consistently use getLogger(__name__), no root logger (#2989)

re
#439 (comment)

I think it's not polite for a library to use the root logger

both of these forms are also used:
```
logger = logging.getLogger(__name__)
logger = logging.getLogger(__file__)
```
I am not sure if there is any reason behind one vs the other? (...I am
guessing maybe just contributed by different people)

it seems to me it'd be better to consistently use
`logging.getLogger(__name__)`

this makes it easier for consumers of the library to set up log
handlers, e.g. for everything with `langchain.` prefix

langchain/agents/agent.py

@@ -30,7 +30,7 @@
 from langchain.tools.base import BaseTool
 from langchain.utilities.asyncio import asyncio_timeout
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 class BaseSingleActionAgent(BaseModel):

langchain/chat_models/azure_openai.py

@@ -9,7 +9,7 @@
 from langchain.chat_models.openai import ChatOpenAI
 from langchain.utils import get_from_dict_or_env
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class AzureChatOpenAI(ChatOpenAI):

langchain/chat_models/openai.py

@@ -26,7 +26,7 @@
 )
 from langchain.utils import get_from_dict_or_env
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 def _create_retry_decorator(llm: ChatOpenAI) -> Callable[[Any], Any]:

langchain/document_loaders/diffbot.py

@@ -7,7 +7,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class DiffbotLoader(BaseLoader):

langchain/document_loaders/directory.py

@@ -12,7 +12,7 @@
 FILE_LOADER_TYPE = Union[
     Type[UnstructuredFileLoader], Type[TextLoader], Type[BSHTMLLoader]
 ]
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 def _is_visible(p: Path) -> bool:

langchain/document_loaders/html_bs.py

@@ -6,7 +6,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class BSHTMLLoader(BaseLoader):

langchain/document_loaders/url.py

@@ -5,7 +5,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class UnstructuredURLLoader(BaseLoader):

langchain/document_loaders/url_playwright.py

@@ -6,7 +6,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class PlaywrightURLLoader(BaseLoader):

langchain/document_loaders/url_selenium.py

@@ -9,7 +9,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 class SeleniumURLLoader(BaseLoader):

langchain/document_loaders/web_base.py

@@ -9,7 +9,7 @@
 from langchain.docstore.document import Document
 from langchain.document_loaders.base import BaseLoader
 
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 default_header_template = {
     "User-Agent": "",

langchain/llms/huggingface_pipeline.py

@@ -12,7 +12,7 @@
 DEFAULT_TASK = "text-generation"
 VALID_TASKS = ("text2text-generation", "text-generation")
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 class HuggingFacePipeline(LLM):

langchain/llms/self_hosted.py

@@ -9,7 +9,7 @@
 from langchain.llms.base import LLM
 from langchain.llms.utils import enforce_stop_tokens
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 def _generate_text(

langchain/llms/self_hosted_hugging_face.py

@@ -12,7 +12,7 @@
 DEFAULT_TASK = "text-generation"
 VALID_TASKS = ("text2text-generation", "text-generation")
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 def _generate_text(

langchain/prompts/loading.py

@@ -14,7 +14,7 @@
 from langchain.utilities.loading import try_load_from_hub
 
 URL_BASE = "https://raw.githubusercontent.com/hwchase17/langchain-hub/master/prompts/"
-logger = logging.getLogger(__file__)
+logger = logging.getLogger(__name__)
 
 
 def load_prompt_from_config(config: dict) -> BasePromptTemplate:

langchain/text_splitter.py

@@ -18,7 +18,7 @@
 
 from langchain.docstore.document import Document
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 class TextSplitter(ABC):

langchain/vectorstores/atlas.py

@@ -11,7 +11,7 @@
 from langchain.embeddings.base import Embeddings
 from langchain.vectorstores.base import VectorStore
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 class AtlasDB(VectorStore):

langchain/vectorstores/chroma.py

@@ -16,7 +16,7 @@
     import chromadb
     import chromadb.config
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 def _results_to_docs(results: Any) -> List[Document]:

langchain/vectorstores/deeplake.py

@@ -13,7 +13,7 @@
 from langchain.vectorstores.base import VectorStore
 from langchain.vectorstores.utils import maximal_marginal_relevance
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 distance_metric_map = {
     "l2": lambda a, b: np.linalg.norm(a - b, axis=1, ord=2),

langchain/vectorstores/redis.py

@@ -16,7 +16,7 @@
 from langchain.utils import get_from_dict_or_env
 from langchain.vectorstores.base import VectorStore
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 # required modules