LocalStack DynamoDB Stream to Lambda

An example .NET Core Lambda consuming a DynamoDB Stream. Runs in LocalStack on Docker.

Usage

Requires .NET Core 2.1, Docker, Docker Compose, the aws cli (or awslocal) and 7Zip on the path if using Windows.

Build and Zip the Lambda

Linux

dotnet publish src/LocalDynamoDbStream
zip -rj function.zip src/LocalDynamoDbStream/bin/Debug/netcoreapp2.1/publish

Windows

dotnet publish src/LocalDynamoDbStream
7z a -tzip function.zip ./src/LocalDynamoDbStream/bin/Debug/netcoreapp2.1/publish/*

Create the Local Infrastructure

Start LocalStack and wait for the provisioning to complete.

docker-compose up

Put an Item into the DynamoDB Table

aws --endpoint-url=http://localhost:4569 dynamodb put-item \
    --table-name local-table \
    --item Id={S="key1"},Value={S="value1"}

Get the CloudWatch Logs for the Lamda Invocation

Note that CloudWatch Logs do not appear to be working from Windows hosts (see here).

aws --endpoint-url=http://localhost:4586 logs filter-log-events \
    --log-group-name /aws/lambda/local-function

Update the Lambda Code

If you have made changes to the Lambda and want to update the existing version, first use the commands above to re-publish and zip, then replace the function using the following.

aws --endpoint-url=http://localhost:4574 lambda update-function-code \
    --function-name local-function \
    --zip-file fileb://function.zip