Remove any time.sleep() from execute. Use inotify instead.

slapos/recipe/librecipe/execute.py

@@ -4,6 +4,46 @@ import signal
 import subprocess
 import time
 
+import inotifyx
+
+def _wait_files_creation(file_list):
+  # Etablish a list of directory and subfiles
+  directories = dict()
+  for dirname, filename in [os.path.split(f) for f in file_list]:
+    directories.setdefault(dirname, dict())
+    directories[dirname][filename] = False
+
+  def all_files_exists():
+    return all([all(files.values()) for files in directories.values()])
+
+  fd = inotifyx.init()
+  try:
+    # Watch every directories where the file are
+    watchdescriptors = dict()
+    for dirname in directories.keys():
+      wd = inotifyx.add_watch(fd,
+                              dirname,
+                              inotifyx.IN_CREATE | inotifyx.IN_DELETE)
+      watchdescriptors[wd] = dirname
+
+    # Set to True the file wich exists
+    for dirname, filename in [os.path.split(f) for f in file_list]:
+      directories[dirname][filename] = os.path.exists(os.path.join(dirname,
+                                                                   filename))
+    # Let's wait for every file creation
+    while not all_files_exists():
+      events_list = inotifyx.get_events(fd)
+      for event in events_list:
+        dirname = watchdescriptors[event.wd]
+        if event.name in directories[dirname]:
+          # One of watched file was created or deleted
+          if event.mask & inotifyx.IN_DELETE:
+            directories[dirname][event.name] = False
+          else:
+            directories[dirname][event.name] = True
+
+  finally:
+    os.close(fd)
 
 def execute(args):
   """Portable execution with process replacement"""
@@ -14,18 +54,7 @@ def execute_wait(args):
   """Execution but after all files in args[1] exists"""
   exec_list = list(args[0])
   file_list = list(args[1])
-  sleep = 60
-  while True:
-    ready = True
-    for f in file_list:
-      if not os.path.exists(f):
-        print 'File %r does not exists, sleeping for %s' % (f, sleep)
-        ready = False
-    if ready:
-      break
-    # XXX: It's the same as ../ca/certificate_authoritiy.py
-    #      We should use pyinotify as well. Or select() on socket.
-    time.sleep(sleep)
+  _wait_files_creation(file_list)
   os.execv(exec_list[0], exec_list + sys.argv[1:])
 
 
@@ -49,16 +78,7 @@ def executee_wait(args):
   env = os.environ.copy()
   for k,v in environment.iteritems():
     env[k] = v
-  sleep = 60
-  while True:
-    ready = True
-    for f in file_list:
-      if not os.path.exists(f):
-        print 'File %r does not exists, sleeping for %s' % (f, sleep)
-        ready = False
-    if ready:
-      break
-    time.sleep(sleep)
+  _wait_files_creation(file_list)
   os.execve(exec_list[0], exec_list + sys.argv[1:], env)
 
 def sig_handler(signal, frame):