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|
package llm
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"log"
"net/http"
"os"
"time"
)
// openAIClient implements Client against OpenAI's Chat Completions API.
type openAIClient struct {
httpClient *http.Client
apiKey string
baseURL string
defaultModel string
logger *log.Logger
}
func newOpenAIFromEnv(apiKey string, logger *log.Logger) Client {
base := os.Getenv("OPENAI_BASE_URL")
if base == "" {
base = "https://api.openai.com/v1"
}
model := os.Getenv("OPENAI_MODEL")
if model == "" {
model = "gpt-4o-mini"
}
return &openAIClient{
httpClient: &http.Client{Timeout: 30 * time.Second},
apiKey: apiKey,
baseURL: base,
defaultModel: model,
logger: logger,
}
}
type oaChatRequest struct {
Model string `json:"model"`
Messages []oaMessage `json:"messages"`
Temperature *float64 `json:"temperature,omitempty"`
MaxTokens *int `json:"max_tokens,omitempty"`
Stop []string `json:"stop,omitempty"`
}
type oaMessage struct {
Role string `json:"role"`
Content string `json:"content"`
}
type oaChatResponse struct {
Choices []struct {
Index int `json:"index"`
Message struct {
Role string `json:"role"`
Content string `json:"content"`
} `json:"message"`
FinishReason string `json:"finish_reason"`
} `json:"choices"`
Error *struct {
Message string `json:"message"`
Type string `json:"type"`
Param any `json:"param"`
Code any `json:"code"`
} `json:"error,omitempty"`
}
func (c *openAIClient) Chat(ctx context.Context, messages []Message, opts ...RequestOption) (string, error) {
if c.apiKey == "" {
return nilStringErr("missing OpenAI API key")
}
o := Options{Model: c.defaultModel}
for _, opt := range opts {
opt(&o)
}
if o.Model == "" {
o.Model = c.defaultModel
}
start := time.Now()
c.logf("chat start model=%s temp=%.2f max_tokens=%d stop=%d messages=%d", o.Model, o.Temperature, o.MaxTokens, len(o.Stop), len(messages))
for i, m := range messages {
c.logf("msg[%d] role=%s size=%d preview=%s", i, m.Role, len(m.Content), trimPreview(m.Content, 200))
}
req := oaChatRequest{Model: o.Model}
req.Messages = make([]oaMessage, len(messages))
for i, m := range messages {
req.Messages[i] = oaMessage{Role: m.Role, Content: m.Content}
}
if o.Temperature != 0 {
req.Temperature = &o.Temperature
}
if o.MaxTokens > 0 {
req.MaxTokens = &o.MaxTokens
}
if len(o.Stop) > 0 {
req.Stop = o.Stop
}
body, err := json.Marshal(req)
if err != nil {
c.logf("marshal error: %v", err)
return "", err
}
endpoint := c.baseURL + "/chat/completions"
c.logf("POST %s", endpoint)
httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
if err != nil {
c.logf("new request error: %v", err)
return "", err
}
httpReq.Header.Set("Content-Type", "application/json")
httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
resp, err := c.httpClient.Do(httpReq)
if err != nil {
c.logf("http error after %s: %v", time.Since(start), err)
return "", err
}
defer resp.Body.Close()
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
var apiErr oaChatResponse
_ = json.NewDecoder(resp.Body).Decode(&apiErr)
if apiErr.Error != nil && apiErr.Error.Message != "" {
c.logf("api error status=%d type=%s msg=%s duration=%s", resp.StatusCode, apiErr.Error.Type, apiErr.Error.Message, time.Since(start))
return "", fmt.Errorf("openai error: %s (status %d)", apiErr.Error.Message, resp.StatusCode)
}
c.logf("http non-2xx status=%d duration=%s", resp.StatusCode, time.Since(start))
return "", fmt.Errorf("openai http error: status %d", resp.StatusCode)
}
var out oaChatResponse
if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
c.logf("decode error after %s: %v", time.Since(start), err)
return "", err
}
if len(out.Choices) == 0 {
c.logf("no choices returned duration=%s", time.Since(start))
return "", errors.New("openai: no choices returned")
}
content := out.Choices[0].Message.Content
c.logf("success choice=0 finish=%s size=%d preview=%s duration=%s", out.Choices[0].FinishReason, len(content), trimPreview(content, 200), time.Since(start))
return content, nil
}
// small helper to keep return type consistent
func nilStringErr(msg string) (string, error) { return "", errors.New(msg) }
func (c *openAIClient) logf(format string, args ...any) {
if c.logger != nil {
c.logger.Printf("llm/openai "+format, args...)
}
}
func trimPreview(s string, n int) string {
if n <= 0 || len(s) <= n {
return s
}
return s[:n] + "…"
}
|
