langchain/libs/community/langchain_community/llms/amazon_api_gateway.py
Eugene Yurtsev bf5193bb99
community[patch]: Upgrade pydantic extra (#25185)
Upgrade to using a literal for specifying the extra which is the
recommended approach in pydantic 2.

This works correctly also in pydantic v1.

```python
from pydantic.v1 import BaseModel

class Foo(BaseModel, extra="forbid"):
    x: int

Foo(x=5, y=1)
```

And 


```python
from pydantic.v1 import BaseModel

class Foo(BaseModel):
    x: int

    class Config:
      extra = "forbid"

Foo(x=5, y=1)
```


## Enum -> literal using grit pattern:

```
engine marzano(0.1)
language python
or {
    `extra=Extra.allow` => `extra="allow"`,
    `extra=Extra.forbid` => `extra="forbid"`,
    `extra=Extra.ignore` => `extra="ignore"`
}
```

Resorted attributes in config and removed doc-string in case we will
need to deal with going back and forth between pydantic v1 and v2 during
the 0.3 release. (This will reduce merge conflicts.)


## Sort attributes in Config:

```
engine marzano(0.1)
language python


function sort($values) js {
    return $values.text.split(',').sort().join("\n");
}


class_definition($name, $body) as $C where {
    $name <: `Config`,
    $body <: block($statements),
    $values = [],
    $statements <: some bubble($values) assignment() as $A where {
        $values += $A
    },
    $body => sort($values),
}

```
2024-08-08 17:20:39 +00:00

102 lines
2.9 KiB
Python

from typing import Any, Dict, List, Mapping, Optional
import requests
from langchain_core.callbacks import CallbackManagerForLLMRun
from langchain_core.language_models.llms import LLM
from langchain_community.llms.utils import enforce_stop_tokens
class ContentHandlerAmazonAPIGateway:
"""Adapter to prepare the inputs from Langchain to a format
that LLM model expects.
It also provides helper function to extract
the generated text from the model response."""
@classmethod
def transform_input(
cls, prompt: str, model_kwargs: Dict[str, Any]
) -> Dict[str, Any]:
return {"inputs": prompt, "parameters": model_kwargs}
@classmethod
def transform_output(cls, response: Any) -> str:
return response.json()[0]["generated_text"]
class AmazonAPIGateway(LLM):
"""Amazon API Gateway to access LLM models hosted on AWS."""
api_url: str
"""API Gateway URL"""
headers: Optional[Dict] = None
"""API Gateway HTTP Headers to send, e.g. for authentication"""
model_kwargs: Optional[Dict] = None
"""Keyword arguments to pass to the model."""
content_handler: ContentHandlerAmazonAPIGateway = ContentHandlerAmazonAPIGateway()
"""The content handler class that provides an input and
output transform functions to handle formats between LLM
and the endpoint.
"""
class Config:
extra = "forbid"
@property
def _identifying_params(self) -> Mapping[str, Any]:
"""Get the identifying parameters."""
_model_kwargs = self.model_kwargs or {}
return {
**{"api_url": self.api_url, "headers": self.headers},
**{"model_kwargs": _model_kwargs},
}
@property
def _llm_type(self) -> str:
"""Return type of llm."""
return "amazon_api_gateway"
def _call(
self,
prompt: str,
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> str:
"""Call out to Amazon API Gateway model.
Args:
prompt: The prompt to pass into the model.
stop: Optional list of stop words to use when generating.
Returns:
The string generated by the model.
Example:
.. code-block:: python
response = se("Tell me a joke.")
"""
_model_kwargs = self.model_kwargs or {}
payload = self.content_handler.transform_input(prompt, _model_kwargs)
try:
response = requests.post(
self.api_url,
headers=self.headers,
json=payload,
)
text = self.content_handler.transform_output(response)
except Exception as error:
raise ValueError(f"Error raised by the service: {error}")
if stop is not None:
text = enforce_stop_tokens(text, stop)
return text