core[minor], anthropic[patch]: Upgrade @root_validator usage to be consistent with pydantic 2 (#25457)

anthropic: Upgrade `@root_validator` usage to be consistent with
pydantic 2
core: support looking up multiple keys from env in from_env factory

libs/core/langchain_core/utils/utils.py

@@ -7,7 +7,7 @@ import importlib
 import os
 import warnings
 from importlib.metadata import version
-from typing import Any, Callable, Dict, Optional, Set, Tuple, Union, overload
+from typing import Any, Callable, Dict, Optional, Sequence, Set, Tuple, Union, overload
 
 from packaging.version import parse
 from requests import HTTPError, Response
@@ -280,13 +280,17 @@ def from_env(key: str, /) -> Callable[[], str]: ...
 def from_env(key: str, /, *, default: str) -> Callable[[], str]: ...
 
 
+@overload
+def from_env(key: Sequence[str], /, *, default: str) -> Callable[[], str]: ...
+
+
 @overload
 def from_env(key: str, /, *, error_message: str) -> Callable[[], str]: ...
 
 
 @overload
 def from_env(
-    key: str, /, *, default: str, error_message: Optional[str]
+    key: Union[str, Sequence[str]], /, *, default: str, error_message: Optional[str]
 ) -> Callable[[], str]: ...
 
 
@@ -301,7 +305,7 @@ def from_env(key: str, /, *, default: None) -> Callable[[], Optional[str]]: ...
 
 
 def from_env(
-    key: str,
+    key: Union[str, Sequence[str]],
     /,
     *,
     default: Union[str, _NoDefaultType, None] = _NoDefault,
@@ -310,7 +314,10 @@ def from_env(
     """Create a factory method that gets a value from an environment variable.
 
     Args:
-        key: The environment variable to look up.
+        key: The environment variable to look up. If a list of keys is provided,
+            the first key found in the environment will be used.
+            If no key is found, the default value will be used if set,
+            otherwise an error will be raised.
         default: The default value to return if the environment variable is not set.
         error_message: the error message which will be raised if the key is not found
             and no default value is provided.
@@ -319,9 +326,15 @@ def from_env(
 
     def get_from_env_fn() -> Optional[str]:
         """Get a value from an environment variable."""
-        if key in os.environ:
+        if isinstance(key, (list, tuple)):
-            return os.environ[key]
+            for k in key:
-        elif isinstance(default, (str, type(None))):
+                if k in os.environ:
+                    return os.environ[k]
+        if isinstance(key, str):
+            if key in os.environ:
+                return os.environ[key]
+
+        if isinstance(default, (str, type(None))):
             return default
         else:
             if error_message:

libs/partners/anthropic/langchain_anthropic/chat_models.py

@@ -1,4 +1,3 @@
-import os
 import re
 import warnings
 from operator import itemgetter
@@ -64,8 +63,9 @@ from langchain_core.runnables import (
 from langchain_core.tools import BaseTool
 from langchain_core.utils import (
     build_extra_kwargs,
-    convert_to_secret_str,
+    from_env,
     get_pydantic_field_names,
+    secret_from_env,
 )
 from langchain_core.utils.function_calling import convert_to_openai_tool
 from langchain_core.utils.pydantic import is_basemodel_subclass
@@ -541,14 +541,26 @@ class ChatAnthropic(BaseChatModel):
     stop_sequences: Optional[List[str]] = Field(None, alias="stop")
     """Default stop sequences."""
 
-    anthropic_api_url: Optional[str] = Field(None, alias="base_url")
+    anthropic_api_url: Optional[str] = Field(
+        alias="base_url",
+        default_factory=from_env(
+            ["ANTHROPIC_API_URL", "ANTHROPIC_BASE_URL"],
+            default="https://api.anthropic.com",
+        ),
+    )
     """Base URL for API requests. Only specify if using a proxy or service emulator.
 
-    If a value isn't passed in and environment variable ANTHROPIC_BASE_URL is set, value
+    If a value isn't passed in, will attempt to read the value first from
-    will be read from there.
+    ANTHROPIC_API_URL and if that is not set, ANTHROPIC_BASE_URL.
+    If neither are set, the default value of 'https://api.anthropic.com' will
+    be used.
     """
 
-    anthropic_api_key: Optional[SecretStr] = Field(None, alias="api_key")
+    anthropic_api_key: SecretStr = Field(
+        alias="api_key",
+        default_factory=secret_from_env("ANTHROPIC_API_KEY", default=""),
+    )
+
     """Automatically read from env var `ANTHROPIC_API_KEY` if not provided."""
 
     default_headers: Optional[Mapping[str, str]] = None
@@ -623,20 +635,10 @@ class ChatAnthropic(BaseChatModel):
         )
         return values
 
-    @root_validator()
+    @root_validator(pre=False, skip_on_failure=True)
-    def validate_environment(cls, values: Dict) -> Dict:
+    def post_init(cls, values: Dict) -> Dict:
-        anthropic_api_key = convert_to_secret_str(
+        api_key = values["anthropic_api_key"].get_secret_value()
-            values.get("anthropic_api_key") or os.environ.get("ANTHROPIC_API_KEY") or ""
+        api_url = values["anthropic_api_url"]
-        )
-        values["anthropic_api_key"] = anthropic_api_key
-        api_key = anthropic_api_key.get_secret_value()
-        api_url = (
-            values.get("anthropic_api_url")
-            or os.environ.get("ANTHROPIC_API_URL")
-            or os.environ.get("ANTHROPIC_BASE_URL")
-            or "https://api.anthropic.com"
-        )
-        values["anthropic_api_url"] = api_url
         client_params = {
             "api_key": api_key,
             "base_url": api_url,

libs/partners/anthropic/langchain_anthropic/llms.py

@@ -23,10 +23,13 @@ from langchain_core.outputs import GenerationChunk
 from langchain_core.prompt_values import PromptValue
 from langchain_core.pydantic_v1 import Field, SecretStr, root_validator
 from langchain_core.utils import (
-    get_from_dict_or_env,
     get_pydantic_field_names,
 )
-from langchain_core.utils.utils import build_extra_kwargs, convert_to_secret_str
+from langchain_core.utils.utils import (
+    build_extra_kwargs,
+    from_env,
+    secret_from_env,
+)
 
 
 class _AnthropicCommon(BaseLanguageModel):
@@ -56,9 +59,25 @@ class _AnthropicCommon(BaseLanguageModel):
     max_retries: int = 2
     """Number of retries allowed for requests sent to the Anthropic Completion API."""
 
-    anthropic_api_url: Optional[str] = None
+    anthropic_api_url: Optional[str] = Field(
+        alias="base_url",
+        default_factory=from_env(
+            "ANTHROPIC_API_URL",
+            default="https://api.anthropic.com",
+        ),
+    )
+    """Base URL for API requests. Only specify if using a proxy or service emulator.
 
-    anthropic_api_key: Optional[SecretStr] = None
+    If a value isn't passed in, will attempt to read the value from
+    ANTHROPIC_API_URL. If not set, the default value of 'https://api.anthropic.com' will
+    be used.
+    """
+
+    anthropic_api_key: SecretStr = Field(
+        alias="api_key",
+        default_factory=secret_from_env("ANTHROPIC_API_KEY", default=""),
+    )
+    """Automatically read from env var `ANTHROPIC_API_KEY` if not provided."""
 
     HUMAN_PROMPT: Optional[str] = None
     AI_PROMPT: Optional[str] = None
@@ -74,20 +93,9 @@ class _AnthropicCommon(BaseLanguageModel):
         )
         return values
 
-    @root_validator()
+    @root_validator(pre=False, skip_on_failure=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that api key and python package exists in environment."""
-        values["anthropic_api_key"] = convert_to_secret_str(
-            get_from_dict_or_env(values, "anthropic_api_key", "ANTHROPIC_API_KEY")
-        )
-        # Get custom api url from environment.
-        values["anthropic_api_url"] = get_from_dict_or_env(
-            values,
-            "anthropic_api_url",
-            "ANTHROPIC_API_URL",
-            default="https://api.anthropic.com",
-        )
-
         values["client"] = anthropic.Anthropic(
             base_url=values["anthropic_api_url"],
             api_key=values["anthropic_api_key"].get_secret_value(),
@@ -158,7 +166,7 @@ class AnthropicLLM(LLM, _AnthropicCommon):
         allow_population_by_field_name = True
         arbitrary_types_allowed = True
 
-    @root_validator()
+    @root_validator(pre=True)
     def raise_warning(cls, values: Dict) -> Dict:
         """Raise warning that this class is deprecated."""
         warnings.warn(