Como usar módulos de modelo

Os módulos de modelo são arquivos auxiliares que executam funções específicas para aumentar a eficiência dos modelos. Por exemplo, você pode ter um módulo que gera nomes exclusivos para recursos. O Deployment Manager pode executar qualquer módulo escrito em linguagem Python ou Jinja.

Antes de começar

Como criar um módulo de modelo

O módulo de modelo é tratado como um arquivo de modelo normal e pode ser escrito em linguagem Jinja ou Python.

Por exemplo, abaixo encontra-se um modelo auxiliar que gera um nome, desde que sejam fornecidos um prefixo e um sufixo.

Jinja


No Jinja, o modelo auxiliar, chamado de "helpers/common.jinja" no exemplo, fica assim:



{%- macro GenerateMachineName(prefix='', suffix='') -%}
    {{ prefix + "-" + suffix }}
{%- endmacro %}

Em seguida, você pode importar esse modelo e usá-lo como um módulo. No modelo do Jinja, é possível usar o módulo da seguinte forma:

# Copyright 2016 Google Inc. All rights reserved.
#
# 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 'helpers/common.jinja' as common %}

resources:
- name: {{ common.GenerateMachineName("myfrontend", "prod") }}
  type: compute.v1.instance
  properties:
    zone: us-central1-f
    machineType: https://www.googleapis.com/compute/v1/projects/{{ env['project'] }}/zones/us-central1-f/machineTypes/f1-micro
    disks:
    - deviceName: boot
      type: PERSISTENT
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/debian-cloud/global/images/family/debian-9
    networkInterfaces:
    - network: https://www.googleapis.com/compute/v1/projects/{{ env['project'] }}/global/networks/default
      accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT

É preciso que os dois arquivos sejam importados pela configuração (incluindo o arquivo helpers/common.jinja):

# Copyright 2015 Google Inc. All rights reserved.
#
# 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.

imports:
- path: helpers/common.jinja
- path: vm-instance-example.jinja

resources:
- name: my-vm
  type: vm-instance-example.jinja

O serviço Deployment Manager expandirá a configuração, e a configuração final fica assim:

resources:
- name: myfrontend-prod
  type: compute.v1.instance
  properties:
    zone: us-central1-f
    machineType: https://www.googleapis.com/compute/v1/projects/myproject/zones/us-central1-f/machineTypes/f1-micro
    disks:
    - deviceName: boot
      type: PERSISTENT
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/debian-cloud/global/images/family/debian-9
    networkInterfaces:
    - network: https://www.googleapis.com/compute/v1/projects/myproject/global/networks/default
      accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT

Python


No Python, o modelo auxiliar, chamado de "helpers/common.py" no exemplo, fica assim:

# Copyright 2016 Google Inc. All rights reserved.
#
# 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.

"""Generates name of a VM."""

def GenerateMachineName(prefix, suffix):
  return prefix + "-" + suffix

Para usá-lo no modelo do Python:

# Copyright 2016 Google Inc. All rights reserved.
#
# 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.

"""Constructs a VM with imported module."""
from helpers import common

COMPUTE_URL_BASE = 'https://www.googleapis.com/compute/v1/'

def GenerateConfig(context):
  """Generates configuration of a VM."""
  resources = [{
      'name': common.GenerateMachineName('myfrontend', 'prod'),
      'type': 'compute.v1.instance',
      'properties': {
          'zone': 'us-central1-f',
          'machineType': COMPUTE_URL_BASE + 'projects/' + context.env['project']
                         + '/zones/us-central1-f/machineTypes/f1-micro',
          'disks': [{
              'deviceName': 'boot',
              'type': 'PERSISTENT',
              'boot': True,
              'autoDelete': True,
              'initializeParams': {
                  'sourceImage': COMPUTE_URL_BASE + 'projects/'
                                 'debian-cloud/global/images/family/debian-9'}
          }],
          'networkInterfaces': [{
              'network': COMPUTE_URL_BASE + 'projects/' + context.env['project']
                         + '/global/networks/default',
              'accessConfigs': [{
                  'name': 'External NAT',
                  'type': 'ONE_TO_ONE_NAT'
              }]
          }]
      }
  }]
  return {'resources': resources}

É preciso que os dois arquivos sejam importados pela configuração (incluindo o arquivo helpers/common.py):

# Copyright 2015 Google Inc. All rights reserved.
#
# 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.

imports:
- path: helpers/common.py
- path: vm-instance-example.py

resources:
- name: my-vm
  type: vm-instance-example.py

Veja aqui um módulo auxiliar mais complicado:

# Copyright 2015 Google Inc. All rights reserved.
#
# 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.
"""Helper methods for working with containers in config."""
import common
import default
import yaml

# Specific properties for this component, also see container_instance
DCKRENV = default.DCKRENV
DCKRIMAGE = default.DCKRIMAGE

MANIFEST = """
version: v1beta2
containers:
  - name: %(name)s
    image: %(dockerImage)s
    ports:
      - name: %(name)s-port
        hostPort: %(port)i
        containerPort: %(port)i
    %(env)s
"""

def GenerateManifest(context):
  """Generates a Container Manifest given a Template context.

  Args:
    context: Template context, which must contain dockerImage and port
        properties, and an optional dockerEnv property.

  Returns:
    A Container Manifest as a YAML string.
  """
  env = ""
  env_list = []
  if DCKRENV in context.properties:
    for key, value in context.properties[DCKRENV].iteritems():
      env_list.append({"name": key, "value": value})
  if env_list:
    env = "env: " + yaml.dump(env_list, default_flow_style=True)

  manifest_yaml_string = MANIFEST % {
      "name": context.env["name"],
      "dockerImage": context.properties[DCKRIMAGE],
      "port": context.properties[default.PORT],
      "env": env
  }
  return common.GenerateEmbeddableYaml(manifest_yaml_string)

A seguir