re-add the 'main' routine to DataSourceMAAS.py

the main function, which was usable for debugging maas was dropped during the
rework branch.  I'm adding it back here as it is very useful.  It is possibly
better implemented some other way than this, but this is good enough.

cloudinit/sources/DataSourceMAAS.py

@@ -262,3 +262,94 @@ datasources = [
 # Return a list of data sources that match this set of dependencies
 def get_datasource_list(depends):
     return sources.list_from_depends(depends, datasources)
+
+
+if __name__ == "__main__":
+    def main():
+        """
+        Call with single argument of directory or http or https url.
+        If url is given additional arguments are allowed, which will be
+        interpreted as consumer_key, token_key, token_secret, consumer_secret
+        """
+        import argparse
+        import pprint
+
+        parser = argparse.ArgumentParser(description='Interact with MAAS DS')
+        parser.add_argument("--config", metavar="file",
+            help="specify DS config file", default=None)
+        parser.add_argument("--ckey", metavar="key",
+            help="the consumer key to auth with", default=None)
+        parser.add_argument("--tkey", metavar="key",
+            help="the token key to auth with", default=None)
+        parser.add_argument("--csec", metavar="secret",
+            help="the consumer secret (likely '')", default="")
+        parser.add_argument("--tsec", metavar="secret",
+            help="the token secret to auth with", default=None)
+        parser.add_argument("--apiver", metavar="version",
+            help="the apiver to use ("" can be used)", default=MD_VERSION)
+
+        subcmds = parser.add_subparsers(title="subcommands", dest="subcmd")
+        subcmds.add_parser('crawl', help="crawl the datasource")
+        subcmds.add_parser('get', help="do a single GET of provided url")
+        subcmds.add_parser('check-seed', help="read andn verify seed at url")
+
+        parser.add_argument("url", help="the data source to query")
+
+        args = parser.parse_args()
+
+        creds = {'consumer_key': args.ckey, 'token_key': args.tkey,
+            'token_secret': args.tsec, 'consumer_secret': args.csec}
+
+        if args.config:
+            import yaml
+            with open(args.config) as fp:
+                cfg = yaml.safe_load(fp)
+            if 'datasource' in cfg:
+                cfg = cfg['datasource']['MAAS']
+            for key in creds.keys():
+                if key in cfg and creds[key] is None:
+                    creds[key] = cfg[key]
+
+        def geturl(url, headers_cb):
+            req = urllib2.Request(url, data=None, headers=headers_cb(url))
+            return(urllib2.urlopen(req).read())
+
+        def printurl(url, headers_cb):
+            print "== %s ==\n%s\n" % (url, geturl(url, headers_cb))
+
+        def crawl(url, headers_cb=None):
+            if url.endswith("/"):
+                for line in geturl(url, headers_cb).splitlines():
+                    if line.endswith("/"):
+                        crawl("%s%s" % (url, line), headers_cb)
+                    else:
+                        printurl("%s%s" % (url, line), headers_cb)
+            else:
+                printurl(url, headers_cb)
+
+        def my_headers(url):
+            headers = {}
+            if creds.get('consumer_key', None) is not None:
+                headers = oauth_headers(url, **creds)
+            return headers
+
+        if args.subcmd == "check-seed":
+            if args.url.startswith("http"):
+                (userdata, metadata) = read_maas_seed_url(args.url,
+                    header_cb=my_headers, version=args.apiver)
+            else:
+                (userdata, metadata) = read_maas_seed_url(args.url)
+            print "=== userdata ==="
+            print userdata
+            print "=== metadata ==="
+            pprint.pprint(metadata)
+
+        elif args.subcmd == "get":
+            printurl(args.url, my_headers)
+
+        elif args.subcmd == "crawl":
+            if not args.url.endswith("/"):
+                args.url = "%s/" % args.url
+            crawl(args.url, my_headers)
+
+    main()