fix(bedrock): improve region inference using boto3 client and support profile arg

Author: Ashutosh0x

src/anthropic/lib/bedrock/_client.py

@@ -67,7 +67,7 @@ def _prepare_options(input_options: FinalRequestOptions) -> FinalRequestOptions:
     return options
 
 
-def _infer_region() -> str:
+def _infer_region(aws_profile: str | None = None) -> str:
     """
     Infer the AWS region from the environment variables or
     from the boto3 session if available.
@@ -76,10 +76,19 @@ def _infer_region() -> str:
     if aws_region is None:
         try:
             import boto3
+            import botocore
 
-            session = boto3.Session()
+            session = boto3.Session(profile_name=aws_profile)
             if session.region_name:
                 aws_region = session.region_name
+            else:
+                # If the region is not in the session, it might be in the config file
+                # but not loaded because AWS_SDK_LOAD_CONFIG is not set.
+                # creating a client might trigger the loading.
+                try:
+                    aws_region = session.client("bedrock").meta.region_name
+                except botocore.exceptions.NoRegionError:
+                    pass
         except ImportError:
             pass
 
@@ -158,11 +167,10 @@ def __init__(
         _strict_response_validation: bool = False,
     ) -> None:
         self.aws_secret_key = aws_secret_key
-
         self.aws_access_key = aws_access_key
 
-        self.aws_region = _infer_region() if aws_region is None else aws_region
         self.aws_profile = aws_profile
+        self.aws_region = _infer_region(aws_profile) if aws_region is None else aws_region
 
         self.aws_session_token = aws_session_token
 
@@ -300,11 +308,10 @@ def __init__(
         _strict_response_validation: bool = False,
     ) -> None:
         self.aws_secret_key = aws_secret_key
-
         self.aws_access_key = aws_access_key
 
-        self.aws_region = _infer_region() if aws_region is None else aws_region
         self.aws_profile = aws_profile
+        self.aws_region = _infer_region(aws_profile) if aws_region is None else aws_region
 
         self.aws_session_token = aws_session_token