### What problem does this PR solve?
Closes#14878.
`VllmModel.Rerank()` in
[internal/entity/models/vllm.go:551](internal/entity/models/vllm.go#L551)
is currently a stub returning `nil, fmt.Errorf("%s, Rerank not
implemented", z.Name())`, and
[conf/models/vllm.json](conf/models/vllm.json) is missing a `rerank`
entry in `url_suffix`. Chat (long-standing) and embeddings (#14688)
already work, so rerank is the last missing leg of the retrieval
pipeline for operators running everything on a single self-hosted vLLM
server — today they have to point rerank at a different provider, which
defeats the point of a fully local deployment.
Upstream vLLM has supported a Jina/Cohere-compatible `POST /v1/rerank`
endpoint since v0.7
([vllm-project/vllm#12376](https://github.com/vllm-project/vllm/pull/12376)).
The request/response shape is essentially identical to the NVIDIA driver
landed in #14778, so this PR mirrors that structure with two
vLLM-specific adjustments.
This PR replaces the stub with a real implementation against vLLM's
`/v1/rerank`:
- `POST {baseURL}/rerank`
- Request body: `{"model": "<modelName>", "query": "<query>",
"documents": [...], "top_n": <int>}` — documents are a flat `[]string`,
**not** wrapped as `{text: "..."}` like NVIDIA's `/ranking`.
- Response body: `{"results": [{"index": int, "relevance_score": float},
...]}` (Jina-compatible; the optional `document` field is ignored since
callers reconstruct text via `Index`).
- `Authorization: Bearer <ApiKey>` is set **only when `APIConfig.ApiKey`
is non-empty**, matching the existing `Embed`/`ListModels` behaviour in
this file. vLLM is a local driver and can be deployed without an API
key.
The return shape matches the existing `*RerankResponse` contract used by
the NVIDIA ([nvidia.go:461](internal/entity/models/nvidia.go#L461)),
Aliyun ([aliyun.go:507](internal/entity/models/aliyun.go#L507)), and
ZhipuAI ([zhipu-ai.go:554](internal/entity/models/zhipu-ai.go#L554))
drivers, i.e. `Data []RerankResult` carrying `{Index, RelevanceScore}`
in the API's ranking order. Callers that need original-input order sort
by `Index`.
Behaviour requirements from the issue, all covered:
1. Empty `documents` → returns `&RerankResponse{}` without an HTTP call.
2. Missing `modelName` → `"model name is required"` validation error.
3. `rerankConfig.TopN` honored when `0 < TopN < len(documents)`;
otherwise `top_n` defaults to `len(documents)` so callers get a score
per input.
4. Non-200 responses return an error including upstream status and body
(`"vLLM rerank API error: <status>, body: <body>"`).
5. Response `index` values are bounds-checked against `len(documents)`.
**Scope:**
- [internal/entity/models/vllm.go](internal/entity/models/vllm.go) —
replaces the `Rerank` stub at line 551 with a real implementation; adds
`vllmRerankRequest`/`vllmRerankResponse` types for the slim subset of
the payload we need. Region/baseURL resolution, 30s context timeout,
conditional bearer header, and error wrapping all follow the existing
patterns in this file.
- [conf/models/vllm.json](conf/models/vllm.json) — adds `"rerank":
"rerank"` to `url_suffix`, joined to the operator-configured vLLM base
URL the same way the NVIDIA driver joins at
[nvidia.go:485](internal/entity/models/nvidia.go#L485).
-
[internal/entity/models/vllm_rerank_test.go](internal/entity/models/vllm_rerank_test.go)
— adds 7 `httptest`-backed tests mirroring `nvidia_rerank_test.go`:
happy path (out-of-order ranking → Index preservation), `top_n` clamp to
`RerankConfig.TopN`, empty-documents short-circuit, missing-model-name
validation, HTTP error propagation, out-of-range index rejection, and a
vLLM-specific `TestVllmRerankWithoutAPIKey` locking in the optional-auth
behaviour that distinguishes this driver from NVIDIA.
**Out of scope:** no interface change, no DDL, no frontend change. Chat,
embeddings, and balance paths are untouched. No new user-facing docs
required beyond the existing rerank model setup page — vLLM joins the
list of providers whose rerank model can be selected once `/v1/rerank`
is exposed by the server.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
The vLLM Go driver shipped with a stub \`Encode\` method that returned
\`not implemented\`, even though vLLM is one of the most common
production-grade self-hosted inference servers and exposes an
OpenAI-compatible embeddings endpoint at \`/v1/embeddings\`.
Users who self-host \`BAAI/bge-m3\`, \`Qwen3-Embedding-*\`,
\`NV-Embed-v2\`, or similar models on vLLM could not run an embedding
call through the Go layer. The existing \`ListModels\` already discovers
the loaded models, but the embedding path failed because \`Encode\` was
a stub.
### What this PR includes
- \`conf/models/vllm.json\`: add \`\"embedding\": \"embeddings\"\` under
\`url_suffix\` so the driver can build the URL from config.
- \`internal/entity/models/vllm.go\`: replace the \`Encode\` stub with a
real implementation. Adds a small local response
type that matches the OpenAI-compatible shape.
No factory change. No interface change.
### How the driver works
- Validate the model name. The API key is optional for self-hosted vLLM,
so the Authorization header is only set when both \`apiConfig\` and
\`ApiKey\` are non-nil and non-empty, the same pattern the recently
merged CheckConnection PR (#14614) uses.
- Resolve the region with a default fallback. Return a clear "missing
base URL" error when the user has not configured
the local access address yet.
- Use a per-call \`context.WithTimeout(30s)\` and
\`http.NewRequestWithContext\`, the same pattern the merged
Aliyun Encode (#14647) and in-flight Ollama Encode (#14664) use.
- Send \`{model, input: [texts]}\` in one request.
- Parse \`data[*].embedding\` and copy each slice into a \`[][]float64\`
indexed by \`data[*].index\`, so the output
order matches the input order.
- Handle both \`float64\` and \`float32\` element types.
- Empty input returns \`[][]float64{}\` with no HTTP call.
- Length mismatch between input and result, out-of-range index, and any
missing slot all return clear errors instead
of silent zero vectors.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### How was this tested?
- \`go build ./internal/entity/models/...\` in a clean go 1.25 image
returns exit 0.
- The full method set on \`VllmModel\` still matches the \`ModelDriver\`
interface.
- Pattern parity with the merged Aliyun Encode (#14647), the in-flight
Ollama Encode (#14664), and the existing
SiliconFlow Encode.
Closes#14687
### What problem does this PR solve?
1. support command:
```
RAGFlow(user)> create provider 'vllm' instance 'test' key 'test-key' url 'base-url' region 'abc';
SUCCESS
RAGFlow(user)> list instances from 'vllm';
+----------+----------------------------------------+----------------------------------+--------------+----------------------------------+--------+
| apiKey | extra | id | instanceName | providerID | status |
+----------+----------------------------------------+----------------------------------+--------------+----------------------------------+--------+
| test-key | {"base_url":"base-url","region":"abc"} | 40213c89430311f1a7cf38a74640adcc | test | b4d40e6142d311f1a4f938a74640adcc | enable |
+----------+----------------------------------------+----------------------------------+--------------+----------------------------------+--------+
```
2. support add vllm model
```
RAGFlow(user)> add model 'Qwen/Qwen2-0.5B' to provider 'vllm' instance 'test' with tokens 131072 chat;
SUCCESS
```
3. add vllm chat
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Refactoring
---------
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
