Creating a timer that invokes a Cloud Functions function
Create a timer, i.e., a trigger that calls a Cloud Functions function based on a schedule.
Getting started
To create a trigger, you need:
-
A function that the trigger will invoke. If you do not have a function:
-
(Optional) A Dead Letter Queue where messages that could not be processed by a function will be redirected. If you do not have a queue, create one.
-
Service accounts with rights to invoke the function and (optionally) write messages to the Dead Letter Queue. You can use the same service account or different ones. If you do not have a service account, create one.
Creating a trigger
Note
The trigger is initiated within 5 minutes of being created.
-
In the management console
, select the folder where you want to create your trigger. -
Select Cloud Functions.
-
In the left-hand panel, select
-
Click Create trigger.
-
Under Basic settings:
- Enter a name and description for the trigger.
- In the Type field, select Timer.
- In the Launched resource field, select Function.
-
Under Timer settings:
- In the Cron expression field, specify the function invocation schedule as a cron expression.
- (Optional) In the Payload field, enter the message to be delivered to the function if the timer triggers in the
payload
field. The data type is a string up to 4,096 characters long.
-
Under Function settings, select a function and specify:
- Function version tag.
- Service account to invoke the function under.
-
(Optional) Under Repeat request settings:
- In the Interval field, specify the time after which the function will be invoked again if the current attempt fails. The values may range from 10 to 60 seconds. The default value is 10 seconds.
- In the Number of attempts field, specify the number of invocation retries before the trigger moves a message to the Dead Letter Queue. The values may range from 1 to 5. The default value is 1.
-
(Optional) Under Dead Letter Queue settings, select the Dead Letter Queue and the service account with write privileges for this queue.
-
Click Create trigger.
If you do not have the Yandex Cloud command line interface yet, install and initialize it.
The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name
or --folder-id
parameter.
To create a trigger that invokes a function, run this command:
yc serverless trigger create timer \
--name <timer_name> \
--cron-expression '<cron_expression>' \
--payload <message> \
--invoke-function-id <function_ID> \
--invoke-function-service-account-id <service_account_ID> \
--retry-attempts 1 \
--retry-interval 10s \
--dlq-queue-id <Dead_Letter_Queue_ID> \
--dlq-service-account-id <service_account_ID>
Where:
--name
: Timer name.--cron-expression
: Function invocation schedule specified as a cron expression.--payload
: Message to be delivered to the function if the timer triggers. The string length must not exceed 4,096 characters.
--invoke-function-id
: Function ID.--invoke-function-service-account-id
: Service account with rights to invoke the function.--retry-attempts
: Number of invocation retries before the trigger moves a message to the Dead Letter Queue. Optional parameter. The values may range from 1 to 5. The default value is 1.--retry-interval
: Time after which the function will be invoked again if the current attempt fails. Optional parameter. The values may range from 10 to 60 seconds. The default value is 10 seconds.--dlq-queue-id
: Dead Letter Queue ID. Optional parameter.--dlq-service-account-id
: Service account with the permission to write messages to the Dead Letter Queue. Optional parameter.
Result:
id: a1sfe084v4**********
folder_id: b1g88tflru**********
created_at: "2019-12-04T08:45:31.131391Z"
name: timer
rule:
timer:
cron_expression: 5 12 * * ? *
payload: <message>
invoke_function_with_retry:
function_id: d4eofc7n0m**********
function_tag: $latest
service_account_id: aje3932acd**********
retry_settings:
retry_attempts: "1"
interval: 10s
dead_letter_queue:
queue-id: yrn:yc:ymq:ru-central1:aoek49ghmk**********:dlq
service-account-id: aje3932acd**********
status: ACTIVE
Terraform
For more information about the provider resources, see the documentation on the Terraform
If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.
If you don't have Terraform, install it and configure the Yandex Cloud provider.
To create a trigger that launches a function:
-
In the configuration file, describe the trigger parameters:
-
name
: Timer name. The name format is as follows:- The name must be from 3 to 63 characters long.
- It may contain lowercase Latin letters, numbers, and hyphens.
- The first character must be a letter and the last character cannot be a hyphen.
-
description
: Trigger description. -
timer
: Trigger settings:cron_expression
: Function invocation schedule specified as a cron expression.payload
: Message to be delivered to the function if the timer triggers. The string length must not exceed 4,096 characters.
-
function
: Settings for the function, which will be activated by the trigger:id
: Function ID.
Here is an example of the configuration file structure:
resource "yandex_function_trigger" "my_trigger" { name = "<timer_name>" description = "<trigger_description>" timer { cron_expression = "* * * * ? *" payload = "<message>" } function { id = "<function_ID>" } }
For more information about resource parameters in Terraform, see the provider documentation
. -
-
Make sure the configuration files are correct.
-
In the command line, go to the directory where you created the configuration file.
-
Run a check using this command:
terraform plan
If the configuration is described correctly, the terminal will display a list of created resources and their parameters. If the configuration contains any errors, Terraform will point them out.
-
-
Deploy cloud resources.
-
If the configuration does not contain any errors, run this command:
terraform apply
-
Confirm creating the resources: type
yes
in the terminal and press Enter.All the resources you need will then be created in the specified folder. You can check the new resources and their configuration using the management console
or this CLI command:yc serverless trigger get <trigger_ID>
-
To create a timer, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.
Checking the result
Check that the trigger operates correctly. Do it by viewing function logs that present information on invocations.