185 lines
5.3 KiB
Python
185 lines
5.3 KiB
Python
# -*- coding: utf-8 -*-
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import time
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import os
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import shutil
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import threading
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import datetime
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import logging
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import threading
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import gevent
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from abc import ABCMeta, abstractmethod
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from labthings.core.lock import StrictLock
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from labthings.core.event import ClientEvent
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class BaseCamera(metaclass=ABCMeta):
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"""
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Base implementation of StreamingCamera.
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"""
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def __init__(self):
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self.thread = None
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self.camera = None
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self.lock = StrictLock(timeout=1, name="Camera")
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self.frame = None
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self.last_access = 0
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self.event = ClientEvent()
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self.stop = False # Used to indicate that the stream loop should break
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self.stream_timeout = 20
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self.stream_timeout_enabled = False
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self.stream_active = False
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self.record_active = False
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@property
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@abstractmethod
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def configuration(self):
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"""The current camera configuration."""
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pass
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@property
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@abstractmethod
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def state(self):
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"""The current read-only camera state."""
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pass
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@property
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def settings(self):
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return self.read_settings()
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@abstractmethod
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def update_settings(self, config: dict):
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"""Update settings from a config dictionary"""
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with self.lock:
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# Apply valid config params to camera object
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for key, value in config.items(): # For each provided setting
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if hasattr(self, key): # If the instance has a matching property
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setattr(self, key, value) # Set to the target value
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@abstractmethod
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def read_settings(self) -> dict:
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"""Return the current settings as a dictionary"""
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return {}
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def __enter__(self):
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"""Create camera on context enter."""
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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"""Close camera stream on context exit."""
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self.close()
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def close(self):
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"""Close the BaseCamera and all attached StreamObjects."""
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logging.info("Closing {}".format(self))
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# Close all StreamObjects
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for capture_list in [self.images.values(), self.videos.values()]:
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for stream_object in capture_list:
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stream_object.close()
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# Empty temp directory
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self.clear_tmp()
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# Stop worker thread
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self.stop_worker()
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logging.info("Closed {}".format(self))
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# START AND STOP WORKER THREAD
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def start_worker(self, timeout: int = 5) -> bool:
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"""Start the background camera thread if it isn't running yet."""
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timeout_time = time.time() + timeout
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self.last_access = time.time()
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self.stop = False
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if not self.stream_active:
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# Spawn a greenlet to handle stream
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# start background frame thread
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self.thread = gevent.spawn(self._thread)
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# wait until frames are available
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logging.info("Waiting for frames")
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while self.get_frame() is None:
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if time.time() > timeout_time:
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raise TimeoutError("Timeout waiting for frames.")
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else:
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time.sleep(0.1)
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return True
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def stop_worker(self, timeout: int = 5) -> bool:
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"""Flag worker thread for stop. Waits for thread close or timeout."""
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logging.debug("Stopping worker thread")
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timeout_time = time.time() + timeout
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if self.stream_active:
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self.stop = True
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self.thread.join() # Wait for stream thread to exit
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logging.debug("Waiting for stream thread to exit.")
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while self.stream_active:
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if time.time() > timeout_time:
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logging.debug("Timeout waiting for worker thread close.")
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raise TimeoutError("Timeout waiting for worker thread close.")
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else:
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time.sleep(0.1)
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return True
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# HANDLE STREAM FRAMES
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def get_frame(self):
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"""Return the current camera frame."""
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self.last_access = time.time()
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# wait for a signal from the camera thread
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self.event.wait()
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self.event.clear()
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return self.frame
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@abstractmethod
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def frames(self):
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"""Create generator that returns frames from the camera."""
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pass
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# WORKER THREAD
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def _thread(self):
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"""Camera background thread."""
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self.frames_iterator = self.frames()
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logging.debug("Entering worker thread.")
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self.stream_active = True
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for frame in self.frames_iterator:
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self.frame = frame
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self.event.set() # send signal to clients
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# Handle timeout
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if (
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self.stream_timeout_enabled
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and ( # If using timeout
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time.time() - self.last_access > self.stream_timeout
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)
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and not self.preview_active # And GPU preview is not active
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):
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self.frames_iterator.close()
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break
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try:
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if self.stop is True:
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logging.debug("Worker thread flagged for stop.")
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self.frames_iterator.close()
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break
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except AttributeError:
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pass
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logging.debug("BaseCamera worker thread exiting...")
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# Set stream_activate state
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self.stream_active = False
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