Serverless Web App Real-Time Data Broadcasting
Publication date: March 24, 2021 (Diagram history)
This architecture shows how to create a movie voting application using AWS AppSync, AWS Lambda, AWS Step Functions, and Amazon DynamoDB. You can use backend and client-facing real-time broadcasting with managed GraphQL subscriptions over WebSockets.
Serverless Web App Real-Time Data Broadcasting
The following steps describe the architecture:
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Amazon CloudWatch Events initiates a workflow in Step Functions every 60 seconds.
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Step Functions triggers Lambda every 10 seconds.
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Lambda calls The Movie DB API to retrieve metadata for a single random movie from the most popular movies list.
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Lambda updates the Movie table, zeroes current votes, and upvotes the leaderboard in the Votes table through GraphQL mutations to AppSync.
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AppSync updates the Movie table in DynamoDB with the single current movie retrieved from Lambda.
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All connected clients subscribed to the backend mutation see the same current movie poster and synopsis on screen through the broadcast.
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Clients vote on the current movie during a 10-second window, and can send and receive chat messages in a public chatroom.
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Lambda updates the leaderboard and client movie votes through AppSync mutations.
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The public chatroom displays current messages on a pub/sub channel through Local Resolver. Messages are not persisted on backend storage, and only new messages are displayed.
Further reading
For additional information, refer to the following resources:
Diagram history
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| Change | Description | Date |
|---|---|---|
Initial publication | Reference architecture diagram first published. | March 24, 2021 |
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