如何获取Azure存储账户容量详情？API返回空JSON的解决及替代方案

调用Azure Monitoring API获取存储账户的UsedCapacity指标时，返回状态码200但结果为空JSON：{"value":[]}，使用的Python代码如下：

import requests
from datetime import datetime, timedelta
from azure.identity import ClientSecretCredential

#start_time = (datetime.utcnow() - timedelta(hours=1)).replace(microsecond=0).isoformat() + "Z"
#end_time = datetime.utcnow().replace(microsecond=0).isoformat() + "Z"

start_time = (datetime.utcnow() - timedelta(hours=23)).replace(microsecond=0).isoformat() + "Z"
end_time = (datetime.utcnow() - timedelta(hours=22)).replace(microsecond=0).isoformat() + "Z"

#print("Start_Time:",start_time)
#print("End_Time:",end_time)

subscription_id = ""
resource_group = ""
storage_account_name = ""
metric_name = "UsedCapacity" 
time_range = f"{start_time}/{end_time}"  
api_version = "2021-05-01"

tenant_id = dbutils.secrets.get(scope="scope",key="tenant-id")
client_id = dbutils.secrets.get(scope="scope", key="clientid")
client_secret = dbutils.secrets.get(scope="sn_scope", key="secret")

token_endpoint = f"https://login.microsoftonline.com/{tenant_id}/oauth2/token" 

data = {
  "grant_type": "client_credentials",
  "client_id": f"{client_id}",  
  "client_secret": f"{client_secret}",  
  "resource": "https://management.azure.com/"
}

response = requests.post(token_endpoint, data=data)

if response.status_code == 200:
  post_response = response.text
  print("POST_Response:",post_response)
  access_token = response.json()["access_token"]
  #print("Access Token:", access_token)
else:
  print("Error generating access token:", response.status_code)


headers = {
  "Authorization": f"Bearer {access_token}",
  "Content-Type" : "application/json"
}


api_url = f"https://management.azure.com/subscriptions/{subscription_id}/resourceGroups/{resource_group}/providers/Microsoft.Storage/storageAccounts/{storage_account_name}/providers/microsoft.insights/metrics?timespan={time_range}&metricnames={metric_name}&api-version={api_version}"


print("API:",api_url)

response = requests.get(api_url,headers=headers)

if response.status_code == 200:
  data = response.text
  print("GET_Response:",data)
else:
  print("Error retrieving metrics data:", response.status_code)
  print("Error Message:",response.text)

• 补充聚合与时间粒度参数：Azure Metrics API必须指定聚合方式才能返回有效数据，原请求URL缺少aggregation参数。修改后的API URL示例：

  https://management.azure.com/subscriptions/{subscription_id}/resourceGroups/{resource_group}/providers/Microsoft.Storage/storageAccounts/{storage_account_name}/providers/microsoft.insights/metrics?timespan={time_range}&metricnames={metric_name}&aggregation=Average&interval=PT1H&api-version={api_version}
  

  针对UsedCapacity，常用聚合方式为Average（时段内平均容量）或Total（时段内总容量），interval=PT1H对应指标默认的1小时聚合粒度。

• 确认时间范围有效性：如果指定的timespan内存储账户无数据写入（如刚创建的空存储账户），会返回空数组。可尝试扩大时间范围，比如查询过去24小时的数据。

• 验证服务主体权限：确保获取token的服务主体已被分配Monitoring Reader或Reader角色（作用范围为目标存储账户、资源组或订阅），RBAC角色分配可能存在15-30分钟的生效延迟。

• 检查存储账户类型：确认目标存储账户为支持UsedCapacity指标的类型（如General Purpose v2、Blob Storage等），部分特殊存储类型（如Premium File Storage）可能不提供该指标。

• Azure Resource Graph API：通过Kusto查询语言获取存储账户使用量，支持批量查询，示例查询语句：

  Resources
  | where type == 'microsoft.storage/storageaccounts'
  | where name == '{storage_account_name}'
  | project name, usedCapacity = toreal(properties.usage.usedCapacity), location
  

  调用时使用Azure Resource Graph的API端点，需确保服务主体拥有Reader权限。

• 存储账户详情API：若仅需获取存储账户的配额配置（非实时使用量），可调用以下接口：

  GET https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Storage/storageAccounts/{accountName}?api-version=2023-01-01
  

内容的提问来源于stack exchange，提问作者Saksham Agarwal