Function Compute:Configure a time trigger

Step 1: Create a time trigger

1. Log on to the Function Compute console.
2. In the left-side navigation pane, click Services and Functions.
3. In the top navigation bar, select the region where your Kubernetes cluster is deployed.
4. On the Services page, find the desired service and click Functions in the Actions column.
5. On the Functions page, click the function that you want to manage.
   
6. On the function details page, click the Triggers tab, select the version or alias from the Version or Alias drop-down list, and then click Create Trigger.
7. In the Create Trigger panel, specify related parameters. After you specify the parameters, click OK.

   Parameter	Description	Example
   Trigger Type	Select Time Trigger.	Time Trigger
   Parameter	The name of the trigger. Enter a custom trigger name.	my_trigger
   Version or Alias	The default value is LATEST. If you want to create a trigger for another version or alias, select a version or alias in the upper-right corner of the function details page. For more information about versions and aliases of a service, see Manage versions and Manage aliases.	LATEST
   Trigger Mode	Select a trigger mode: Interval: Enter a positive integer n in the Interval field. The function is triggered every n minutes. Select Custom Time: Select a time zone and specify the dates, days of a week, and time. The function is triggered at the specified time. Custom Settings: Specify a cron expression in the CRON Expression field. The function is triggered at the time specified by the cron expression.	Interval: 5 minutes
   Trigger Message	Enter custom parameters. The trigger message is used as the value of payload in event.	awesome-fc

   You can configure the CRON Expression parameter to set the time zone. The following items describe the cron expression.

   • Cron expression (UTC time)

     By default, the cron expression uses the Coordinated Universal Time (UTC) time. For example, if you want to schedule a function at 12:00 (UTC+8) every day, you must use 0 0 4 * * *, which specifies that the function is scheduled at 04:00 (UTC) every day.

   • Cron expression (UTC+8)

     If you want to trigger a function based on a specific time zone, you can use the CRON_TZ expression. For example, if you want to trigger the function at 04:00 on the first day of every month (UTC+8), you can use CRON_TZ=Asia/Shanghai 0 0 4 1 * *. The time zone expression varies with the region.

     Note

     If daylight saving time (DST) and winter time are used in your time zone, a function is executed more frequently or less frequently when the time changes between the DST and the winter time. We recommend that you do not set the execution time to a time point when a change between DST and winter time occurs.

   After the trigger is created, it is displayed on the Triggers tab.

Step 2: Configure the input parameters of the function

1. On the function details page, click the Code tab and click the icon. From the drop-down list that appears, select Configure Test Parameters.
2. In the Configure Test Parameters panel, click the Create New Test Event or Modify Existing Test Event tab, and specify Event Name and the event content. After you specify the parameters, click OK.

   A time trigger uses the following event format to trigger a function:

   {
       "triggerTime":"2018-02-09T05:49:00Z",
       "triggerName":"timer-trigger",
       "payload":"awesome-fc"
   }            

   Parameter	Type	Example	Description
   triggerTime	String	2018-02-09T05:49:00Z	The time when the function is triggered.
   triggerName	String	timer-trigger	The name of the time trigger.
   payload	String	awesome-fc	The value of Trigger Message that you entered when you created the trigger.

Step 3: Write the function code and test the function

After you create the time trigger, you can write function code and test the function to verify whether the code is correct. When the specified time arrives, the time trigger automatically triggers the function.

1. On the function details page, click the Code tab, enter function code in the code editor, and then click Save.
   This example uses the Python function code.

   import json
   import logging
   
   logger = logging.getLogger()
   
   def handler(event, context):
       logger.info('event: %s', event)
   
       evt = json.loads(event)
       triggerName = evt["triggerName"]
       triggerTime = evt["triggerTime"]
       message = evt["payload"]
       creds = context.credentials
       logger.info('access_key_id: %s', creds.access_key_id)
       logger.info("message = %s", message)                        

2. On the function details page, click the Code tab and click Test Function.
   After the function is executed, you can view the result on the Code tab.

Additional information

To modify or delete an existing trigger, see Manage triggers.