From 1621311b66c33749caafc6b0291412c6b4d376a3 Mon Sep 17 00:00:00 2001
From: Marko Kreen
Date: Wed, 7 Dec 2011 12:10:34 +0200
Subject: skytools.signal_pidfile: ignore empty pidfile, some cleanups

Empty pidfile can happen if old process failed to write it
for some reason.
---
 python/skytools/scripting.py | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

(limited to 'python/skytools/scripting.py')

diff --git a/python/skytools/scripting.py b/python/skytools/scripting.py
index b0badda9..583c6464 100644
--- a/python/skytools/scripting.py
+++ b/python/skytools/scripting.py
@@ -36,10 +36,14 @@ def signal_pidfile(pidfile, sig):
 
     Returns True is successful, False if pidfile does not exist
     or process itself is dead.  Any other errors will passed
-    as exceptions.
-    """
+    as exceptions."""
+
+    ln = ''
     try:
-        pid = int(open(pidfile, 'r').readline())
+        f = open(pidfile, 'r')
+        ln = f.readline().strip()
+        f.close()
+        pid = int(ln)
         os.kill(pid, sig)
         return True
     except IOError, ex:
@@ -49,6 +53,10 @@ def signal_pidfile(pidfile, sig):
         if ex.errno != errno.ESRCH:
             raise
     except ValueError, ex:
+        # this leaves slight race when someone is just creating the file,
+        # but more common case is old empty file.
+        if not ln:
+            return False
         raise ValueError('Corrupt pidfile: %s' % pidfile)
     return False
 
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