use workunit output for cpp command running

While working on moving reporting to a separate thread, I found that the cpp plugin wasn't using workunit output files, so it's output wasn't being managed by the run_tracker.

This changes the cpp run_command to use a workunit for the stdout / stderr files, and also adds the RUN label to the cpp run task.

Testing Done:
Ran contrib tests after changes, ci baking in PR.

Bugs closed: 1549

Reviewed at https://rbcommons.com/s/twitter/r/2223/

contrib/cpp/src/python/pants/contrib/cpp/tasks/cpp_binary_create.py

@@ -83,7 +83,7 @@ def add_library(tgt):
     if self.get_options().ld_options != None:
       cmd.extend(('-Wl,{0}'.format(o) for o in self.get_options().ld_options.split(' ')))
 
-    with self.context.new_workunit(name='cpp-link', labels=[WorkUnit.COMPILER]):
-      self.run_command(cmd)
+    with self.context.new_workunit(name='cpp-link', labels=[WorkUnit.COMPILER]) as workunit:
+      self.run_command(cmd, workunit)
 
     return output

contrib/cpp/src/python/pants/contrib/cpp/tasks/cpp_compile.py

@@ -91,7 +91,7 @@ def _compile(self, target, source):
       cmd.extend([self.get_options().cc_options])
 
     # TODO: submit_async_work with self.run_command, [(cmd)] as a Work object.
-    with self.context.new_workunit(name='cpp-compile', labels=[WorkUnit.COMPILER]):
-      self.run_command(cmd)
+    with self.context.new_workunit(name='cpp-compile', labels=[WorkUnit.COMPILER]) as workunit:
+      self.run_command(cmd, workunit)
 
     self.context.log.info('Built c++ object: {0}'.format(obj))

contrib/cpp/src/python/pants/contrib/cpp/tasks/cpp_library_create.py

@@ -65,7 +65,7 @@ def _link_library(self, target, objects):
     cmd.extend([output])
     cmd.extend(objects)
 
-    with self.context.new_workunit(name='cpp-link', labels=[WorkUnit.COMPILER]):
-      self.run_command(cmd)
+    with self.context.new_workunit(name='cpp-link', labels=[WorkUnit.COMPILER]) as workunit:
+      self.run_command(cmd, workunit)
 
     return output

contrib/cpp/src/python/pants/contrib/cpp/tasks/cpp_run.py

@@ -37,10 +37,10 @@ def prepare(cls, options, round_manager):
   def execute(self):
     binary = self.require_single_root_target()
     if isinstance(binary, CppBinary):
-      with self.context.new_workunit(name='cpp-run', labels=[WorkUnit.TASK]):
+      with self.context.new_workunit(name='cpp-run', labels=[WorkUnit.RUN]) as workunit:
         cmd = [os.path.join(binary.workdir, binary.id, binary.name)]
         args = self.get_options().args + self.get_passthru_args()
         if args != None:
           cmd.extend(args)
 
-        self.run_command(cmd)
+        self.run_command(cmd, workunit)

contrib/cpp/src/python/pants/contrib/cpp/tasks/cpp_task.py

@@ -39,11 +39,11 @@ def register_options(cls, register):
   def execute(self):
     raise NotImplementedError('execute must be implemented by subclasses of CppTask')
 
-  def run_command(self, cmd):
+  def run_command(self, cmd, workunit):
     try:
       self.context.log.debug('Executing: {0}'.format(cmd))
       # TODO: capture stdout/stderr and redirect to log
-      subprocess.check_call(cmd)
+      subprocess.check_call(cmd, stdout=workunit.output('stdout'), stderr=workunit.output('stderr'))
     except subprocess.CalledProcessError as e:
       raise TaskError('Execution failed: {0}'.format(e))
     except:

contrib/cpp/tests/python/pants_test/contrib/cpp/test_cpp_integration.py

@@ -64,7 +64,7 @@ def test_cpp_binary_with_library_compile(self):
   def test_cpp_run(self):
     pants_run = self.run_pants(['run', self.TEST_RUN_TARGET])
     self.assert_success(pants_run)
-    self.assertIn('[cpp-run]Hello, pants!\nGoodbye, pants!\n',
+    self.assertIn('[cpp-run]\nHello, pants!\nGoodbye, pants!\n',
                   pants_run.stdout_data)
 
   def _binary_test(self, target):