[STORM-499] Document and clean up shaded dependncy resolution with maven

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.9.3
• Fix Version/s: 0.9.3
• Component/s: documentation, storm-core
• Assignee: P. Taylor Goetz
• Reporter: Robert Joseph Evans
• Created: 17/Sep/14 16:26
• Updated: 05/Oct/15 01:43
• Resolved: 21/Oct/14 19:30

Description

After STORM-447 went in several dependencies have been shaded. They no longer exist in their normal form on the storm classpath, but the pom.xml that is installed with maven lists them as provided.

This can become an issue if their topology does not call out dependencies properly and they depend on something like guava, assuming that it will be available from storm.

from https://github.com/apache/incubator-storm/pull/219 it looks like we should add

<keepDependenciesWithProvidedScope>false</keepDependenciesWithProvidedScope>

to help fix this, and add some documentation about how the maven assembly plug-in decides what to pull in, to give users instructions on how to depend on the shaded version of a package if they want to, or to be sure that they are including all of their real dependencies in their pom so in the future when we shade other things they are not caught off guard.