Add support for optional max concurrency (#643)

**Added optional Semaphore-based concurrency control for #642** 
As for the default value for `max_concurrency`, I don't know the ratio
of API users vs. local LLM users, so the proposed default is an
opinionated value of `16`
* I *think* more people use OpenAI API for now vs. local LLMs, thus
default is not `-1` (no limit)
* `16` seems to be reasonably fast and doesn't seem to hit throughput
limit in my experience

**Tests**
Embedding for 1k documents finished in <2min and subsequent Testset
generation for `test_size=1000` proceeding without getting stuck:
<img width="693" alt="image"
src="https://github.com/explodinggradients/ragas/assets/6729737/d83fecc8-a815-43ee-a3b0-3395d7a9d244">

another 30s passes:
<img width="725" alt="image"
src="https://github.com/explodinggradients/ragas/assets/6729737/d4ab08ba-5a79-45f6-84b1-e563f107d682">

---------

Co-authored-by: Jithin James <jamesjithin97@gmail.com>

src/ragas/embeddings/base.py

@@ -44,7 +44,9 @@ def set_run_config(self, run_config: RunConfig):
 
 class LangchainEmbeddingsWrapper(BaseRagasEmbeddings):
     def __init__(
-        self, embeddings: Embeddings, run_config: t.Optional[RunConfig] = None
+        self,
+        embeddings: Embeddings,
+        run_config: t.Optional[RunConfig] = None
     ):
         self.embeddings = embeddings
         if run_config is None:

src/ragas/evaluation.py

@@ -44,7 +44,6 @@ def evaluate(
     embeddings: t.Optional[BaseRagasEmbeddings | LangchainEmbeddings] = None,
     callbacks: Callbacks = [],
     is_async: bool = False,
-    max_workers: t.Optional[int] = None,
     run_config: t.Optional[RunConfig] = None,
     raise_exceptions: bool = True,
     column_map: t.Dict[str, str] = {},
@@ -77,9 +76,6 @@ def evaluate(
         evaluation is run by calling the `metric.ascore` method. In case the llm or
         embeddings does not support async then the evaluation can be run in sync mode
         with `is_async=False`. Default is False.
-    max_workers: int, optional
-        The number of workers to use for the evaluation. This is used by the
-        `ThreadpoolExecutor` to run the evaluation in sync mode.
     run_config: RunConfig, optional
         Configuration for runtime settings like timeout and retries. If not provided,
         default values are used.
@@ -128,8 +124,7 @@ def evaluate(
         raise ValueError("Provide dataset!")
 
     # default run_config
-    if run_config is None:
-        run_config = RunConfig()
+    run_config = run_config or RunConfig()
     # default metrics
     if metrics is None:
         from ragas.metrics import (
@@ -184,6 +179,7 @@ def evaluate(
         desc="Evaluating",
         keep_progress_bar=True,
         raise_exceptions=raise_exceptions,
+        run_config=run_config,
     )
     # new evaluation chain
     row_run_managers = []

src/ragas/executor.py

@@ -1,4 +1,5 @@
 from __future__ import annotations
+import sys
 
 import asyncio
 import logging
@@ -10,6 +11,7 @@
 from tqdm.auto import tqdm
 
 from ragas.exceptions import MaxRetriesExceeded
+from ragas.run_config import RunConfig
 
 logger = logging.getLogger(__name__)
 
@@ -22,6 +24,19 @@ def runner_exception_hook(args: threading.ExceptHookArgs):
 # set a custom exception hook
 # threading.excepthook = runner_exception_hook
 
+def as_completed(loop, coros, max_workers):
+    loop_arg_dict = {"loop": loop} if sys.version_info[:2] < (3, 10) else {}
+    if max_workers == -1:
+        return asyncio.as_completed(coros, **loop_arg_dict)
+
+    # loop argument is removed since Python 3.10
+    semaphore = asyncio.Semaphore(max_workers, **loop_arg_dict)
+    async def sema_coro(coro):
+        async with semaphore:
+            return await coro
+
+    sema_coros = [sema_coro(c) for c in coros]
+    return asyncio.as_completed(sema_coros, **loop_arg_dict)
 
 class Runner(threading.Thread):
     def __init__(
@@ -30,26 +45,29 @@ def __init__(
         desc: str,
         keep_progress_bar: bool = True,
         raise_exceptions: bool = True,
+        run_config: t.Optional[RunConfig] = None
     ):
         super().__init__()
         self.jobs = jobs
         self.desc = desc
         self.keep_progress_bar = keep_progress_bar
         self.raise_exceptions = raise_exceptions
-        self.futures = []
+        self.run_config = run_config or RunConfig()
 
         # create task
         self.loop = asyncio.new_event_loop()
-        for job in self.jobs:
-            coroutine, name = job
-            self.futures.append(self.loop.create_task(coroutine, name=name))
+        self.futures = as_completed(
+            loop=self.loop,
+            coros=[coro for coro, _ in self.jobs],
+            max_workers=self.run_config.max_workers
+        )
 
     async def _aresults(self) -> t.List[t.Any]:
         results = []
         for future in tqdm(
-            asyncio.as_completed(self.futures),
+            self.futures,
             desc=self.desc,
-            total=len(self.futures),
+            total=len(self.jobs),
             # whether you want to keep the progress bar after completion
             leave=self.keep_progress_bar,
         ):
@@ -75,7 +93,6 @@ def run(self):
             results = self.loop.run_until_complete(self._aresults())
         finally:
             self.results = results
-            [f.cancel() for f in self.futures]
             self.loop.stop()
 
 
@@ -85,6 +102,7 @@ class Executor:
     keep_progress_bar: bool = True
     jobs: t.List[t.Any] = field(default_factory=list, repr=False)
     raise_exceptions: bool = False
+    run_config: t.Optional[RunConfig] = field(default_factory=RunConfig, repr=False)
 
     def wrap_callable_with_index(self, callable: t.Callable, counter):
         async def wrapped_callable_async(*args, **kwargs):
@@ -104,6 +122,7 @@ def results(self) -> t.List[t.Any]:
             desc=self.desc,
             keep_progress_bar=self.keep_progress_bar,
             raise_exceptions=self.raise_exceptions,
+            run_config=self.run_config,
         )
         executor_job.start()
         try:

src/ragas/llms/base.py

@@ -119,7 +119,9 @@ class LangchainLLMWrapper(BaseRagasLLM):
     """
 
     def __init__(
-        self, langchain_llm: BaseLanguageModel, run_config: t.Optional[RunConfig] = None
+        self,
+        langchain_llm: BaseLanguageModel,
+        run_config: t.Optional[RunConfig] = None
     ):
         self.langchain_llm = langchain_llm
         if run_config is None:
@@ -204,7 +206,8 @@ def set_run_config(self, run_config: RunConfig):
 
 
 def llm_factory(
-    model: str = "gpt-3.5-turbo-16k", run_config: t.Optional[RunConfig] = None
+    model: str = "gpt-3.5-turbo-16k",
+    run_config: t.Optional[RunConfig] = None
 ) -> BaseRagasLLM:
     timeout = None
     if run_config is not None:

src/ragas/run_config.py

@@ -20,6 +20,7 @@ class RunConfig:
     timeout: int = 60
     max_retries: int = 10
     max_wait: int = 60
+    max_workers: int = 16
     exception_types: t.Union[
         t.Type[BaseException],
         t.Tuple[t.Type[BaseException], ...],

src/ragas/testset/docstore.py

@@ -78,7 +78,7 @@ class Direction(str, Enum):
     PREV = "prev"
     UP = "up"
     DOWN = "down"
-
+    
 
 class Node(Document):
     keyphrases: t.List[str] = Field(default_factory=list, repr=False)
@@ -196,6 +196,7 @@ class InMemoryDocumentStore(DocumentStore):
     nodes: t.List[Node] = field(default_factory=list)
     node_embeddings_list: t.List[Embedding] = field(default_factory=list)
     node_map: t.Dict[str, Node] = field(default_factory=dict)
+    run_config: t.Optional[RunConfig] = None
 
     def _embed_items(self, items: t.Union[t.Sequence[Document], t.Sequence[Node]]):
         ...
@@ -213,9 +214,7 @@ def add_documents(self, docs: t.Sequence[Document], show_progress=True):
         ]
         self.add_nodes(nodes, show_progress=show_progress)
 
-    def add_nodes(
-        self, nodes: t.Sequence[Node], show_progress=True, desc: str = "embedding nodes"
-    ):
+    def add_nodes(self, nodes: t.Sequence[Node], show_progress=True):
         assert self.embeddings is not None, "Embeddings must be set"
         assert self.extractor is not None, "Extractor must be set"
 
@@ -228,6 +227,7 @@ def add_nodes(
             desc="embedding nodes",
             keep_progress_bar=False,
             raise_exceptions=True,
+            run_config=self.run_config,
         )
         result_idx = 0
         for i, n in enumerate(nodes):
@@ -356,3 +356,4 @@ def get_similar(
     def set_run_config(self, run_config: RunConfig):
         if self.embeddings:
             self.embeddings.set_run_config(run_config)
+        self.run_config = run_config

src/ragas/testset/evolutions.py

@@ -88,7 +88,11 @@ def merge_nodes(nodes: CurrentNodes) -> Node:
             new_node.embedding = np.average(node_embeddings, axis=0)
         return new_node
 
-    def init(self, is_async: bool = True, run_config: t.Optional[RunConfig] = None):
+    def init(
+        self,
+        is_async: bool = True,
+        run_config: t.Optional[RunConfig] = None
+    ):
         self.is_async = is_async
         if run_config is None:
             run_config = RunConfig()
@@ -335,7 +339,11 @@ class ComplexEvolution(Evolution):
         default_factory=lambda: compress_question_prompt
     )
 
-    def init(self, is_async: bool = True, run_config: t.Optional[RunConfig] = None):
+    def init(
+        self,
+        is_async: bool = True,
+        run_config: t.Optional[RunConfig] = None
+    ):
         if run_config is None:
             run_config = RunConfig()
         super().init(is_async=is_async, run_config=run_config)

src/ragas/testset/generator.py

@@ -77,6 +77,7 @@ def with_openai(
         critic_llm: str = "gpt-4",
         embeddings: str = "text-embedding-ada-002",
         docstore: t.Optional[DocumentStore] = None,
+        run_config: t.Optional[RunConfig] = None,
         chunk_size: int = 1024,
     ) -> "TestsetGenerator":
         generator_llm_model = LangchainLLMWrapper(ChatOpenAI(model=generator_llm))
@@ -93,6 +94,7 @@ def with_openai(
                 splitter=splitter,
                 embeddings=embeddings_model,
                 extractor=keyphrase_extractor,
+                run_config=run_config,
             )
             return cls(
                 generator_llm=generator_llm_model,
@@ -118,7 +120,7 @@ def generate_with_llamaindex_docs(
         with_debugging_logs=False,
         is_async: bool = True,
         raise_exceptions: bool = True,
-        run_config: t.Optional[RunConfig] = None,
+        run_config: t.Optional[RunConfig] = None
     ):
         # chunk documents and add to docstore
         self.docstore.add_documents(
@@ -144,7 +146,7 @@ def generate_with_langchain_docs(
         with_debugging_logs=False,
         is_async: bool = True,
         raise_exceptions: bool = True,
-        run_config: t.Optional[RunConfig] = None,
+        run_config: t.Optional[RunConfig] = None
     ):
         # chunk documents and add to docstore
         self.docstore.add_documents(
@@ -182,7 +184,7 @@ def generate(
         with_debugging_logs=False,
         is_async: bool = True,
         raise_exceptions: bool = True,
-        run_config: t.Optional[RunConfig] = None,
+        run_config: t.Optional[RunConfig] = None
     ):
         # validate distributions
         if not check_if_sum_is_close(list(distributions.values()), 1.0, 3):
@@ -213,6 +215,7 @@ def generate(
             desc="Generating",
             keep_progress_bar=True,
             raise_exceptions=raise_exceptions,
+            run_config=run_config,
         )
 
         current_nodes = [