[auto-discovery][jmx] a jmxfetch restart should prompt AD check reload.

agent.py

@@ -48,7 +48,7 @@
 )
 from daemon import AgentSupervisor, Daemon
 from emitter import http_emitter
-from jmxfetch import get_jmx_checks
+from jmxfetch import get_jmx_checks, JMXFetch
 
 # utils
 from utils.cloud_metadata import EC2
@@ -103,6 +103,7 @@ def __init__(self, pidfile, autorestart, start_event=True, in_developer_mode=Fal
         self.sd_backend = None
         self.supervisor_proxy = None
         self.sd_pipe = None
+        self.last_jmx_piped = None
 
     def _handle_sigterm(self, signum, frame):
         """Handles SIGTERM and SIGINT, which gracefully stops the agent."""
@@ -342,6 +343,12 @@ def run(self, config=None):
                 try:
                     self.sd_backend.reload_check_configs = get_config_store(
                         self._agentConfig).crawl_config_template()
+
+                    # JMXFetch restarts should prompt reload
+                    jmx_launch = JMXFetch._get_jmx_launchtime()
+                    if self.last_jmx_piped and self.last_jmx_piped < jmx_launch:
+                        self.sd_backend.reload_check_configs = True
+
                 except Exception as e:
                     log.warn('Something went wrong while looking for config template changes: %s' % str(e))
 
@@ -454,6 +461,7 @@ def _submit_jmx_service_discovery(self, jmx_sd_configs):
                 # JMX will unblock when it reads on the other end.
                 os.write(self.sd_pipe, buffer)
                 os.write(self.sd_pipe, SD_CONFIG_TERM)
+                self.last_jmx_piped = time.time()
         except Exception as e:
             log.exception("unable to submit YAML via pipe: %s", e)
         else:

jmxfetch.py

@@ -70,6 +70,8 @@
     'list_limited_attributes': "List attributes that do match one of your instances configuration but that are not being collected because it would exceed the number of metrics that can be collected",
     JMX_COLLECT_COMMAND: "Start the collection of metrics based on your current configuration and display them in the console"}
 
+JMX_LAUNCH_FILE = 'jmx.launch'
+
 LINK_TO_DOC = "See http://docs.datadoghq.com/integrations/java/ for more information"
 
 
@@ -336,6 +338,16 @@ def _start(self, path_to_java, java_run_opts, jmx_checks, command, reporter, too
             log.exception("Couldn't launch JMXFetch")
             raise
 
+    @staticmethod
+    def _get_jmx_launchtime():
+        fpath = os.path.join(get_jmx_pipe_path(), JMX_LAUNCH_FILE)
+        try:
+            _stat = os.stat(fpath)
+        except OSError as e:
+            raise e
+
+        return _stat.st_atime
+
     @staticmethod
     def _is_jmx_check(check_config, check_name, checks_list):
         init_config = check_config.get('init_config', {}) or {}