log subprocess calls.

[nodemanager.git] / tools.py

diff --git a/tools.py b/tools.py
index f41f981..bc4b49e 100644 (file)
--- a/tools.py
+++ b/tools.py
@@ -6,6 +6,8 @@ import os
 import pwd
 import tempfile
 import threading
+import fcntl
+import commands
 
 import logger
 
@@ -35,7 +37,8 @@ def daemon():
     os.umask(0)
     devnull = os.open(os.devnull, os.O_RDWR)
     os.dup2(devnull, 0)
-    crashlog = os.open('/root/nm.stderr', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
+    # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
+    crashlog = os.open('/var/log/nm.daemon', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
     os.dup2(crashlog, 1)
     os.dup2(crashlog, 2)
 
@@ -88,3 +91,52 @@ def write_temp_file(do_write, mode=None, uidgid=None):
     try: do_write(f)
     finally: f.close()
     return temporary_filename
+
+# utilities functions to get (cached) information from the node
+
+# get node_id from /etc/planetlab/node_id and cache it
+_node_id=None
+def node_id():
+    global _node_id
+    if _node_id is None:
+        try:
+            _node_id=int(file("/etc/planetlab/node_id").read())
+        except:
+            _node_id=""
+    return _node_id
+
+# get slicefamily from /etc/planetlab/slicefamily and cache it
+# http://svn.planet-lab.org/wiki/SliceFamily
+_slicefamily=None
+def slicefamily():
+    global _slicefamily
+    if _slicefamily is None:
+        try:
+            _slicefamily=file("/etc/planetlab/slicefamily").read().strip()
+        except:
+            _slicefamily=""
+    return _slicefamily
+
+_root_context_arch=None
+def root_context_arch():
+    global _root_context_arch
+    if not _root_context_arch:
+        _root_context_arch=commands.getoutput("uname -i")
+    return _root_context_arch
+
+
+class NMLock:
+    def __init__(self, file):
+        logger.log("Lock %s initialized." % file, 2)
+        self.fd = os.open(file, os.O_RDWR|os.O_CREAT, 0600)
+        flags = fcntl.fcntl(self.fd, fcntl.F_GETFD)
+        flags |= fcntl.FD_CLOEXEC
+        fcntl.fcntl(self.fd, fcntl.F_SETFD, flags)
+    def __del__(self):
+        os.close(self.fd)
+    def acquire(self):
+        logger.log("Lock acquired.", 2)
+        fcntl.lockf(self.fd, fcntl.LOCK_SH)
+    def release(self):
+        logger.log("Lock released.", 2)
+        fcntl.lockf(self.fd, fcntl.LOCK_UN)