[jmxfetch] Allow adding custom jars to JMXFetch's classpath

conf.d/jmx.yaml.example

@@ -1,4 +1,7 @@
 init_config:
+  # custom_jar_paths: # Optional, allows specifying custom jars that will be added to the classpath of the agent's JVM
+  #   - /path/to/custom/jarfile.jar
+  #   - /path/to/another/custom/jarfile2.jar
 
 instances:
   # - host: localhost

jmxfetch.py

@@ -108,7 +108,8 @@ def configure(self, checks_list=None, clean_status_file=True):
         if clean_status_file:
             JMXFiles.clean_status_file()
 
-        self.jmx_checks, self.invalid_checks, self.java_bin_path, self.java_options, self.tools_jar_path = \
+        self.jmx_checks, self.invalid_checks, self.java_bin_path, self.java_options, \
+            self.tools_jar_path, self.custom_jar_paths = \
             self.get_configuration(self.confd_path, checks_list=checks_list)
 
     def should_run(self):
@@ -143,7 +144,7 @@ def run(self, command=None, checks_list=None, reporter=None, redirect_std_stream
 
             if len(self.jmx_checks) > 0:
                 return self._start(self.java_bin_path, self.java_options, self.jmx_checks,
-                                   command, reporter, self.tools_jar_path, redirect_std_streams)
+                                   command, reporter, self.tools_jar_path, self.custom_jar_paths, redirect_std_streams)
             else:
                 # We're exiting purposefully, so exit with zero (supervisor's expected
                 # code). HACK: Sleep a little bit so supervisor thinks we've started cleanly
@@ -184,6 +185,7 @@ def get_configuration(cls, confd_path, checks_list=None):
         java_bin_path = None
         java_options = None
         tools_jar_path = None
+        custom_jar_paths = []
         invalid_checks = {}
 
         for conf in glob.glob(os.path.join(confd_path, '*.yaml')):
@@ -202,7 +204,7 @@ def get_configuration(cls, confd_path, checks_list=None):
                     continue
 
                 try:
-                    is_jmx, check_java_bin_path, check_java_options, check_tools_jar_path = \
+                    is_jmx, check_java_bin_path, check_java_options, check_tools_jar_path, check_custom_jar_paths = \
                         cls._is_jmx_check(check_config, check_name, checks_list)
                     if is_jmx:
                         jmx_checks.append(filename)
@@ -212,15 +214,16 @@ def get_configuration(cls, confd_path, checks_list=None):
                             java_options = check_java_options
                         if tools_jar_path is None and check_tools_jar_path is not None:
                             tools_jar_path = check_tools_jar_path
+                        custom_jar_paths.extend(check_custom_jar_paths)
                 except InvalidJMXConfiguration, e:
                     log.error("%s check does not have a valid JMX configuration: %s" % (check_name, e))
                     # Make sure check_name is a string - Fix issues with Windows
                     check_name = check_name.encode('ascii', 'ignore')
                     invalid_checks[check_name] = str(e)
 
-        return (jmx_checks, invalid_checks, java_bin_path, java_options, tools_jar_path)
+        return (jmx_checks, invalid_checks, java_bin_path, java_options, tools_jar_path, custom_jar_paths)
 
-    def _start(self, path_to_java, java_run_opts, jmx_checks, command, reporter, tools_jar_path, redirect_std_streams):
+    def _start(self, path_to_java, java_run_opts, jmx_checks, command, reporter, tools_jar_path, custom_jar_paths, redirect_std_streams):
         statsd_port = self.agentConfig.get('dogstatsd_port', "8125")
         if reporter is None:
             reporter = "statsd:%s" % str(statsd_port)
@@ -232,10 +235,11 @@ def _start(self, path_to_java, java_run_opts, jmx_checks, command, reporter, too
             path_to_jmxfetch = self._get_path_to_jmxfetch()
             path_to_status_file = JMXFiles.get_status_file_path()
 
-            if tools_jar_path is None:
-                classpath = path_to_jmxfetch
-            else:
-                classpath = r"%s:%s" % (tools_jar_path, path_to_jmxfetch)
+            classpath = path_to_jmxfetch
+            if tools_jar_path is not None:
+                classpath = r"%s:%s" % (tools_jar_path, classpath)
+            if custom_jar_paths:
+                classpath = r"%s:%s" % (':'.join(custom_jar_paths), classpath)
 
             subprocess_args = [
                 path_to_java,  # Path to the java bin
@@ -319,6 +323,7 @@ def _is_jmx_check(check_config, check_name, checks_list):
         is_jmx = False
         is_attach_api = False
         tools_jar_path = init_config.get("tools_jar_path")
+        custom_jar_paths = init_config.get("custom_jar_paths")
 
         if init_config is None:
             init_config = {}
@@ -407,7 +412,14 @@ def _is_jmx_check(check_config, check_name, checks_list):
             else:
                 tools_jar_path = None
 
-        return is_jmx, java_bin_path, java_options, tools_jar_path
+            if custom_jar_paths:
+                if isinstance(custom_jar_paths, basestring):
+                    custom_jar_paths = [custom_jar_paths]
+                for custom_jar_path in custom_jar_paths:
+                    if not os.path.isfile(custom_jar_path):
+                        raise InvalidJMXConfiguration("Unable to find custom jar at %s" % custom_jar_path)
+
+        return is_jmx, java_bin_path, java_options, tools_jar_path, custom_jar_paths
 
     def _get_path_to_jmxfetch(self):
         if not Platform.is_windows():