Create a trigger for Message Queue that sends messages to the Cloud Functions function
Create a trigger for a message queue in Message Queue and process the messages using the Cloud Functions function.
Warning
- You can only create a trigger for a standard message queue.
- The trigger must be in the same cloud as the queue from which it reads messages.
- Only one trigger can be created for each message queue.
Getting started
To create a trigger, you need:
-
A function to be invoked by the trigger. If you do not have a function:
-
Service accounts with the following permissions:
- To invoke a function.
- To read from the queue the trigger receives messages from.
You can use the same service account or different ones. If you do not have a service account, create one.
-
Message queue the trigger will collect messages from. If you do not have a queue, 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 a trigger. -
Select Cloud Functions.
-
In the left-hand panel, select
Triggers. -
Click Create trigger.
-
Under Basic settings:
- Enter a name and description for the trigger.
- In the Type field, select Message Queue.
- In the Launched resource field, select Function.
-
Under Message Queue message settings, select a message queue and a service account with permissions to read messages from this queue.
-
Under Batch message settings, specify:
- Waiting time, s. The values may range from 0 to 20 seconds. The default value is 10 seconds.
- Batch size. The values may range from 1 to 1,000. The default value is 1.
The trigger groups messages for a period of time not exceeding the specified timeout and sends them to a function. The number of messages cannot exceed the specified batch size.
-
Under Function settings, select a function and specify:
- Function version tag.
- Service account to invoke the function under.
-
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 message-queue \
--name <trigger_name> \
--queue <queue_ID> \
--queue-service-account-id <service_account_ID> \
--invoke-function-id <function_ID> \
--invoke-function-service-account-id <service_account_ID> \
--batch-size <message_group_size> \
--batch-cutoff <maximum_timeout>
Where:
-
--name
: Trigger name. -
--queue
: Queue IDTo find out the queue ID:
- In the management console
, go the folder containing the queue. - Select Message Queue.
- Select the queue.
- You can see the queue ID under General information in the ARN field.
- In the management console
-
--invoke-function-id
: Function ID. -
--queue-service-account-name
: ID of the service account with permissions to read messages from the queue. -
--invoke-function-service-account-id
: ID of the service account with the permissions to invoke the function. -
--batch-size
: Message batch size. This is an optional parameter. The values may range from 1 to 1,000. The default value is 1. -
--batch-cutoff
: Maximum wait time. This is an optional parameter. The values may range from 0 to 20 seconds. The default value is 10 seconds. The trigger groups messages for a period not exceedingbatch-cutoff
and sends them to a function. The number of messages cannot exceedbatch-size
.
Result:
id: dd0cspdch6**********
folder_id: aoek49ghmk**********
created_at: "2019-08-28T12:14:45.762915Z"
name: ymq-trigger
rule:
message_queue:
queue_id: yrn:yc:ymq:ru-central1:aoek49ghmk**********:my-mq
service_account_id: bfbqqeo6jk**********
batch_settings:
size: "1"
cutoff: 10s
invoke_function:
function_id: b09e5lu91t**********
function_tag: $latest
service_account_id: bfbqqeo6j**********
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 for Message Queue:
-
In the configuration file, describe the trigger parameters:
resource "yandex_function_trigger" "my_trigger" { name = "<trigger_name>" description = "<trigger_description>" function { id = "<function_ID>" service_account_id = "<service_account_ID>" } message_queue { queue_id = "<queue_ID>" service_account_id = "<service_account_ID>" batch_size = "<message_group_size>" batch_cutoff = "<maximum_timeout>" }
Where:
-
name
: Trigger 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. -
function
: Function parameters:id
: Function ID.service_account_id
: ID of the service account with the permissions to invoke the function.
-
message_queue
: Trigger parameters:-
queue_id
: Message queue ID.To find out the queue ID:
- In the management console
, go the folder containing the queue. - Select Message Queue.
- Select the queue.
- You can see the queue ID under General information in the ARN field.
- In the management console
-
service_account_id
: ID of the service account with permissions to read messages from the queue. -
batch_size
: Message batch size. This is an optional parameter. The values may range from 1 to 1,000. The default value is 1. -
batch_cutoff
: Maximum wait time. This is an optional parameter. The values may range from 0 to 20 seconds. The default value is 10 seconds. The trigger groups messages for a period not exceedingbatch-cutoff
and sends them to a function. The number of messages cannot exceedbatch-size
.
-
For more information about the
yandex_function_trigger
resource parameters, see the provider documentation . -
-
Create resources:
-
In the terminal, change to the folder where you edited the configuration file.
-
Make sure the configuration file is correct using the command:
terraform validate
If the configuration is correct, the following message is returned:
Success! The configuration is valid.
-
Run the command:
terraform plan
The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.
-
Apply the configuration changes:
terraform apply
-
Confirm the changes: type
yes
in the terminal and press Enter.
Terraform will create all the required resources. You can check the new resources using the management console
or this CLI command:yc serverless trigger list
-
To create a trigger for Yandex Message Queue, 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.
Check that the number of enqueued messages is decreasing. To do this, view the queue statistics:
- In the management console
, select Message Queue. - Select the queue that you created the trigger for.
- Go to Monitoring. Check the Messages in the queue chart.