chore(samples): Samples for preemptible instances (#213)

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>

compute/compute/snippets/sample_preemptible.py

@@ -0,0 +1,193 @@
+#  Copyright 2022 Google LLC
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+# [START compute_preemptible_history]
+import datetime
+
+# [END compute_preemptible_history]
+# [START compute_preemptible_create]
+import sys
+
+# [END compute_preemptible_create]
+
+# [START compute_preemptible_history]
+from typing import List, Tuple
+
+# [END compute_preemptible_history]
+
+# [START compute_preemptible_create]
+# [START compute_preemptible_check]
+# [START compute_preemptible_history]
+from google.cloud import compute_v1
+
+# [END compute_preemptible_history]
+# [END compute_preemptible_check]
+# [END compute_preemptible_create]
+
+# [START compute_preemptible_history]
+from google.cloud.compute_v1.services.zone_operations import pagers
+
+# [END compute_preemptible_history]
+
+
+# [START compute_preemptible_create]
+def create_preemptible_instance(
+    project_id: str, zone: str, instance_name: str,
+) -> compute_v1.Instance:
+    """
+    Send an instance creation request to the Compute Engine API and wait for it to complete.
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone you want to use. For example: "us-west3-b"
+        instance_name: name of the new virtual machine.
+    Returns:
+        Instance object.
+    """
+    instance_client = compute_v1.InstancesClient()
+    operation_client = compute_v1.ZoneOperationsClient()
+
+    # Describe the size and source image of the boot disk to attach to the instance.
+    disk = compute_v1.AttachedDisk()
+    initialize_params = compute_v1.AttachedDiskInitializeParams()
+    initialize_params.source_image = (
+        "projects/debian-cloud/global/images/family/debian-10"
+    )
+    initialize_params.disk_size_gb = 10
+    disk.initialize_params = initialize_params
+    disk.auto_delete = True
+    disk.boot = True
+    disk.type_ = "PERSISTENT"
+
+    # Use the default VPC network.
+    network_interface = compute_v1.NetworkInterface()
+    network_interface.name = "default"
+
+    # Collect information into the Instance object.
+    instance = compute_v1.Instance()
+    instance.name = instance_name
+    instance.disks = [disk]
+    instance.machine_type = f"zones/{zone}/machineTypes/e2-small"
+    instance.network_interfaces = [network_interface]
+
+    # Set the preemptible setting
+    instance.scheduling = compute_v1.Scheduling()
+    instance.scheduling.preemptible = True
+
+    # Prepare the request to insert an instance.
+    request = compute_v1.InsertInstanceRequest()
+    request.zone = zone
+    request.project = project_id
+    request.instance_resource = instance
+
+    # Wait for the create operation to complete.
+    print(f"Creating the {instance_name} instance in {zone}...")
+    operation = instance_client.insert_unary(request=request)
+    while operation.status != compute_v1.Operation.Status.DONE:
+        operation = operation_client.wait(
+            operation=operation.name, zone=zone, project=project_id
+        )
+    if operation.error:
+        print("Error during creation:", operation.error, file=sys.stderr)
+    if operation.warnings:
+        print("Warning during creation:", operation.warnings, file=sys.stderr)
+    print(f"Instance {instance_name} created.")
+    return instance_client.get(project=project_id, zone=zone, instance=instance_name)
+
+
+# [END compute_preemptible_create]
+
+
+# [START compute_preemptible_check]
+def is_preemptible(project_id: str, zone: str, instance_name: str) -> bool:
+    """
+    Check if a given instance is preemptible or not.
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone you want to use. For example: "us-west3-b"
+        instance_name: name of the virtual machine to check.
+    Returns:
+        The preemptible status of the instance.
+    """
+    instance_client = compute_v1.InstancesClient()
+    instance = instance_client.get(
+        project=project_id, zone=zone, instance=instance_name
+    )
+    return instance.scheduling.preemptible
+
+
+# [END compute_preemptible_check]
+
+
+# [START compute_preemptible_history]
+def list_zone_operations(
+    project_id: str, zone: str, filter: str = ""
+) -> pagers.ListPager:
+    """
+    List all recent operations the happened in given zone in a project. Optionally filter those
+    operations by providing a filter. More about using the filter can be found here:
+    https://cloud.google.com/compute/docs/reference/rest/v1/zoneOperations/list
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone you want to use. For example: "us-west3-b"
+        instance_name: name of the virtual machine to look for.
+    Returns:
+        List of preemption operations in given zone.
+    """
+    operation_client = compute_v1.ZoneOperationsClient()
+    request = compute_v1.ListZoneOperationsRequest()
+    request.project = project_id
+    request.zone = zone
+    request.filter = filter
+
+    return operation_client.list(request)
+
+
+def preemption_history(
+    project_id: str, zone: str, instance_name: str = None
+) -> List[Tuple[str, datetime.datetime]]:
+    """
+    Get a list of preemption operations from given zone in a project. Optionally limit
+    the results to instance name.
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone you want to use. For example: "us-west3-b"
+        instance_name: name of the virtual machine to look for.
+    Returns:
+        List of preemption operations in given zone.
+    """
+    if instance_name:
+        filter = (
+            f'operationType="compute.instances.preempted" '
+            f"AND targetLink:instances/{instance_name}"
+        )
+    else:
+        filter = 'operationType="compute.instances.preempted"'
+
+    history = []
+
+    for operation in list_zone_operations(project_id, zone, filter):
+        this_instance_name = operation.target_link.rsplit("/", maxsplit=1)[1]
+        if instance_name and this_instance_name == instance_name:
+            # The filter used is not 100% accurate, it's `contains` not `equals`
+            # So we need to check the name to make sure it's the one we want.
+            moment = datetime.datetime.fromisoformat(operation.insert_time)
+            history.append((instance_name, moment))
+
+    return history
+
+
+# [END compute_preemptible_history]

compute/compute/snippets/test_sample_preemptible.py

@@ -0,0 +1,58 @@
+#  Copyright 2022 Google LLC
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+import uuid
+
+import google.auth
+import pytest
+
+from quickstart import delete_instance
+from sample_preemptible import create_preemptible_instance
+from sample_preemptible import is_preemptible
+from sample_preemptible import list_zone_operations
+
+PROJECT = google.auth.default()[1]
+INSTANCE_ZONE = "europe-central2-c"
+
+
+@pytest.fixture
+def autodelete_instance_name():
+    instance_name = "i" + uuid.uuid4().hex[:10]
+
+    yield instance_name
+
+    delete_instance(PROJECT, INSTANCE_ZONE, instance_name)
+
+
+def test_preemptible_creation(autodelete_instance_name):
+    instance = create_preemptible_instance(
+        PROJECT, INSTANCE_ZONE, autodelete_instance_name
+    )
+
+    assert instance.name == autodelete_instance_name
+    assert is_preemptible(PROJECT, INSTANCE_ZONE, instance.name)
+
+    operations = list_zone_operations(
+        PROJECT,
+        INSTANCE_ZONE,
+        f'targetLink="https://www.googleapis.com/compute/v1/projects/'
+        f'{PROJECT}/zones/{INSTANCE_ZONE}/instances/{instance.name}"',
+    )
+
+    # Since ListPagers don't support len(), we need to check it manually
+    try:
+        next(iter(operations))
+    except StopIteration:
+        pytest.fail(
+            "There should be at least one operation for this instance at this point."
+        )