timeout option added

common_helper_process/fail_safe_subprocess.py

-from subprocess import Popen, PIPE, STDOUT
+from subprocess import Popen, PIPE, STDOUT, TimeoutExpired
+import logging
 
 
-def execute_shell_command(shell_command):
+def execute_shell_command(shell_command, timeout=None):
     """
     Execute a shell command and return STDOUT and STDERR in one combined result string.
     This function shall not raise any errors
@@ -10,10 +11,10 @@ def execute_shell_command(shell_command):
     :type shell_command: str
     :return: str
     """
-    return execute_shell_command_get_return_code(shell_command)[0]
+    return execute_shell_command_get_return_code(shell_command, timeout=timeout)[0]
 
 
-def execute_shell_command_get_return_code(shell_command):
+def execute_shell_command_get_return_code(shell_command, timeout=None):
     """
     Execute a shell command and return a tuple (program output, return code)
     Program ouput includes STDOUT and STDERR.
@@ -21,11 +22,20 @@ def execute_shell_command_get_return_code(shell_command):
 
     :param shell_command: command to execute
     :type shell_command: str
+    :param timeout: kill process after timeout seconds
+    :type: timeout: int
     :return: str, int
     """
     output = ""
     rc = 1
-    with Popen(shell_command, shell=True, stdout=PIPE, stderr=STDOUT) as pl:
-        output = pl.communicate()[0].decode('utf-8', errors='replace')
+    pl = Popen(shell_command, shell=True, stdout=PIPE, stderr=STDOUT)
+    try:
+        output = pl.communicate(timeout=timeout)[0].decode('utf-8', errors='replace')
         rc = pl.returncode
+    except TimeoutExpired:
+        logging.warning("Execution timeout!")
+        pl.kill()
+        output = pl.communicate()[0].decode('utf-8', errors='replace')
+        output += "\n\nERROR: execution timed out!"
+        rc = 1
     return output, rc

test/test_fail_safe_subprocess.py

 import unittest
+from time import time
 
 from common_helper_process import execute_shell_command
 from common_helper_process.fail_safe_subprocess import execute_shell_command_get_return_code
@@ -23,3 +24,11 @@ class TestProcessHelper(unittest.TestCase):
         output, rc = execute_shell_command_get_return_code("echo 'test 123' 1>&2 && exit 2")
         self.assertEqual(output, 'test 123\n', 'result not correct')
         self.assertEqual(rc, 2, 'return code not correct')
+
+    def test_execute_shell_command_time_out(self):
+        start_time = time()
+        output, rc = execute_shell_command_get_return_code("echo 'test 123' && for i in {1..10}; do sleep 1; done", timeout=1)
+        run_time = time() - start_time
+        self.assertEqual(output, 'test 123\n\n\nERROR: execution timed out!', 'timeout message not added')
+        self.assertEqual(rc, 1, 'return code not correct')
+        self.assertGreater(5, run_time, "command not aborted")