Serverless Node lambdas (PatchLambdaFunction and BulkUpdateFunction) for patching DynamoDB data.

• node v18.16.0
• Docker
• SAM CLI

1. Follow build steps in hvt-data to prepare local dataset
2. npm i
3. cp .env.development .env
4. npm run build:dev
5. npm run start:dev
6. Send an HTTP request to the lambda's URI (curl --request PUT http://localhost:3001/<DYNAMODB_TABLE_NAME>/<ITEM_ID>?keyName=<ITEM_KEYNAME> \--header 'Content-Type: application/json' \--data-raw '{"test":"test"}')
   • E.G. ITEM_ID=c6af9ab6-7b62-11ed-9ae1-93e8dgadbdef, ITEM_KEYNAME=id

1. Run lambdas in debug mode: npm run start:dev -- -d 5858
2. Add a breakpoint to the lambda being tested (src/handler/patfch.ts)
3. Run the debug config from VS Code that corresponds to lambda being tested (GetLambdaFunction)
4. Send an HTTP request to the lambda's URI (curl --request PUT http://localhost:3001/<DYNAMODB_TABLE_NAME>/<ITEM_ID>?keyName=<ITEM_KEYNAME> \--header 'Content-Type: application/json' \--data-raw '{"test":"test"}')
   • E.G. ITEM_ID=c6af9ab6-7b62-11ed-9ae1-93e8dgadbdef, ITEM_KEYNAME=id

• The Jest framework is used to run tests and collect code coverage
• To run the tests, run the following command within the root directory of the project: npm test
• Coverage results will be displayed on terminal and stored in the coverage directory
  • The coverage requirements can be set in jest.config.js

1. npm i
2. add environment variables to .env
3. npm run build:prod
4. to build with commit id
5. npm run build:prod -- --emv.commit=<commit-hash>
6. Zip file can be found in ./dist/

By using a utility wrapper (src/util/logger) surrounding console.log, the awsRequestId and a "correlation ID" is output with every debug/info/warn/error message.

For this pattern to work, every service/lambda must forward their correlation ID to subsequent services via a header e.g. X-Correlation-Id.

In practice, the first lambda invoked by an initial request will not have received the X-Correlation-Id header, so its correlationId gets defaulted to its lambdaRequestId. This correlationId should then be used when invoking subsequent lambdas via the X-Correlation-Id header. Every lambda called subsequently will then check for that X-Correlation-Id header and inject it into their logs.

This shows an example of what the log looks like from the first invoked lambda:

2020-09-10T17:03:04.891Z	5ff37fce-5ace-114c-9120-a1406cc8d11d	INFO	{"apiRequestId":"c6af9ac6-7b61-11e6-9a41-93e8deadbeef","correlationId":"5ff37fce-5ace-114c-9120-a1406cc8d11d","message":"Here's a gnarly info message from lambda 1 - notice how my correlationId has been set to my lambdaRequestId?"}

This shows an example of what the logs look like from the second invoked lambda (called via the first lambda):

2020-09-10T17:05:31.627Z	32ff455b-057d-1dd7-98b8-7034bf182dc8	INFO	{"apiRequestId":"d9222e0a-6bd9-49e0-84dd-ffe0680bd141","correlationId":"5ff37fce-5ace-114c-9120-a1406cc8d11d","message":"Here's a gnarly info message from lambda 2 - notice how my correlationId is the same as the lambda 1"}