CODEWITHSUNDEEP
amazon-web-servicesaws-lambdaserverless
trinth
trinth

Reputation: 6047

Do event notifications get lost during lambda function update?

I have a Lambda function that listens to S3 create requests. If I update the function, is there a brief amount of time where I am losing S3 notifications or do events continue to be served by the old version of the function?

If they are being lost, is there a recommended way to deal with the transition so events don't get lost?

Upvotes: 1

Views: 223

Answers (1)

Lex
Lex

Reputation: 5014

The old version continues to run until the new version is up. No traffic/requests will be lost. Multiple lambda are stored allowing you to rollback.

When a function update request is made (even without a specific function version) an alias is created with an ARN and deployed then $LATEST is swapped to point to the new version.

A point of interest: You can actually slowly migrate your new lambda over with Traffic Shifting Allowing you to monitor your new function with a subset of production traffic until you gain confidence to roll it out all the way.

Upvotes: 3

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