147 lines
4.4 KiB
Plaintext
147 lines
4.4 KiB
Plaintext
---
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title: "SGLang"
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description: "SGL/SGLang API conversion guide - OpenAI-compatible format, parameter handling, streaming, tool support"
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icon: "s"
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---
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## Overview
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SGL (SGLang) is an **OpenAI-compatible local/remote inference engine** used for serving models with high throughput. Bifrost delegates all operations to the OpenAI provider implementation. Key features:
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- **OpenAI API compatibility** - Identical request/response format
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- **Full streaming support** - Server-Sent Events with usage tracking
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- **Tool calling** - Complete function definition and execution
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- **Text embeddings** - Support for embedding models
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- **Parameter filtering** - Removes unsupported fields for compatibility
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### Supported Operations
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| Operation | Non-Streaming | Streaming | Endpoint |
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|-----------|---------------|-----------|----------|
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| Chat Completions | ✅ | ✅ | `/v1/chat/completions` |
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| Responses API | ✅ | ✅ | `/v1/chat/completions` |
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| Text Completions | ✅ | ✅ | `/v1/completions` |
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| Embeddings | ✅ | - | `/v1/embeddings` |
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| List Models | ✅ | - | `/v1/models` |
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| Image Generation | ❌ | ❌ | - |
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| Speech (TTS) | ❌ | ❌ | - |
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| Transcriptions (STT) | ❌ | ❌ | - |
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| Files | ❌ | ❌ | - |
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| Batch | ❌ | ❌ | - |
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<Note>
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**Unsupported Operations** (❌): Speech, Transcriptions, Files, and Batch are not supported by the upstream SGL API. These return `UnsupportedOperationError`.
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SGL is typically self-hosted. Ensure BaseURL is configured correctly pointing to your SGL instance (e.g., `http://localhost:8000`).
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</Note>
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---
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# 1. Chat Completions
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## Request Parameters
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SGL supports all standard OpenAI chat completion parameters. For full parameter reference and behavior, see [OpenAI Chat Completions](/providers/supported-providers/openai#1-chat-completions).
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### Filtered Parameters
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Removed for SGL compatibility:
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- `prompt_cache_key` - Not supported
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- `verbosity` - Anthropic-specific
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- `store` - Not supported
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- `service_tier` - OpenAI-specific
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SGL supports all standard OpenAI message types, tools, responses, and streaming formats. For details on message handling, tool conversion, responses, and streaming, refer to [OpenAI Chat Completions](/providers/supported-providers/openai#1-chat-completions).
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---
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# 2. Responses API
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Fallback to Chat Completions with format conversion:
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```
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ResponsesRequest → ChatRequest → Response conversion
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```
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Same parameter support as Chat Completions.
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---
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# 3. Text Completions
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SGL supports legacy text completion format:
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| Parameter | Mapping |
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|-----------|---------|
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| `prompt` | Direct pass-through |
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| `max_tokens` | max_tokens |
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| `temperature`, `top_p` | Direct pass-through |
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| `frequency_penalty`, `presence_penalty` | Supported |
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---
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# 4. Embeddings
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SGL supports text embeddings for vector generation:
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| Parameter | Notes |
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|-----------|-------|
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| `input` | Text or array of texts |
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| `model` | Embedding model name |
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| `encoding_format` | "float" or "base64" |
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| `dimensions` | Model-specific dimension count |
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Response returns embedding vectors with usage information.
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---
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# 5. List Models
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Lists available models from SGL server with capabilities.
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---
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## Unsupported Features
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| Feature | Reason |
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|---------|--------|
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| Speech/TTS | Not offered by SGL API |
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| Transcription/STT | Not offered by SGL API |
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| Batch Operations | Not offered by SGL API |
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| File Management | Not offered by SGL API |
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---
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<Note>
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SGL requires BaseURL configuration pointing to your SGL instance (e.g., `http://localhost:8000` for local, `https://sgl.example.com` for remote).
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</Note>
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## Caveats
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<Accordion title="BaseURL Configuration Required">
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**Severity**: High
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**Behavior**: BaseURL must be explicitly configured
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**Impact**: Requests fail without proper configuration
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**Code**: Validated in NewSGLProvider
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</Accordion>
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<Accordion title="Cache Control Stripped">
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**Severity**: Medium
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**Behavior**: Cache control directives are removed from messages
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**Impact**: Prompt caching features don't work
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**Code**: Stripped during JSON marshaling
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</Accordion>
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<Accordion title="Parameter Filtering">
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**Severity**: Low
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**Behavior**: OpenAI-specific fields filtered out
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**Impact**: prompt_cache_key, verbosity, store removed
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**Code**: filterOpenAISpecificParameters
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</Accordion>
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<Accordion title="User Field Size Limit">
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**Severity**: Low
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**Behavior**: User field > 64 characters silently dropped
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**Impact**: Longer user identifiers are lost
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**Code**: SanitizeUserField enforces 64-char max
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</Accordion>
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