docs(samples): Changing machine type sample (#9042)

* docs(samples): Changing machine type sample

* Applying suggestions

* Wording fix

* Update compute/client_library/ingredients/instances/change_machine_type.py

Co-authored-by: Dan Lee <[email protected]>

* Applying suggestions

---------

Co-authored-by: Karl Weinmeister <[email protected]>
Co-authored-by: Dan Lee <[email protected]>

compute/client_library/ingredients/instances/change_machine_type.py

@@ -0,0 +1,58 @@
+#  Copyright 2023 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.
+
+# This is an ingredient file. It is not meant to be run directly. Check the samples/snippets
+# folder for complete code samples that are ready to be used.
+# Disabling flake8 for the ingredients file, as it would fail F821 - undefined name check.
+# flake8: noqa
+
+from google.cloud import compute_v1
+
+
+# <INGREDIENT change_machine_type>
+def change_machine_type(
+        project_id: str,
+        zone: str,
+        instance_name: str,
+        new_machine_type: str
+) -> None:
+    """
+    Changes the machine type of VM. The VM needs to be in the 'TERMINATED' state for this operation to be successful.
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone your instance belongs to.
+        instance_name: name of the VM you want to modify.
+        new_machine_type: the new machine type you want to use for the VM.
+            For example: `e2-standard-8`, `e2-custom-4-2048` or `m1-ultramem-40`
+            More about machine types: https://cloud.google.com/compute/docs/machine-resource
+    """
+    client = compute_v1.InstancesClient()
+    instance = client.get(project=project_id, zone=zone, instance=instance_name)
+
+    if instance.status != compute_v1.Instance.Status.TERMINATED.name:
+        raise RuntimeError(f"Only machines in TERMINATED state can have their machine type changed. "
+                           f"{instance.name} is in {instance.status}({instance.status_message}) state.")
+
+    machine_type = compute_v1.InstancesSetMachineTypeRequest()
+    machine_type.machine_type = f"projects/{project_id}/zones/{zone}/machineTypes/{new_machine_type}"
+    operation = client.set_machine_type(
+        project=project_id,
+        zone=zone,
+        instance=instance_name,
+        instances_set_machine_type_request_resource=machine_type,
+    )
+
+    wait_for_extended_operation(operation, "changing machine type")
+# </INGREDIENT>

compute/client_library/recipes/instances/change_machine_type.py

@@ -0,0 +1,22 @@
+#  Copyright 2023 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.
+# flake8: noqa
+
+# <REGION compute_change_machine_type>
+# <IMPORTS/>
+
+# <INGREDIENT wait_for_extended_operation />
+
+# <INGREDIENT change_machine_type />
+# </REGION compute_change_machine_type>

compute/client_library/snippets/instances/change_machine_type.py

@@ -0,0 +1,114 @@
+#  Copyright 2023 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.
+# flake8: noqa
+
+
+# This file is automatically generated. Please do not modify it directly.
+# Find the relevant recipe file in the samples/recipes or samples/ingredients
+# directory and apply your changes there.
+
+
+# [START compute_change_machine_type]
+import sys
+from typing import Any
+
+from google.api_core.extended_operation import ExtendedOperation
+from google.cloud import compute_v1
+
+
+def wait_for_extended_operation(
+    operation: ExtendedOperation, verbose_name: str = "operation", timeout: int = 300
+) -> Any:
+    """
+    This method will wait for the extended (long-running) operation to
+    complete. If the operation is successful, it will return its result.
+    If the operation ends with an error, an exception will be raised.
+    If there were any warnings during the execution of the operation
+    they will be printed to sys.stderr.
+
+    Args:
+        operation: a long-running operation you want to wait on.
+        verbose_name: (optional) a more verbose name of the operation,
+            used only during error and warning reporting.
+        timeout: how long (in seconds) to wait for operation to finish.
+            If None, wait indefinitely.
+
+    Returns:
+        Whatever the operation.result() returns.
+
+    Raises:
+        This method will raise the exception received from `operation.exception()`
+        or RuntimeError if there is no exception set, but there is an `error_code`
+        set for the `operation`.
+
+        In case of an operation taking longer than `timeout` seconds to complete,
+        a `concurrent.futures.TimeoutError` will be raised.
+    """
+    result = operation.result(timeout=timeout)
+
+    if operation.error_code:
+        print(
+            f"Error during {verbose_name}: [Code: {operation.error_code}]: {operation.error_message}",
+            file=sys.stderr,
+            flush=True,
+        )
+        print(f"Operation ID: {operation.name}", file=sys.stderr, flush=True)
+        raise operation.exception() or RuntimeError(operation.error_message)
+
+    if operation.warnings:
+        print(f"Warnings during {verbose_name}:\n", file=sys.stderr, flush=True)
+        for warning in operation.warnings:
+            print(f" - {warning.code}: {warning.message}", file=sys.stderr, flush=True)
+
+    return result
+
+
+def change_machine_type(
+    project_id: str, zone: str, instance_name: str, new_machine_type: str
+) -> None:
+    """
+    Changes the machine type of VM. The VM needs to be in the 'TERMINATED' state for this operation to be successful.
+
+    Args:
+        project_id: project ID or project number of the Cloud project you want to use.
+        zone: name of the zone your instance belongs to.
+        instance_name: name of the VM you want to modify.
+        new_machine_type: the new machine type you want to use for the VM.
+            For example: `e2-standard-8`, `e2-custom-4-2048` or `m1-ultramem-40`
+            More about machine types: https://cloud.google.com/compute/docs/machine-resource
+    """
+    client = compute_v1.InstancesClient()
+    instance = client.get(project=project_id, zone=zone, instance=instance_name)
+
+    if instance.status != compute_v1.Instance.Status.TERMINATED.name:
+        raise RuntimeError(
+            f"Only machines in TERMINATED state can have their machine type changed. "
+            f"{instance.name} is in {instance.status}({instance.status_message}) state."
+        )
+
+    machine_type = compute_v1.InstancesSetMachineTypeRequest()
+    machine_type.machine_type = (
+        f"projects/{project_id}/zones/{zone}/machineTypes/{new_machine_type}"
+    )
+    operation = client.set_machine_type(
+        project=project_id,
+        zone=zone,
+        instance=instance_name,
+        instances_set_machine_type_request_resource=machine_type,
+    )
+
+    wait_for_extended_operation(operation, "changing machine type")
+
+
+# [END compute_change_machine_type]

compute/client_library/snippets/tests/test_instance_start_stop.py

@@ -23,6 +23,8 @@
 
 from ..disks.clone_encrypted_disk import create_disk_from_customer_encrypted_disk
 from ..disks.delete import delete_disk
+from ..instances.change_machine_type import change_machine_type
+from ..instances.get import get_instance
 from ..instances.start import start_instance
 from ..instances.start_encrypted import start_instance_with_encryption_key
 from ..instances.stop import stop_instance
@@ -187,3 +189,14 @@ def test_clone_encrypted_disk(autodelete_disk_name, compute_encrypted_instance):
         encryption_key=KEY_B64)
 
     assert new_disk.name == autodelete_disk_name
+
+
+def test_change_machine_type(compute_instance):
+    assert _get_status(compute_instance) == "RUNNING"
+
+    stop_instance(PROJECT, INSTANCE_ZONE, compute_instance.name)
+
+    assert not get_instance(PROJECT, INSTANCE_ZONE, compute_instance.name).machine_type.endswith("e2-standard-2")
+    change_machine_type(PROJECT, INSTANCE_ZONE, compute_instance.name, "e2-standard-2")
+
+    assert get_instance(PROJECT, INSTANCE_ZONE, compute_instance.name).machine_type.endswith("e2-standard-2")