Ravi Sir's Cards › AWS
Avoid recursive S3 events
What is a VPC: your own private network inside one AWS Region, example ThreeTierVpc 10.0.0.0/16.
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What this card says
Why do we need it?
If Lambda writes a thumb into the same prefix it listens on, every write fires another invoke forever.
What is it?
Guard: only process keys under uploads/ (or skip any key starting with thumbs/). Write thumbs elsewhere.
How to do it
Event notification prefix uploads/. In code: if key.startswith("thumbs/"): return. Dest prefix THUMB_PREFIX=thumbs/.
thumbs/
Example
One upload creates exactly one thumb and one DynamoDB row — CloudWatch shows a single invoke.