Ensure caliper is shaded in bench, add bench desc, use RUN so that ou…

…tput is printed

caliper depends on guava 11 which is incompatible with guavas above 15 due to deprecated method removals, adding main to the jvm tool registration causes it to be shaded, which means the older guava won't interfer with code under test that depends on newer guava versions.

I also added a description and set the WorkUnit.RUN label so that the caliper output will be printed to the console by default.

Testing Done:
tested against a target with a dependency on guava 16, which failed to run without shading. CI in PR

Bugs closed: 1674

Reviewed at https://rbcommons.com/s/twitter/r/2353/

BUILD.tools

@@ -59,9 +59,9 @@ jar_library(name = 'cobertura-report',
 
 jar_library(name = 'benchmark-caliper-0.5',
             jars = [
-              # TODO(Eric Ayers) Caliper is old and breaks with guava 16. Add jmh support?
-              jar(org = 'com.google.caliper', name = 'caliper', rev = '0.5-rc1')
-                .exclude(org='com.google.guava', name='guava')
+              # TODO (Eric Ayers) Caliper is old. Add jmh support?
+              # The caliper tool is shaded, and so shouldn't interfere with Guava 16.
+              jar(org = 'com.google.caliper', name = 'caliper', rev = '0.5-rc1'),
             ])
 
 jar_library(name = 'benchmark-java-allocation-instrumenter-2.1',

src/python/pants/backend/jvm/register.py

@@ -168,7 +168,7 @@ def register_goals():
 
   # Testing.
   task(name='junit', action=JUnitRun).install('test').with_description('Test compiled code.')
-  task(name='bench', action=BenchmarkRun).install('bench')
+  task(name='bench', action=BenchmarkRun).install('bench').with_description('Run benchmark tests.')
 
   # Running.
   task(name='jvm', action=JvmRun, serialize=False).install('run').with_description(

src/python/pants/backend/jvm/tasks/BUILD

@@ -42,6 +42,7 @@ python_library(
     ':jvm_task',
     ':jvm_tool_task_mixin',
     'src/python/pants/backend/core/tasks:task',
+    'src/python/pants/base:workunit',
     'src/python/pants/java:util',
   ],
 )

src/python/pants/backend/jvm/tasks/benchmark_run.py

@@ -11,16 +11,19 @@
 from pants.backend.jvm.tasks.jvm_task import JvmTask
 from pants.backend.jvm.tasks.jvm_tool_task_mixin import JvmToolTaskMixin
 from pants.base.exceptions import TaskError
+from pants.base.workunit import WorkUnit
 from pants.java.util import execute_java
 
 
 class BenchmarkRun(JvmTask, JvmToolTaskMixin):
+  _CALIPER_MAIN = 'com.google.caliper.Runner'
+
   @classmethod
   def register_options(cls, register):
     super(BenchmarkRun, cls).register_options(register)
     register('--target', help='Name of the benchmark class. This is a mandatory argument.')
     register('--memory', default=False, action='store_true', help='Enable memory profiling.')
-    cls.register_jvm_tool(register, 'benchmark-tool', default=['//:benchmark-caliper-0.5'])
+    cls.register_jvm_tool(register, 'benchmark-tool', main=cls._CALIPER_MAIN, default=['//:benchmark-caliper-0.5'])
     cls.register_jvm_tool(register, 'benchmark-agent',
                           default=['//:benchmark-java-allocation-instrumenter-2.1'])
 
@@ -65,12 +68,12 @@ def execute(self):
 
     classpath = self.classpath(self.context.targets(), benchmark_tools_classpath)
 
-    caliper_main = 'com.google.caliper.Runner'
     exit_code = execute_java(classpath=classpath,
-                             main=caliper_main,
+                             main=self._CALIPER_MAIN,
                              jvm_options=self.jvm_options,
                              args=self.args,
                              workunit_factory=self.context.new_workunit,
-                             workunit_name='caliper')
+                             workunit_name='caliper',
+                             workunit_labels=[WorkUnit.RUN])
     if exit_code != 0:
-      raise TaskError('java {} ... exited non-zero ({})'.format(caliper_main, exit_code))
+      raise TaskError('java {} ... exited non-zero ({})'.format(self._CALIPER_MAIN, exit_code))