package openai import ( "encoding/json" "fmt" "strings" "time" "github.com/google/uuid" "github.com/labstack/echo/v4" "github.com/mudler/LocalAI/core/backend" "github.com/mudler/LocalAI/core/config" "github.com/mudler/LocalAI/core/http/middleware" "github.com/mudler/LocalAI/core/schema" "github.com/mudler/LocalAI/pkg/functions" reason "github.com/mudler/LocalAI/pkg/reasoning" "github.com/mudler/LocalAI/core/templates" "github.com/mudler/LocalAI/pkg/model" "github.com/mudler/xlog" ) // ChatEndpoint is the OpenAI Completion API endpoint https://platform.openai.com/docs/api-reference/chat/create // @Summary Generate a chat completions for a given prompt and model. // @Param request body schema.OpenAIRequest true "query params" // @Success 200 {object} schema.OpenAIResponse "Response" // @Router /v1/chat/completions [post] func ChatEndpoint(cl *config.ModelConfigLoader, ml *model.ModelLoader, evaluator *templates.Evaluator, startupOptions *config.ApplicationConfig) echo.HandlerFunc { var id, textContentToReturn string var created int process := func(s string, req *schema.OpenAIRequest, config *config.ModelConfig, loader *model.ModelLoader, responses chan schema.OpenAIResponse, extraUsage bool) error { initialMessage := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{Delta: &schema.Message{Role: "assistant"}, Index: 0, FinishReason: nil}}, Object: "chat.completion.chunk", } responses <- initialMessage // Detect if thinking token is already in prompt or template // When UseTokenizerTemplate is enabled, predInput is empty, so we check the template var template string if config.TemplateConfig.UseTokenizerTemplate { template = config.GetModelTemplate() } else { template = s } thinkingStartToken := reason.DetectThinkingStartToken(template, &config.ReasoningConfig) // Track accumulated content for reasoning extraction accumulatedContent := "" lastEmittedReasoning := "" lastEmittedCleanedContent := "" _, _, err := ComputeChoices(req, s, config, cl, startupOptions, loader, func(s string, c *[]schema.Choice) {}, func(s string, tokenUsage backend.TokenUsage) bool { accumulatedContent += s currentReasoning, cleanedContent := reason.ExtractReasoningWithConfig(accumulatedContent, thinkingStartToken, config.ReasoningConfig) // Calculate new reasoning delta (what we haven't emitted yet) var reasoningDelta *string if currentReasoning != lastEmittedReasoning { // Extract only the new part if len(currentReasoning) > len(lastEmittedReasoning) && strings.HasPrefix(currentReasoning, lastEmittedReasoning) { newReasoning := currentReasoning[len(lastEmittedReasoning):] reasoningDelta = &newReasoning lastEmittedReasoning = currentReasoning } else if currentReasoning != "" { // If reasoning changed in a non-append way, emit the full current reasoning reasoningDelta = ¤tReasoning lastEmittedReasoning = currentReasoning } } // Calculate content delta from cleaned content var deltaContent string if len(cleanedContent) > len(lastEmittedCleanedContent) && strings.HasPrefix(cleanedContent, lastEmittedCleanedContent) { deltaContent = cleanedContent[len(lastEmittedCleanedContent):] lastEmittedCleanedContent = cleanedContent } else if cleanedContent != lastEmittedCleanedContent { // If cleaned content changed but not in a simple append, extract delta from cleaned content // This handles cases where thinking tags are removed mid-stream if lastEmittedCleanedContent == "" { deltaContent = cleanedContent lastEmittedCleanedContent = cleanedContent } else { // Content changed in non-append way, use the new cleaned content deltaContent = cleanedContent lastEmittedCleanedContent = cleanedContent } } // Only emit content if there's actual content (not just thinking tags) // If deltaContent is empty, we still emit the response but with empty content usage := schema.OpenAIUsage{ PromptTokens: tokenUsage.Prompt, CompletionTokens: tokenUsage.Completion, TotalTokens: tokenUsage.Prompt + tokenUsage.Completion, } if extraUsage { usage.TimingTokenGeneration = tokenUsage.TimingTokenGeneration usage.TimingPromptProcessing = tokenUsage.TimingPromptProcessing } delta := &schema.Message{} // Only include content if there's actual content (not just thinking tags) if deltaContent != "" { delta.Content = &deltaContent } if reasoningDelta != nil && *reasoningDelta != "" { delta.Reasoning = reasoningDelta } resp := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{Delta: delta, Index: 0, FinishReason: nil}}, Object: "chat.completion.chunk", Usage: usage, } responses <- resp return true }) close(responses) return err } processTools := func(noAction string, prompt string, req *schema.OpenAIRequest, config *config.ModelConfig, loader *model.ModelLoader, responses chan schema.OpenAIResponse, extraUsage bool) error { // Detect if thinking token is already in prompt or template var template string if config.TemplateConfig.UseTokenizerTemplate { template = config.GetModelTemplate() } else { template = prompt } thinkingStartToken := reason.DetectThinkingStartToken(template, &config.ReasoningConfig) result := "" lastEmittedCount := 0 _, tokenUsage, err := ComputeChoices(req, prompt, config, cl, startupOptions, loader, func(s string, c *[]schema.Choice) {}, func(s string, usage backend.TokenUsage) bool { result += s // Try incremental XML parsing for streaming support using iterative parser // This allows emitting partial tool calls as they're being generated cleanedResult := functions.CleanupLLMResult(result, config.FunctionsConfig) // Determine XML format from config var xmlFormat *functions.XMLToolCallFormat if config.FunctionsConfig.XMLFormat != nil { xmlFormat = config.FunctionsConfig.XMLFormat } else if config.FunctionsConfig.XMLFormatPreset != "" { xmlFormat = functions.GetXMLFormatPreset(config.FunctionsConfig.XMLFormatPreset) } // Use iterative parser for streaming (partial parsing enabled) // Try XML parsing first partialResults, parseErr := functions.ParseXMLIterative(cleanedResult, xmlFormat, true) if parseErr == nil && len(partialResults) > 0 { // Emit new XML tool calls that weren't emitted before if len(partialResults) > lastEmittedCount { for i := lastEmittedCount; i < len(partialResults); i++ { toolCall := partialResults[i] initialMessage := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, Choices: []schema.Choice{{ Delta: &schema.Message{ Role: "assistant", ToolCalls: []schema.ToolCall{ { Index: i, ID: id, Type: "function", FunctionCall: schema.FunctionCall{ Name: toolCall.Name, }, }, }, }, Index: 0, FinishReason: nil, }}, Object: "chat.completion.chunk", } select { case responses <- initialMessage: default: } } lastEmittedCount = len(partialResults) } } else { // Try JSON tool call parsing for streaming // Check if the result looks like JSON tool calls jsonResults, jsonErr := functions.ParseJSONIterative(cleanedResult, true) if jsonErr == nil && len(jsonResults) > 0 { // Check if these are tool calls (have "name" and optionally "arguments") for _, jsonObj := range jsonResults { if name, ok := jsonObj["name"].(string); ok && name != "" { // This looks like a tool call args := "{}" if argsVal, ok := jsonObj["arguments"]; ok { if argsStr, ok := argsVal.(string); ok { args = argsStr } else { argsBytes, _ := json.Marshal(argsVal) args = string(argsBytes) } } // Emit tool call initialMessage := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, Choices: []schema.Choice{{ Delta: &schema.Message{ Role: "assistant", ToolCalls: []schema.ToolCall{ { Index: lastEmittedCount, ID: id, Type: "function", FunctionCall: schema.FunctionCall{ Name: name, Arguments: args, }, }, }, }, Index: 0, FinishReason: nil, }}, Object: "chat.completion.chunk", } select { case responses <- initialMessage: default: } lastEmittedCount++ } } } } return true }) if err != nil { return err } // Prepend thinking token if needed, then extract reasoning before processing tool calls reasoning, result := reason.ExtractReasoningWithConfig(result, thinkingStartToken, config.ReasoningConfig) textContentToReturn = functions.ParseTextContent(result, config.FunctionsConfig) result = functions.CleanupLLMResult(result, config.FunctionsConfig) functionResults := functions.ParseFunctionCall(result, config.FunctionsConfig) xlog.Debug("Text content to return", "text", textContentToReturn) noActionToRun := len(functionResults) > 0 && functionResults[0].Name == noAction || len(functionResults) == 0 switch { case noActionToRun: initialMessage := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{Delta: &schema.Message{Role: "assistant"}, Index: 0, FinishReason: nil}}, Object: "chat.completion.chunk", } responses <- initialMessage result, err := handleQuestion(config, functionResults, result, prompt) if err != nil { xlog.Error("error handling question", "error", err) return err } usage := schema.OpenAIUsage{ PromptTokens: tokenUsage.Prompt, CompletionTokens: tokenUsage.Completion, TotalTokens: tokenUsage.Prompt + tokenUsage.Completion, } if extraUsage { usage.TimingTokenGeneration = tokenUsage.TimingTokenGeneration usage.TimingPromptProcessing = tokenUsage.TimingPromptProcessing } var deltaReasoning *string if reasoning != "" { deltaReasoning = &reasoning } delta := &schema.Message{Content: &result} if deltaReasoning != nil { delta.Reasoning = deltaReasoning } resp := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{Delta: delta, Index: 0, FinishReason: nil}}, Object: "chat.completion.chunk", Usage: usage, } responses <- resp default: for i, ss := range functionResults { name, args := ss.Name, ss.Arguments initialMessage := schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{ Delta: &schema.Message{ Role: "assistant", ToolCalls: []schema.ToolCall{ { Index: i, ID: id, Type: "function", FunctionCall: schema.FunctionCall{ Name: name, }, }, }, }, Index: 0, FinishReason: nil, }}, Object: "chat.completion.chunk", } responses <- initialMessage responses <- schema.OpenAIResponse{ ID: id, Created: created, Model: req.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{{ Delta: &schema.Message{ Role: "assistant", Content: &textContentToReturn, ToolCalls: []schema.ToolCall{ { Index: i, ID: id, Type: "function", FunctionCall: schema.FunctionCall{ Arguments: args, }, }, }, }, Index: 0, FinishReason: nil, }}, Object: "chat.completion.chunk", } } } close(responses) return err } return func(c echo.Context) error { textContentToReturn = "" id = uuid.New().String() created = int(time.Now().Unix()) input, ok := c.Get(middleware.CONTEXT_LOCALS_KEY_LOCALAI_REQUEST).(*schema.OpenAIRequest) if !ok || input.Model == "" { return echo.ErrBadRequest } extraUsage := c.Request().Header.Get("Extra-Usage") != "" config, ok := c.Get(middleware.CONTEXT_LOCALS_KEY_MODEL_CONFIG).(*config.ModelConfig) if !ok || config == nil { return echo.ErrBadRequest } xlog.Debug("Chat endpoint configuration read", "config", config) funcs := input.Functions shouldUseFn := len(input.Functions) > 0 && config.ShouldUseFunctions() strictMode := false xlog.Debug("Tool call routing decision", "shouldUseFn", shouldUseFn, "len(input.Functions)", len(input.Functions), "len(input.Tools)", len(input.Tools), "config.ShouldUseFunctions()", config.ShouldUseFunctions(), "config.FunctionToCall()", config.FunctionToCall(), ) for _, f := range input.Functions { if f.Strict { strictMode = true break } } // Allow the user to set custom actions via config file // to be "embedded" in each model noActionName := "answer" noActionDescription := "use this action to answer without performing any action" if config.FunctionsConfig.NoActionFunctionName != "" { noActionName = config.FunctionsConfig.NoActionFunctionName } if config.FunctionsConfig.NoActionDescriptionName != "" { noActionDescription = config.FunctionsConfig.NoActionDescriptionName } // If we are using a response format, we need to generate a grammar for it if config.ResponseFormatMap != nil { d := schema.ChatCompletionResponseFormat{} dat, err := json.Marshal(config.ResponseFormatMap) if err != nil { return err } err = json.Unmarshal(dat, &d) if err != nil { return err } switch d.Type { case "json_object": input.Grammar = functions.JSONBNF case "json_schema": d := schema.JsonSchemaRequest{} dat, err := json.Marshal(config.ResponseFormatMap) if err != nil { return err } err = json.Unmarshal(dat, &d) if err != nil { return err } fs := &functions.JSONFunctionStructure{ AnyOf: []functions.Item{d.JsonSchema.Schema}, } g, err := fs.Grammar(config.FunctionsConfig.GrammarOptions()...) if err == nil { input.Grammar = g } else { xlog.Error("Failed generating grammar", "error", err) } } } config.Grammar = input.Grammar if shouldUseFn { xlog.Debug("Response needs to process functions") } switch { // Generates grammar with internal's LocalAI engine case (!config.FunctionsConfig.GrammarConfig.NoGrammar || strictMode) && shouldUseFn: noActionGrammar := functions.Function{ Name: noActionName, Description: noActionDescription, Parameters: map[string]interface{}{ "properties": map[string]interface{}{ "message": map[string]interface{}{ "type": "string", "description": "The message to reply the user with", }}, }, } // Append the no action function if !config.FunctionsConfig.DisableNoAction && !strictMode { funcs = append(funcs, noActionGrammar) } // Force picking one of the functions by the request if config.FunctionToCall() != "" { funcs = funcs.Select(config.FunctionToCall()) } // Update input grammar or json_schema based on use_llama_grammar option jsStruct := funcs.ToJSONStructure(config.FunctionsConfig.FunctionNameKey, config.FunctionsConfig.FunctionNameKey) g, err := jsStruct.Grammar(config.FunctionsConfig.GrammarOptions()...) if err == nil { config.Grammar = g } else { xlog.Error("Failed generating grammar", "error", err) } case input.JSONFunctionGrammarObject != nil: g, err := input.JSONFunctionGrammarObject.Grammar(config.FunctionsConfig.GrammarOptions()...) if err == nil { config.Grammar = g } else { xlog.Error("Failed generating grammar", "error", err) } default: // Force picking one of the functions by the request if config.FunctionToCall() != "" { funcs = funcs.Select(config.FunctionToCall()) } } // process functions if we have any defined or if we have a function call string // functions are not supported in stream mode (yet?) toStream := input.Stream xlog.Debug("Parameters", "config", config) var predInput string // If we are using the tokenizer template, we don't need to process the messages // unless we are processing functions if !config.TemplateConfig.UseTokenizerTemplate { predInput = evaluator.TemplateMessages(*input, input.Messages, config, funcs, shouldUseFn) xlog.Debug("Prompt (after templating)", "prompt", predInput) if config.Grammar != "" { xlog.Debug("Grammar", "grammar", config.Grammar) } } switch { case toStream: xlog.Debug("Stream request received") c.Response().Header().Set("Content-Type", "text/event-stream") c.Response().Header().Set("Cache-Control", "no-cache") c.Response().Header().Set("Connection", "keep-alive") c.Response().Header().Set("X-Correlation-ID", id) responses := make(chan schema.OpenAIResponse) ended := make(chan error, 1) go func() { if !shouldUseFn { ended <- process(predInput, input, config, ml, responses, extraUsage) } else { ended <- processTools(noActionName, predInput, input, config, ml, responses, extraUsage) } }() usage := &schema.OpenAIUsage{} toolsCalled := false LOOP: for { select { case <-input.Context.Done(): // Context was cancelled (client disconnected or request cancelled) xlog.Debug("Request context cancelled, stopping stream") input.Cancel() break LOOP case ev := <-responses: if len(ev.Choices) == 0 { xlog.Debug("No choices in the response, skipping") continue } usage = &ev.Usage // Copy a pointer to the latest usage chunk so that the stop message can reference it if len(ev.Choices[0].Delta.ToolCalls) > 0 { toolsCalled = true } respData, err := json.Marshal(ev) if err != nil { xlog.Debug("Failed to marshal response", "error", err) input.Cancel() continue } xlog.Debug("Sending chunk", "chunk", string(respData)) _, err = fmt.Fprintf(c.Response().Writer, "data: %s\n\n", string(respData)) if err != nil { xlog.Debug("Sending chunk failed", "error", err) input.Cancel() return err } c.Response().Flush() case err := <-ended: if err == nil { break LOOP } xlog.Error("Stream ended with error", "error", err) stopReason := FinishReasonStop resp := &schema.OpenAIResponse{ ID: id, Created: created, Model: input.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{ { FinishReason: &stopReason, Index: 0, Delta: &schema.Message{Content: "Internal error: " + err.Error()}, }}, Object: "chat.completion.chunk", Usage: *usage, } respData, marshalErr := json.Marshal(resp) if marshalErr != nil { xlog.Error("Failed to marshal error response", "error", marshalErr) // Send a simple error message as fallback fmt.Fprintf(c.Response().Writer, "data: {\"error\":\"Internal error\"}\n\n") } else { fmt.Fprintf(c.Response().Writer, "data: %s\n\n", respData) } fmt.Fprintf(c.Response().Writer, "data: [DONE]\n\n") c.Response().Flush() return nil } } finishReason := FinishReasonStop if toolsCalled && len(input.Tools) > 0 { finishReason = FinishReasonToolCalls } else if toolsCalled { finishReason = FinishReasonFunctionCall } resp := &schema.OpenAIResponse{ ID: id, Created: created, Model: input.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: []schema.Choice{ { FinishReason: &finishReason, Index: 0, Delta: &schema.Message{}, }}, Object: "chat.completion.chunk", Usage: *usage, } respData, _ := json.Marshal(resp) fmt.Fprintf(c.Response().Writer, "data: %s\n\n", respData) fmt.Fprintf(c.Response().Writer, "data: [DONE]\n\n") c.Response().Flush() xlog.Debug("Stream ended") return nil // no streaming mode default: // Detect if thinking token is already in prompt or template var template string if config.TemplateConfig.UseTokenizerTemplate { template = config.GetModelTemplate() // TODO: this should be the parsed jinja template. But for now this is the best we can do. } else { template = predInput } thinkingStartToken := reason.DetectThinkingStartToken(template, &config.ReasoningConfig) xlog.Debug("Thinking start token", "thinkingStartToken", thinkingStartToken, "template", template) var emptyRetryNeeded bool tokenCallback := func(s string, c *[]schema.Choice) { // Prepend thinking token if needed, then extract reasoning from the response reasoning, s := reason.ExtractReasoningWithConfig(s, thinkingStartToken, config.ReasoningConfig) if !shouldUseFn { stopReason := FinishReasonStop message := &schema.Message{Role: "assistant", Content: &s} if reasoning != "" { message.Reasoning = &reasoning } *c = append(*c, schema.Choice{FinishReason: &stopReason, Index: 0, Message: message}) return } textContentToReturn = functions.ParseTextContent(s, config.FunctionsConfig) s = functions.CleanupLLMResult(s, config.FunctionsConfig) results := functions.ParseFunctionCall(s, config.FunctionsConfig) xlog.Debug("Text content to return", "text", textContentToReturn) noActionsToRun := len(results) > 0 && results[0].Name == noActionName || len(results) == 0 switch { case noActionsToRun: if s == "" && textContentToReturn == "" { xlog.Warn("Backend returned empty content in tool-calling context, will retry") emptyRetryNeeded = true return } result, err := handleQuestion(config, results, s, predInput) if err != nil { xlog.Error("error handling question", "error", err) emptyRetryNeeded = true return } stopReason := FinishReasonStop message := &schema.Message{Role: "assistant", Content: &result} if reasoning != "" { message.Reasoning = &reasoning } *c = append(*c, schema.Choice{ FinishReason: &stopReason, Message: message}) default: toolCallsReason := FinishReasonToolCalls toolChoice := schema.Choice{ FinishReason: &toolCallsReason, Message: &schema.Message{ Role: "assistant", }, } if reasoning != "" { toolChoice.Message.Reasoning = &reasoning } for _, ss := range results { name, args := ss.Name, ss.Arguments if len(input.Tools) > 0 { // If we are using tools, we condense the function calls into // a single response choice with all the tools toolChoice.Message.Content = textContentToReturn toolChoice.Message.ToolCalls = append(toolChoice.Message.ToolCalls, schema.ToolCall{ ID: id, Type: "function", FunctionCall: schema.FunctionCall{ Name: name, Arguments: args, }, }, ) } else { // otherwise we return more choices directly (deprecated) functionCallReason := FinishReasonFunctionCall message := &schema.Message{ Role: "assistant", Content: &textContentToReturn, FunctionCall: map[string]interface{}{ "name": name, "arguments": args, }, } if reasoning != "" { message.Reasoning = &reasoning } *c = append(*c, schema.Choice{ FinishReason: &functionCallReason, Message: message, }) } } if len(input.Tools) > 0 { // we need to append our result if we are using tools *c = append(*c, toolChoice) } } } // Echo properly supports context cancellation via c.Request().Context() // No workaround needed! const maxEmptyRetries = 5 var result []schema.Choice var tokenUsage backend.TokenUsage var err error for attempt := 0; attempt <= maxEmptyRetries; attempt++ { emptyRetryNeeded = false result, tokenUsage, err = ComputeChoices( input, predInput, config, cl, startupOptions, ml, tokenCallback, nil, ) if err != nil || !emptyRetryNeeded { break } xlog.Warn("Retrying prediction due to empty backend response", "attempt", attempt+1, "maxRetries", maxEmptyRetries) } if err != nil { return err } if emptyRetryNeeded { xlog.Warn("All retries exhausted, backend still returning empty content") stopReason := FinishReasonStop empty := "" result = append(result, schema.Choice{ FinishReason: &stopReason, Index: 0, Message: &schema.Message{Role: "assistant", Content: &empty}, }) } usage := schema.OpenAIUsage{ PromptTokens: tokenUsage.Prompt, CompletionTokens: tokenUsage.Completion, TotalTokens: tokenUsage.Prompt + tokenUsage.Completion, } if extraUsage { usage.TimingTokenGeneration = tokenUsage.TimingTokenGeneration usage.TimingPromptProcessing = tokenUsage.TimingPromptProcessing } resp := &schema.OpenAIResponse{ ID: id, Created: created, Model: input.Model, // we have to return what the user sent here, due to OpenAI spec. Choices: result, Object: "chat.completion", Usage: usage, } respData, _ := json.Marshal(resp) xlog.Debug("Response", "response", string(respData)) // Return the prediction in the response body return c.JSON(200, resp) } } } func handleQuestion(config *config.ModelConfig, funcResults []functions.FuncCallResults, result, prompt string) (string, error) { if len(funcResults) == 0 && result != "" { xlog.Debug("nothing function results but we had a message from the LLM") return result, nil } xlog.Debug("nothing to do, computing a reply") arg := "" if len(funcResults) > 0 { arg = funcResults[0].Arguments } // If there is a message that the LLM already sends as part of the JSON reply, use it arguments := map[string]interface{}{} if err := json.Unmarshal([]byte(arg), &arguments); err != nil { xlog.Debug("handleQuestion: function result did not contain a valid JSON object") } m, exists := arguments["message"] if exists { switch message := m.(type) { case string: if message != "" { xlog.Debug("Reply received from LLM", "message", message) message = backend.Finetune(*config, prompt, message) xlog.Debug("Reply received from LLM(finetuned)", "message", message) return message, nil } } } xlog.Debug("No action received from LLM, without a message, computing a reply") return "", fmt.Errorf("no action received from LLM, without a message, computing a reply") }