Reducing Messaging Costs with Basic Ingest

Basic Ingest enables you to securely send device data to the AWS services supported by AWS IoT Rule Actions without incurring messaging costs. Basic Ingest optimizes data flow by removing the publish/subscribe message broker from the ingestion path, so it's more cost effective.

To use Basic Ingest, you send messages from your devices or applications with topic names that start with $aws/rules/rule-name as their first three levels, where rule-name is the name of your AWS IoT rule to trigger.

You can use an existing rule with Basic Ingest simply by adding the Basic Ingest prefix ($aws/rules/rule-name) to the message topic by which you normally trigger the rule. For example, if you have a rule named BuildingManager that is triggered by messages with topics like Buildings/Building5/Floor2/Room201/Lights ("sql": "SELECT * FROM 'Buildings/#'"), you can trigger the same rule with Basic Ingest by sending a message with topic $aws/rules/BuildingManager/Buildings/Building5/Floor2/Room201/Lights.

Be aware that:

• Your devices and rules cannot subscribe to Basic Ingest reserved topics. For more information, see Reserved Topics.

• If you need a publish/subscribe broker to distribute messages to multiple subscribers (for example, to deliver messages to other devices and the rules engine), you should continue to use the AWS IoT message broker to handle the message distribution. Just publish your messages on topics other than Basic Ingest topics.

Using Basic Ingest

Make sure your device or application is using a policy that has publish permissions on $aws/rules/*. Or you can specify permission for individual rules with $aws/rules/rule-name/* in the policy. Otherwise, your devices and applications can continue to use their existing connections with AWS IoT Core.

When the message reaches the rules engine, there is no difference in execution or error handling between rules triggered from Basic Ingest and those triggered through message broker subscriptions.

You can, of course, create rules for use with Basic Ingest. Keep in mind the following:

• The initial prefix of a Basic Ingest topic ($aws/rules/rule-name) isn't available to the topic(Decimal) function.

• If you define a rule that is triggered only with Basic Ingest, the FROM clause is optional in the sql field of the rule definition. It's still required if the rule is also triggered by other messages that must be sent through the message broker (for example, because those other messages must be distributed to multiple subscribers). For more information, see AWS IoT SQL Reference.

• The first three levels of the Basic Ingest topic ($aws/rules/rule-name) are not counted toward the eight segment length limit or toward the 256 total character limit for a topic. Otherwise, the same restrictions apply as documented in AWS IoT Limits.

• If a message is received with a Basic Ingest topic that specifies an inactive rule or a rule that doesn't exist, an error log is created in an Amazon CloudWatch log to help you with debugging. For more information, see Rules Engine Logs. A RuleNotFound metric is indicated and you can create alarms on this metric. For more information, see Rule Metrics in AWS IoT Metrics.

• You can still publish with QoS 1 on Basic Ingest topics. You receive a PUBACK after the message is successfully delivered to the rules engine. Receiving a PUBACK does not mean that your rule actions were completed successfully. You can configure an error action to handle errors during action execution. See Error Handling (Error Action).