Merge pull request #3 from AurelienLourot/detect-hardware

Detect NVIDIA hardware

requirements.txt

@@ -1,3 +1,4 @@
 ops
 
 ruamel.yaml
+pylspci

src/charm.py

@@ -21,6 +21,7 @@ from ops.charm import CharmBase
 from ops.main import main
 from ops.model import ActiveStatus
 
+from pylspci.parsers import SimpleParser
 from ruamel.yaml import YAML
 
 
@@ -29,20 +30,61 @@ class NovaComputeNvidiaVgpuCharm(CharmBase):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.framework.observe(self.on.install, self._on_install)
+        self.framework.observe(self.on.upgrade_charm, self._on_upgrade_charm)
         self.framework.observe(self.on.config_changed, self._on_config_changed)
 
     def _on_install(self, _):
         """install hook."""
-        self.unit.status = ActiveStatus('Unit is ready')
+        self.__set_ready_unit_status()
+
+    def _on_upgrade_charm(self, _):
+        """upgrade-charm hook."""
+        self.__set_ready_unit_status()
 
     def _on_config_changed(self, _):
         """config-changed hook."""
+        if not self._has_nvidia_gpu_hardware():
+            return
+
         vgpu_device_mappings_str = self.config.get('vgpu-device-mappings')
         if vgpu_device_mappings_str is not None:
             vgpu_device_mappings = YAML().load(vgpu_device_mappings_str)
             logging.debug('vgpu-device-mappings={}'.format(
                 vgpu_device_mappings))
 
+    def __set_ready_unit_status(self):
+        """Set the unit status to active/ready."""
+        unit_status_msg = (
+            'Unit is ready: '
+            + ('no ' if not self._has_nvidia_gpu_hardware() else '')
+            + 'NVIDIA GPU found')
+        self.unit.status = ActiveStatus(unit_status_msg)
+
+    @staticmethod
+    def _has_nvidia_gpu_hardware():
+        """Search for NVIDIA GPU hardware.
+
+        :returns: True if some NVIDIA GPU hardware is found on the current
+                  unit.
+        :rtype: bool
+        """
+        nvidia_gpu_hardware_found = False
+        for device in SimpleParser().run():
+            device_class = device.cls.name
+            device_vendor = device.vendor.name
+            device_subsystem_vendor = device.subsystem_vendor.name
+            if '3D' in device_class and ('NVIDIA' in device_vendor or
+                                         'NVIDIA' in device_subsystem_vendor):
+                logging.debug('NVIDIA GPU found: {}'.format(device))
+                # NOTE(lourot): we could `break` out here but it's interesting
+                # for debugging purposes to print them all.
+                nvidia_gpu_hardware_found = True
+
+        if not nvidia_gpu_hardware_found:
+            logging.debug('No NVIDIA GPU found.')
+
+        return nvidia_gpu_hardware_found
+
 
 if __name__ == '__main__':
     main(NovaComputeNvidiaVgpuCharm)