"Heartbeat failed because Expecting value" Exception Handling

chris_cho — Thu, 04 Sep 2025 10:13:52 GMT

Hello,

I created a custom Dynatrace Extension using APIs ingesting data from one system into Dynatrace BizEvents, based on a custom scheduler. The execution of data ingestion take few minutes exceeding the regular 60 seconds/1 minute, that is set to execute query method. The executions of the process based on the schedule are successful. Checking the logs from python3.log file, I notice sometimes I am getting an exception from executing the _heartbeat method from the SDK module extension.py
/var/lib/dynatrace/remotepluginmodule/agent/runtime/extensions/python_venvs/custom_<custom_extension_name>_0.0.8/lib/python3.10/site-packages/dynatrace_extension/sdk/extension.py

First, it starts with an error
Error HTTP 400 from http://127.0.0.1:14599/alive/-5515299317920783049: b'Bad Request - unable to parse status
and continues with another
Heartbeat failed because Expecting value: line 1 column 1 (char 0), response b'not set'

As it can be seen in the screenshot the exceptions are triggered by different thread executor ThreadPoolExecutor-0_2, than the one executes the process ThreadPoolExecutor-0_0

Below is the code of fastcheck method, nothing particular:
def fastcheck(self) -> Status:
"""
Use to check if the extension can run.
If this Activegate cannot run this extension, you can
raise an Exception or return StatusValue.ERROR.
This does not run for OneAgent extensions.
"""
return Status(StatusValue.OK, "Fastcheck - TODO:: Check the connections.")

Screenshot of logs

Screenshot of the extension.py _heartbeat method

Please let me know if you have any thoughts.

Re: "Heartbeat failed because Expecting value" Exception Handling

david_lopes — Sat, 20 Dec 2025 04:24:23 GMT

It will be hard to help without the extension code, basically scheduled methods have a status that can be optionally reported, it looks like one of your scheduled methods might not be correctly created our you are using an old version of the SDK with a new OA/AG.

topic Re: "Heartbeat failed because Expecting value" Exception Handling in Extensions

"Heartbeat failed because Expecting value" Exception Handling

Re: "Heartbeat failed because Expecting value" Exception Handling