Lambda has a long way to go, it's a promising product but if you want to develop anything for it, it's a bit painful and archaic.

I've had issues with the temp memory. It is completely unreliable, you have to store files when processing in /tmp/ and for whatever reason, reading from this results is patchy. I had to resort to storing every file I process in the RAM.

The tooling is only just taking off now, 6 months ago simulation was painful, at least there is AWS SAM now and docker support.

However despite the pain, it's giving me a solution for scalable video encoding that is very cost competitive and I don't have to worry about submitting jobs and monitoring resources.