shell: document query parameters

Change-Id: I3263aaf88e8cbd9d52446d92e4413248eb52382e
Closes-Bug: #1567937

gnocchiclient/utils.py

@@ -90,6 +90,20 @@ class MalformedQuery(Exception):
             "Malformed Query: %s" % reason)
 
 
+def add_query_argument(cmd, parser):
+    return parser.add_argument(
+        cmd,
+        help="A query to filter resource. "
+        "The syntax is a combination of attribute, operator and value. "
+        "For example: id=90d58eea-70d7-4294-a49a-170dcdf44c3c would filter "
+        "resource with a certain id. More complex queries can be built, "
+        "e.g.: not (flavor_id!=\"1\" and memory>=24). "
+        "Use \"\" to force data to be interpreted as string. "
+        "Supported operators are: not, and, ∧ or, ∨, >=, <=, !=, >, <, =, ==, "
+        "eq, ne, lt, gt, ge, le, in, like, ≠, ≥, ≤, like, in.",
+        type=search_query_builder)
+
+
 def search_query_builder(query):
     try:
         parsed_query = expr.parseString(query, parseAll=True)[0]

gnocchiclient/v1/metric_cli.py

@@ -219,8 +219,7 @@ class CliMeasuresAggregation(lister.Lister):
         parser.add_argument("--needed-overlap", type=float,
                             help=("percent of datapoints in each "
                                   "metrics required"))
-        parser.add_argument("--query", help="Query",
-                            type=utils.search_query_builder),
+        utils.add_query_argument("--query", parser)
         parser.add_argument("--resource-type", default="generic",
                             help="Resource type to query"),
         return parser

gnocchiclient/v1/resource_cli.py

@@ -89,8 +89,7 @@ class CliResourceSearch(CliResourceList):
 
     def get_parser(self, prog_name):
         parser = super(CliResourceSearch, self).get_parser(prog_name)
-        parser.add_argument("query", help="Query",
-                            type=utils.search_query_builder)
+        utils.add_query_argument("query", parser)
         return parser
 
     def take_action(self, parsed_args):