[prefix_cmd] Add support for a prefix command for user-code executables

beat/core/agent.py

@@ -391,8 +391,8 @@ class Agent(object):
     logger.debug("Exiting processing context...")
 
 
-  def run(self, configuration, timeout_in_minutes=0, daemon=0):
-    """Runs the algorithm code
+  def run(self, configuration, timeout_in_minutes=0, daemon=0, prefix_cmd=None):
+    """Runs the user algorithm code, possibly as another system user or group
 
 
     Parameters:
@@ -400,15 +400,18 @@ class Agent(object):
       configuration (object): A *valid*, preloaded
         :py:class:`beat.core.execution.Executor` object.
 
-      timeout_in_minutes (int): The number of minutes to wait for the user
-        process to execute. After this amount of time, the user process is
+      timeout_in_minutes (int, Optional): The number of minutes to wait for the
+        user process to execute. After this amount of time, the user process is
         killed with :py:attr:`signal.SIGKILL`. If set to zero, no timeout will
         be applied.
 
-      daemon (int): If this variable is set, then we don't really start the
-        user process, but just kick out 0MQ server, print the command-line and
-        sleep for that many seconds. You're supposed to start the client by
-        hand then and debug it.
+      daemon (int, Optional): If this variable is set, then we don't really
+        start the user process, but just kick out 0MQ server, print the
+        command-line and sleep for that many seconds. You're supposed to start
+        the client by hand then and debug it.
+
+      prefix_cmd (list, Optional): A prefix to the command to execute allowing
+        you to encapsulate the user executable
 
     """
 
@@ -428,11 +431,14 @@ class Agent(object):
       cmd = ['sleep', str(daemon)]
       logger.debug("Daemon mode: sleeping for %d seconds", daemon)
 
+    if prefix_cmd is not None:
+      cmd = prefix_cmd + cmd
+
     self.process = async.Popen(
             cmd=cmd,
             virtual_memory_in_megabytes=self.virtual_memory_in_megabytes,
             max_cpu_percent=self.max_cpu_percent,
-            cpulimit_path=self.cpulimit_path
+            cpulimit_path=self.cpulimit_path,
             )
 
     # provide a tip on how to stop the test

beat/core/async.py

@@ -233,7 +233,7 @@ class Popen(gevent.subprocess.Popen):
     virtual_memory_in_megabytes = max(virtual_memory_in_megabytes, 0)
     cmd = _sandbox_memory(cmd, virtual_memory_in_megabytes)
 
-    logger.debug("Running command `%s'" % ' '.join(cmd))
+    logger.debug("Running command `%s'", ' '.join(cmd))
 
     super(Popen, self).__init__(
             cmd,

beat/core/execution.py

@@ -539,7 +539,7 @@ class Executor(object):
 
   def process(self, execute_path=None, virtual_memory_in_megabytes=0,
           max_cpu_percent=0, cpulimit_path=None, timeout_in_minutes=0,
-          daemon=0):
+          daemon=0, prefix_cmd=None):
     """Executes the user algorithm code using an external program.
 
     If ``executable`` is set, then execute the process using an external
@@ -596,6 +596,9 @@ class Executor(object):
         sleep for that many seconds. You're supposed to start the client by
         hand then and debug it.
 
+      prefix_cmd (list, Optional): A prefix to the command to execute allowing
+        you to encapsulate the user executable
+
 
     Returns:
 
@@ -623,7 +626,7 @@ class Executor(object):
 
       #synchronous call - always returns after a certain timeout
       retval = runner.run(self, timeout_in_minutes=timeout_in_minutes,
-              daemon=daemon)
+              daemon=daemon, prefix_cmd=prefix_cmd)
 
       #adds I/O statistics from the current executor, if its complete already
       #otherwise, it means the running process went bananas, ignore it ;-)

beat/core/test/test_execution.py

@@ -87,7 +87,7 @@ def load_result(executor):
   return data
 
 
-def execute(label, expected_result):
+def execute(label, expected_result, prefix_cmd=None):
   """Executes the full experiment, block after block, returning results. If an
   error occurs, returns information about the err'd block. Otherwise, returns
   ``None``.
@@ -115,7 +115,7 @@ def execute(label, expected_result):
     assert executor.valid, '\n  * %s' % '\n  * '.join(executor.errors)
 
     with executor:
-      result = executor.process()
+      result = executor.process(prefix_cmd=prefix_cmd)
       assert result
       assert 'status' in result
       assert 'stdout' in result
@@ -171,8 +171,8 @@ def test_single_1_single():
 
 @slow
 @nose.tools.with_setup(teardown=cleanup)
-def test_single_1_add():
-  assert execute('user/user/single/1/single_add', [{'out_data': 43}]) is None
+def test_single_1_add_prefix_cmd():
+  assert execute('user/user/single/1/single_add', [{'out_data': 43}], ['/usr/bin/time']) is None
 
 @slow
 @nose.tools.with_setup(teardown=cleanup)