-#
-# Something relevant
-#
+
"""A very simple logger that tries to be concurrency-safe."""
import os, sys
-import subprocess
import time
import traceback
+import subprocess
+import select
+LOG_FILE = '/var/log/nodemanager'
+LOG_SLIVERS = '/var/lib/nodemanager/getslivers.txt'
+LOG_DATABASE = '/var/lib/nodemanager/database.txt'
-LOG_FILE = '/var/log/nm'
-LOG_SLIVERS = '/var/log/getslivers.txt'
-
-# Thierry - trying to debug this for 4.2
# basically define 3 levels
LOG_NONE=0
LOG_NODE=1
LOG_LEVEL=level
def verbose(msg):
- log(msg,LOG_VERBOSE)
+ log('(v) '+msg,LOG_VERBOSE)
def log(msg,level=LOG_NODE):
"""Write <msg> to the log file if level >= current log level (default LOG_NODE)."""
sys.stderr.write(msg)
sys.stderr.flush()
-def log_call(*args):
- log('running command %s' % ' '.join(args))
- try: subprocess.check_call(args, close_fds=True)
- except: log_exc()
-
-def log_exc(name = None):
+def log_exc(msg="",name=None):
"""Log the traceback resulting from an exception."""
- if name:
- log("operation on %s failed. \n %s" %(name, traceback.format_exc()))
+ if name:
+ log("%s: EXCEPTION caught <%s> \n %s" %(name, msg, traceback.format_exc()))
else:
- log(traceback.format_exc())
+ log("EXCEPTION caught <%s> \n %s" %(msg, traceback.format_exc()))
-def log_slivers (data):
+########## snapshot data to a file
+# for some reason the various modules are still triggered even when the
+# data from PLC cannot be reached
+# we show this message instead of the exception stack instead in this case
+def log_missing_data (msg,key):
+ log("%s: could not find the %s key in data (PLC connection down?) - IGNORED"%(msg,key))
+
+def log_data_in_file (data, file, message="",level=LOG_NODE):
+ if (level > LOG_LEVEL):
+ return
import pprint, time
try:
- f=open(LOG_SLIVERS,'w')
- now=time.strftime("GetSlivers stored on %Y.%m.%d at %H:%M:%S", time.localtime())
+ f=open(file,'w')
+ now=time.strftime("Last update: %Y.%m.%d at %H:%M:%S %Z", time.localtime())
f.write(now+'\n')
+ if message: f.write('Message:'+message+'\n')
pp=pprint.PrettyPrinter(stream=f,indent=2)
pp.pprint(data)
f.close()
+ verbose("logger:.log_data_in_file Owerwrote %s"%file)
except:
- log_verbose('Cannot save GetSlivers in %s'%LOG_SLIVERS)
+ log_exc('logger.log_data_in_file failed - file=%s - message=%r'%(file,message))
+
+def log_slivers (data):
+ log_data_in_file (data, LOG_SLIVERS, "raw GetSlivers")
+def log_database (db):
+ log_data_in_file (db, LOG_DATABASE, "raw database")
+
+#################### child processes
+# avoid waiting until the process returns;
+# that makes debugging of hanging children hard
+
+class Buffer:
+ def __init__ (self,message='log_call: '):
+ self.buffer=''
+ self.message=message
+
+ def add (self,c):
+ self.buffer += c
+ if c=='\n': self.flush()
+
+ def flush (self):
+ if self.buffer:
+ log (self.message + self.buffer)
+ self.buffer=''
+
+# time out in seconds - avoid hanging subprocesses - default is 5 minutes
+default_timeout_minutes=5
+
+# returns a bool that is True when everything goes fine and the retcod is 0
+def log_call(command,timeout=default_timeout_minutes*60,poll=1):
+ message=" ".join(command)
+ log("log_call: running command %s" % message)
+ verbose("log_call: timeout=%r s" % timeout)
+ verbose("log_call: poll=%r s" % poll)
+ trigger=time.time()+timeout
+ result = False
+ try:
+ child = subprocess.Popen(command, bufsize=1,
+ stdout=subprocess.PIPE, stderr=subprocess.STDOUT, close_fds=True)
+ buffer = Buffer()
+ while True:
+ # see if anything can be read within the poll interval
+ (r,w,x)=select.select([child.stdout],[],[],poll)
+ if r: buffer.add(child.stdout.read(1))
+ # is process over ?
+ returncode=child.poll()
+ # yes
+ if returncode != None:
+ buffer.flush()
+ # child is done and return 0
+ if returncode == 0:
+ log("log_call:end command (%s) completed" % message)
+ result=True
+ break
+ # child has failed
+ else:
+ log("log_call:end command (%s) returned with code %d" %(message,returncode))
+ break
+ # no : still within timeout ?
+ if time.time() >= trigger:
+ buffer.flush()
+ child.terminate()
+ log("log_call:end terminating command (%s) - exceeded timeout %d s"%(message,timeout))
+ break
+ except: log_exc("failed to run command %s" % message)
+ return result