* Use getopt to handle command-line option.

* Include a help command.

sge/show-cluster-usage.py

@@ -27,6 +27,14 @@ import re
 import subprocess
 import sys
 
+class ParseError(RuntimeError):
+  pass
+
+class ProgramError(RuntimeError):
+  pass
+
+MYSELF = 'show-cluster-usage.py'
+
 
 def analyze_cluster_usage_by_users(qstat_f):
   """Provides a summary analysis of cluster usage by users.
@@ -91,20 +99,60 @@ def print_cluster_usage_by_users(usage):
                  len(urec['xjobids'])))
 
 
+def help():
+  msg = """\
+%(CMD)s - Shows cluster usage from SGE information
 
-def main_default(save_qstat=True):
+The information is mainly drawn from `qstat -f` output,
+and analyzes the usage of the cluster in various ways..
+
+Usage:
+
+%(CMD)s
+%(CMD)s [qstat_file] [--save]
+    Shows the cluster usage aggregated per user.
+""" \
+    % dict(CMD=MYSELF)
+  print(msg)
+
+
+def main_default(argv):
   """Main default function:
   - By default we invoke qstat -f and prints the analysis.
   - If argv[1] is given, then we read in the file and 
     use that for the analysis.
   """
   from time import localtime, strftime
+  from getopt import getopt, GetoptError
 
   dtime = localtime()
   dtimestr = strftime("%Y%m%d-%H%M", dtime)
 
-  if len(sys.argv) > 1:
-    qstat_f_current = open(sys.argv[1], "r").read().splitlines()
+  # Skip program name and first command:
+  cmdargs_in = argv[1:]
+  try:
+    cmdopts, cmdargs = getopt(cmdargs_in,
+                              "hs",
+                              ["save",
+                               "help"])
+  except GetoptError as err:
+    sys.stderr.writelines([str(err), "\n"])
+    return 2
+
+  # Process flag arguments
+  show_disabled_nodes = False
+  save_qstat = False
+  for o,a in cmdopts:
+    if o in ('-h', '--help'):
+      help()
+      return 0
+    elif o in ('-s', '--save'):
+      save_qstat = True
+    else:
+      raise ProgramError, "Unhandled option in main program: %s %s" % (o,a)
+
+  if len(cmdargs) > 1:
+    qstat_f_current = open(cmdargs[1], "r").read().splitlines()
   else:
     qstat_f_current = pipe_out(('qstat', '-f'), split=True)
     if save_qstat:
@@ -114,7 +162,7 @@ def main_default(save_qstat=True):
 
   summary = analyze_cluster_usage_by_users(qstat_f_current)
   print_cluster_usage_by_users(summary)
-
+  return 0
 
 
 # ---------------------------------------------------------------------------
@@ -164,4 +212,4 @@ def str_fmt_heading(fmt):
 # stub main code
 
 if __name__ == "__main__" and not "get_ipython" in globals():
-  main_default()
+  sys.exit(main_default(sys.argv))