### What problem does this PR solve?
Closes#15089.
Adds PPIO support to the Go model-provider layer so PPIO instances can
be routed through the Go API server with the same OpenAI-compatible
chat, streaming, model listing, and connection-check flow used by other
SaaS providers.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
## Summary
- Added a PPIO Go model driver.
- Added the PPIO provider catalog and default OpenAI-compatible API URL.
- Registered PPIO in the model factory.
- Added focused provider and provider-manager tests.
## What changed
- Implemented chat completions, SSE streaming, ListModels, and
CheckConnection for PPIO.
- Covered request shape, stream termination, reasoning fallback, model
listing, custom base URLs, safe transport setup, unsupported methods,
and provider config loading.
- Kept the provider catalog aligned with the existing RAGFlow PPIO
factory model set.
- Cleaned up pre-existing Go model package validation blockers so the
scoped provider tests can run normally with vet enabled.
## Why
The existing Python/provider catalog path includes PPIO, but the Go
model-provider layer did not have a PPIO driver, so the Go API server
could not instantiate or use PPIO as requested in #15089.
## Summary
- Replaces the `"no such method"` stub on `XinferenceModel.Embed`
(`internal/entity/models/xinference.go`) with a real implementation
against Xinference's OpenAI-compatible `/v1/embeddings` endpoint.
- Adds the `"embedding": "v1/embeddings"` URL suffix to
`conf/models/xinference.json`.
- Mirrors the Python `XinferenceEmbed` class in
`rag/llm/embedding_model.py:407` for payload shape (OpenAI-compatible
`model + input` → `data[*].index + data[*].embedding`) and tolerates the
same no-auth default Xinference deployments use. Authorization is only
sent when a non-empty API key is configured, via the existing
`setXinferenceAuth` helper.
- Reuses the existing `normalizeXinferenceBaseURL` + `baseURLForRegion`
helpers so both `http://127.0.0.1:9997` and `http://127.0.0.1:9997/v1`
resolve to the same `/v1/embeddings` target without doubled `/v1`.
- Validates response indices — duplicate, missing, or out-of-range
`data[*].index` values fail with a clear error rather than silently
producing misaligned vectors.
- Returns `[]EmbeddingData` in original input order (placed by `Index`)
so downstream callers can index positionally without re-sorting.
- Forwards `EmbeddingConfig.Dimension` as `dimensions` when `> 0`,
matching the OpenAI cluster pattern.
Closes#14810
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
Fixes#14816
The Xinference Go driver landed chat in #14938 and Embed is in review in
#14932, but `Rerank` shipped as a stub that returns `"xinference, no
such method"`. Tenants who launch a rerank model with `--model-type
rerank` on their Xinference instance cannot route it through the Go API
server. This PR fills the gap.
Xinference exposes an OpenAI-compatible REST API. The rerank endpoint is
at `POST <base>/v1/rerank` and accepts the Cohere-shaped body `{model,
query, documents, top_n}`, returning `{results: [{index,
relevance_score}]}` — the same wire shape used by the merged NVIDIA
(#14778), Aliyun (#14676), Gitee (#14656), ZhipuAI (#14608), Novita
(#15014), and LocalAI (#14813) Rerank implementations. Documented in
[Xinference rerank
docs](https://inference.readthedocs.io/en/v1.6.1/models/model_abilities/rerank.html);
the [builtin rerank model
catalog](https://inference.readthedocs.io/en/stable/models/builtin/rerank/)
lists `bge-reranker-base`, `bge-reranker-large`, `bge-reranker-v2-m3`,
and others.
### What problem does this PR solve?
Closes#14808.
Adds a Go model driver for Xinference so self-hosted Xinference chat
models can be used through the Go provider layer instead of falling
through to the dummy driver. Xinference exposes an OpenAI-compatible API
under `/v1`; the driver accepts either a root endpoint such as
`http://127.0.0.1:9997` or an OpenAI-compatible endpoint such as
`http://127.0.0.1:9997/v1` and normalizes it before calling chat or
model-listing routes.
### What is changed?
- Add `internal/entity/models/xinference.go` implementing `ModelDriver`
for Xinference chat.
- Route provider name `xinference` in
`internal/entity/models/factory.go`.
- Add `conf/models/xinference.json` as a local provider config.
- Add focused unit tests in `internal/entity/models/xinference_test.go`.
Initial method coverage:
- `ChatWithMessages`: POST `/v1/chat/completions`.
- `ChatStreamlyWithSender`: SSE streaming from `/v1/chat/completions`.
- `ListModels`: GET `/v1/models`.
- `CheckConnection`: lightweight `ListModels` probe.
- Optional auth: send `Authorization: Bearer <api_key>` only when a
non-empty key is configured, matching Xinference no-auth and
auth-enabled deployments.
- `Balance`, `Embed`, `Rerank`, ASR, TTS, and OCR return `no such
method` for this initial chat-provider PR.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Bug Fix (non-breaking change which fixes an issue)
### Tests
- `go test -vet=off -run TestXinference -count=1
./internal/entity/models/...`
- `go test -vet=off -count=1 ./internal/entity/models/...`
### References
- Xinference docs:
https://inference.readthedocs.io/zh-cn/latest/index.html
- OpenAI-compatible chat usage:
https://inference.readthedocs.io/zh-cn/latest/getting_started/using_xinference.html
- API key auth:
https://inference.readthedocs.io/zh-cn/latest/user_guide/auth_system.html
---------
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
