[jmxfetch] Check that a name is set when the jmx_url option is used

conf.d/jmx.yaml.example

@@ -8,9 +8,15 @@ instances:
   #   port: 7199
   #   user: username
   #   password: password
-  #   process_name_regex: .*process_name.* # Instead of specifying a host, and port. The agent can connect using the attach api.
+
+  #   # If the agent needs to connect to a non-default JMX URL, specify it here instead of a host and a port
+  #   # If you use this you need to specify a 'name' for the instance, below
+  #   jmx_url: "service:jmx:rmi:///jndi/rmi://myhost.host:9999/custompath"
+
+  #   process_name_regex: .*process_name.* # Instead of specifying a host and port or jmx_url, the agent can connect using the attach api.
   #                                        # This requires the JDK to be installed and the path to tools.jar to be set below.
   #   tools_jar_path: /usr/lib/jvm/java-7-openjdk-amd64/lib/tools.jar # To be set when process_name_regex is set
+
   #   name: jmx_instance
   #   # java_bin_path: /path/to/java # Optional, should be set if the agent cannot find your java executable
   #   # java_options: "-Xmx200m -Xms50m" # Optional, Java JVM options

jmxfetch.py

@@ -352,9 +352,15 @@ def _is_jmx_check(check_config, check_name, checks_list):
 
                 # Support for attach api using a process name regex
                 proc_regex = inst.get('process_name_regex')
+                # Support for a custom jmx URL
+                jmx_url = inst.get('jmx_url')
+                name = inst.get('name')
 
                 if proc_regex is not None:
                     is_attach_api = True
+                elif jmx_url is not None:
+                    if name is None:
+                        raise InvalidJMXConfiguration("A name must be specified when using a jmx_url")
                 else:
                     if host is None:
                         raise InvalidJMXConfiguration("A host must be specified")