guest_worker/sorteerhoed/central_management.py

import logging
import yaml
from sorteerhoed import HITStore
import os
import subprocess
import boto3
import threading
from queue import Queue
from sorteerhoed.plotter import Plotter
import queue
from sorteerhoed.sqs import SqsListener
from sorteerhoed.webserver import Server
import time
from sorteerhoed.Signal import Signal
import io
from PIL import Image
import datetime
from shutil import copyfile
import colorsys
import tqdm


class Level(object):
    """
    Level image effect adapted from https://stackoverflow.com/a/3125421
    """
    
    def __init__(self, minv, maxv, gamma):
        self.minv= minv/255.0
        self.maxv= maxv/255.0
        self._interval= self.maxv - self.minv
        self._invgamma= 1.0/gamma

    def new_level(self, value):
        if value <= self.minv: return 0.0
        if value >= self.maxv: return 1.0
        return ((value - self.minv)/self._interval)**self._invgamma

    def convert_and_level(self, band_values):
        h, s, v= colorsys.rgb_to_hsv(*(i/255.0 for i in band_values))
        new_v= self.new_level(v)
        return tuple(int(255*i)
                for i
                in colorsys.hsv_to_rgb(h, s, new_v))

    @classmethod
    def level_image(cls, image, minv=0, maxv=255, gamma=1.0):
        """Level the brightness of image (a PIL.Image instance)
        All values ≤ minv will become 0
        All values ≥ maxv will become 255
        gamma controls the curve for all values between minv and maxv"""

        if image.mode != "RGB":
            raise ValueError("this works with RGB images only")

        new_image= image.copy()

        leveller= cls(minv, maxv, gamma)
        levelled_data= [
            leveller.convert_and_level(data)
            for data in image.getdata()]
        new_image.putdata(levelled_data)
        return new_image

class CentralManagement():
    """
    Central management reads config and controls process flow

    The HIT Store is the archive of hits
    mturk thread communicates with mturk
    server thread is tornado communicating with the turkers and with the status interface on the installation
    Plotter thread reads plotter queue and sends it to there
    Scanner is for now a simpe imagescan command
    SQS: thread that listens for updates from Amazon
    """
    def __init__(self, debug_mode):
        self.logger = logging.getLogger("sorteerhoed").getChild('management')
        self.debug = debug_mode
        self.currentHit = None
        self.lastHitTime = None

        self.eventQueue = Queue()
        self.statusPageQueue = Queue()
        self.isRunning = threading.Event()
        self.isScanning = threading.Event()
        self.scanLock = threading.Lock()
        self.notPaused = threading.Event()
        self.lightStatus = 0


    def loadConfig(self, filename, args):
        self.configFile = filename
        self.args = args

        self.reloadConfig()

        varDb = os.path.join(
#             self.config['storage_dir'],
            'hit_store.db'
            )
        self.store = HITStore.Store(varDb, logLevel=logging.DEBUG if self.debug else logging.INFO)
        self.store.registerUpdateHook(self.updateLightHook)  # change light based on status

        self.logger.debug(f"Loaded configuration: {self.config}")

    def reloadConfig(self):
        # reload config settings
        with open(self.configFile, 'r') as fp:
            self.logger.debug('Load config from {}'.format(self.configFile))
            self.config = yaml.safe_load(fp)

        if self.args.no_plotter:
            self.config['dummy_plotter'] = True
        self.config['for_real'] = self.args.for_real


#         self.panopticon = Panopticon(self, self.config, self.voiceStorage)
    def start(self):
        self.isRunning.set()
        self.notPaused.set()

        try:

            # M-turk connection
            MTURK_SANDBOX = 'https://mturk-requester-sandbox.us-east-1.amazonaws.com'
            MTURK_REAL = 'https://mturk-requester.us-east-1.amazonaws.com'
            # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/mturk.html#MTurk.Client
            self.mturk = boto3.client('mturk',
               aws_access_key_id = self.config['amazon']['user_id'],
               aws_secret_access_key = self.config['amazon']['user_secret'],
               region_name='us-east-1',
               endpoint_url = MTURK_REAL if self.config['for_real'] else MTURK_SANDBOX
            )

            self.logger.info(f"Mechanical turk account balance: {self.mturk.get_account_balance()['AvailableBalance']}")
            if not self.config['for_real']:
                self.logger.info("Remove block from sandbox worker account")
                self.mturk.delete_worker_block(WorkerId='A1CK46PK9VEUH5', Reason='Myself on Sandbox')

            # clear any pending hits:
            pending_hits = self.mturk.list_hits(MaxResults=100)
            for pending_hit in pending_hits['HITs']:
#                 print(pending_hit['HITId'], pending_hit['HITStatus'])
                if pending_hit['HITStatus'] == 'Assignable':
                    self.logger.warn(f"Expire stale hit: {pending_hit['HITId']}: {pending_hit['HITStatus']}")
                    self.mturk.update_expiration_for_hit(
                        HITId=pending_hit['HITId'],
                        ExpireAt=datetime.datetime.fromisoformat('2015-01-01')
                    )
                    self.mturk.delete_hit(HITId=pending_hit['HITId'])
                    staleHit = self.store.getHitByRemoteId(pending_hit['HITId'])
                    staleHit.delete()
                    self.store.saveHIT(staleHit)
                    

            self.sqs = SqsListener(self.config, self.eventQueue, self.isRunning)
            sqsThread = threading.Thread(target=self.sqs.start, name='sqs')
            sqsThread.start()

            # the plotter itself
            self.plotter = Plotter(self.config, self.eventQueue, self.isRunning, self.scanLock)
            plotterThread = threading.Thread(target=self.plotter.start, name='plotter')
            plotterThread.start()

            # webserver for turks and status
            self.server = Server(self.config, self.eventQueue, self.isRunning, self.plotter.q, self.store)
            serverThread = threading.Thread(target=self.server.start, name='server')
            serverThread.start()

            # event listener:
            dispatcherThread = threading.Thread(target=self.eventListener, name='dispatcher')
            dispatcherThread.start()

            self.eventQueue.put(Signal('start', {'ding':'test'}))

            while self.isRunning.is_set():
                time.sleep(.5)
        except Exception as e:
            self.logger.exception(e)
        finally:
            self.logger.warning("Stopping Central Managment")
            self.isRunning.clear()
            self.server.stop()

            self.expireCurrentHit()

    def expireCurrentHit(self):
        if self.currentHit and not self.currentHit.isConfirmed():
            if self.currentHit.hit_id:  # hit pending at Amazon
                self.logger.warn(f"Expire hit: {self.currentHit.hit_id}")
                self.mturk.update_expiration_for_hit(
                    HITId=self.currentHit.hit_id,
                    ExpireAt=datetime.datetime.fromisoformat('2015-01-01')
                )
                try:
                    self.mturk.delete_hit(HITId=self.currentHit.hit_id)
                except Exception as e:
                    self.logger.exception(e)
            
            if not self.currentHit.isSubmitted():
                self.currentHit.delete()
                self.store.saveHIT(self.currentHit)
    
    
    def eventListener(self):
        while self.isRunning.is_set():
            try:
                signal = self.eventQueue.get(True, 1)
            except queue.Empty:
                pass
#                 self.logger.log(5, "Empty queue.")
            else:
                try:
                    """
                    Possible events:
                    - SQS events: accept/abandoned/returned/submitted
                    - webserver events: open, draw, submit
                    - scan complete
                    - HIT created
                    - Plotter complete
                    -
                    """
                    self.logger.info(f"SIGNAL: {signal}")
                    if signal.name == 'start':
                        self.makeHit()
                        self.lastHitTime = datetime.datetime.now()
                    elif signal.name == 'hit.scan':
                        # start a scan
                        if signal.params['id'] != self.currentHit.id:
                            self.logger.info(f"Hit.scan had wrong id: {signal}")
                            continue
#                         self.statusPageQueue.add(dict(hit_id=signal.params['id'], transition='scanning'))

                    elif signal.name == 'hit.scanned':
                        # TODO: wrap up hit & make new HIT
                        if signal.params['hit_id'] != self.currentHit.id:
                            self.logger.info(f"Hit.scanned had wrong id: {signal}")
                            continue

                        self.currentHit.scanned_at = datetime.datetime.utcnow()
                        self.store.saveHIT(self.currentHit)
                        
                        time_diff = datetime.datetime.now() - self.lastHitTime
                        to_wait = 10 - time_diff.total_seconds()
#                         self.statusPageQueue.add(dict(hit_id=self.currentHit.id, state='scan'))

                        if to_wait > 0:
                            self.logger.warn(f"Sleep until next hit: {to_wait}s")
                            time.sleep(to_wait)
                        else:
                            self.logger.info(f"No need to wait: {to_wait}s")

                        self.makeHit()
                        self.lastHitTime = datetime.datetime.now()
                    elif signal.name == 'hit.creating':
#                         self.statusPageQueue.add(dict(hit_id=signal.params['id'], transition='create_hit'))
                        pass
                    elif signal.name == 'hit.created':
#                         self.statusPageQueue.add(dict(hit_id=signal.params['id'], remote_id=signal.params['remote_id'], state='hit'))
                        pass
                    elif signal.name == 'scan.start':
                        pass
                    elif signal.name == 'scan.finished':
                        # probably see hit.scanned
                        pass

                    elif signal.name == 'hit.assignment':
                        # Create new assignment
                        if signal.params['hit_id'] != self.currentHit.id:
                            continue
                        assignment = self.currentHit.getAssignmentById(signal.params['assignment_id'])
                        
                    elif signal.name == 'assignment.info':
                        assignment = self.currentHit.getAssignmentById(signal.params['assignment_id'])
                        if not assignment:
                            self.logger.warning(f"assignment.info assignment.id not for current hit assignments: {signal}")

                        change = False
                        for name, value in signal.params.items():
                            if name == 'ip':
                                assignment.turk_ip = value
                            if name == 'location':
                                assignment.turk_country = value
                            if name == 'os':
                                assignment.turk_os = value
                            if name == 'browser':
                                assignment.turk_browser = value
                            change = True
                            self.logger.debug(f'Set assignment: {name} to {value}')
                            
                        if change:
                            self.store.saveAssignment(assignment)
                            
                    elif signal.name == 'server.open':
                        self.currentHit.open_page_at = datetime.datetime.utcnow()
                        self.store.saveHIT(self.currentHit)
                        self.setLight(True)
                    elif signal.name == 'assignment.submit':
                        a = self.currentHit.getLastAssignment()
                        if a.assignment_id != signal.params['assignment_id']:
                            self.logger.critical(f"Submit of invalid assignment_id: {signal}")
                            
                        a.submit_page_at = datetime.datetime.utcnow()
                        self.store.saveAssignment(a)
                        self.plotter.park()
                        # park always triggers a plotter.finished after being processed

                    elif signal.name[:4] == 'sqs.':
                        if signal.params['event']['HITId'] != self.currentHit.hit_id:
                            self.logger.warning(f"SQS hit.info hit_id != currenthit.id: {signal}, update status for older HIT")
                            sqsHit = self.store.getHitByRemoteId(signal.params['event']['HITId'])
                            updateStatus = False
                        else:
                            sqsHit = self.currentHit
                            updateStatus = True
                            
                        sqsAssignment = sqsHit.getAssignmentById(signal.params['event']['AssignmentId'])
                        if not sqsAssignment:
                            self.logger.critical(f"Invalid assignmentId given for hit: {signal.params['event']}")
                            continue

                        if signal.name == 'sqs.AssignmentAccepted':
                            self.logger.info(f'Set status progress to accepted')
                            sqsAssignment.accept_at = datetime.datetime.strptime(signal.params['event']['EventTimestamp'],"%Y-%m-%dT%H:%M:%SZ")
                            sqsAssignment.worker_id = signal.params['event']['WorkerId']
                            # {'event': {'HITGroupId': '301G7MYOAJ85NEW128ZDGF5DSBW53S', 'EventType': 'AssignmentAccepted', 'EventTimestamp': '2019-10-23T20:16:10Z', 'HITId': '3IH9TRB0FBAKKZFP3JUD6D9YWQ1I1F', 'AssignmentId': '3BF51CHDTWLN3ZGHRKDUHFKPWIJ0H3', 'WorkerId': 'A1CK46PK9VEUH5', 'HITTypeId': '3EYXOXDEN7RX0YSMN4UMVN01AYKZJ0'}}
                        elif signal.name == 'sqs.AssignmentAbandoned':
                            self.logger.info(f'Set status progress to abandoned')
                            #{'event': {'HITGroupId': '301G7MYOAJ85NEW128ZDGF5DSBW53S', 'EventType': 'AssignmentAbandoned', 'EventTimestamp': '2019-10-23T20:23:06Z', 'HITId': '3JHB4BPSFKKFQ263K4EFULI3LC79QJ', 'AssignmentId': '3U088ZLJVL450PB6MJZUIIUCB6VW0Y', 'WorkerId': 'A1CK46PK9VEUH5', 'HITTypeId': '3EYXOXDEN7RX0YSMN4UMVN01AYKZJ0'}}
                            sqsAssignment.abandoned_at = datetime.datetime.strptime(signal.params['event']['EventTimestamp'],"%Y-%m-%dT%H:%M:%SZ")
#                             if updateStatus:
#                                 self.setLight(False)
                            self.mturk.create_worker_block(WorkerId=signal.params['event']['WorkerId'], Reason='Accepted task without working on it.')

                        elif signal.name == 'sqs.AssignmentReturned':
                            self.logger.info(f'Set status progress to returned')
                            sqsAssignment.returned_at = datetime.datetime.strptime(signal.params['event']['EventTimestamp'],"%Y-%m-%dT%H:%M:%SZ")
                            # {'event': {'HITGroupId': '301G7MYOAJ85NEW128ZDGF5DSBW53S', 'EventType': 'AssignmentReturned', 'EventTimestamp': '2019-10-23T20:16:47Z', 'HITId': '3IH9TRB0FBAKKZFP3JUD6D9YWQ1I1F', 'AssignmentId': '3BF51CHDTWLN3ZGHRKDUHFKPWIJ0H3', 'WorkerId': 'A1CK46PK9VEUH5', 'HITTypeId': '3EYXOXDEN7RX0YSMN4UMVN01AYKZJ0'}}
                        elif signal.name == 'sqs.AssignmentSubmitted':
                            # {'MessageId': '4b37dfdf-6a12-455d-a111-9a361eb54d88', 'ReceiptHandle': 'AQEBHc0yAdIrEmAV3S8TIoDCRxrItDEvjy0VQko56/Lb+ifszC0gdZ0Bbed24HGHZYr5DSnWkgBJ/H59ZXxFS1iVEH9sC8+YrmKKOTrKvW3gj6xYiBU2fBb8JRq+sEiNSxWLw2waxr1VYdpn/SWcoOJCv6PlS7P9EB/2IQ++rCklhVwV7RfARHy4J87bjk5R3+uEXUUi00INhCeunCbu642Mq4c239TFRHq3mwM6gkdydK+AP1MrXGKKAE1W5nMbwEWAwAN8KfoM1NkkUg5rTSYWmxxZMdVs/QRNcMFKVSf1bop2eCALSoG6l3Iu7+UXIl4HLh+rHp4bc8NoftbUJUii8YXeiNGU3wCM9T1kOerwYVgksK93KQrioD3ee8navYExQRXne2+TrUZUDkxRIdtPGA==', 'MD5OfBody': '01ccb1efe47a84b68704c4dc611a4d8d', 'Body': '{"Events":[{"Answer":"<?xml version=\\"1.0\\" encoding=\\"ASCII\\"?><QuestionFormAnswers xmlns=\\"http://mechanicalturk.amazonaws.com/AWSMechanicalTurkDataSchemas/2005-10-01/QuestionFormAnswers.xsd\\"><Answer><QuestionIdentifier>surveycode<\\/QuestionIdentifier><FreeText>test<\\/FreeText><\\/Answer><\\/QuestionFormAnswers>","HITGroupId":"301G7MYOAJ85NEW128ZDGF5DSBW53S","EventType":"AssignmentSubmitted","EventTimestamp":"2019-10-30T08:01:43Z","HITId":"3NSCTNUR2ZY42ZXASI4CS5YWV0S5AB","AssignmentId":"3ZAZR5XV02TTOCBR9MCLCNQV1XKCZL","WorkerId":"A1CK46PK9VEUH5","HITTypeId":"3EYXOXDEN7RX0YSMN4UMVN01AYKZJ0"}],"EventDocId":"34af4cd7f2829216f222d4b6e66f3a3ff9ad8ea6","SourceAccount":"600103077174","CustomerId":"A1CK46PK9VEUH5","EventDocVersion":"2014-08-15"}'}
                            self.logger.info(f'Set status progress to submitted')
                            sqsAssignment.answer = signal.params['event']['Answer']
                            if sqsAssignment.uuid not in sqsAssignment.answer:
                                self.logger.critical(f"Not a valid answer given?! {sqsAssignment.answer}")

                            if not sqsAssignment.submit_page_at:
                                # page not submitted, hit is. Nevertheless, create new hit.
                                try:
                                    self.mturk.reject_assignment(AssignmentId=signal.params['event']['AssignmentId'], RequesterFeedback='Did not do the assignment')
                                except Exception as e:
                                    self.logger.exception(e)
                                self.makeHit()
                            else:
                                sqsAssignment.confirmed_at = datetime.datetime.strptime(signal.params['event']['EventTimestamp'],"%Y-%m-%dT%H:%M:%SZ")
                            
                            # block de worker na succesvolle submit, om dubbele workers te voorkomen
                            # TODO: Disabled after worker mail, use quals instead
                            #self.mturk.create_worker_block(WorkerId=signal.params['event']['WorkerId'], Reason='Every worker can only work once on the taks.')
                            #self.logger.warn("Block worker after submission")


                        self.store.saveHIT(sqsHit)
                        
                    elif signal.name == 'plotter.finished':
                        # is _always_ triggered after submit due to plotter.park()
                        if self.currentHit and self.currentHit.isSubmitted():
                            self.currentHit.plotted_at = datetime.datetime.utcnow()
                            self.store.saveHIT(self.currentHit)
                            
                            self.logger.info("Start scan thread")
                            scan = threading.Thread(target=self.scanImage, name='scan')
                            scan.start()
                    elif signal.name == 'plotter.parked':
                        # should this have the code from plotter.finished?
                        pass
                    else:
                        self.logger.critical(f"Unknown signal: {signal.name}")
                except Exception as e:
                    self.logger.critical(f"Exception on handling {signal}")
                    self.logger.exception(e)

    def makeHit(self):
        self.expireCurrentHit()  # expire hit if it is there

        self.eventQueue.put(Signal('hit.creating', {'id': self.currentHit.id if self.currentHit else 'start'}))

        self.reloadConfig() # reload new config values if they are set

#         self.notPaused.wait()

        self.currentHit = self.store.createHIT()
        self.store.currentHit = self.currentHit

        self.logger.info(f"Make HIT {self.currentHit.id}")

        question = '''<?xml version="1.0" encoding="UTF-8"?>
<ExternalQuestion xmlns="http://mechanicalturk.amazonaws.com/AWSMechanicalTurkDataSchemas/2006-07-14/ExternalQuestion.xsd">
  <ExternalURL>https://guest.rubenvandeven.com:8888/draw?id={HIT_NR}</ExternalURL>
  <FrameHeight>0</FrameHeight>
</ExternalQuestion>
        '''.replace("{HIT_NR}",str(self.currentHit.id))
        estimatedHitDuration = self.store.getEstimatedHitDuration()


        # set minimum rate, if they take longer we increase the pay
        fee = max(self.config['minimum_fee'], (self.config['hour_rate_aim']/3600.) * estimatedHitDuration)
        self.currentHit.fee = fee
        self.logger.info(f"Based on average duration of {estimatedHitDuration} fee should be {fee}/hit to get hourly rate of {self.config['hour_rate_aim']}")
        new_hit = self.mturk.create_hit(
            Title = 'Trace the drawn line',
            Description = 'Draw a line over the sketched line in the image',
            Keywords = 'polygons, trace, draw',
            Reward = "{:.2f}".format(fee),
            MaxAssignments = 1,
            LifetimeInSeconds = self.config['hit_lifetime'],
            AssignmentDurationInSeconds = self.store.getHitTimeout(),
            AutoApprovalDelayInSeconds = self.config['hit_autoapprove_delay'],
            Question = question,
        )

        self.logger.info(f"Created hit: {new_hit}")
        if not self.config['for_real']:
            self.logger.info("https://workersandbox.mturk.com/mturk/preview?groupId=" + new_hit['HIT']['HITGroupId'])
        else:
            self.logger.info("https://worker.mturk.com/mturk/preview?groupId=" + new_hit['HIT']['HITGroupId'])

        self.currentHit.hit_id = new_hit['HIT']['HITId']

        self.store.saveHIT(self.currentHit)
        # self.server.statusPage.set('hit_id', new_hit['HIT']['HITId'])
        # self.server.statusPage.set('hit_created', self.currentHit.created_at)
        # self.server.statusPage.set('fee', f"${self.currentHit.fee:.2f}")
        # self.server.statusPage.set('state', self.currentHit.getStatus())

        self.eventQueue.put(Signal('hit.created', {'id': self.currentHit.id, 'remote_id': self.currentHit.hit_id}))

    #     mturk.send_test_event_notification()
        if self.config['amazon']['sqs_url']:
            notification_info= self.mturk.update_notification_settings(
                HITTypeId=new_hit['HIT']['HITTypeId'],
                Notification = {
                    'Destination' : self.config['amazon']['sqs_url'],
                    'Transport': 'SQS',
                    'Version': '2014-08-15',
                    'EventTypes': [
                            'AssignmentAccepted',
                            'AssignmentAbandoned',
                            'AssignmentReturned',
                            'AssignmentSubmitted',
#                             'AssignmentRejected',
        #                     'AssignmentApproved',
#                             'HITCreated',
        #                     'HITExpired',
        #                     'HITReviewable',
        #                     'HITExtended',
        #                     'HITDisposed',
        #                     'Ping',
                    ]
                },
                Active=True
            )
            self.logger.debug(notification_info)

    def cleanDrawing(self):
        with self.scanLock:
            self.eventQueue.put(Signal('scan.start'))
            # Scan to reset
            cmd = [
                'sudo', 'scanimage', '-d', 'epkowa','--resolution=100',
                '-l','25' #y axis, margin from top of the scanner, hence increasing this, moves the scanned image upwards
                ,'-t','22', # x axis, margin from left side scanner (seen from the outside)
                '-x',str(181),
                '-y',str(245)
            ]
            proc = subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
            # opens connection to scanner, but only starts scanning when output becomes ready:
            _, e = proc.communicate(80)
            time.sleep(5) # sleep a few seconds for scanner to return to start position
        if e:
            self.logger.critical(f"Scanner caused: {e.decode()}")

        self.eventQueue.put(Signal('system.reset'))
        self.eventQueue.put(Signal('scan.finished'))

    def reset(self) -> str:
        self.plotter.park()
#         Very confusing to have scanning on a reset (because often nothing has happened), so don't do itd
#         scan = threading.Thread(target=self.cleanDrawing, name='reset')
#         scan.start()
        self.server.statusPage.clearAssignment()

    def scanImage(self) -> str:
        """
        Run scanimage on scaner and returns a string with the filename
        """
        
        with self.scanLock:
            if self.config['dummy_plotter']:
                self.eventQueue.put(Signal('hit.scan', {'id':self.currentHit.id}))
                self.eventQueue.put(Signal('scan.start'))
                self.logger.warning("Fake scanner for a few seconds")
                for i in tqdm.tqdm(range(5)):
                    time.sleep(1)
                self.eventQueue.put(Signal('hit.scanned', {'hit_id':self.currentHit.id}))
                self.eventQueue.put(Signal('scan.finished'))
                return
                
            
            cmd = [
                'sudo', 'scanimage', '-d', 'epkowa', '--format', 'tiff',
                    '--resolution=100', # lower res, faster (more powerful) scan & wipe
                    '-l','25' #y axis, margin from top of the scanner, hence increasing this, moves the scanned image upwards
                    ,'-t','22', # x axis, margin from left side scanner (seen from the outside)
    		        '-x',str(181),
                    '-y',str(245)
            ]
            self.logger.info(f"{cmd}")
            filename = self.currentHit.getImagePath()
    
            self.eventQueue.put(Signal('hit.scan', {'id':self.currentHit.id}))
            self.eventQueue.put(Signal('scan.start'))
            proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            # opens connection to scanner, but only starts scanning when output becomes ready:
            o, e = proc.communicate(80)
            if e:
                self.logger.critical(f"Scanner caused: {e.decode()}")
                # Should this clear self.isRunning.clear() ?
    
            try:
                f = io.BytesIO(o)
                img = Image.open(f)
                img = img.transpose(Image.ROTATE_90).transpose(Image.FLIP_TOP_BOTTOM)
                tunedImg = Level.level_image(img, self.config['level']['min'], self.config['level']['max'], self.config['level']['gamma'])
                tunedImg.save(filename)
            except Exception as e:
                self.logger.critical("Cannot create image from scan. Did scanner work?")
                self.logger.exception(e)
                copyfile('www/basic.svg', filename)
    
            time.sleep(5) # sleep a few seconds for scanner to return to start position
    
            self.eventQueue.put(Signal('hit.scanned', {'hit_id':self.currentHit.id}))
            self.eventQueue.put(Signal('scan.finished'))

    def setLight(self, on):
        value = 1 if on else 0
        
        if self.lightStatus == value:
            return
        self.lightStatus = value
        
        cmd = [
            'usbrelay', f'HURTM_1={value}'
        ]
        self.logger.info(f"Trigger light {cmd}")
        code = subprocess.call(cmd)
        if code > 0:
            self.logger.warning(f"Error on light change: {code}")

    def updateLightHook(self, hit = None):
        # ignore hit attribute, which comes from the HITstore
        self.setLight(self.getLightStatus())

    def getLightStatus(self) -> bool:
        if not self.currentHit:
            return False
        a = self.currentHit.getLastAssignment()
        if not a:
            return False
        if self.currentHit.plotted_at: # wait till plotter is done
            return False
        return True