299 ollama client does not work with stream

[BalasubramanyamEvani]

What does this PR do?

This PR addresses the issue where the application fails to work when the stream parameter is set to True in the adalflow.components.model_client.ollama_client::OllamaClient class. The issue is traced to the adalflow.core.generator.py _post_call method, which does not currently handle streaming correctly.

Fixes #299

• Implements separate cases for handling streaming and non-streaming responses in the _post_call method.
  • For streaming responses: Processes the raw response from the completion generator as it is yielded and passes it to the output_processors.
  • For non-streaming responses: Retains the existing behavior.

Usage Updates

The updated usage for the stream parameter is as follows:

ollama_ai = {
    "model_client": OllamaClient(host=host),
    "model_kwargs": {
        "model": "phi3:latest",
        "stream": True,
    },
}

generator = Generator(**ollama_ai)
output = generator({"input_str": "What is the capital of France?"})
for chunk in output.data:
    print(chunk.data, end="", flush=True)

# For stream: False
# print(output.data)

Tests Added

• A new test case, TestGeneratorWithStream, is added in test_generator.py to verify the streaming behavior.
  • The test mocks the GeneratorType response from the parse_chat_completion method and validates the output for streamed data.

Tests output (local) after changes:

======================================================== test session starts =========================================================
platform linux -- Python 3.12.8, pytest-8.3.4, pluggy-1.5.0
rootdir: /home/AdalFlow
configfile: pyproject.toml
plugins: anyio-4.4.0, mock-3.14.0
collected 231 items / 1 skipped                                                                                                      

adalflow/tests/test_AzureClient.py ..                                                                                          [  0%]
adalflow/tests/test_base_data_class.py ..............                                                                          [  6%]
adalflow/tests/test_component.py ...                                                                                           [  8%]
adalflow/tests/test_componentlist.py .............                                                                             [ 13%]
adalflow/tests/test_data.py ...                                                                                                [ 15%]
adalflow/tests/test_data_class_parser.py ......                                                                                [ 17%]
adalflow/tests/test_data_classes.py ....                                                                                       [ 19%]
adalflow/tests/test_data_loader.py .......                                                                                     [ 22%]
adalflow/tests/test_dataclass_object_functions.py ................                                                             [ 29%]
adalflow/tests/test_evaluators.py ..s                                                                                          [ 30%]
adalflow/tests/test_faiss_retriever.py .........                                                                               [ 34%]
adalflow/tests/test_function_expression_parse.py ........................                                                      [ 45%]
adalflow/tests/test_generator.py ......                                                                                        [ 47%]
adalflow/tests/test_generator_call_logger.py ...                                                                               [ 48%]
adalflow/tests/test_grad_component.py ......                                                                                   [ 51%]
adalflow/tests/test_groq_client.py ..                                                                                          [ 52%]
adalflow/tests/test_lancedb_retriver.py ........                                                                               [ 55%]
adalflow/tests/test_lazy_import.py ........                                                                                    [ 59%]
adalflow/tests/test_logger.py ......                                                                                           [ 61%]
adalflow/tests/test_memory.py ...                                                                                              [ 63%]
adalflow/tests/test_model_client.py ...                                                                                        [ 64%]
adalflow/tests/test_ollama_client.py ..                                                                                        [ 65%]
adalflow/tests/test_openai_client.py ..                                                                                        [ 66%]
adalflow/tests/test_output_parser.py ......                                                                                    [ 68%]
adalflow/tests/test_parameter.py ............                                                                                  [ 74%]
adalflow/tests/test_parameter_text_grad.py ...                                                                                 [ 75%]
adalflow/tests/test_random_sample.py .....                                                                                     [ 77%]
adalflow/tests/test_sequential.py ...............                                                                              [ 83%]
adalflow/tests/test_string_parser.py ..........................                                                                [ 95%]
adalflow/tests/test_text_splitter.py .........                                                                                 [ 99%]
adalflow/tests/test_tool.py ..                                                                                                 [100%]

========================================================== warnings summary ==========================================================
adalflow/tests/test_ollama_client.py::TestOllamaModelClient::test_ollama_embedding_client
adalflow/tests/test_ollama_client.py::TestOllamaModelClient::test_ollama_llm_client
  /home/AdalFlow/adalflow/adalflow/components/model_client/ollama_client.py:165: UserWarning: Better to provide host or set OLLAMA_HOST env variable. We will use the default host http://localhost:11434 for now.
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
============================================= 230 passed, 2 skipped, 2 warnings in 3.75s =============================================

Breaking Changes

As far as I can test, this PR does not introduce any breaking changes. Existing functionality for non-streaming cases remains unaffected.

---

Before submitting

• Was this discussed/agreed via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes? (if necessary)
• Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you list all the breaking changes introduced by this pull request?

---

[liyin2015]

please also check this pr as it is highly related.

Updates in the generator requires to be minimized

#158

[liyin2015]

it specifies only one output, but you returned a tuple.

Ensure we add code linting @fm1320 by developers to check these basics

[BalasubramanyamEvani]

Thanks for. the review. Yes, that's my fault. I will fix this.

[liyin2015]

dont separate the code, it changed too much, and its better to minimize the change, so just add the initial code back to the else

[BalasubramanyamEvani]

Understood. I’ll proceed with this approach then. It seems there’s no longer a need for the additional _process_chunk function I had added earlier then?