add is-process-older-than-dependency-set script

CHANGES.txt

+0.54.dev0 (2016-02-23)
+======================
+
+* The egg provides `is-process-older-than-dependency-set` script to check if
+  process needs to be restarted because is runnnig on an old version of its
+  loaded module.
+
 0.50 (2015-07-20)
 =================
 

setup.py

@@ -69,6 +69,7 @@ setup(name=name,
           'equeue = slapos.equeue:main',
           'htpasswd = slapos.htpasswd:main',
           'is-local-tcp-port-opened = slapos.promise.is_local_tcp_port_opened:main',
+          'is-process-older-than-dependency-set = slapos.promise.is_process_older_than_dependency_set:main',
           'killpidfromfile = slapos.systool:killpidfromfile', # BBB
           'runResiliencyUnitTestTestNode = slapos.resiliencytest:runUnitTest',
           'runResiliencyScalabilityTestNode = slapos.resiliencytest:runResiliencyTest',

slapos/promise/is_process_older_than_dependency_set/__init__.py

+#!/usr/bin/env python
+"""
+Check if a process is running with an old version of the modules
+found in the defined python paths.
+
+It parses all folders containing an `__init__.py` file and checks if
+a file modification date is greater than the start date of the
+process.
+"""
+
+import sys
+import os
+import errno
+
+import psutil
+
+def moduleIsModifiedSince(top, last_modified, followlinks=False):
+  for root, dir_list, file_list in os.walk(top, followlinks=followlinks):
+    if "__init__.py" not in file_list:
+      del dir_list[:]
+      continue
+    for name in file_list:
+      path = os.path.join(root, name)
+      if last_modified > os.stat(path).st_mtime:
+        return True
+  return False
+
+def isProcessOlderThanDependencySet(pid, python_path_list):
+  start_time = psutil.Process(pid).create_time()
+  return any(moduleIsModifiedSince(product_path, start_time) for product_path in python_path_list)
+
+def isProcessFromPidFileOlderThanDependencySet(pid_file_path, python_path_list):
+  with open(pid_file_path, "r") as f:
+    pid = int(f.readline())
+  return isProcessOlderThanDependencySet(pid, python_path_list)
+
+def main():
+  pid_file_path, python_path_list = sys.argv[1], sys.argv[2:]
+  try:
+    if isProcessFromPidFileOlderThanDependencySet(pid_file_path, python_path_list):
+      return 1
+    return 0
+  except (OSError, IOError) as err:
+    if err.errno == errno.ENOENT:
+      return 0
+    raise
+  except psutil.NoSuchProcess:
+    return 0
+
+if __name__ == "__main__":
+  sys.exit(main())