docs(samples): Adding samples for instance from template creation (#159)

* docs(samples): Adding samples for instance from template creation

compute/compute/snippets/sample_instance_from_template.py

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+#  Copyright 2021 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_instances_create_from_template]
+# [START compute_instances_create_from_template_with_overrides]
+from google.cloud import compute_v1
+# [END compute_instances_create_from_template_with_overrides]
+
+
+def create_instance_from_template(
+    project_id: str, zone: str, instance_name: str, instance_template_url: str
+) -> compute_v1.Instance:
+    """
+    Creates a Compute Engine VM instance from an instance template.
+
+    Args:
+        project_id: ID or number of the project you want to use.
+        zone: Name of the zone you want to check, for example: us-west3-b
+        instance_name: Name of the new instance.
+        instance_template_url: URL of the instance template used for creating the new instance.
+            It can be a full or partial URL.
+            Examples:
+            - https://www.googleapis.com/compute/v1/projects/project/global/instanceTemplates/example-instance-template
+            - projects/project/global/instanceTemplates/example-instance-template
+            - global/instanceTemplates/example-instance-template
+
+    Returns:
+        Instance object.
+    """
+    operation_client = compute_v1.ZoneOperationsClient()
+    instance_client = compute_v1.InstancesClient()
+
+    instance_insert_request = compute_v1.InsertInstanceRequest()
+    instance_insert_request.project = project_id
+    instance_insert_request.zone = zone
+    instance_insert_request.source_instance_template = instance_template_url
+    instance_insert_request.instance_resource.name = instance_name
+
+    op = instance_client.insert(instance_insert_request)
+    operation_client.wait(project=project_id, zone=zone, operation=op.name)
+
+    return instance_client.get(project=project_id, zone=zone, instance=instance_name)
+
+
+# [END compute_instances_create_from_template]
+
+
+# [START compute_instances_create_from_template_with_overrides]
+def create_instance_from_template_with_overrides(
+    project_id: str,
+    zone: str,
+    instance_name: str,
+    instance_template_name: str,
+    machine_type: str,
+    new_disk_source_image: str,
+) -> compute_v1.Instance:
+    """
+    Creates a Compute Engine VM instance from an instance template, changing the machine type and
+    adding a new disk created from a source image.
+
+    Args:
+        project_id: ID or number of the project you want to use.
+        zone: Name of the zone you want to check, for example: us-west3-b
+        instance_name: Name of the new instance.
+        instance_template_name: Name of the instance template used for creating the new instance.
+        machine_type: Machine type you want to set in following format:
+            "zones/{zone}/machineTypes/{type_name}". For example:
+            - "zones/europe-west3-c/machineTypes/f1-micro"
+            - You can find the list of available machine types using:
+              https://cloud.google.com/sdk/gcloud/reference/compute/machine-types/list
+        newDiskSourceImage: Path the the disk image you want to use for your new
+            disk. This can be one of the public images
+            (like "projects/debian-cloud/global/images/family/debian-10")
+            or a private image you have access to.
+            For a list of available public images, see the documentation:
+            http://cloud.google.com/compute/docs/images
+
+    Returns:
+        Instance object.
+    """
+    operation_client = compute_v1.ZoneOperationsClient()
+    instance_client = compute_v1.InstancesClient()
+    instance_template_client = compute_v1.InstanceTemplatesClient()
+
+    # Retrieve an instance template by name.
+    instance_template = instance_template_client.get(
+        project=project_id, instance_template=instance_template_name
+    )
+
+    # Adjust diskType field of the instance template to use the URL formatting required by instances.insert.diskType
+    # For instance template, there is only a name, not URL.
+    for disk in instance_template.properties.disks:
+        if disk.initialize_params.disk_type:
+            disk.initialize_params.disk_type = (
+                f"zones/{zone}/diskTypes/{disk.initialize_params.disk_type}"
+            )
+
+    instance = compute_v1.Instance()
+    instance.name = instance_name
+    instance.machine_type = machine_type
+    instance.disks = instance_template.properties.disks
+
+    new_disk = compute_v1.AttachedDisk()
+    new_disk.initialize_params.disk_size_gb = 50
+    new_disk.initialize_params.source_image = new_disk_source_image
+    new_disk.auto_delete = True
+    new_disk.boot = False
+    new_disk.type_ = compute_v1.AttachedDisk.Type.PERSISTENT
+
+    instance.disks.append(new_disk)
+
+    instance_insert_request = compute_v1.InsertInstanceRequest()
+    instance_insert_request.project = project_id
+    instance_insert_request.zone = zone
+    instance_insert_request.instance_resource = instance
+    instance_insert_request.source_instance_template = instance_template.self_link
+
+    op = instance_client.insert(instance_insert_request)
+    operation_client.wait(project=project_id, zone=zone, operation=op.name)
+
+    return instance_client.get(project=project_id, zone=zone, instance=instance_name)
+
+
+# [END compute_instances_create_from_template_with_overrides]

compute/compute/snippets/test_sample_instance_from_template.py

@@ -0,0 +1,98 @@
+#  Copyright 2021 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
+from google.cloud import compute_v1
+import pytest
+
+from quickstart import delete_instance
+from sample_instance_from_template import (
+    create_instance_from_template,
+    create_instance_from_template_with_overrides,
+)
+
+
+PROJECT = google.auth.default()[1]
+INSTANCE_ZONE = "us-central1-b"
+
+
+@pytest.fixture
+def instance_template():
+    disk = compute_v1.AttachedDisk()
+    initialize_params = compute_v1.AttachedDiskInitializeParams()
+    initialize_params.source_image = (
+        "projects/debian-cloud/global/images/family/debian-11"
+    )
+    initialize_params.disk_size_gb = 25
+    disk.initialize_params = initialize_params
+    disk.auto_delete = True
+    disk.boot = True
+
+    network_interface = compute_v1.NetworkInterface()
+    network_interface.name = "global/networks/default"
+
+    template = compute_v1.InstanceTemplate()
+    template.name = "test-template-" + uuid.uuid4().hex[:10]
+    template.properties.disks = [disk]
+    template.properties.machine_type = "e2-standard-4"
+    template.properties.network_interfaces = [network_interface]
+
+    template_client = compute_v1.InstanceTemplatesClient()
+    operation_client = compute_v1.GlobalOperationsClient()
+    op = template_client.insert(project=PROJECT, instance_template_resource=template)
+    operation_client.wait(project=PROJECT, operation=op.name)
+
+    template = template_client.get(project=PROJECT, instance_template=template.name)
+
+    yield template
+
+    op = template_client.delete(project=PROJECT, instance_template=template.name)
+    operation_client.wait(project=PROJECT, operation=op.name)
+
+
+@pytest.fixture()
+def autodelete_instance_name():
+    instance_name = "test-instance-" + uuid.uuid4().hex[:10]
+    yield instance_name
+    delete_instance(PROJECT, INSTANCE_ZONE, instance_name)
+
+
+def test_create_instance_from_template(instance_template, autodelete_instance_name):
+    instance = create_instance_from_template(
+        PROJECT, INSTANCE_ZONE, autodelete_instance_name, instance_template.self_link
+    )
+
+    assert instance.name == autodelete_instance_name
+    assert instance.zone.endswith(INSTANCE_ZONE)
+
+
+def test_create_instance_from_template_override(
+    instance_template, autodelete_instance_name
+):
+    image_client = compute_v1.ImagesClient()
+
+    image = image_client.get_from_family(project="centos-cloud", family="centos-8")
+    instance = create_instance_from_template_with_overrides(
+        PROJECT,
+        INSTANCE_ZONE,
+        autodelete_instance_name,
+        instance_template.name,
+        f"zones/{INSTANCE_ZONE}/machineTypes/n2-standard-2",
+        image.self_link,
+    )
+
+    assert instance.name == autodelete_instance_name
+    assert instance.machine_type.endswith("n2-standard-2")
+    assert len(instance.disks) == 2