Add Options library

git-svn-id: https://svn.mcs.anl.gov/repos/bcfg/trunk/bcfg2@1830 ce84e21b-d406-0410-9b95-82705330c041

1 files changed, 93 insertions, 0 deletions

diff --git a/src/lib/Options.py b/src/lib/Options.py
new file mode 100644
index 000000000..7b3ef109f
--- /dev/null
+++ b/src/lib/Options.py
@@ -0,0 +1,93 @@
+'''Option parsing library for utilities'''
+__revision__ = '$Revision$'
+
+import getopt, os, sys, ConfigParser
+# (option, env, cfpath, default value, option desc, boolean, arg desc)
+# ((option, arg desc, opt desc), env, cfpath, default, boolean)
+bootstrap = {'configfile': (('-C', '<configfile>', 'Path to config file'), 
+                             'BCFG2_CONF', False, '/etc/bcfg2.conf',  False)}
+
+class OptionFailure(Exception):
+    pass
+
+class BasicOptionParser:
+    '''Basic OptionParser takes input from command line arguments, environment variables, and defaults'''
+    def __init__(self, name, optionspec, configfile=False, dogetopt=False):
+        self.name = name
+        self.dogetopt = dogetopt
+        self.configfile = configfile
+        self.optionspec = optionspec
+        if dogetopt:
+            self.shortopt = ''
+            self.helpmsg = ''
+            # longopts aren't yet supported
+            self.longopt = []
+            for option, info in optionspec.iteritems():
+                (opt, argd, optd) = info[0]
+                self.helpmsg += opt.ljust(3)
+                if opt.count('-') == 1:
+                    self.shortopt += opt[1]
+                else:
+                    print "unsupported option %s" % (opt)
+                    continue
+                if info[4]:
+                    self.helpmsg += 24 * ' '
+                else:
+                    self.shortopt += ':'
+                    self.helpmsg += "%-24s" % (argd)
+                self.helpmsg += "%s\n" % (optd)
+
+    def parse(self):
+        '''Parse options'''
+        ret = {}
+        if self.dogetopt:
+            try:
+                opts, args = getopt.getopt(sys.argv[1:], self.shortopt, self.longopt)
+            except getopt.GetoptError, err:
+                print "%s Usage:" % (self.name)
+                print err
+                print self.helpmsg
+                raise OptionFailure, err
+            if '-h' in sys.argv:
+                print "%s Usage:" % (self.name)
+                print self.helpmsg
+                raise SystemExit, 1
+        if self.configfile:
+            cf = ConfigParser.ConfigParser()
+            cf.read(self.configfile)
+        for key, (option, envvar, cfpath, default, boolean) in self.optionspec.iteritems():
+            if self.dogetopt:
+                optinfo = [opt[1] for opt in opts if opt[0] == option[0]]
+                if optinfo:
+                    if boolean:
+                        ret[key] = True
+                    else:
+                        ret[key] = optinfo[0]
+                    continue
+            if option[0] in sys.argv:
+                if boolean:
+                    ret[key] = True
+                else:
+                    ret[key] = sys.argv[sys.argv.index(option[0]) + 1]
+                continue
+            elif envvar and os.environ.has_key(envvar):
+                ret[key] = os.environ[envvar]
+                continue
+            elif self.configfile and cfpath:
+                try:
+                    value = apply(cf.get, cfpath)
+                    ret[key] = value
+                    continue
+                except:
+                    pass
+            else:
+                ret[key] = default
+                continue
+        return ret
+    
+class OptionParser(BasicOptionParser):
+    '''OptionParser bootstraps option parsing, getting the value of the config file'''
+    def __init__(self, name, ospec):
+        # first find the cf file
+        cfpath = BasicOptionParser('bootstrap', bootstrap).parse()['configfile']
+        BasicOptionParser.__init__(self, name, ospec, cfpath, dogetopt=True)