First draft of new API plugin system

openflexure_microscope/common/labthings/plugins.py

@@ -0,0 +1,119 @@
+import logging
+import collections
+import copy
+
+from importlib import util
+import sys
+
+from openflexure_microscope.config import USER_CONFIG_DIR
+from openflexure_microscope.utilities import camel_to_snake, camel_to_spine
+
+
+class BasePlugin:
+    """
+    Parent class for all plugins.
+
+    Handles binding route views and forms.
+    """
+
+    def __init__(self):
+        self._views = (
+            {}
+        )  # Key: Full, Python-safe ID. Val: Original rule, and view class
+        self._rules = {}  # Key: Original rule. Val: View class
+        self._gui = None
+
+    @property
+    def views(self):
+        return self._views
+
+    def add_view(self, rule, view_class, **kwargs):
+        # Remove all leading slashes from view route
+        cleaned_rule = rule
+        while cleaned_rule[0] == "/":
+            cleaned_rule = cleaned_rule[1:]
+
+        # Expand the rule to include plugin name
+        full_rule = "/{}/{}".format(self._name_uri_safe, cleaned_rule)
+
+        view_id = cleaned_rule.replace("/", "_").replace("<", "").replace(">", "")
+
+        # Create a Python-safe route ID
+        logging.debug(view_id)
+
+        # Store route information in a dictionary
+        d = {"rule": full_rule, "view": view_class, "kwargs": kwargs}
+
+        # Add view to private views dictionary
+        self._views[view_id] = d
+        # Store the rule expansion information
+        self._rules[rule] = self._views[view_id]
+
+    @property
+    def gui(self):
+        print(self._gui)
+        # Handle missing/no GUI
+        if not self._gui:
+            return None
+        # Handle GUI as a dictionary-returning callable function
+        elif isinstance(self._gui, collections.Callable):
+            api_gui = self._gui()
+        # Handle GUI as a static dictionary
+        elif isinstance(self._gui, dict):
+            api_gui = copy.deepcopy(self._gui)
+        # Handle borked GUI
+        else:
+            raise ValueError(
+                "GUI must be a dictionary, or a dictionary-returning function with no arguments."
+            )
+
+        api_gui["id"] = self._name
+
+        if "forms" in api_gui and isinstance(api_gui["forms"], list):
+            for form in api_gui["forms"]:
+                if "route" in form and form["route"] in self._rules.keys():
+                    form["route"] = self._rules[form["route"]]["rule"]
+                else:
+                    logging.warn(
+                        "No valid expandable route found for {}".format(form["route"])
+                    )
+        return api_gui
+
+    def set_gui(self, form_dictionary: dict):
+        self._gui = form_dictionary
+
+    @property
+    def _name(self):
+        return self.__class__.__name__
+
+    @property
+    def _name_python_safe(self):
+        return camel_to_snake(self._name)
+
+    @property
+    def _name_uri_safe(self):
+        return camel_to_spine(self._name)
+
+    def _full_name(self):
+        module = self.__class__.__module__
+        if module is None or module == str.__class__.__module__:
+            return self.__class__.__name__  # Avoid reporting __builtin__
+        else:
+            return module + "." + self.__class__.__name__
+
+
+def find_plugins(plugin_path, module_name="plugins"):
+    print(f"Loading plugins from {plugin_path}")
+    # plugin_path = os.path.join(USER_CONFIG_DIR, "microscope_plugins")
+    # plugins = importlib.machinery.SourceFileLoader(
+    #    module_name, plugin_path
+    # ).exec_module()
+    logging.debug(f"Loading plugins from {plugin_path}")
+
+    spec = util.spec_from_file_location(module_name, plugin_path)
+    mod = util.module_from_spec(spec)
+    sys.modules[spec.name] = mod
+
+    spec.loader.exec_module(mod)
+
+    return mod