feat: add LangChainGo Huggingface backend (#446)

Co-authored-by: Ettore Di Giacinto <mudler@users.noreply.github.com>

pkg/langchain/huggingface.go

@@ -0,0 +1,47 @@
+package langchain
+
+import (
+	"context"
+
+	"github.com/tmc/langchaingo/llms"
+	"github.com/tmc/langchaingo/llms/huggingface"
+)
+
+type HuggingFace struct {
+	modelPath string
+}
+
+func NewHuggingFace(repoId string) (*HuggingFace, error) {
+	return &HuggingFace{
+		modelPath: repoId,
+	}, nil
+}
+
+func (s *HuggingFace) PredictHuggingFace(text string, opts ...PredictOption) (*Predict, error) {
+	po := NewPredictOptions(opts...)
+
+	// Init client
+	llm, err := huggingface.New()
+	if err != nil {
+		return nil, err
+	}
+
+	// Convert from LocalAI to LangChainGo format of options
+	co := []llms.CallOption{
+		llms.WithModel(po.Model),
+		llms.WithMaxTokens(po.MaxTokens),
+		llms.WithTemperature(po.Temperature),
+		llms.WithStopWords(po.StopWords),
+	}
+
+	// Call Inference API
+	ctx := context.Background()
+	completion, err := llm.Call(ctx, text, co...)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Predict{
+		Completion: completion,
+	}, nil
+}

pkg/langchain/langchain.go

@@ -0,0 +1,57 @@
+package langchain
+
+type PredictOptions struct {
+	Model string `json:"model"`
+	// MaxTokens is the maximum number of tokens to generate.
+	MaxTokens int `json:"max_tokens"`
+	// Temperature is the temperature for sampling, between 0 and 1.
+	Temperature float64 `json:"temperature"`
+	// StopWords is a list of words to stop on.
+	StopWords []string `json:"stop_words"`
+}
+
+type PredictOption func(p *PredictOptions)
+
+var DefaultOptions = PredictOptions{
+	Model:       "gpt2",
+	MaxTokens:   200,
+	Temperature: 0.96,
+	StopWords:   nil,
+}
+
+type Predict struct {
+	Completion string
+}
+
+func SetModel(model string) PredictOption {
+	return func(o *PredictOptions) {
+		o.Model = model
+	}
+}
+
+func SetTemperature(temperature float64) PredictOption {
+	return func(o *PredictOptions) {
+		o.Temperature = temperature
+	}
+}
+
+func SetMaxTokens(maxTokens int) PredictOption {
+	return func(o *PredictOptions) {
+		o.MaxTokens = maxTokens
+	}
+}
+
+func SetStopWords(stopWords []string) PredictOption {
+	return func(o *PredictOptions) {
+		o.StopWords = stopWords
+	}
+}
+
+// NewPredictOptions Create a new PredictOptions object with the given options.
+func NewPredictOptions(opts ...PredictOption) PredictOptions {
+	p := DefaultOptions
+	for _, opt := range opts {
+		opt(&p)
+	}
+	return p
+}

pkg/model/initializers.go

@@ -7,6 +7,7 @@ import (
 
 	rwkv "github.com/donomii/go-rwkv.cpp"
 	whisper "github.com/ggerganov/whisper.cpp/bindings/go/pkg/whisper"
+	"github.com/go-skynet/LocalAI/pkg/langchain"
 	"github.com/go-skynet/LocalAI/pkg/stablediffusion"
 	bloomz "github.com/go-skynet/bloomz.cpp"
 	bert "github.com/go-skynet/go-bert.cpp"
@@ -36,6 +37,7 @@ const (
 	RwkvBackend            = "rwkv"
 	WhisperBackend         = "whisper"
 	StableDiffusionBackend = "stablediffusion"
+	LCHuggingFaceBackend   = "langchain-huggingface"
 )
 
 var backends []string = []string{
@@ -100,6 +102,10 @@ var whisperModel = func(modelFile string) (interface{}, error) {
 	return whisper.New(modelFile)
 }
 
+var lcHuggingFace = func(repoId string) (interface{}, error) {
+	return langchain.NewHuggingFace(repoId)
+}
+
 func llamaLM(opts ...llama.ModelOption) func(string) (interface{}, error) {
 	return func(s string) (interface{}, error) {
 		return llama.New(s, opts...)
@@ -159,6 +165,8 @@ func (ml *ModelLoader) BackendLoader(backendString string, modelFile string, lla
 		return ml.LoadModel(modelFile, rwkvLM(filepath.Join(ml.ModelPath, modelFile+tokenizerSuffix), threads))
 	case WhisperBackend:
 		return ml.LoadModel(modelFile, whisperModel)
+	case LCHuggingFaceBackend:
+		return ml.LoadModel(modelFile, lcHuggingFace)
 	default:
 		return nil, fmt.Errorf("backend unsupported: %s", backendString)
 	}