# What does this PR do? This gracefully handles the case where the vLLM server responded to a completion request with no choices, which can happen in certain vLLM error situations. Previously, we'd error out with a stack trace about a list index out of range. Now, we just log a warning to the user and move past any chunks with an empty choices list. A specific example of the type of stack trace this fixes: ``` File "/app/llama-stack-source/llama_stack/providers/remote/inference/vllm/vllm.py", line 170, in _process_vllm_chat_completion_stream_response choice = chunk.choices[0] ~~~~~~~~~~~~~^^^ IndexError: list index out of range ``` Now, instead of erroring out with that stack trace, we log a warning that vLLM failed to generate any completions and alert the user to check the vLLM server logs for details. This is related to #1277 and addresses the stack trace shown in that issue, although does not in and of itself change the functional behavior of vLLM tool calling. ## Test Plan As part of this fix, I added new unit tests to trigger this same error and verify it no longer happens. That is `test_process_vllm_chat_completion_stream_response_no_choices` in the new `tests/unit/providers/inference/test_remote_vllm.py`. I also added a couple of more tests to trigger and verify the last couple of remote vllm provider bug fixes - specifically a test for #1236 (builtin tool calling) and #1325 (vLLM <= v0.6.3). This required fixing the signature of `_process_vllm_chat_completion_stream_response` to accept the actual type of chunks it was getting passed - specifically changing from our openai_compat `OpenAICompatCompletionResponse` to `openai.types.chat.chat_completion_chunk.ChatCompletionChunk`. It was not actually getting passed `OpenAICompatCompletionResponse` objects before, and was using attributes that didn't exist on those objects. So, the signature now matches the type of object it's actually passed. Run these new unit tests like this: ``` pytest tests/unit/providers/inference/test_remote_vllm.py ``` Additionally, I ensured the existing `test_text_inference.py` tests passed via: ``` VLLM_URL="http://localhost:8000/v1" \ INFERENCE_MODEL="meta-llama/Llama-3.2-3B-Instruct" \ LLAMA_STACK_CONFIG=remote-vllm \ python -m pytest -v tests/integration/inference/test_text_inference.py \ --inference-model "meta-llama/Llama-3.2-3B-Instruct" \ --vision-inference-model "" ``` Signed-off-by: Ben Browning <bbrownin@redhat.com> |
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Llama Stack
Quick Start | Documentation | Colab Notebook
Llama Stack standardizes the core building blocks that simplify AI application development. It codifies best practices across the Llama ecosystem. More specifically, it provides
- Unified API layer for Inference, RAG, Agents, Tools, Safety, Evals, and Telemetry.
- Plugin architecture to support the rich ecosystem of different API implementations in various environments, including local development, on-premises, cloud, and mobile.
- Prepackaged verified distributions which offer a one-stop solution for developers to get started quickly and reliably in any environment.
- Multiple developer interfaces like CLI and SDKs for Python, Typescript, iOS, and Android.
- Standalone applications as examples for how to build production-grade AI applications with Llama Stack.
Llama Stack Benefits
- Flexible Options: Developers can choose their preferred infrastructure without changing APIs and enjoy flexible deployment choices.
- Consistent Experience: With its unified APIs, Llama Stack makes it easier to build, test, and deploy AI applications with consistent application behavior.
- Robust Ecosystem: Llama Stack is already integrated with distribution partners (cloud providers, hardware vendors, and AI-focused companies) that offer tailored infrastructure, software, and services for deploying Llama models.
By reducing friction and complexity, Llama Stack empowers developers to focus on what they do best: building transformative generative AI applications.
API Providers
Here is a list of the various API providers and available distributions that can help developers get started easily with Llama Stack.
API Provider Builder | Environments | Agents | Inference | Memory | Safety | Telemetry |
---|---|---|---|---|---|---|
Meta Reference | Single Node | ✅ | ✅ | ✅ | ✅ | ✅ |
SambaNova | Hosted | ✅ | ||||
Cerebras | Hosted | ✅ | ||||
Fireworks | Hosted | ✅ | ✅ | ✅ | ||
AWS Bedrock | Hosted | ✅ | ✅ | |||
Together | Hosted | ✅ | ✅ | ✅ | ||
Groq | Hosted | ✅ | ||||
Ollama | Single Node | ✅ | ||||
TGI | Hosted and Single Node | ✅ | ||||
NVIDIA NIM | Hosted and Single Node | ✅ | ||||
Chroma | Single Node | ✅ | ||||
PG Vector | Single Node | ✅ | ||||
PyTorch ExecuTorch | On-device iOS | ✅ | ✅ | |||
vLLM | Hosted and Single Node | ✅ |
Distributions
A Llama Stack Distribution (or "distro") is a pre-configured bundle of provider implementations for each API component. Distributions make it easy to get started with a specific deployment scenario - you can begin with a local development setup (eg. ollama) and seamlessly transition to production (eg. Fireworks) without changing your application code. Here are some of the distributions we support:
Distribution | Llama Stack Docker | Start This Distribution |
---|---|---|
Meta Reference | llamastack/distribution-meta-reference-gpu | Guide |
Meta Reference Quantized | llamastack/distribution-meta-reference-quantized-gpu | Guide |
SambaNova | llamastack/distribution-sambanova | Guide |
Cerebras | llamastack/distribution-cerebras | Guide |
Ollama | llamastack/distribution-ollama | Guide |
TGI | llamastack/distribution-tgi | Guide |
Together | llamastack/distribution-together | Guide |
Fireworks | llamastack/distribution-fireworks | Guide |
vLLM | llamastack/distribution-remote-vllm | Guide |
Installation
You have two ways to install this repository:
-
Install as a package: You can install the repository directly from PyPI by running the following command:
pip install llama-stack
-
Install from source: If you prefer to install from the source code, we recommend using uv. Then, run the following commands:
git clone git@github.com:meta-llama/llama-stack.git cd llama-stack uv sync uv pip install -e .
Documentation
Please checkout our Documentation page for more details.
- CLI references
- llama (server-side) CLI Reference: Guide for using the
llama
CLI to work with Llama models (download, study prompts), and building/starting a Llama Stack distribution. - llama (client-side) CLI Reference: Guide for using the
llama-stack-client
CLI, which allows you to query information about the distribution.
- llama (server-side) CLI Reference: Guide for using the
- Getting Started
- Quick guide to start a Llama Stack server.
- Jupyter notebook to walk-through how to use simple text and vision inference llama_stack_client APIs
- The complete Llama Stack lesson Colab notebook of the new Llama 3.2 course on Deeplearning.ai.
- A Zero-to-Hero Guide that guide you through all the key components of llama stack with code samples.
- Contributing
- Adding a new API Provider to walk-through how to add a new API provider.
Llama Stack Client SDKs
Language | Client SDK | Package |
---|---|---|
Python | llama-stack-client-python | |
Swift | llama-stack-client-swift | |
Typescript | llama-stack-client-typescript | |
Kotlin | llama-stack-client-kotlin |
Check out our client SDKs for connecting to a Llama Stack server in your preferred language, you can choose from python, typescript, swift, and kotlin programming languages to quickly build your applications.
You can find more example scripts with client SDKs to talk with the Llama Stack server in our llama-stack-apps repo.