Allow extensions to depend upon other extensions

[dlvenable]

I want to have an extension and use another extension.

For example, I want to create a new plugin that will use the AwsCredentialsSupplier class which is provided by the AWS Plugin extension.

public class NewExtensionsPlugin implements ExtensionPlugin {

    @DataPrepperPluginConstructor
    public NewExtensionsPlugin(AwsCredentialsSupplier awsCredentialsSupplier) {
    }

Currently, this is not supported.

See the following code where this is not yet allowed:

data-prepper/data-prepper-core/src/main/java/org/opensearch/dataprepper/plugin/ExtensionLoader.java

Lines 54 to 62 in affe0b2

	private static class NoArgumentsArgumentsContext implements PluginArgumentsContext {
	@Override
	public Object[] createArguments(final Class<?>[] parameterTypes) {
	if(parameterTypes.length != 0) {
	throw new InvalidPluginDefinitionException("No arguments are permitted for extensions constructors.");
	}
	return new Object[0];
	}
	}

Proposed solution:

Allow ExtensionPlugin classes to add an annotation which defines what components the provide. This can allow the plugin framework to create a dependency tree.

@ExtensionProvides(value = {ClassSuppliedOne.class, ClassSuppliedTwo.class})

For example, in the AwsPlugin:

@ExtensionProvides(value = {AwsCredentialsSupplier.class})
public class AwsPlugin implements ExtensionPlugin {
    ...
    @Override
    public void apply(final ExtensionPoints extensionPoints) {
        extensionPoints.addExtensionProvider(new AwsExtensionProvider(defaultAwsCredentialsSupplier));
    }
}

What needs to happen:

• Load extensions in the necessary order. If Extension B depends on Extension A, then Extension A must load first.
• Update the ExtensionLoader to get extensions and inject them.

[dlvenable]

We recently added the ability to order how extensions are loaded in #5816. The goal of that change was to support alternative extension implementations.

data-prepper/data-prepper-plugin-framework/src/main/java/org/opensearch/dataprepper/plugin/PluginCreatorContext.java

Lines 22 to 25 in 9409ba7

	@Bean(name = "extensionsLoaderComparator")
	public Comparator<ExtensionLoader.ExtensionPluginWithContext> extensionsLoaderComparator() {
	return Comparator.comparing(ExtensionLoader.ExtensionPluginWithContext::isConfigured).reversed();
	}

However, since this means we now sort how extensions are loaded, we can make use of this to determine the order of loading such that dependency extensions are loaded before dependent extensions.