如何启动由Lambda触发的ECS任务并返回公共IP地址？

1. 创建ECS任务定义，并指定要运行的Docker映像
2. 创建ECS服务，并关联刚才创建的任务定义
3. 在Lambda函数中调用ECS的RunTask API启动任务，并提取任务启动后的容器实例ID
4. 使用容器实例ID调用DescribeContainerInstances API获取容器实例的公共IP地址

代码示例：

import boto3

ecs_client = boto3.client('ecs')
ec2_client = boto3.client('ec2')

def lambda_handler(event, context):
    # ECS任务定义
    task_definition = "my-ecs-task"
    # ECS集群名称
    cluster = "my-ecs-cluster"
    # 启动任务的子网ID
    subnet_id = "subnet-12345678"
    # 启动任务的安全组ID
    security_group_id = "sg-12345678"

    # 启动ECS任务
    response = ecs_client.run_task(
        taskDefinition=task_definition,
        launchType="FARGATE",
        networkConfiguration={
            "awsvpcConfiguration": {
                "subnets": [subnet_id],
                "securityGroups": [security_group_id],
                "assignPublicIp": "ENABLED"
            }
        },
        cluster=cluster
    )
    # 提取容器实例ID
    container_instance_id = response['tasks'][0]['containerInstanceArn'].split('/')[1]

    # 获取容器实例
    container_instances = ecs_client.describe_container_instances(
        cluster=cluster,
        containerInstances=[container_instance_id]
    )['containerInstances']
    # 提取公共IP地址
    public_ip = container_instances[0]['ec2InstanceId']

    # 获取EC2实例
    ec2_instance = ec2_client.describe_instances(
        InstanceIds=[public_ip]
    )['Reservations'][0]['Instances'][0]
    public_ip = ec2_instance.get('PublicIpAddress', '')

    return {
        'statusCode': 200,
        'body': public_ip
    }