Hosted AspNetCoreServer with BackgroundService?

[lucasteles]

Can I run the AspNetCoreServer lambda with a BackgroundService (IHostedService)?

If yes, what would this imply?

[normj]

You technically could but the IHostedService would only run while a request is being processed. As soon as the request is complete the the Lambda compute environment would be frozen and there is no guarantees it would ever be unfrozen. For example Lambda could terminated the Lambda compute environment and spin up a new environment for the next event. So running an IHostedService in a Lambda ASP.NET Core function has limited usefulness.

[lucasteles]

@normj this is what I was expecting...
Maybe would be better to have Eventbrite or SNS call an URL of my API?

Is there a way to define a handler for them even using minimal API AspNetCoreServer.Hosting ?

[lucasteles]

In other words.

Is possible to have other events handlers inside an AspNetCoreServer Lambda with minimal API?

Something like builder.Services.AddAWSLambdaHandler<CloudWatchEvent<object>>( (input, context) => { ... })

[normj]

It sounds like you want a background service running all of the time. If that is your need Lambda probably isn't the best fit and you should run it as a Fargate container or something. Lambda is great for event based work loads like HTTP requests.

[rajeshaz09]

@normj
I have one initialisation scenario.

During initialisation, I am preparing common objects to avoid doing same for each and every request. Initialisation contains following items

1. Get 6 files from S3 - static content
2. Get data from database - one database call - call every 15 minutes to update
3. Get access_token - Refresh every 25 minutes before access_token expires. I need to make live call to another service to get data. I can't use SQS. Only specific Api need access_token.

My idea is

1. Use BackgroundService (IHostedService) for initialisation.
2. Wait until starting initialisation finished in request pipeline. During cold start or Whenever AWS decide to start new environment for lambda function, may be initial couple of requests takes some time. Thats ok for me.
3. Only starting initialisation is important for me. Subsequent refresh can be delayed.

I have following questions.

1. What happens when lambda environment unfrozen? does HostedService's resume?
2. Am i insane :) any other alternative which i couldn't able to think :(

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Hello! Reopening this discussion to make it searchable.