feat(bedrock): automatically infer AWS Region (#974)

Author: karpetrosyan

src/anthropic/lib/bedrock/_client.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import os
+import logging
 import urllib.parse
 from typing import Any, Union, Mapping, TypeVar
 from typing_extensions import Self, override
@@ -26,6 +27,8 @@
 from ...resources.messages import Messages, AsyncMessages
 from ...resources.completions import Completions, AsyncCompletions
 
+log: logging.Logger = logging.getLogger(__name__)
+
 DEFAULT_VERSION = "bedrock-2023-05-31"
 
 _HttpxClientT = TypeVar("_HttpxClientT", bound=Union[httpx.Client, httpx.AsyncClient])
@@ -64,6 +67,29 @@ def _prepare_options(input_options: FinalRequestOptions) -> FinalRequestOptions:
     return options
 
 
+def _infer_region() -> str:
+    """
+    Infer the AWS region from the environment variables or
+    from the boto3 session if available.
+    """
+    aws_region = os.environ.get("AWS_REGION")
+    if aws_region is None:
+        try:
+            import boto3
+
+            session = boto3.Session()
+            if session.region_name:
+                aws_region = session.region_name
+        except ImportError:
+            pass
+
+    if aws_region is None:
+        log.warning("No AWS region specified, defaulting to us-east-1")
+        aws_region = "us-east-1"  # fall back to legacy behavior
+
+    return aws_region
+
+
 class BaseBedrockClient(BaseClient[_HttpxClientT, _DefaultStreamT]):
     @override
     def _make_status_error(
@@ -135,9 +161,7 @@ def __init__(
 
         self.aws_access_key = aws_access_key
 
-        if aws_region is None:
-            aws_region = os.environ.get("AWS_REGION") or "us-east-1"
-        self.aws_region = aws_region
+        self.aws_region = _infer_region() if aws_region is None else aws_region
         self.aws_profile = aws_profile
 
         self.aws_session_token = aws_session_token
@@ -279,9 +303,7 @@ def __init__(
 
         self.aws_access_key = aws_access_key
 
-        if aws_region is None:
-            aws_region = os.environ.get("AWS_REGION") or "us-east-1"
-        self.aws_region = aws_region
+        self.aws_region = _infer_region() if aws_region is None else aws_region
         self.aws_profile = aws_profile
 
         self.aws_session_token = aws_session_token

tests/lib/test_bedrock.py

@@ -1,5 +1,7 @@
 import re
-from typing import cast
+import typing as t
+import tempfile
+from typing import TypedDict, cast
 from typing_extensions import Protocol
 
 import httpx
@@ -24,6 +26,41 @@ class MockRequestCall(Protocol):
     request: httpx.Request
 
 
+class AwsConfigProfile(TypedDict):
+    # Available regions: https://docs.aws.amazon.com/global-infrastructure/latest/regions/aws-regions.html#available-regions
+    name: t.Union[t.Literal["default"], str]
+    region: str
+
+
+def profile_to_ini(profile: AwsConfigProfile) -> str:
+    """
+    Convert an AWS config profile to an INI format string.
+    """
+
+    profile_name = profile["name"] if profile["name"] == "default" else f"profile {profile['name']}"
+    return f"[{profile_name}]\nregion = {profile['region']}\n"
+
+
+@pytest.fixture
+def profiles() -> t.List[AwsConfigProfile]:
+    return [
+        {"name": "default", "region": "us-east-2"},
+    ]
+
+
+@pytest.fixture
+def mock_aws_config(
+    profiles: t.List[AwsConfigProfile],
+    monkeypatch: t.Any,
+) -> t.Iterable[None]:
+    with tempfile.NamedTemporaryFile(mode="w+", delete=True) as temp_file:
+        for profile in profiles:
+            temp_file.write(profile_to_ini(profile))
+        temp_file.flush()
+        monkeypatch.setenv("AWS_CONFIG_FILE", str(temp_file.name))
+        yield
+
+
 @pytest.mark.filterwarnings("ignore::DeprecationWarning")
 @pytest.mark.respx()
 def test_messages_retries(respx_mock: MockRouter) -> None:
@@ -127,3 +164,34 @@ def test_application_inference_profile(respx_mock: MockRouter) -> None:
         calls[1].request.url
         == "https://bedrock-runtime.us-east-1.amazonaws.com/model/arn:aws:bedrock:us-east-1:123456789012:application-inference-profile%2Fjf2sje1c0jnb/invoke"
     )
+
+
+def test_region_infer_from_profile(
+    mock_aws_config: None,  # noqa: ARG001
+    profiles: t.List[AwsConfigProfile],
+) -> None:
+    client = AnthropicBedrock()
+    assert client.aws_region == profiles[0]["region"]
+
+
+@pytest.mark.parametrize(
+    "profiles, aws_profile",
+    [
+        pytest.param([{"name": "default", "region": "us-east-2"}], "default", id="default profile"),
+        pytest.param(
+            [{"name": "default", "region": "us-east-2"}, {"name": "custom", "region": "us-west-1"}],
+            "custom",
+            id="custom profile",
+        ),
+    ],
+)
+def test_region_infer_from_specified_profile(
+    mock_aws_config: None,  # noqa: ARG001
+    profiles: t.List[AwsConfigProfile],
+    aws_profile: str,
+    monkeypatch: t.Any,
+) -> None:
+    monkeypatch.setenv("AWS_PROFILE", aws_profile)
+    client = AnthropicBedrock()
+
+    assert client.aws_region == next(profile for profile in profiles if profile["name"] == aws_profile)["region"]

tests/lib/test_vertex.py

@@ -124,7 +124,7 @@ def test_global_region_base_url(self) -> None:
         client = AnthropicVertex(region="global", project_id="test-project", access_token="fake-token")
         assert str(client.base_url).rstrip("/") == "https://aiplatform.googleapis.com/v1"
 
-    @pytest.mark.parametrize('region', ["us-central1", "europe-west1", "asia-southeast1"])
+    @pytest.mark.parametrize("region", ["us-central1", "europe-west1", "asia-southeast1"])
     def test_regional_base_url(self, region: str) -> None:
         """Test that regional endpoints use the correct base URL format."""
         client = AnthropicVertex(region=region, project_id="test-project", access_token="fake-token")
@@ -138,7 +138,7 @@ def test_env_var_base_url_override(self, monkeypatch: pytest.MonkeyPatch) -> Non
         monkeypatch.setenv("ANTHROPIC_VERTEX_BASE_URL", test_url)
 
         client = AnthropicVertex(
-            region="global", # we expect this to get ignored since the user is providing a base_url
+            region="global",  # we expect this to get ignored since the user is providing a base_url
             project_id="test-project",
             access_token="fake-token",
             base_url="https://test.googleapis.com/v1",
@@ -270,7 +270,7 @@ def test_env_var_base_url_override(self, monkeypatch: pytest.MonkeyPatch) -> Non
         monkeypatch.setenv("ANTHROPIC_VERTEX_BASE_URL", test_url)
 
         client = AsyncAnthropicVertex(
-            region="global", # we expect this to get ignored since the user is providing a base_url
+            region="global",  # we expect this to get ignored since the user is providing a base_url
             project_id="test-project",
             access_token="fake-token",
             base_url="https://test.googleapis.com/v1",