Mask api key for Together LLM (#13981)

- **Description:** Add unit tests and mask api key for Together LLM
- **Issue:** the issue
https://github.com/langchain-ai/langchain/issues/12165 ,
  - **Dependencies:** N/A
  - **Tag maintainer:** ?,
  - **Twitter handle:** N/A

---------

Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

libs/langchain/langchain/llms/together.py

@@ -3,7 +3,7 @@ import logging
 from typing import Any, Dict, List, Optional
 
 from aiohttp import ClientSession
-from langchain_core.pydantic_v1 import Extra, root_validator
+from langchain_core.pydantic_v1 import Extra, SecretStr, root_validator
 
 from langchain.callbacks.manager import (
     AsyncCallbackManagerForLLMRun,
@@ -11,7 +11,7 @@ from langchain.callbacks.manager import (
 )
 from langchain.llms.base import LLM
 from langchain.utilities.requests import Requests
-from langchain.utils import get_from_dict_or_env
+from langchain.utils import convert_to_secret_str, get_from_dict_or_env
 
 logger = logging.getLogger(__name__)
 
@@ -28,7 +28,7 @@ class Together(LLM):
 
     base_url: str = "https://api.together.xyz/inference"
     """Base inference API URL."""
-    together_api_key: str
+    together_api_key: SecretStr
     """Together AI API key. Get it here: https://api.together.xyz/settings/api-keys"""
     model: str
     """Model name. Available models listed here: 
@@ -69,8 +69,8 @@ class Together(LLM):
     @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that api key exists in environment."""
-        values["together_api_key"] = get_from_dict_or_env(
-            values, "together_api_key", "TOGETHER_API_KEY"
+        values["together_api_key"] = convert_to_secret_str(
+            get_from_dict_or_env(values, "together_api_key", "TOGETHER_API_KEY")
         )
         return values
 
@@ -116,7 +116,7 @@ class Together(LLM):
         """
 
         headers = {
-            "Authorization": f"Bearer {self.together_api_key}",
+            "Authorization": f"Bearer {self.together_api_key.get_secret_value()}",
             "Content-Type": "application/json",
         }
         stop_to_use = stop[0] if stop and len(stop) == 1 else stop
@@ -167,7 +167,7 @@ class Together(LLM):
             The string generated by the model.
         """
         headers = {
-            "Authorization": f"Bearer {self.together_api_key}",
+            "Authorization": f"Bearer {self.together_api_key.get_secret_value()}",
             "Content-Type": "application/json",
         }
         stop_to_use = stop[0] if stop and len(stop) == 1 else stop

libs/langchain/tests/unit_tests/llms/test_together.py

@@ -0,0 +1,61 @@
+"""Test Together LLM"""
+from typing import cast
+
+from langchain_core.pydantic_v1 import SecretStr
+from pytest import CaptureFixture, MonkeyPatch
+
+from langchain.llms.together import Together
+
+
+def test_together_api_key_is_secret_string() -> None:
+    """Test that the API key is stored as a SecretStr."""
+    llm = Together(
+        together_api_key="secret-api-key",
+        model="togethercomputer/RedPajama-INCITE-7B-Base",
+        temperature=0.2,
+        max_tokens=250,
+    )
+    assert isinstance(llm.together_api_key, SecretStr)
+
+
+def test_together_api_key_masked_when_passed_from_env(
+    monkeypatch: MonkeyPatch, capsys: CaptureFixture
+) -> None:
+    """Test that the API key is masked when passed from an environment variable."""
+    monkeypatch.setenv("TOGETHER_API_KEY", "secret-api-key")
+    llm = Together(
+        model="togethercomputer/RedPajama-INCITE-7B-Base",
+        temperature=0.2,
+        max_tokens=250,
+    )
+    print(llm.together_api_key, end="")
+    captured = capsys.readouterr()
+
+    assert captured.out == "**********"
+
+
+def test_together_api_key_masked_when_passed_via_constructor(
+    capsys: CaptureFixture,
+) -> None:
+    """Test that the API key is masked when passed via the constructor."""
+    llm = Together(
+        together_api_key="secret-api-key",
+        model="togethercomputer/RedPajama-INCITE-7B-Base",
+        temperature=0.2,
+        max_tokens=250,
+    )
+    print(llm.together_api_key, end="")
+    captured = capsys.readouterr()
+
+    assert captured.out == "**********"
+
+
+def test_together_uses_actual_secret_value_from_secretstr() -> None:
+    """Test that the actual secret value is correctly retrieved."""
+    llm = Together(
+        together_api_key="secret-api-key",
+        model="togethercomputer/RedPajama-INCITE-7B-Base",
+        temperature=0.2,
+        max_tokens=250,
+    )
+    assert cast(SecretStr, llm.together_api_key).get_secret_value() == "secret-api-key"