Microscope now only attaches to hardware once an API request is made.

openflexure_microscope/api/v1.py

@@ -11,6 +11,7 @@ import numpy as np
 from importlib import import_module
 import time
 import datetime
+import os
 
 from flask import (
     Flask, render_template, Response,
@@ -29,11 +30,6 @@ import logging, sys
 
 logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)
 
-# Create the microscope object globally (common to all spawned server threads)
-api_microscope = Microscope(
-    StreamingCamera(), 
-    OpenFlexureStage("/dev/ttyUSB0")
-)
 
 # Create flask app
 app = Flask(__name__)
@@ -45,9 +41,29 @@ def not_found(error):
 
 # Some useful functions
 # TODO: Maybe auto-generate API URI base from module name
-def uri(suffix, base='/api/v1'):
-    return base + suffix
+def uri(suffix, base=None):
+    if not base:
+        api_ver = os.path.splitext(os.path.basename(__file__))[0]
+        base = "/api/{}".format(api_ver)
+    uri = base + suffix
+    logging.debug("Created app route: {}".format(uri))
+    return uri
 
+# Create a dummy microscope object, with no hardware attachments
+api_microscope = Microscope(None, None)
+logging.debug("Created an empty microscope in global.")
+
+# After app starts, but before first request, attach hardware to global microscope
+@app.before_first_request
+def attach_microscope():
+    # Create the microscope object globally (common to all spawned server threads)
+    global api_microscope
+    logging.debug("First request made. Populating microscope with hardware...")
+    api_microscope.attach(
+        StreamingCamera(),
+        OpenFlexureStage("/dev/ttyUSB0")
+    )
+    logging.debug("Microscope successfully attached!")
 
 ##### WEBAPP ROUTES ######
 

openflexure_microscope/microscope.py

@@ -2,7 +2,7 @@
 """
 Defines a microscope object, binding a camera and stage with basic functionality.
 """
-
+import logging
 import numpy as np
 
 from openflexure_stage import OpenFlexureStage
@@ -20,11 +20,7 @@ class Microscope(object):
         microscope (:py:class:`openflexure_stage.stage.OpenFlexureStage`): stage object
     """
     def __init__(self, camera: StreamingCamera, stage: OpenFlexureStage):
-        print("Assigning camera")
-        self.camera = camera  #: :py:class:`openflexure_microscope.camera.pi.StreamingCamera`: Picamera object
-        print("Assigning stage")
-        self.stage = stage  #: :py:class:`openflexure_stage.stage.OpenFlexureStage`: OpenFlexure stage object
-        self.stage.backlash = np.zeros(3, dtype=np.int)
+        self.attach(camera, stage)
 
     def __enter__(self):
         """Create microscope on context enter."""
@@ -38,6 +34,27 @@ class Microscope(object):
         """Shut down the microscope hardware."""
         self.camera.close()
         self.stage.close()
+    
+    def attach(self, camera: StreamingCamera, stage: OpenFlexureStage):
+        """
+        Retroactively attaches a camera and stage to the microscope object.
+
+        Allows the microscope to be created as a "dummy", with hardware communications
+        opened at a later time.
+
+        Args:
+            camera (:py:class:`openflexure_microscope.camera.pi.StreamingCamera`): camera object
+            microscope (:py:class:`openflexure_stage.stage.OpenFlexureStage`): stage object
+        """
+
+        self.camera = camera  #: :py:class:`openflexure_microscope.camera.pi.StreamingCamera`: Picamera object
+        if isinstance(camera, StreamingCamera):
+            logging.info("Attached camera {}".format(camera))
+
+        self.stage = stage  #: :py:class:`openflexure_stage.stage.OpenFlexureStage`: OpenFlexure stage object
+        if isinstance(self.stage, OpenFlexureStage):  # If a stage object has been attached
+            logging.info("Attached stage {}".format(stage))
+            self.stage.backlash = np.zeros(3, dtype=np.int)
 
     # Create unified state
     @property