Update opts.py to allow for 'None' timeout-value in client_options

docs/command_line_reference.rst

@@ -670,8 +670,9 @@ We support the following data types:
 * Strings: Have to be enclosed in single quotes. Example: ``ca_certs:'/path/to/CA_certs'``
 * Numbers: There is nothing special about numbers. Example: ``sniffer_timeout:60``
 * Booleans: Specify either ``true`` or ``false``. Example: ``use_ssl:true``
+* None: Specify ``None`` without quotes.``'None'`` will be treated as string. Example: ``timeout:None``
 
-Default value: ``timeout:60`` (applies any time ``timeout`` is not specified)
+Default value: ``timeout:60`` (applies any time ``timeout`` is not specified. Set ``timeout:None`` to omit any timeouts)
 
 Rally recognizes the following client options in addition:
 

esrally/utils/opts.py

@@ -53,6 +53,15 @@ def to_bool(v):
         raise ValueError("Could not convert value '%s'" % v)
 
 
+def to_none(v):
+    if v is None:
+        return None
+    elif v.lower() == "none":
+        return None
+    else:
+        raise ValueError("Could not convert value '%s'" % v)
+
+
 def kv_to_map(kvs):
     def convert(v):
         # string (specified explicitly)
@@ -76,6 +85,12 @@ def convert(v):
             return to_bool(v)
         except ValueError:
             pass
+
+        try:
+            return to_none(v)
+        except ValueError:
+            pass
+
         # treat it as string by default
         return v
 
@@ -197,7 +212,8 @@ def parse_options(self):
         default_client_map = kv_to_map([ClientOptions.DEFAULT_CLIENT_OPTIONS])
         if self.argvalue == ClientOptions.DEFAULT_CLIENT_OPTIONS and self.target_hosts is not None:
             # --client-options unset but multi-clusters used in --target-hosts? apply options defaults for all cluster names.
-            self.parsed_options = {cluster_name: default_client_map for cluster_name in self.target_hosts.all_hosts.keys()}
+            self.parsed_options = {cluster_name: default_client_map for cluster_name in
+                                   self.target_hosts.all_hosts.keys()}
         else:
             self.parsed_options = to_dict(self.argvalue, default_parser=ClientOptions.normalize_to_dict)
 

tests/utils/opts_test.py

@@ -58,12 +58,20 @@ def test_kv_to_map(self):
         assert opts.kv_to_map(["k:3"]) == {"k": 3}
         # implicit treatment as string
         assert opts.kv_to_map(["k:v"]) == {"k": "v"}
-        assert opts.kv_to_map(["k:'v'", "size:4", "empty:false", "temperature:0.5"]) == {
+        assert opts.kv_to_map(["k:'v'", "size:4", "empty:false", "temperature:0.5", "timeout:None"]) == {
             "k": "v",
             "size": 4,
             "empty": False,
             "temperature": 0.5,
+            "timeout": None,
         }
+        # When passing 'None' with quotes, treat it as string
+        assert opts.kv_to_map(["k:'None'"]) == {"k": "None"}
+        # When passing None without quotes, treat it as pythonic None
+        assert opts.kv_to_map(["k:None"]) == {"k": None}
+        assert opts.kv_to_map(["k:none"]) == {"k": None}
+        assert opts.kv_to_map(["k:NONE"]) == {"k": None}
+
 
     def test_to_dict_with_inline_json(self):
         assert opts.to_dict('{"default": ["127.0.0.1:9200","10.17.0.5:19200"]}') == {"default": ["127.0.0.1:9200", "10.17.0.5:19200"]}