[Frontend] Rerank API (Jina- and Cohere-compatible API) (#12376)

Signed-off-by: Kyle Mistele <kyle@mistele.com>

vllm/entrypoints/openai/protocol.py

@@ -1018,6 +1018,52 @@ class ScoreRequest(OpenAIBaseModel):
         return PoolingParams(additional_data=self.additional_data)
 
 
+class RerankRequest(OpenAIBaseModel):
+    model: str
+    query: str
+    documents: List[str]
+    top_n: int = Field(default_factory=lambda: 0)
+    truncate_prompt_tokens: Optional[Annotated[int, Field(ge=1)]] = None
+
+    # doc: begin-rerank-pooling-params
+    additional_data: Optional[Any] = None
+    # doc: end-rerank-pooling-params
+
+    # doc: begin-rerank-extra-params
+    priority: int = Field(
+        default=0,
+        description=(
+            "The priority of the request (lower means earlier handling; "
+            "default: 0). Any priority other than 0 will raise an error "
+            "if the served model does not use priority scheduling."))
+
+    # doc: end-rerank-extra-params
+
+    def to_pooling_params(self):
+        return PoolingParams(additional_data=self.additional_data)
+
+
+class RerankDocument(BaseModel):
+    text: str
+
+
+class RerankResult(BaseModel):
+    index: int
+    document: RerankDocument
+    relevance_score: float
+
+
+class RerankUsage(BaseModel):
+    total_tokens: int
+
+
+class RerankResponse(OpenAIBaseModel):
+    id: str
+    model: str
+    usage: RerankUsage
+    results: List[RerankResult]
+
+
 class CompletionLogProbs(OpenAIBaseModel):
     text_offset: List[int] = Field(default_factory=list)
     token_logprobs: List[Optional[float]] = Field(default_factory=list)