Description
Dear Developers,
I created an example for s3:
peterborkuti@dbc5d3d
It works, but as I read aws best practices for lambda:
https://docs.aws.amazon.com/lambda/latest/dg/best-practices.html
"Initialize SDK clients and database connections outside of the function handler"
I could not do it (I am absolute beginner in Rust but I have solid knowledge in Java and JavaScript)
What I tried
creating static/const but client creation is async
const client: Client = get_client().await;
static mut
static mut client : Option<Client> = None;
...
// in main:
client = Some(get_client().await); // but it is unsafe
using lambdas context in main
pub(crate) async fn function_handler<F1, Fut1, F2, Fut2>(fn_get_file: F1, fn_put_file: F2, event: LambdaEvent<S3Event>) -> Result<(), Error>
where
F1: Fn(&str, &str) -> Fut1,
Fut1: Future<Output = Option<Cursor<Vec<u8>>>>,
F2: Fn(&str, &str, ByteStream) -> Fut2,
Fut2: Future<Output = ()>
{
(With the above handler testing would be very easy, I think, because the client is "embedded" in the fn_get_file and fn_put_file functions, so when testing we do not need sdk client at all)
in main I tried to binding the client parameters to fn_get_file and fn_put_file:
let client = get_client().await;
let clientRef = |x:Client| &x;
let clientBroker = move || clientRef(client);
let fn_get_file = move |bucket: &str, key: &str| get_file(&clientBroker(), bucket, key);
let fn_put_file = |bucket: &str, key: &str, bytes: ByteStream| put_file(&clientBroker(), bucket, key, bytes);
let fn_function_handler = |event: LambdaEvent<S3Event>| function_handler(fn_get_file, fn_put_file, event);
run(service_fn(fn_function_handler)).await
First I had lifetime issues (tried to solve with "move" and now I got:"expected a closure that implements the Fn trait, but this closure only implements FnOnce":
Do you have any ideas how to do it?
Thank you in advance
Péter