add options to log_shell for check_call and check_output

lib/OperationalLogging.py

@@ -232,8 +232,14 @@ def long_debug(message):
     long_log(logging.DEBUG, message)
 
 
-def log_shell(arg_list, **kwargs):
-    """Pass arg_list to a subprocess call and log all output."""
+def log_shell(arg_list, raise_err=False, return_output=False, **kwargs):
+    """Pass arg_list to a subprocess call and log all output.
+
+    raise_err: (like subprocess.check_call) if True,
+               raises a RuntimeError if exit code is non-zero
+    return_output: (like subprocess.check_output) returns any output
+                   from shell call instead of the exit code
+    """
     logging.info('Starting child process of ppid={}'.format(os.getppid()))
     logging.info('Executing: {}'.format(' '.join(arg_list)))
     try:
@@ -243,21 +249,27 @@ def log_shell(arg_list, **kwargs):
                 parent_name, line_num = os.path.basename(f[1]), f[2]
                 break
 
+        proc_output = ""
         proc = subprocess.Popen(arg_list, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kwargs)
         for line in iter(proc.stdout.readline, b''):
             if not line:
                 break
+            proc_output += line
             logging.getLogger('_sub').info(line.rstrip(), extra={'parentname':parent_name, 'parentline':line_num})
         return_code = proc.wait()
         if return_code:
-            logging.warning('{} failed with exit code {}'.format(' '.join(arg_list), return_code))
-            return return_code
+            if raise_err:
+                logging.error('{} failed with exit code {}'.format(' '.join(arg_list), return_code))
+                raise RuntimeError('{} failed with exit code {}'.format(' '.join(arg_list), return_code))
+            else:
+                logging.warning('{} failed with exit code {}'.format(' '.join(arg_list), return_code))
+                return proc_output if return_output else return_code
     except OSError as err:
         logging.error('Error while executing %s: %s', ' '.join(arg_list), str(err))
         return err
     else:
         logging.info('Successfully finished: %s', ' '.join(arg_list))
-        return 0
+        return proc_output if return_output else return_code
 
 
 def stack_trace(log_level=logging.ERROR):