Listify/Lambdas

Components

APIs

Contains logic to retrieve data from merchant APIs.

Lists

Contains client-facing Lambdas which are typically a rather thin wrapper over the database (MariaDB on AWS's RDS service) and other AWS services.

General Client-facing Serverside Flow

Client -> API Gateway endpoint -> Lambda  -> (same) API Gateway endpoint -> (same) Client
            |         .           |    .
           \ /       / \         \ /  / \
            '         |           '    |  
           AWS Cognito          MariaDB instance/Other AWS services(SES, Cognito)

Scraping

Contains logic to orchestrate runs using a scraping utility to collect merchant data and store it in the database

Common Troubleshooting

Logs

• Logs may be written to by printing to the stdout. (Fancier logging is also possible, but currently not implemented)
• Logs are avalaible on AWS's Cloudwatch under Log Groups -> {Lambda name}
• Logs typically persist after deletion of the associated Lambda

Incomplete runs

Often if a run fails to complete, it is because the standard allocated time and memory/cpu is inadaquate.

• Symptoms:
  • The running time (available in the Cloudwatch logs) is almost exactly the maximum time.
• Resolutions:
  • Time may be increased.
  • CPU may be increased. CPU is proportional to memory, so CPU is increased by increasing memory allocation.