iop/apps/node/internal/adapters/ollama/ollama.go

// Package ollama provides an Adapter that calls a local Ollama server.
package ollama

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"go.uber.org/zap"

	"iop/apps/node/internal/runtime"
	"iop/packages/config"
)

const Name = "ollama"

type Ollama struct {
	baseURL     string
	contextSize int
	client      *http.Client
	logger      *zap.Logger
}

func New(cfg config.OllamaConf, logger *zap.Logger) *Ollama {
	baseURL := strings.TrimRight(cfg.BaseURL, "/")
	if baseURL == "" {
		baseURL = "http://localhost:11434"
	}
	return &Ollama{
		baseURL:     baseURL,
		contextSize: cfg.ContextSize,
		client:      &http.Client{},
		logger:      logger,
	}
}

func (o *Ollama) Name() string { return Name }

func (o *Ollama) Capabilities(_ context.Context) (runtime.Capabilities, error) {
	targets := o.fetchTargets()
	return runtime.Capabilities{
		AdapterName:    Name,
		Targets:        targets,
		MaxConcurrency: 4,
	}, nil
}

func (o *Ollama) Execute(ctx context.Context, spec runtime.ExecutionSpec, sink runtime.EventSink) error {
	model := strings.TrimSpace(spec.Target)
	if model == "" {
		model = stringInput(spec.Input, "model")
	}
	if model == "" {
		return fmt.Errorf("ollama adapter: target/model is required")
	}
	messages := ollamaMessagesFromInput(spec.Input)
	if len(messages) == 0 {
		return fmt.Errorf("ollama adapter: prompt/messages are required")
	}

	if err := sink.Emit(ctx, runtime.RuntimeEvent{
		RunID:     spec.RunID,
		Type:      runtime.EventTypeStart,
		Timestamp: time.Now(),
	}); err != nil {
		return err
	}

	chatReq := ollamaChatRequest{
		Model:    model,
		Messages: messages,
		Stream:   true,
	}
	if o.contextSize > 0 {
		chatReq.Options = &ollamaOptions{NumCtx: o.contextSize}
	}
	body, err := json.Marshal(chatReq)
	if err != nil {
		return fmt.Errorf("ollama adapter: marshal request: %w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, joinURL(o.baseURL, "/api/chat"), bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("ollama adapter: build request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	o.logger.Info("ollama adapter executing",
		zap.String("run_id", spec.RunID),
		zap.String("target", model),
		zap.String("base_url", o.baseURL),
		zap.Int("context_size", o.contextSize),
	)
	resp, err := o.client.Do(req)
	if err != nil {
		_ = emitError(ctx, sink, spec.RunID, fmt.Sprintf("ollama request failed: %v", err))
		return fmt.Errorf("ollama adapter: request: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		msg := readLimited(resp.Body, 4096)
		if msg == "" {
			msg = resp.Status
		}
		_ = emitError(ctx, sink, spec.RunID, fmt.Sprintf("ollama returned %s: %s", resp.Status, msg))
		return fmt.Errorf("ollama adapter: non-2xx response: %s", resp.Status)
	}

	decoder := json.NewDecoder(resp.Body)
	outputTokens := 0
	for {
		var chunk ollamaChatChunk
		if err := decoder.Decode(&chunk); err != nil {
			if err == io.EOF {
				break
			}
			_ = emitError(ctx, sink, spec.RunID, fmt.Sprintf("ollama stream decode failed: %v", err))
			return fmt.Errorf("ollama adapter: decode stream: %w", err)
		}
		if chunk.Error != "" {
			_ = emitError(ctx, sink, spec.RunID, chunk.Error)
			return fmt.Errorf("ollama adapter: %s", chunk.Error)
		}
		if chunk.Message.Content != "" {
			outputTokens += len(strings.Fields(chunk.Message.Content))
			if err := sink.Emit(ctx, runtime.RuntimeEvent{
				RunID:     spec.RunID,
				Type:      runtime.EventTypeDelta,
				Delta:     chunk.Message.Content,
				Timestamp: time.Now(),
			}); err != nil {
				return err
			}
		}
		if chunk.Done {
			inputTokens := chunk.PromptEvalCount
			if inputTokens == 0 {
				inputTokens = countMessageWords(messages)
			}
			if chunk.EvalCount > 0 {
				outputTokens = chunk.EvalCount
			}
			return sink.Emit(ctx, runtime.RuntimeEvent{
				RunID:   spec.RunID,
				Type:    runtime.EventTypeComplete,
				Message: "ollama chat complete",
				Usage: &runtime.UsageStats{
					InputTokens:  inputTokens,
					OutputTokens: outputTokens,
				},
				Timestamp: time.Now(),
			})
		}
	}
	_ = emitError(ctx, sink, spec.RunID, "ollama stream ended without done=true")
	return fmt.Errorf("ollama adapter: stream ended without done=true")
}

func (o *Ollama) fetchTargets() []string {
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, joinURL(o.baseURL, "/api/tags"), nil)
	if err != nil {
		return nil
	}
	resp, err := o.client.Do(req)
	if err != nil {
		return nil
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil
	}
	var tags ollamaTagsResponse
	if err := json.NewDecoder(resp.Body).Decode(&tags); err != nil {
		return nil
	}
	out := make([]string, 0, len(tags.Models))
	for _, model := range tags.Models {
		if model.Name != "" {
			out = append(out, model.Name)
		}
	}
	return out
}

func ollamaMessagesFromInput(input map[string]any) []ollamaMessage {
	if raw, ok := input["messages"].([]any); ok {
		out := make([]ollamaMessage, 0, len(raw))
		for _, item := range raw {
			m, ok := item.(map[string]any)
			if !ok {
				continue
			}
			role, _ := m["role"].(string)
			content, _ := m["content"].(string)
			role = strings.TrimSpace(role)
			content = strings.TrimSpace(content)
			if role == "" || content == "" {
				continue
			}
			out = append(out, ollamaMessage{Role: role, Content: content})
		}
		if len(out) > 0 {
			return out
		}
	}
	prompt := strings.TrimSpace(stringInput(input, "prompt"))
	if prompt == "" {
		return nil
	}
	return []ollamaMessage{{Role: "user", Content: prompt}}
}

func stringInput(input map[string]any, key string) string {
	if input == nil {
		return ""
	}
	if v, ok := input[key].(string); ok {
		return v
	}
	return ""
}

func countMessageWords(messages []ollamaMessage) int {
	n := 0
	for _, msg := range messages {
		n += len(strings.Fields(msg.Content))
	}
	return n
}

func emitError(ctx context.Context, sink runtime.EventSink, runID, msg string) error {
	return sink.Emit(ctx, runtime.RuntimeEvent{
		RunID:     runID,
		Type:      runtime.EventTypeError,
		Error:     msg,
		Timestamp: time.Now(),
	})
}

func joinURL(baseURL, path string) string {
	u, err := url.Parse(baseURL)
	if err != nil {
		return strings.TrimRight(baseURL, "/") + path
	}
	u.Path = strings.TrimRight(u.Path, "/") + path
	return u.String()
}

func readLimited(r io.Reader, limit int64) string {
	b, _ := io.ReadAll(io.LimitReader(r, limit))
	return strings.TrimSpace(string(b))
}

type ollamaChatRequest struct {
	Model    string          `json:"model"`
	Messages []ollamaMessage `json:"messages"`
	Stream   bool            `json:"stream"`
	Options  *ollamaOptions  `json:"options,omitempty"`
}

type ollamaOptions struct {
	NumCtx int `json:"num_ctx,omitempty"`
}

type ollamaMessage struct {
	Role    string `json:"role"`
	Content string `json:"content"`
}

type ollamaChatChunk struct {
	Message         ollamaMessage `json:"message"`
	Done            bool          `json:"done"`
	PromptEvalCount int           `json:"prompt_eval_count"`
	EvalCount       int           `json:"eval_count"`
	Error           string        `json:"error"`
}

type ollamaTagsResponse struct {
	Models []struct {
		Name string `json:"name"`
	} `json:"models"`
}