Agent returns empty/invalid JSON response on update_agent, causing JSONDecodeError

[Arunps04]

Summary

When attempting to update the agent using the update_agent method, the agent responds with an empty or invalid JSON response, causing a requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0) error on the client side (press app).

App Versions

{
	"frappe": "15.75.0",
	"press": "0.7.0"
}

Route

Form/Database Server/m1.zinyecloud.com

Traceback

Traceback (most recent call last):
  File "env/lib/python3.10/site-packages/requests/models.py", line 971, in json
    return complexjson.loads(self.text, **kwargs)
  File "/usr/lib/python3.10/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.10/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.10/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
 
During handling of the above exception, another exception occurred:
 
Traceback (most recent call last):
  File "apps/frappe/frappe/app.py", line 115, in application
    response = frappe.api.handle(request)
  File "apps/frappe/frappe/api/__init__.py", line 49, in handle
    data = endpoint(**arguments)
  File "apps/frappe/frappe/api/v1.py", line 36, in handle_rpc_call
    return frappe.handler.handle()
  File "apps/frappe/frappe/handler.py", line 51, in handle
    data = execute_cmd(cmd)
  File "apps/frappe/frappe/handler.py", line 84, in execute_cmd
    return frappe.call(method, **frappe.form_dict)
  File "apps/frappe/frappe/__init__.py", line 1754, in call
    return fn(*args, **newargs)
  File "apps/frappe/frappe/handler.py", line 334, in run_doc_method
    response = doc.run_method(method)
  File "apps/frappe/frappe/model/document.py", line 1007, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "apps/frappe/frappe/model/document.py", line 1367, in composer
    return composed(self, method, *args, **kwargs)
  File "apps/frappe/frappe/model/document.py", line 1349, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "apps/frappe/frappe/model/document.py", line 1004, in fn
    return method_object(*args, **kwargs)
  File "apps/frappe/frappe/utils/typing_validations.py", line 32, in wrapper
    return func(*args, **kwargs)
  File "apps/press/press/press/doctype/server/server.py", line 475, in update_agent
    return agent.update()
  File "apps/press/press/agent.py", line 1173, in update
    return self.post("update", data={"url": url, "branch": branch})
  File "apps/press/press/agent.py", line 880, in post
    return self.request("POST", path, data, raises=raises)
  File "apps/press/press/agent.py", line 920, in request
    self.handle_request_failure(agent_job, response)
  File "apps/press/press/agent.py", line 909, in request
    json_response = response.json()
  File "env/lib/python3.10/site-packages/requests/models.py", line 975, in json
    raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Request Data

{
	"type": "POST",
	"args": {
		"docs": "{\"name\":\"m1.zinyecloud.com\", ... }",
		"method": "update_agent"
	},
	"headers": {},
	"error_handlers": {},
	"url": "/api/method/run_doc_method",
	"request_id": null
}

Response Data

{
	"exception": "requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)",
	"exc_type": "JSONDecodeError",
	"_exc_source": "press (app)"
}

Additional Information

• This started occurring in the new setups.
• The agent should always return a valid JSON response, even on error.
• There may be an unhandled exception or crash in the agent code.
• Please investigate recent changes and ensure robust error handling for all endpoints.

[cogk]

Updating Agent also means restarting it: the connection is therefore dropped, which means that no response is returned by Agent (exactly the observed result). I'm not sure there is a way to prevent it with making the update asynchronous on Agent's side, which is difficult, less robust, and also probably useless.

This started occurring in the new setups.

Did it really not occur before?