Python / Boto3 / 如何獲得帶有分頁的標簽列表？

Question

我想使用 boto3 獲得一個 rds 和每個標簽列表，沒有 100 個限制。

這是獲取 rds 列表和每個標簽的代碼。

client = boto3.client('rds')
instances = client.describe_db_instances()['DBInstances']

for i in instances:
    db_instance_name = i['DBInstanceIdentifier']
    arn = i['DBInstanceArn']
    tags = client.list_tags_for_resource(ResourceName=arn)
    for item in tags['TagList']:
        if item['Key'] == 'Name':
            print(db_instance_name,item['Value'])

這是分頁的代碼。

def all_rds_instances(page_size=20):
    client = session.client('rds')
    marker = ""
    pool = []
    while True:
        for instance in pool:
            yield instance
        if marker is None:
            break
        result = client.describe_db_instances(MaxRecords=page_size, Marker=marker)
        marker = result.get("Marker")
        pool = result.get("DBInstances")

我怎樣才能結合這兩個代碼？

Answer 1

您只需要更改 for 循環以迭代您的 all_rds_instances 生成器。

您的腳本如下所示：

import boto3

client = boto3.client('rds')

def all_rds_instances(page_size=20):
    marker = ''
    pool = []
    while True:
        for instance in pool:
            yield instance
        if marker is None:
            break
        result = client.describe_db_instances(MaxRecords=page_size, Marker=marker)
        marker = result.get('Marker')
        pool = result.get('DBInstances')


for i in all_rds_instances():
    db_instance_name = i['DBInstanceIdentifier']
    arn = i['DBInstanceArn']
    tags = client.list_tags_for_resource(ResourceName=arn)
    for item in tags['TagList']:
        if item['Key'] == 'Name':
            print(db_instance_name, item['Value'])

當您使用yield關鍵字時，您的 function 將成為生成器，並且它的工作方式與 python 中的任何可迭代對象相同。

關於生成器如何在這里工作有一些很酷的答案