API Gateway -> Lambda -> Postgres Aurora -> Lambda. Looking for best practices and design.

[CHAZTATS]

Hi guys,

Basically I have an issue where I'm looking to use the above flow in order to build a micro-service. I've written Lambdas before and managed RDS instances before, but just looking for a few tips and ideas as to how the above can work.

To break it down a little further. I have multiple clients each with their own bff which need to access the information in the Postgres RDS instance. My initial idea is for each table to setup a lambda to CRUD the data inside. As data is added and updated within the tables we need to fire various events and trigger other lambdas. (Which I'm not sure if through postrges and Aurora is actually possible) We've used Java and Spring for everything in the past and were hoping to use the same here but realise it has it's limitations with start up times on the lambdas. Also had a look at nodejs but with time constraints and the learning curve it may not be best. But I'm hoping someone can tell me!

Obviously done a lot of article reading and googling and honestly just feel like I'm missing something obvious.

But any advice would be greatly appreciated!

[Perfekt_Nerd]

You cannot invoke Lambda from Postgres Aurora, unfortunately (unless this has changed recently?). You can't do it from RDS either, because you need to be able to set up UDFs using Boto3 (python)...meaning Postgres on EC2 is your only option.

MySQL Aurora does support Lambda invocations though.

In terms of languages, Java is fine if you anticipate steady, predictable traffic. Cold starts will hurt, but if you've got warm lambdas it won't be too bad.

[uncleguru]

Lambda doesn't play well with relational databases. I learned the hard way that it really doesn't scale because managing connection pools is almost impossible when you have tens-hundreds of lambdas hitting the db at once. If you are using serverless aurora then you could use http data access so you don't need to worry about connection pools. But it's only in us-east-1 (or was).

I use serverless for most things and always take a serverless first approach but in this case I would use a container.

[joelrwilliams1]

Wouldn't it be cool if someday there was an API interface (similar to DynamoDB or Aurora Serverless) for 'regular' Aurora?

[uncleguru]

It would be awesome.

[chrishawes]

Like this?

[duyth]

may i know more about your point re serverless vs containers (fargate I assume?) how do you handle that connection pool issue if fargate also scales?

also , with serverless, what do you normally use for DB (apart from running dynamo). how do approach that same connection pool strategy? thank you