Merge SettingsManager and SystemControl Things.

src/openflexure_microscope_server/things/system.py

@@ -0,0 +1,116 @@
+"""OpenFlexure System.
+
+A module to control the underlying microscope system and to expose information about
+the microscope, server, and thing states to the web API.
+"""
+
+from collections.abc import Mapping
+from socket import gethostname
+from typing import Optional
+from uuid import UUID, uuid4
+import subprocess
+import os
+
+from pydantic import BaseModel
+
+import labthings_fastapi as lt
+
+from openflexure_microscope_server.utilities import VersionData, robust_version_strings
+
+
+class CommandOutput(BaseModel):
+    """A pydantic model passing the STDOUT and STDERR from a subprocess over HTTP."""
+
+    output: str
+    error: str
+
+
+class OpenFlexureSystem(lt.Thing):
+    """Describe and control the OpenFlexure system.
+
+    This Things:
+
+    * Exposes information about the Microscope, Server, and Thing states to the web
+        API.
+    * Controls the underlying OS on the Raspberry Pi allowing shutdown and restarting
+        of the system.
+    """
+
+    _microscope_id: Optional[str] = None
+
+    @lt.thing_setting
+    def microscope_id(self) -> UUID:
+        """A unique identifier for this microscope."""
+        if self._microscope_id is None:
+            self._microscope_id = str(uuid4())
+        return UUID(self._microscope_id)
+
+    @microscope_id.setter
+    def microscope_id(self, uuid: UUID):
+        # TODO make read only but still settable from disk
+        self._microscope_id = uuid
+
+    @lt.thing_property
+    def hostname(self) -> str:
+        """The hostname of the microscope, as reported by its operating system."""
+        return gethostname()
+
+    _version_data: Optional[VersionData] = None
+
+    @lt.thing_property
+    def version_data(self) -> VersionData:
+        """The version string and version source for the server.
+
+        The source may be a commit hash if installed from git. "TOML" if installed from
+        source, or "Dist" if installed from a distribution package.
+
+        If the version or its source cannot be determined an error will be Logged.
+        """
+        # Don't save as a setting as it may change. Get the version string the first
+        # time the property is requested this boot.
+        if self._version_data is None:
+            self._version_data = robust_version_strings()
+        return self._version_data
+
+    @lt.thing_property
+    def is_raspberrypi(self) -> bool:
+        """Return True if running on a Raspberry Pi."""
+        return os.path.exists("/usr/bin/raspi-config")
+
+    @lt.thing_action
+    def shutdown(self) -> CommandOutput:
+        """Attempt to shutdown the device."""
+        p = subprocess.Popen(
+            ["sudo", "shutdown", "-h", "now"],
+            stderr=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+        )
+
+        out, err = p.communicate()
+        return CommandOutput(output=out, error=err)
+
+    @lt.thing_action
+    def reboot(self) -> CommandOutput:
+        """Attempt to reboot the device."""
+        p = subprocess.Popen(
+            ["sudo", "shutdown", "-r", "now"],
+            stderr=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+        )
+        out, err = p.communicate()
+        return CommandOutput(output=out, error=err)
+
+    @lt.thing_action
+    def get_things_state(self, metadata_getter: lt.deps.GetThingStates) -> Mapping:
+        """Metadata summarising the current state of all Things in the server."""
+        return metadata_getter()
+
+    @property
+    def thing_state(self) -> Mapping:
+        """Summary metadata describing the current state of the Thing."""
+        return {
+            "hostname": self.hostname,
+            "microscope-uuid": str(self.microscope_id),
+            "version": self.version_data.version,
+            "version_source": self.version_data.version_source,
+        }