fix: re-entrant Collector threads on musl-based systems.

Signed-off-by: Paulo Vital <paulo.vital@ibm.com>

Author: pvital

src/instana/collector/base.py

@@ -8,9 +8,10 @@
 
 import queue  # pylint: disable=import-error
 import threading
+import time
 
 from instana.log import logger
-from instana.util import DictionaryOfStan, every
+from instana.util import DictionaryOfStan
 
 
 class BaseCollector(object):
@@ -76,22 +77,22 @@ def start(self):
         """
         if self.is_reporting_thread_running():
             if self.thread_shutdown.is_set():
-                # Shutdown still in progress; Reschedule this start in 5 seconds from now
+                # Force a restart. 
+                self.thread_shutdown.clear()
+                # Reschedule this start in 5 seconds from now
                 timer = threading.Timer(5, self.start)
                 timer.daemon = True
                 timer.name = "Collector Timed Start"
                 timer.start()
                 return
             logger.debug(
-                "BaseCollector.start non-fatal: call but thread already running (started: %s)",
-                self.started,
+                f"BaseCollector.start non-fatal: call but thread already running (started: {self.started})"
             )
-            return
 
         if self.agent.can_send():
             logger.debug("BaseCollector.start: launching collection thread")
             self.thread_shutdown.clear()
-            self.reporting_thread = threading.Thread(target=self.thread_loop, args=())
+            self.reporting_thread = threading.Thread(target=self.background_report, args=())
             self.reporting_thread.daemon = True
             self.reporting_thread.name = self.THREAD_NAME
             self.reporting_thread.start()
@@ -113,37 +114,25 @@ def shutdown(self, report_final=True):
             self.prepare_and_report_data()
         self.started = False
 
-    def thread_loop(self):
-        """
-        Just a loop that is run in the background thread.
-        @return: None
-        """
-        every(
-            self.report_interval,
-            self.background_report,
-            "Instana Collector: prepare_and_report_data",
-        )
-
-    def background_report(self):
+    def background_report(self) -> None:
         """
         The main work-horse method to report data in the background thread.
-        @return: Boolean
-        """
-        if self.thread_shutdown.is_set():
-            logger.debug(
-                "Thread shutdown signal is active: Shutting down reporting thread"
-            )
-            return False
-
-        self.prepare_and_report_data()
 
-        if self.thread_shutdown.is_set():
-            logger.debug(
-                "Thread shutdown signal is active: Shutting down reporting thread"
-            )
-            return False
+        This method runs indefinitely, preparing and reporting data at regular 
+        intervals.
+        It checks for a shutdown signal and stops execution if it's set.
+        
+        @return: None
+        """
+        while True:
+            if self.thread_shutdown.is_set():
+                logger.debug(
+                    "Thread shutdown signal is active: Shutting down reporting thread"
+                )
+                break
 
-        return True
+            self.prepare_and_report_data()
+            time.sleep(self.report_interval)
 
     def prepare_and_report_data(self):
         """

src/instana/util/__init__.py

@@ -1,14 +1,12 @@
 # (c) Copyright IBM Corp. 2021
 # (c) Copyright Instana Inc. 2020
 
+import importlib.metadata
 import json
-import time
 from collections import defaultdict
 from urllib import parse
 
-import importlib.metadata
-
-from ..log import logger
+from instana.log import logger
 
 
 def nested_dictionary():
@@ -111,30 +109,6 @@ def get_default_gateway():
         logger.warning("get_default_gateway: ", exc_info=True)
 
 
-def every(delay, task, name):
-    """
-    Executes a task every `delay` seconds
-
-    :param delay: the delay in seconds
-    :param task: the method to run.  The method should return False if you want the loop to stop.
-    :return: None
-    """
-    next_time = time.time() + delay
-
-    while True:
-        time.sleep(max(0, next_time - time.time()))
-        try:
-            if task() is False:
-                break
-        except Exception:
-            logger.debug(
-                "Problem while executing repetitive task: %s", name, exc_info=True
-            )
-
-        # skip tasks if we are behind schedule:
-        next_time += (time.time() - next_time) // delay * delay + delay
-
-
 def validate_url(url):
     """
     Validate if <url> is a valid url