community[minor]: add support for Guardrails for Amazon Bedrock (#15099)

Added support for optionally supplying 'Guardrails for Amazon Bedrock'
on both types of model invocations (batch/regular and streaming) and for
all models supported by the Amazon Bedrock service.

@baskaryan  @hwchase17

```python 
llm = Bedrock(model_id="<model_id>", client=bedrock,
                  model_kwargs={},
                  guardrails={"id": " <guardrail_id>",
                              "version": "<guardrail_version>",
                               "trace": True}, callbacks=[BedrockAsyncCallbackHandler()])

class BedrockAsyncCallbackHandler(AsyncCallbackHandler):
    """Async callback handler that can be used to handle callbacks from langchain."""

    async def on_llm_error(
            self,
            error: BaseException,
            **kwargs: Any,
    ) -> Any:
        reason = kwargs.get("reason")
        if reason == "GUARDRAIL_INTERVENED":
           # kwargs contains additional trace information sent by 'Guardrails for Bedrock' service.
            print(f"""Guardrails: {kwargs}""")


# streaming 
llm = Bedrock(model_id="<model_id>", client=bedrock,
                  model_kwargs={},
                  streaming=True,
                  guardrails={"id": "<guardrail_id>",
                              "version": "<guardrail_version>"})
```

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/community/tests/integration_tests/llms/test_bedrock.py

@@ -0,0 +1,136 @@
+"""
+Test Amazon Bedrock API wrapper and services i.e 'Guardrails for Amazon Bedrock'.
+You can get a list of models from the bedrock client by running 'bedrock_models()'
+
+"""
+
+import os
+from typing import Any
+
+import pytest
+from langchain_core.callbacks import AsyncCallbackHandler
+
+from langchain_community.llms.bedrock import Bedrock
+
+# this is the guardrails id for the model you want to test
+GUARDRAILS_ID = os.environ.get("GUARDRAILS_ID", "7jarelix77")
+# this is the guardrails version for the model you want to test
+GUARDRAILS_VERSION = os.environ.get("GUARDRAILS_VERSION", "1")
+# this should trigger the guardrails - you can change this to any text you want which
+# will trigger the guardrails
+GUARDRAILS_TRIGGER = os.environ.get(
+    "GUARDRAILS_TRIGGERING_QUERY", "I want to talk about politics."
+)
+
+
+class BedrockAsyncCallbackHandler(AsyncCallbackHandler):
+    """Async callback handler that can be used to handle callbacks from langchain."""
+
+    guardrails_intervened = False
+
+    async def on_llm_error(
+        self,
+        error: BaseException,
+        **kwargs: Any,
+    ) -> Any:
+        reason = kwargs.get("reason")
+        if reason == "GUARDRAIL_INTERVENED":
+            self.guardrails_intervened = True
+
+    def get_response(self):
+        return self.guardrails_intervened
+
+
+@pytest.fixture(autouse=True)
+def bedrock_runtime_client():
+    import boto3
+
+    try:
+        client = boto3.client(
+            "bedrock-runtime",
+            region_name=os.environ.get("AWS_REGION", "us-east-1"),
+        )
+        return client
+    except Exception as e:
+        pytest.fail(f"can not connect to bedrock-runtime client: {e}", pytrace=False)
+
+
+@pytest.fixture(autouse=True)
+def bedrock_client():
+    import boto3
+
+    try:
+        client = boto3.client(
+            "bedrock",
+            region_name=os.environ.get("AWS_REGION", "us-east-1"),
+        )
+        return client
+    except Exception as e:
+        pytest.fail(f"can not connect to bedrock client: {e}", pytrace=False)
+
+
+@pytest.fixture
+def bedrock_models(bedrock_client):
+    """List bedrock models."""
+    response = bedrock_client.list_foundation_models().get("modelSummaries")
+    models = {}
+    for model in response:
+        models[model.get("modelId")] = model.get("modelName")
+    return models
+
+
+def test_claude_instant_v1(bedrock_runtime_client, bedrock_models):
+    try:
+        llm = Bedrock(
+            model_id="anthropic.claude-instant-v1",
+            client=bedrock_runtime_client,
+            model_kwargs={},
+        )
+        output = llm("Say something positive:")
+        assert isinstance(output, str)
+    except Exception as e:
+        pytest.fail(f"can not instantiate claude-instant-v1: {e}", pytrace=False)
+
+
+def test_amazon_bedrock_guardrails_no_intervention_for_valid_query(
+    bedrock_runtime_client, bedrock_models
+):
+    try:
+        llm = Bedrock(
+            model_id="anthropic.claude-instant-v1",
+            client=bedrock_runtime_client,
+            model_kwargs={},
+            guardrails={
+                "id": GUARDRAILS_ID,
+                "version": GUARDRAILS_VERSION,
+                "trace": False,
+            },
+        )
+        output = llm("Say something positive:")
+        assert isinstance(output, str)
+    except Exception as e:
+        pytest.fail(f"can not instantiate claude-instant-v1: {e}", pytrace=False)
+
+
+def test_amazon_bedrock_guardrails_intervention_for_invalid_query(
+    bedrock_runtime_client, bedrock_models
+):
+    try:
+        handler = BedrockAsyncCallbackHandler()
+        llm = Bedrock(
+            model_id="anthropic.claude-instant-v1",
+            client=bedrock_runtime_client,
+            model_kwargs={},
+            guardrails={
+                "id": GUARDRAILS_ID,
+                "version": GUARDRAILS_VERSION,
+                "trace": True,
+            },
+            callbacks=[handler],
+        )
+    except Exception as e:
+        pytest.fail(f"can not instantiate claude-instant-v1: {e}", pytrace=False)
+    else:
+        llm(GUARDRAILS_TRIGGER)
+        guardrails_intervened = handler.get_response()
+        assert guardrails_intervened is True