Define a function

Define function code

1. Log on to the Function Compute console.
2. In the top navigation bar, select your region.
3. In the left-side navigation pane, click Service/Function.
4. Find the target function in the target service and click the name of the function.
5. Click the Code tab and write code in the code editor.

   In the following example, Python is used to define the function:

   # -*- coding: utf-8 -*-
   import logging
   import json, random, string, time
   from aliyunsdkcore import client
   from aliyunsdkecs.request.v20140526.DeleteSnapshotRequest import DeleteSnapshotRequest
   from aliyunsdkecs.request.v20140526.CreateSnapshotRequest import CreateSnapshotRequest
   from aliyunsdkecs.request.v20140526.DescribeDisksRequest import DescribeDisksRequest
   from aliyunsdkcore.auth.credentials import StsTokenCredential
   
   LOGGER = logging.getLogger()
   clt = None
   
   def handler(event, context):
     creds = context.credentials
     sts_token_credential = StsTokenCredential(creds.access_key_id, creds.access_key_secret, creds.security_token)
     '''
     {
       "product": "ECS",
       "content": {
           "executeFinishTime": "2018-06-08T01:25:37Z",
           "executeStartTime": "2018-06-08T01:23:37Z",
           "ecsInstanceName": "timewarp",
           "eventId": "e-t4nhcpqcu8fqushpn3mm",
           "eventType": "InstanceFailure.Reboot",
           "ecsInstanceId": "i-bp18l0uopocfc98xxxx" 
       },
       "resourceId": "acs:ecs:cn-hangzhou:12345678:instance/i-bp18l0uopocfc98xxxx",
       "level": "CRITICAL",
       "instanceName": "instanceName",
       "status": "Executing",
       "name": "Instance:SystemFailure.Reboot:Executing", 
       "regionId": "cn-hangzhou"
     }
     '''
   
     evt = json.loads(event)
     content = evt.get("content");
     ecsInstanceId = content.get("ecsInstanceId");
     regionId = evt.get("regionId");
   
     global clt
     clt = client.AcsClient(region_id=regionId, credential=sts_token_credential)
     name = evt.get("name");
     name = name.lower()
   
     if name in [ 'Instance:SystemFailure.Reboot:Executing'.lower(), "Instance:InstanceFailure.Reboot:Executing".lower()]:
       pass
       # do other things
   
     if name in ['Instance:SystemFailure.Reboot:Executed'.lower(), "Instance:InstanceFailure.Reboot:Executed".lower()]:
       request = DescribeDisksRequest()
       request.add_query_param("RegionId", regionId)
       request.set_InstanceId(ecsInstanceId)
       response = _send_request(request)
       disks = response.get('Disks').get('Disk', [])
       for disk in disks:
         diskId = disk["DiskId"]
         SnapshotId = create_ecs_snap_by_id(diskId)
         LOGGER.info("Create ecs snap sucess, ecs id = %s , disk id = %s ", ecsInstanceId, diskId)
   
   def create_ecs_snap_by_id(disk_id):
       LOGGER.info("Create ecs snap, disk id is %s ", disk_id)
       request = CreateSnapshotRequest()
       request.set_DiskId(disk_id)
       request.set_SnapshotName("reboot_" + ''.join(random.choice(string.ascii_lowercase) for _ in range(6)))
       response = _send_request(request)
       return response.get("SnapshotId")
   
   # send open api request
   def _send_request(request):
       request.set_accept_format('json')
       try:
           response_str = clt.do_action_with_exception(request)
           LOGGER.info(response_str)
           response_detail = json.loads(response_str)
           return response_detail
       except Exception as e:
           LOGGER.error(e)