Support for referrencing image name on gcp backend (#654)

Author: tcarmet

runner_manager/backend/gcloud.py

@@ -73,6 +73,11 @@ def wait_for_operation(
 
     @property
     def image(self) -> Image:
+        if self.instance_config.image is not None:
+            return self.image_client.get(
+                project=self.instance_config.image_project,
+                image=self.instance_config.image,
+            )
         return self.image_client.get_from_family(
             project=self.instance_config.image_project,
             family=self.instance_config.image_family,

runner_manager/models/backend.py

@@ -108,6 +108,7 @@ class GCPConfig(BackendConfig):
 class GCPInstanceConfig(InstanceConfig):
     image_family: str = "ubuntu-2004-lts"
     image_project: str = "ubuntu-os-cloud"
+    image: Optional[str] = None
     machine_type: str = "e2-small"
     subnetwork: str = "default"
     enable_nested_virtualization: bool = True