Should IoT things be used as an AppSync data source?

Question

Our system has IoT things (devices), and a web frontend in Amplify.
An example user story in the browser: "Search for a device by the county it belongs to, then show all telemetry readings created by this device."

For storage, the *county* could be an Attribute on the Thing. *Telemetry readings* could be DynamoDB Items in a Table.

It would seem that the solution would be an AppSync query layer which queries both DynamoDB, and a custom lambda which queries the IoT registry.

Questions: 
Is splitting data sources an antipattern? It feels like leveraging the IoT registry for business logic queries isn't intended.

Is there a better AppSync resolver strategy? I don't like adding extra layers that require maintenance and monitoring. In this case, the lambda to translate queries and the AppSync queries.

This feels like it should be a very common scenario, but I haven't found solutions for dynamic data access to IoT things in an application.

cloudyy · Accepted Answer

I agree with you - splitting data sources (DynamoDB and IoT registry) with AppSync and a Lambda function is not necessarily an anti-pattern, but it can add complexity. Potential Performance Impact.

Alternative Solution Options:

**1/ AWS IoT Core Thing Groups**

Leverage AWS IoT Core Thing Groups to categorize devices by county (attribute).
 
Store telemetry readings directly in DynamoDB with a foreign key referencing the Thing Group (county).
 
Use AppSync resolvers to directly query DynamoDB based on county (Thing Group) and filter telemetry readings for the specific device ID.

Cons : Requires additional configuration and management of Thing Groups.

2/ Or Maybe

Combine Thing Groups for coarse-grained filtering by county.

Use GSIs(Global Secondary Indexes) within DynamoDB for efficient retrieval of specific device telemetry data.

Remember, there's no one-size-fits-all solution.

Evaluate your specific needs and choose the approach that offers the best balance between simplicity, performance, and cost.

Should IoT things be used as an AppSync data source?

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