Question

使用AWS Boto3资源服务我得到了所有ec2实例的列表：

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    <EventTrigger RoutedEvent="ToggleButton.Loaded">
        <SkipStoryboardToFill BeginStoryboardName="checkedSB" />
        <SkipStoryboardToFill BeginStoryboardName="uncheckedSB" />
    </EventTrigger>
    <DataTrigger Binding="{Binding IsChecked, RelativeSource={RelativeSource Self}}" Value="true">
        <DataTrigger.EnterActions>
            <BeginStoryboard Name="checkedSB">
                <Storyboard Storyboard.TargetProperty="Width">
                    <DoubleAnimation To="150"/>
                </Storyboard>
            </BeginStoryboard>
        </DataTrigger.EnterActions>
        <DataTrigger.ExitActions>
            <BeginStoryboard Name="uncheckedSB">
                <Storyboard Storyboard.TargetProperty="Width">
                    <DoubleAnimation To="50"/>
                </Storyboard>
            </BeginStoryboard>
        </DataTrigger.ExitActions>
    </DataTrigger>
</Style.Triggers>

每当我使用我的`ec2_instance'变量做某事时 - 它接缝重新加载整个实例列表..

有没有办法只需拉一次列表然后再处理它（过滤器等）

我做的例子：

获取列表并在过滤某些值后将其显示为菜单：

在我的Aws（）课程中：

ec2_instances = ec2.instances.all()

在我的菜单模块中：

    def load_ec2_instance(self, region):
    """
    Load the EC2 instances a region
    :param region:
    :rtype: list
    :return: a list of the instances in a region or None if there are no instances
    """
    ec2 = self._get_resource("ec2", region)
    ec2_instances = ec2.instances.all()
    counter = collections.Counter(ec2_instances);
    ec2_size = sum(counter.itervalues());
    if ec2_size == 0:
        return None
    return ec2_instances

这需要时间取决于我的互联网连接，但我看到，当我断开我的互联网 - 它无法过滤.. 我只有12个实例，所以过滤它们的循环不应该花费时间..

更新我将Aws（）类更改为模块，我正在使用这两个函数：

       instances = Aws.get_instance().load_ec2_instance(chosen_region)
       show_environments_menu(instances)

        def show_environments_menu(instances):
            subprocess.call("clear")
            print "Please choose the environment your instance is located in:"
            environments = Aws.get_instance().get_environments_from_instances(instances)
            for i, environment in enumerate(environments):
                print "%d. %s" % (i + 1, environment)

        def get_environments_from_instances(self, instances):
        """
        Get all the environments available from instances lists
        :param list instances: the list of instance
        :rtype: list
        :return: a list of the environments
        """
        environments = []
        for instance in instances:
            tags = instance.tags
            for tag in tags:
                key = tag.get("Key")
                if key == "Environment":
                    environment = tag.get("Value").strip()
                    if environment not in environments:
                        environments.append(environment)
        return environments

Answer 1

对于仍然面临此问题的人

尝试使用ec2客户端而不是资源。 boto3中的资源是更高级别的，并为您做更多的工作，而客户端只是给你你所要求的。

当你使用客户端时，你会得到python词典对象，你可以在内存中操作你的心灵内容。请参阅下面的示例。您可以编辑它以使用列表推导和方法等。

有关描述ec2实例的ec2客户端方法的文档，请参阅EC2.Client.describe_instances。

import boto3
ec2 = boto3.client("ec2", region_name = 'us-west-2')
reservations = ec2.describe_instances()['Reservations']
instances = []
for reservation in reservations:
     for instance in reservation['Instances']:
         instances.append(instance)

environments = []
for instance in instances:
    for tag in instance['Tags']:
        if tag['Key'] == 'Environment':
            environments.append(tag['Value'])

Python AWS boto3实例列表始终更新

1 个答案: