AccountStream

Overview

AccountStream streams updated account information to our contact discovery service. It pulls information from two places:

• The DynamoDB accounts table
• A filtered stream of DynamoDB updates

As AccountStream streams data down to a client, it also streams down continuation tokens regularly. A client may request a new stream with a previous continuation token, and in so doing only receive updates from when that continuation token was initially provided to them.

See the GRPC streaming service at src/main/proto/accountstream.proto for the specific interface.

This system relies on an AWS lambda (code in the filter-cds-updates subdirectory), which receives a DynamoDB update stream from the Accounts table and filters out just the subset of updates that contact discovery would find useful. It drops those into a Kinesis stream, which AccountStream pulls from.

Should a client not have a continuation token, it will receive all relevant account records, then a continuous set of updates. AccountStream's GRPC streams will never willingly close; a connected client will receive updates ad infinitum. Only a client close or a server error will cause the stream to stop.

Building

AccountStream is a Micronaut process. It can be locally built with

mvn clean verify

and locally run with

mvn mn:run

Lambda can be built/tested with

cd filter-cds-updates
mvn clean verify