From a1864a5257b9075a75653897fd603db8698c4ac2 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Fri, 10 Jul 2026 22:00:04 +0200
Subject: [PATCH] log: route task/component status output through logging, not
 print()

AttributeChange (the common base of every ATask and component ABC) now
sets self.log = logging.getLogger(type(self).__name__), so components
no longer need to hand-type their own name into each message. Wired
logging.basicConfig() in server/brewpi.py with a bare "%(name)s:
%(message)s" formatter - Tee (see prior commit) still supplies the
"<date>T<time>:" prefix, so lines read "<date>T<time>:<component>:
<message>" without double-stamping, and third-party loggers
(websockets, asyncio) now get the same formatting for free.

Converted the print() call sites that were standing in for this in
tasks/ and components/ (leaving __main__ demo blocks and explicit
debug-dump helpers alone).
---
 components/actor/heater_hendi.py         |  6 ++--
 components/actor/hendiCtrl.py            | 14 +++++----
 components/actor/pololu1376.py           | 10 ++++---
 components/actor/stirrerpololu1376.py    | 14 ++++-----
 components/sensor/tempSensor_max31865.py |  6 ++--
 server/brewpi.py                         | 36 +++++++++++++++---------
 tasks/heater.py                          |  4 +--
 tasks/server_log.py                      |  2 +-
 tasks/stirrer.py                         |  4 +--
 tasks/sud.py                             |  2 +-
 tasks/tempsensor.py                      |  4 +--
 utils/value.py                           |  7 +++++
 12 files changed, 64 insertions(+), 45 deletions(-)

diff --git a/components/actor/heater_hendi.py b/components/actor/heater_hendi.py
index efdfdad..fd8b206 100755
--- a/components/actor/heater_hendi.py
+++ b/components/actor/heater_hendi.py
@@ -45,7 +45,7 @@ class HeaterHendi(AHeater):
 			# tick loop (with self.device.open(): activate(True)/(False)) and
 			# from a client's Connect/Disconnect command, neither of which
 			# expect activate() itself to ever raise.
-			print(f"HeaterHendi: comm error in activate({enable}): {e}")
+			self.log.error(f"comm error in activate({enable}): {e}")
 			self.disconnect()
 
 	def is_activated(self):
@@ -55,7 +55,7 @@ class HeaterHendi(AHeater):
 			s = self.hendi.isRemoteEnable()
 			return '1' in s
 		except Exception as e:
-			print(f"HeaterHendi: comm error in is_activated: {e}")
+			self.log.error(f"comm error in is_activated: {e}")
 			self.disconnect()
 			return False
 
@@ -72,7 +72,7 @@ class HeaterHendi(AHeater):
 			self.hendi.setPowerWatts(power)
 			self.power_eff = self.hendi.getPowerWatts() if power > 0 else 0
 		except Exception as e:
-			print(f"HeaterHendi: comm error in process: {e}")
+			self.log.error(f"comm error in process: {e}")
 			self.disconnect()
 			self.power_eff = 0
 
diff --git a/components/actor/hendiCtrl.py b/components/actor/hendiCtrl.py
index afec45a..1b46ac8 100755
--- a/components/actor/hendiCtrl.py
+++ b/components/actor/hendiCtrl.py
@@ -1,5 +1,6 @@
 #!/usr/bin/python3
 
+import logging
 import time
 import serial
 import sys
@@ -11,6 +12,7 @@ class HendiException(Exception):
 
 class HendiCtrl:
 	def __init__(self, port, speed, debug=False):
+		self.log = logging.getLogger(type(self).__name__)
 		self.debug = debug
 		self.prompt = b':'
 		self.sw_id = None
@@ -48,7 +50,7 @@ class HendiCtrl:
 		try:
 			self.ser.open()
 		except serial.SerialException as e:
-			print(f"HendiCtrl: connect failed: {e}")
+			self.log.error(f"connect failed: {e}")
 			return False
 		# The port itself is what "connected" means - a failed version query
 		# (e.g. the device sitting in its ungraceful-disconnect lockout, see
@@ -57,9 +59,9 @@ class HendiCtrl:
 		try:
 			self.sw_id = self.getSoftwareIdentifier()
 			self.sw_ver = self.getSoftwareVersion()
-			print(f"{self.sw_id}, F/W-Version: {self.sw_ver}")
+			self.log.info(f"{self.sw_id}, F/W-Version: {self.sw_ver}")
 		except HendiException:
-			print("HendiCtrl: Hendi not found")
+			self.log.warning("Hendi not found")
 		return True
 
 	@contextmanager
@@ -91,7 +93,7 @@ class HendiCtrl:
 		self.ser.rts = True
 
 	def firmware_update(self, filename):
-		print("Start firmware update")
+		self.log.info("Start firmware update")
 		self.enter_bootloader()
 		self.ser.readline()
 
@@ -122,7 +124,7 @@ class HendiCtrl:
 		self.ser.flushInput()
 		data = s.encode()
 		if self.debug:
-			print(f"HendiCtrl: -> {data!r}")
+			self.log.debug(f"-> {data!r}")
 		self.ser.write(data + b'\r')
 
 	def __read(self):
@@ -132,7 +134,7 @@ class HendiCtrl:
 		# Read answer line
 		answer_raw = self.ser.readline()
 		if self.debug:
-			print(f"HendiCtrl: <- echo={echo!r} answer={answer_raw!r}")
+			self.log.debug(f"<- echo={echo!r} answer={answer_raw!r}")
 		answer = answer_raw.decode('utf-8').replace('\r', '').replace('\n', '')
 		if ':' in answer:
 			result = answer.split(':')
diff --git a/components/actor/pololu1376.py b/components/actor/pololu1376.py
index 8d0669a..925119b 100644
--- a/components/actor/pololu1376.py
+++ b/components/actor/pololu1376.py
@@ -1,3 +1,4 @@
+import logging
 import time
 import serial
 import enum
@@ -68,6 +69,7 @@ class StatusError(enum.IntFlag):
 
 class Pololu1376:
 	def __init__(self, serial_port):
+		self.log = logging.getLogger(type(self).__name__)
 		# Deferred-open pyserial idiom: serial_port is constructed with no
 		# port set (see components/actor/stirrerpololu1376.py), so it isn't
 		# actually opened until connect() is called - a missing/unplugged
@@ -88,7 +90,7 @@ class Pololu1376:
 				self.ser.close()
 				self.ser.open()
 			except serial.SerialException as e:
-				print(f"Pololu1376: connect failed: {e}")
+				self.log.error(f"connect failed: {e}")
 				return False
 		# set_output_flow_control() requires the port to already be open -
 		# can only happen here, after open() above, not at construction time.
@@ -96,10 +98,10 @@ class Pololu1376:
 		try:
 			self.stop()
 			self.firmware_version = self.get_firmware_version()
-			print("Pololu1376 F/W-Version:", self.firmware_version)
+			self.log.info("F/W-Version: {}".format(self.firmware_version))
 			return True
 		except Exception as e:
-			print(f"Pololu1376: connect failed: {e}")
+			self.log.error(f"connect failed: {e}")
 			self.ser.close()
 			self.firmware_version = None
 			return False
@@ -142,7 +144,7 @@ class Pololu1376:
 		rsp = self.cmd("GO")
 		errors = self.get_status_errors()
 		if errors:
-			print(f"Pololu1376: ERROR - still in fail-safe after GO, active errors: {errors!r}")
+			self.log.error(f"still in fail-safe after GO, active errors: {errors!r}")
 		return rsp
 
 	def stop(self):
diff --git a/components/actor/stirrerpololu1376.py b/components/actor/stirrerpololu1376.py
index 39e5d9b..e4f16fe 100644
--- a/components/actor/stirrerpololu1376.py
+++ b/components/actor/stirrerpololu1376.py
@@ -46,7 +46,7 @@ class StirrerPololu1376(AStirrer):
 		if not self.connected:
 			return
 		try:
-			print("activate {}".format(enable))
+			self.log.debug("activate {}".format(enable))
 			if enable:
 				self.drv.go()
 			else:
@@ -58,7 +58,7 @@ class StirrerPololu1376(AStirrer):
 			# loop (with self.device.open(): activate(True)/(False)) and
 			# from a client's Connect/Disconnect command, neither of which
 			# expect activate() itself to ever raise.
-			print(f"StirrerPololu1376: comm error in activate({enable}): {e}")
+			self.log.error(f"comm error in activate({enable}): {e}")
 			self.disconnect()
 
 	def _on_set_speed(self, speed):
@@ -66,9 +66,9 @@ class StirrerPololu1376(AStirrer):
 			return
 		try:
 			self.drv.motor_forward(speed)
-			print("Set speed to {} %".format(speed))
+			self.log.debug("Set speed to {} %".format(speed))
 		except Exception as e:
-			print(f"StirrerPololu1376: comm error in _on_set_speed: {e}")
+			self.log.error(f"comm error in _on_set_speed: {e}")
 			self.disconnect()
 
 	def _on_process(self):
@@ -77,12 +77,12 @@ class StirrerPololu1376(AStirrer):
 		try:
 			errors = self.drv.get_status_errors()
 			if errors:
-				print(f"StirrerPololu1376: motor controller reports errors: {errors!r}")
+				self.log.warning(f"motor controller reports errors: {errors!r}")
 				if StatusError.SAFE_START_VIOLATION in errors:
-					print("Recover after safe start violation!")
+					self.log.warning("Recover after safe start violation!")
 					self.drv.go()
 		except Exception as e:
-			print(f"StirrerPololu1376: comm error in _on_process: {e}")
+			self.log.error(f"comm error in _on_process: {e}")
 			self.disconnect()
 		
 
diff --git a/components/sensor/tempSensor_max31865.py b/components/sensor/tempSensor_max31865.py
index eecf98b..1c3ba03 100755
--- a/components/sensor/tempSensor_max31865.py
+++ b/components/sensor/tempSensor_max31865.py
@@ -25,7 +25,7 @@ class TempSensor_max31865(ATemperatureSensor):
 			# temperature()'s own except handler already retries via
 			# reopen() on the next tick, same recovery path as a later
 			# runtime failure.
-			print(f"TempSensor_max31865: could not open SPI at startup: {e}")
+			self.log.error(f"could not open SPI at startup: {e}")
 
 	def _open_spi(self):
 		self.spi.open(0, 0)
@@ -56,7 +56,7 @@ class TempSensor_max31865(ATemperatureSensor):
 		try:
 			self._open_spi()
 		except Exception as e:
-			print(f"TempSensor_max31865: reopen failed: {e}")
+			self.log.error(f"reopen failed: {e}")
 
 	def read_reg(self, addr):
 		reg = self.spi.xfer([addr, 0xFF])
@@ -98,7 +98,7 @@ class TempSensor_max31865(ATemperatureSensor):
 			# nothing restarts a dead ATask). reopen() gives the SPI bus a
 			# chance to recover from a wedged state without a full process/
 			# Pi reboot - see docs/pi_deployment_notes.md.
-			print(f"TempSensor_max31865: comm error reading sensor, reopening SPI: {e}")
+			self.log.error(f"comm error reading sensor, reopening SPI: {e}")
 			self.reopen()
 		return self.temp
 
diff --git a/server/brewpi.py b/server/brewpi.py
index 6bb79a2..e7d1066 100755
--- a/server/brewpi.py
+++ b/server/brewpi.py
@@ -2,6 +2,7 @@
 import asyncio
 import functools
 import json
+import logging
 import os
 import signal
 import sys
@@ -20,20 +21,23 @@ from tasks import TaskManager, TempSensorTask, HeaterTask, PotTask, TcTask, Stir
 
 import argparse as ap
 
+log = logging.getLogger('brewpi')
+
 
 class Tee:
 	"""Duplicates writes to multiple streams - used to mirror stdout/stderr
-	(everything the rest of the codebase already reaches via print()) into
-	a log file under logs/ as well as the console, without having to touch
-	every print() call site.
+	into a log file under logs/ as well as the console, without every
+	writer needing to know about either.
 
-	Also stamps every line with a "<date>T<time>:" prefix (existing print()
-	call sites already start their message with "Component: ..." - see e.g.
-	tasks/stirrer.py - so the combined line reads
-	"<date>T<time>:<component>: <message>"), so log entries can be
-	correlated with the JSON sample logs (ServerLogTask/SudLogTask) without
-	relying on journalctl's own timestamps, which aren't present in the
-	mirrored log files themselves."""
+	Also stamps every line with a "<date>T<time>:" prefix. Every task/
+	component logs via logging (see utils/value.py's AttributeChange, which
+	gives self.log to all of them), configured below with a bare
+	"%(name)s:%(message)s" formatter - Tee supplies the timestamp instead,
+	so the combined line reads "<date>T<time>:<component>:<message>" (see
+	logging.basicConfig() call below) without double-stamping. This lets
+	log entries be correlated with the JSON sample logs (ServerLogTask/
+	SudLogTask) without relying on journalctl's own timestamps, which
+	aren't present in the mirrored log files themselves."""
 
 	def __init__(self, *streams):
 		self.streams = streams
@@ -92,7 +96,11 @@ if __name__ == '__main__':
 	latest_log_file = open(latest_log_path, "w", buffering=1)
 	sys.stdout = Tee(sys.stdout, log_file, latest_log_file)
 	sys.stderr = Tee(sys.stderr, log_file, latest_log_file)
-	print("Logging to {}".format(log_path))
+	# No "%(asctime)s" here - Tee (above) already stamps every mirrored
+	# line with "<date>T<time>:", so this only contributes the
+	# "<component>:<message>" part (see Tee's own docstring).
+	logging.basicConfig(stream=sys.stdout, level=logging.INFO, format='%(name)s:%(message)s')
+	log.info("Logging to {}".format(log_path))
 
 	config = json.load(open(args.config))
 	dispatcher = MessageDispatcher()
@@ -246,7 +254,7 @@ if __name__ == '__main__':
 	http_handler = functools.partial(SimpleHTTPRequestHandler, directory=web_dir)
 	http_server = ThreadingHTTPServer(("0.0.0.0", args.http_port), http_handler)
 	threading.Thread(target=http_server.serve_forever, daemon=True).start()
-	print("Serving {} on http://0.0.0.0:{}".format(web_dir, args.http_port))
+	log.info("Serving {} on http://0.0.0.0:{}".format(web_dir, args.http_port))
 
 	# systemd's `stop`/`restart` send SIGTERM, whose default disposition is to
 	# kill the process immediately - skipping the finally: block below
@@ -259,7 +267,7 @@ if __name__ == '__main__':
 	try:
 		loop.run_forever()
 	except KeyboardInterrupt:
-		print("\nShutting down...")
+		log.info("Shutting down...")
 	finally:
 		# Cancel all tasks so their finally blocks (e.g. HeaterTask's/
 		# StirrerTask's `with device.open()`) get a chance to run before we
@@ -278,4 +286,4 @@ if __name__ == '__main__':
 		stirrer.activate(False)
 		http_server.shutdown()
 		loop.close()
-		print("Server stopped.")
+		log.info("Server stopped.")
diff --git a/tasks/heater.py b/tasks/heater.py
index f186793..824b3ea 100755
--- a/tasks/heater.py
+++ b/tasks/heater.py
@@ -178,11 +178,11 @@ class HeaterTask(ATask):
 						try:
 							self.device.process()
 						except Exception as e:
-							print(f"HeaterTask: comm error, marking disconnected: {e}")
+							self.log.error(f"comm error, marking disconnected: {e}")
 							self.disconnect()
 						await asyncio.sleep(self.interval)
 			except Exception as e:
-				print(f"HeaterTask: unexpected error, recovering: {e}")
+				self.log.error(f"unexpected error, recovering: {e}")
 				try:
 					self.disconnect()
 				except Exception:
diff --git a/tasks/server_log.py b/tasks/server_log.py
index 4c1179e..a09f288 100644
--- a/tasks/server_log.py
+++ b/tasks/server_log.py
@@ -143,4 +143,4 @@ class ServerLogTask(ATask):
 		for name in (filename, self._latest_filename()):
 			with open(os.path.join(self.path, name), 'w') as f:
 				json.dump(log_data, f, indent='\t')
-		print('Server log: wrote {} samples to {}'.format(len(self._samples), filename))
+		self.log.info('Wrote {} samples to {}'.format(len(self._samples), filename))
diff --git a/tasks/stirrer.py b/tasks/stirrer.py
index 24bc8c0..a028580 100644
--- a/tasks/stirrer.py
+++ b/tasks/stirrer.py
@@ -88,11 +88,11 @@ class StirrerTask(ATask):
 						try:
 							self.device.process()
 						except Exception as e:
-							print(f"StirrerTask: comm error, marking disconnected: {e}")
+							self.log.error(f"comm error, marking disconnected: {e}")
 							self.disconnect()
 						await asyncio.sleep(self.interval)
 			except Exception as e:
-				print(f"StirrerTask: unexpected error, recovering: {e}")
+				self.log.error(f"unexpected error, recovering: {e}")
 				try:
 					self.disconnect()
 				except Exception:
diff --git a/tasks/sud.py b/tasks/sud.py
index 43355ff..0dee87f 100644
--- a/tasks/sud.py
+++ b/tasks/sud.py
@@ -634,7 +634,7 @@ class SudTask(ATask):
 		await self.msg_handler.send(data)
 
 	async def on_process(self):
-		print("{}: Started with interval {} s".format(self.msg_handler.get_key(), self.interval))
+		self.log.info("Started with interval {} s".format(self.interval))
 
 		self.sud.set_on_changed('step', self.on_step_changed)
 		self.sud.set_on_changed('state', self.on_state_changed)
diff --git a/tasks/tempsensor.py b/tasks/tempsensor.py
index 687485a..636d9bb 100644
--- a/tasks/tempsensor.py
+++ b/tasks/tempsensor.py
@@ -24,7 +24,7 @@ class TempSensorTask(ATask):
 		try:
 			self.sensor.temperature()
 		except Exception as e:
-			print(f"TempSensorTask: comm error priming sensor: {e}")
+			self.log.error(f"comm error priming sensor: {e}")
 		self.sensor.set_on_changed("temp", ChangedFloat(self.on_temp_changed, prec=1).set)
 
 	def on_temp_changed(self, value):
@@ -44,5 +44,5 @@ class TempSensorTask(ATask):
 			try:
 				self.sensor.temperature()
 			except Exception as e:
-				print(f"TempSensorTask: comm error reading sensor: {e}")
+				self.log.error(f"comm error reading sensor: {e}")
 			await asyncio.sleep(self.interval)
diff --git a/utils/value.py b/utils/value.py
index 39507f1..d17e335 100644
--- a/utils/value.py
+++ b/utils/value.py
@@ -1,3 +1,4 @@
+import logging
 
 
 class Value:
@@ -53,6 +54,12 @@ class ChangedInteger(object):
 class AttributeChange(object):
 	def __init__(self):
 		self.callbacks = {}
+		# Common ancestor of every task (tasks/task.py's ATask) and component
+		# (Connectable/APid/APlant/ATemperatureSensor) - giving it a logger
+		# here makes self.log available everywhere via one change, named
+		# after the concrete subclass so log lines self-identify their
+		# component without each call site typing it out.
+		self.log = logging.getLogger(type(self).__name__)
 
 	def set_on_changed(self, key, on_changed):
 		if key not in self.callbacks: