feat(bedrock): automatically infer AWS Region in Bedrock clients

[karpetrosyan]

closes #892 and #537

[dtmeadows]

This overall LGTM @karpetrosyan! Could we just remove the workflow change before merging?

[dtmeadows]

mind removing this before merging?

[karpetrosyan]

yes, sure!

[karpetrosyan]

done

[karpetrosyan]

@dtmeadows fyi, seems like I can't merge this

[dtmeadows]

@michael-cohen-io mind reviewing and merging this when you get a sec?

[RobertCraigie]

actually do you know if this can make fs calls?

[karpetrosyan]

I don't fully understand what 'making fs calls' means. It has access to the standard library, which I assume it uses to read the AWS config file.

[RobertCraigie]

ah sorry, yeah I meant "does it call blocking IO functions" which if it does we should try and call it asynchronously...

but that might be difficult?

[karpetrosyan]

It definitely does, but I think it's okay. It won't block the event loop repeatedly—just once during initialization

[RobertCraigie]

users may instantiate the client in their business logic inside async functions so I think it is somewhat important unfortunately.

if wrapping this in async is too annoying, I think for now we could cache the boto3.Session object?

[karpetrosyan]

if wrapping this in async is too annoying, I think for now we could cache the boto3.Session object?

In that case, users with an async codebase will still be blocked the first time they call it — am I getting that right? Honestly, I don't think it's worth doing anything about. Many clients block for a few milliseconds during initialization. For example, httpx.AsyncClient takes around 50-150ms to create (which means the event loop is blocked for that time), while boto3.Session() blocks for just 5ms. Programmers should avoid creating such objects inside a (for/while) loop — that would kill performance anyway (they're supposed to be created once). So if it's done only once, is a 5ms delay really that critical?

you can check setup time with this script:

# /// script
# requires-python = ">=3.9"
# dependencies = [
#     "boto3",
#     "httpx",
# ]
# ///

import boto3
import time
import httpx

t1 = time.monotonic_ns()
boto3.Session()
t2 = time.monotonic_ns()

print(f"boto3 Time taken: {(t2 - t1) / 1_000_000} ms")

t1 = time.monotonic_ns()
httpx.Client()
t2 = time.monotonic_ns()

print(f"httpx Time taken: {(t2 - t1) / 1_000_000} ms")