correct?

I mean, modules can run arbitrary code. The JDBC classloader just picks up whatever jars are in the jdbc/ folder. Nothing's stopping you from just dropping your own JAR there other than the prospect of having to clean it up eventually.

[Kevin.Herron]

Another trick you can do is just add an additional classpath entry to ignition.conf, e.g.

wrapper.java.classpath.3=lib/core/custom

and drop any extra JAR files you want in there.

edit: though I'm not sure that's the right place for JDBC hackage...