Creating a trigger for a broker topic
Create a trigger for a Yandex IoT Core broker topic and process message copies using a function in Cloud Functions.
Warning
The trigger must be in the same cloud as the broker whose topic it reads messages from.
Getting started
To create a trigger, you will need:
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Function the trigger will invoke. If you do not have a function:
-
Optionally, a dead-letter queue where to redirect the messages the function failed to process. If you do not have a queue, create one.
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Service accounts with permissions to invoke the function and, optionally, write 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.
- Broker whose topic the trigger will receive message copies from. If you do not have a broker, create one.
Creating a trigger
Note
The trigger is initiated within five minutes after it is created.
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In the management console, select the folder where you want to create a trigger.
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Go to Cloud Functions.
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In the left-hand panel, select Triggers.
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Click Create trigger.
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Under Basic settings:
- Enter a name and description for the trigger.
- In the Type field, select
IoT Core (broker). - In the Launched resource field, select
Function.
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Under IoT Core message settings:
- In the Broker field, specify the broker.
- Optionally, in the MQTT topic field, specify an MQTT topic. If no MQTT topic is set, the trigger fires for all broker topics.
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Under Batch message settings, specify:
- Waiting time, s. The values may range from 1 to 60 seconds. The default value is 1 second.
- Batch size. The values may range from 1 to 100. The default value is 1.
The trigger groups messages within the specified wait time period and sends them to the function. The number of messages cannot exceed the specified batch size.
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Under Function settings, select a function and specify:
- Function version tag.
- Service account to use for invoking the function.
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Optionally, under Repeat request settings:
- In the Interval field, specify how long to wait before retrying the function if it 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 function retries before the trigger sends a message to the dead letter queue. The values may range from 1 to 5. The default value is 1.
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Optionally, under Dead Letter Queue settings, select a dead-letter queue and a service account with write permissions for that queue.
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Click Create trigger.
If you do not have the Yandex Cloud CLI yet, install and initialize it.
The folder used by default is the one specified when creating the CLI profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also specify a different folder for any command using --folder-name or --folder-id. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.
To create a trigger that invokes a function, run this command:
yc serverless trigger create iot-broker \
--name <trigger_name> \
--broker-id <broker_ID> \
--mqtt-topic '<MQTT_topic>' \
--batch-size <message_batch_size> \
--batch-cutoff <maximum_wait_time> \
--invoke-function-id <function_ID> \
--invoke-function-service-account-id <service_account_ID> \
--retry-attempts <number_of_retry_attempts> \
--retry-interval <interval_between_retry_attempts> \
--dlq-queue-id <dead-letter_queue_ID> \
--dlq-service-account-id <service_account_ID>
Where:
--name: Trigger name.--broker-id: Broker ID.--mqtt-topic: MQTT topic you want to create a trigger for. This is an optional setting. If you skip it, the trigger will fire for all broker topics.
--batch-size: Size of the message batch from MQTT topics. This is an optional parameter. The values may range from 1 to 10. The default value is 1.--batch-cutoff: Maximum waiting time. This is an optional parameter. The values may range from 1 to 60 seconds. The default value is 1 second. The trigger groups messages for a period not exceedingbatch-cutoffand sends them to a function. The number of messages cannot exceedbatch-size.
--invoke-function-id: Function ID.--invoke-function-service-account-id: ID of the service account with permissions to invoke the function.--retry-attempts: Number of invocation retries before the trigger sends a message to the dead-letter queue. This is an optional setting. The values may range from 1 to 5. The default value is 1.--retry-interval: Time to wait before retrying the function if it fails. This is an optional setting. The values may range from 10 to 60 seconds. The default value is 10 seconds.--dlq-queue-id: Dead-letter queue ID. This is an optional setting.--dlq-service-account-id: ID of the service account with write permissions for the dead-letter queue. This is an optional setting.
Result:
id: a1sl0mkmimfj********
folder_id: b1g88tflru0e********
created_at: "2019-09-25T13:54:35.654935Z"
name: iot-broker-trigger
rule:
iot_broker_message:
broker_id: arenou2oj4**********
mqtt_topic: topic-for-broker
batch_settings:
size: "1"
cutoff: 0s
invoke_function:
function_id: d4eofc7n0m03********
function_tag: $latest
service_account_id: aje3932acd0c********
retry_settings:
retry_attempts: "1"
interval: 10s
status: ACTIVE
To create a trigger for Yandex IoT Core, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.
Checking the result
Check that the trigger works correctly. To do this, view function logs that show information on invocations.