cli: precache generator

- Adds precache generator for all verbs in grammar
- ignore precache.py

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>

.gitignore

@@ -49,6 +49,7 @@ git-remote-https.exe.stackdump
 *.swp
 tools/devcloud/devcloudbox/.vagrant
 tools/cli/cloudmonkey/marvin/
+tools/cli/cloudmonkey/precache.py
 *.jar
 *.war
 *.mar

tools/cli/cloudmonkey/cachegen.py

@@ -0,0 +1,92 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+try:
+    from common import grammar
+    from marvin.cloudstackAPI import *
+    from marvin import cloudstackAPI
+except ImportError, e:
+    pass
+
+completions = cloudstackAPI.__all__
+
+
+def get_api_module(api_name, api_class_strs=[]):
+    try:
+        api_mod = __import__("marvin.cloudstackAPI.%s" % api_name,
+                             globals(), locals(), api_class_strs, -1)
+    except ImportError, e:
+        print "Error: API not found", e
+        return None
+    return api_mod
+
+
+def main():
+    """
+    cachegen.py creates a precached dictionary for all the available verbs in
+    the predefined grammar of cloudmonkey, it dumps the dictionary in an
+    importable python module. This way we cheat on the runtime overhead of
+    completing commands and help docs. This reduces the overall search and
+    cache_miss (computation) complexity from O(n) to O(1) for any valid cmd.
+    """
+    # datastructure {'verb': {cmd': ['api', [params], doc, required=[]]}}
+    cache_verbs = {}
+    for verb in grammar:
+        completions_found = filter(lambda x: x.startswith(verb), completions)
+        cache_verbs[verb] = {}
+        for api_name in completions_found:
+            api_cmd_str = "%sCmd" % api_name
+            api_mod = get_api_module(api_name, [api_cmd_str])
+            if api_mod is None:
+                continue
+            try:
+                api_cmd = getattr(api_mod, api_cmd_str)()
+                required = api_cmd.required
+                doc = api_mod.__doc__
+            except AttributeError, e:
+                print "Error: API attribute %s not found!" % e
+            params = filter(lambda x: '__' not in x and 'required' not in x,
+                            dir(api_cmd))
+            if len(required) > 0:
+                doc += "\nRequired args: %s" % " ".join(required)
+            doc += "\nArgs: %s" % " ".join(params)
+            api_name_lower = api_name.replace(verb, '').lower()
+            cache_verbs[verb][api_name_lower] = [api_name, params, doc,
+                                                 required]
+    f = open("precache.py", "w")
+    f.write("""# Auto-generated code by cachegen.py
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.""")
+    f.write("\nprecached_verbs = %s" % cache_verbs)
+    f.close()
+
+if __name__ == "__main__":
+    main()