Aws-lambda-dotnet: Guidance for HttpClient life-cycle in Lambdas

[scionwest]

Microsoft recommends, for most use-cases, that you create a singleton of HttpClient, configure it and share it for the life-cycle of the app, or Http request in some cases.

How do Lambda's work in regards to this? Each time my Lambda fires (regardless if cold/warm) is it the same process running each time or a new dotnet process? If it's a new dotnet process each time then I can safely just instantiate and dispose of the HttpClient because it's only used once through-out the life-cycle of the Lambda. If the same process is re-used (with the handler invoked multiple times) then I need to handle the life-cycle of my HttpClient differently.

Any guidance on how we should treat the usage of HttpClient in Lambda's would be appreciated.

[normj]

Here is my talk from NDC Minnesota last month. If you skip ahead to about 2:40 into I go through the lifecycle of a Lambda environment which will hopefully clear things up for you.

https://vimeo.com/271358846

[scionwest]

Answered my question, thanks!

[judedaryl]

This was so helpful! Although this is 2 years too late, Thanks! @normj

[az-oolloow]

Thanks @normj

For anyone who comes across this searching for answers - create a singleton HttpClient, it should survive a few invocations of events until such time that you had a long period of inactivity and Lambda destroys the environment running your code.