Creé un script para implementar imágenes de Docker actualizadas en un servicio de ensayo en ECS, de modo que la definición de tarea correspondiente se refiera a las versiones actuales de las imágenes de Docker. No sé con certeza si sigo las mejores prácticas, por lo que agradeceríamos recibir comentarios.
Para que el script funcione, necesita una instancia de ECS de repuesto o un deploymentConfiguration.minimumHealthyPercentvalor para que ECS pueda robar una instancia para implementar la definición de tarea actualizada.
Mi algoritmo es así:
- Etiquete las imágenes de Docker correspondientes a los contenedores en la definición de la tarea con la revisión de Git.
- Inserte las etiquetas de imagen de Docker en los registros correspondientes.
- Anule el registro de definiciones de tareas antiguas en la familia de definiciones de tareas.
- Registre una nueva definición de tarea, ahora refiriéndose a las imágenes de Docker etiquetadas con las revisiones actuales de Git.
- Servicio de actualización para utilizar una nueva definición de tarea.
Mi código pegado a continuación:
deploy-ecs
#!/usr/bin/env python3
import subprocess
import sys
import os.path
import json
import re
import argparse
import tempfile
_root_dir = os.path.abspath(os.path.normpath(os.path.dirname(__file__)))
sys.path.insert(0, _root_dir)
from _common import *
def _run_ecs_command(args):
run_command(['aws', 'ecs', ] + args)
def _get_ecs_output(args):
return json.loads(run_command(['aws', 'ecs', ] + args, return_stdout=True))
def _tag_image(tag, qualified_image_name, purge):
log_info('Tagging image \'{}\' as \'{}\'...'.format(
qualified_image_name, tag))
log_info('Pulling image from registry in order to tag...')
run_command(
['docker', 'pull', qualified_image_name], capture_stdout=False)
run_command(['docker', 'tag', '-f', qualified_image_name, '{}:{}'.format(
qualified_image_name, tag), ])
log_info('Pushing image tag to registry...')
run_command(['docker', 'push', '{}:{}'.format(
qualified_image_name, tag), ], capture_stdout=False)
if purge:
log_info('Deleting pulled image...')
run_command(
['docker', 'rmi', '{}:latest'.format(qualified_image_name), ])
run_command(
['docker', 'rmi', '{}:{}'.format(qualified_image_name, tag), ])
def _register_task_definition(task_definition_fpath, purge):
with open(task_definition_fpath, 'rt') as f:
task_definition = json.loads(f.read())
task_family = task_definition['family']
tag = run_command([
'git', 'rev-parse', '--short', 'HEAD', ], return_stdout=True).strip()
for container_def in task_definition['containerDefinitions']:
image_name = container_def['image']
_tag_image(tag, image_name, purge)
container_def['image'] = '{}:{}'.format(image_name, tag)
log_info('Finding existing task definitions of family \'{}\'...'.format(
task_family
))
existing_task_definitions = _get_ecs_output(['list-task-definitions', ])[
'taskDefinitionArns']
for existing_task_definition in [
td for td in existing_task_definitions if re.match(
r'arn:aws:ecs+:[^:]+:[^:]+:task-definition/{}:\d+'.format(
task_family),
td)]:
log_info('Deregistering task definition \'{}\'...'.format(
existing_task_definition))
_run_ecs_command([
'deregister-task-definition', '--task-definition',
existing_task_definition, ])
with tempfile.NamedTemporaryFile(mode='wt', suffix='.json') as f:
task_def_str = json.dumps(task_definition)
f.write(task_def_str)
f.flush()
log_info('Registering task definition...')
result = _get_ecs_output([
'register-task-definition',
'--cli-input-json', 'file://{}'.format(f.name),
])
return '{}:{}'.format(task_family, result['taskDefinition']['revision'])
def _update_service(service_fpath, task_def_name):
with open(service_fpath, 'rt') as f:
service_config = json.loads(f.read())
services = _get_ecs_output(['list-services', ])[
'serviceArns']
for service in [s for s in services if re.match(
r'arn:aws:ecs:[^:]+:[^:]+:service/{}'.format(
service_config['serviceName']),
s
)]:
log_info('Updating service with new task definition...')
_run_ecs_command([
'update-service', '--service', service,
'--task-definition', task_def_name,
])
parser = argparse.ArgumentParser(
description="""Deploy latest Docker image to staging server.
The task definition file is used as the task definition, whereas
the service file is used to configure the service.
""")
parser.add_argument(
'task_definition_file', help='Your task definition JSON file')
parser.add_argument('service_file', help='Your service JSON file')
parser.add_argument(
'--purge_image', action='store_true', default=False,
help='Purge Docker image after tagging?')
args = parser.parse_args()
task_definition_file = os.path.abspath(args.task_definition_file)
service_file = os.path.abspath(args.service_file)
os.chdir(_root_dir)
task_def_name = _register_task_definition(
task_definition_file, args.purge_image)
_update_service(service_file, task_def_name)
_common.py
import sys
import subprocess
__all__ = ['log_info', 'handle_error', 'run_command', ]
def log_info(msg):
sys.stdout.write('* {}\n'.format(msg))
sys.stdout.flush()
def handle_error(msg):
sys.stderr.write('* {}\n'.format(msg))
sys.exit(1)
def run_command(
command, ignore_error=False, return_stdout=False, capture_stdout=True):
if not isinstance(command, (list, tuple)):
command = [command, ]
command_str = ' '.join(command)
log_info('Running command {}'.format(command_str))
try:
if capture_stdout:
stdout = subprocess.check_output(command)
else:
subprocess.check_call(command)
stdout = None
except subprocess.CalledProcessError as err:
if not ignore_error:
handle_error('Command failed: {}'.format(err))
else:
return stdout.decode() if return_stdout else None