Remove camera creation from Observatory (#612)

* Camera dependency injection.
* Basic `create_cameras_from_config` function.
* **Behavior Change** Accessing `observatory.primary_camera` will now always return a camera if `observatory.has_cameras`.

bin/pocs_shell

@@ -17,6 +17,7 @@ from astropy.utils import console
 from pocs import hardware
 from pocs.core import POCS
 from pocs.observatory import Observatory
+from pocs.camera import create_cameras_from_config
 from pocs.scheduler.field import Field
 from pocs.scheduler.observation import Observation
 from pocs.utils import current_time
@@ -152,7 +153,8 @@ class PocsShell(Cmd):
             simulator = []
 
         try:
-            observatory = Observatory(simulator=simulator)
+            cameras = create_cameras_from_config()
+            observatory = Observatory(simulator=simulator, cameras=cameras)
             self.pocs = POCS(observatory, messaging=True)
             self.pocs.initialize()
         except error.PanError:

pocs/camera/__init__.py

@@ -1,2 +1,185 @@
+from collections import OrderedDict
+import re
+import shutil
+import subprocess
+
+from pocs.utils import error
+from pocs.utils import load_module
+from pocs.utils.config import load_config
+
 from pocs.camera.camera import AbstractCamera  # pragma: no flakes
 from pocs.camera.camera import AbstractGPhotoCamera  # pragma: no flakes
+
+from pocs.utils import logger as logger_module
+
+
+def list_connected_cameras():
+    """Detect connected cameras.
+
+    Uses gphoto2 to try and detect which cameras are connected. Cameras should
+    be known and placed in config but this is a useful utility.
+
+    Returns:
+        list: A list of the ports with detected cameras.
+    """
+
+    gphoto2 = shutil.which('gphoto2')
+    command = [gphoto2, '--auto-detect']
+    result = subprocess.check_output(command)
+    lines = result.decode('utf-8').split('\n')
+
+    ports = []
+
+    for line in lines:
+        camera_match = re.match(r'([\w\d\s_\.]{30})\s(usb:\d{3},\d{3})', line)
+        if camera_match:
+            # camera_name = camera_match.group(1).strip()
+            port = camera_match.group(2).strip()
+            ports.append(port)
+
+    return ports
+
+
+def create_cameras_from_config(config=None, logger=None, **kwargs):
+    """Create camera object(s) based on the config.
+
+    Creates a camera for each camera item listed in the config. Ensures the
+    appropriate camera module is loaded.
+
+    Args:
+        **kwargs (dict): Can pass a `cameras` object that overrides the info in
+            the configuration file. Can also pass `auto_detect`(bool) to try and
+            automatically discover the ports.
+
+    Returns:
+        OrderedDict: An ordered dictionary of created camera objects, with the
+            camera name as key and camera instance as value. Returns an empty
+            OrderedDict if there is no camera configuration items.
+
+    Raises:
+        error.CameraNotFound: Raised if camera cannot be found at specified port or if
+            auto_detect=True and no cameras are found.
+        error.PanError: Description
+    """
+    if not logger:
+        logger = logger_module.get_root_logger()
+
+    if not config:
+        config = load_config(**kwargs)
+
+    # Helper method to first check kwargs then config
+    def kwargs_or_config(item, default=None):
+        return kwargs.get(item, config.get(item, default))
+
+    cameras = OrderedDict()
+    camera_info = kwargs_or_config('cameras')
+    if not camera_info:
+        logger.info('No camera information in config.')
+        return cameras
+
+    logger.debug("Camera config: {}".format(camera_info))
+
+    a_simulator = 'camera' in kwargs_or_config('simulator', default=list())
+    auto_detect = kwargs_or_config('auto_detect', default=False)
+
+    ports = list()
+
+    # Lookup the connected ports if not using a simulator
+    if not a_simulator and auto_detect:
+        logger.debug("Auto-detecting ports for cameras")
+        try:
+            ports = list_connected_cameras()
+        except Exception as e:
+            logger.warning(e)
+
+        if len(ports) == 0:
+            raise error.PanError(
+                msg="No cameras detected. Use --simulator=camera for simulator.")
+        else:
+            logger.debug("Detected Ports: {}".format(ports))
+
+    primary_camera = None
+
+    device_info = camera_info['devices']
+    for cam_num, device_config in enumerate(device_info):
+        cam_name = 'Cam{:02d}'.format(cam_num)
+
+        if not a_simulator:
+            camera_model = device_config.get('model')
+
+            # Assign an auto-detected port. If none are left, skip
+            if auto_detect:
+                try:
+                    camera_port = ports.pop()
+                except IndexError:
+                    logger.warning(
+                        "No ports left for {}, skipping.".format(cam_name))
+                    continue
+            else:
+                try:
+                    camera_port = device_config['port']
+                except KeyError:
+                    raise error.CameraNotFound(
+                        msg="No port specified and auto_detect=False")
+
+            camera_focuser = device_config.get('focuser', None)
+            camera_readout = device_config.get('readout_time', 6.0)
+
+        else:
+            logger.debug('Using camera simulator.')
+            # Set up a simulated camera with fully configured simulated
+            # focuser
+            camera_model = 'simulator'
+            camera_port = '/dev/camera/simulator'
+            camera_focuser = {'model': 'simulator',
+                              'focus_port': '/dev/ttyFAKE',
+                              'initial_position': 20000,
+                              'autofocus_range': (40, 80),
+                              'autofocus_step': (10, 20),
+                              'autofocus_seconds': 0.1,
+                              'autofocus_size': 500}
+            camera_readout = 0.5
+
+        camera_set_point = device_config.get('set_point', None)
+        camera_filter = device_config.get('filter_type', None)
+
+        logger.debug('Creating camera: {}'.format(camera_model))
+
+        try:
+            module = load_module('pocs.camera.{}'.format(camera_model))
+            logger.debug('Camera module: {}'.format(module))
+        except ImportError:
+            raise error.CameraNotFound(msg=camera_model)
+        else:
+            # Create the camera object
+            cam = module.Camera(name=cam_name,
+                                model=camera_model,
+                                port=camera_port,
+                                set_point=camera_set_point,
+                                filter_type=camera_filter,
+                                focuser=camera_focuser,
+                                readout_time=camera_readout)
+
+            is_primary = ''
+            if camera_info.get('primary', '') == cam.uid:
+                primary_camera = cam
+                is_primary = ' [Primary]'
+
+            logger.debug("Camera created: {} {} {}".format(
+                cam.name, cam.uid, is_primary))
+
+            cameras[cam_name] = cam
+
+    if len(cameras) == 0:
+        raise error.CameraNotFound(
+            msg="No cameras available. Exiting.", exit=True)
+
+    # If no camera was specified as primary use the first
+    if primary_camera is None:
+        primary_camera = cameras['Cam00']
+        primary_camera.is_primary = True
+
+    logger.debug("Primary camera: {}", primary_camera)
+    logger.debug("{} cameras created", len(cameras))
+
+    return cameras