120 lines
2.8 KiB
Go
120 lines
2.8 KiB
Go
package llm
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"strconv"
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"strings"
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"time"
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)
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// Client calls an OpenAI-compatible chat completions endpoint.
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type Client struct {
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baseURL string
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apiKey string
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model string
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httpClient *http.Client
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}
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// New constructs a Client.
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func New(baseURL, apiKey, model string, timeout time.Duration) *Client {
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return &Client{
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baseURL: strings.TrimRight(baseURL, "/"),
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apiKey: apiKey,
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model: model,
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httpClient: &http.Client{Timeout: timeout},
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}
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}
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type chatRequest struct {
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Model string `json:"model"`
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Messages []message `json:"messages"`
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Temperature float64 `json:"temperature"`
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}
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type message struct {
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Role string `json:"role"`
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Content string `json:"content"`
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}
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type chatResponse struct {
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Choices []struct {
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Message message `json:"message"`
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} `json:"choices"`
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}
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// Complete sends a system + user message and returns the assistant's reply.
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// Retries once on HTTP 429 using Retry-After header or 5s backoff.
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func (c *Client) Complete(ctx context.Context, system, user string) (string, error) {
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body := chatRequest{
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Model: c.model,
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Messages: []message{
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{Role: "system", Content: system},
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{Role: "user", Content: user},
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},
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Temperature: 0.2,
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}
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b, err := json.Marshal(body)
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if err != nil {
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return "", fmt.Errorf("marshal request: %w", err)
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}
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do := func() (*http.Response, error) {
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/chat/completions", bytes.NewReader(b))
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if err != nil {
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return nil, fmt.Errorf("build request: %w", err)
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}
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req.Header.Set("Content-Type", "application/json")
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if c.apiKey != "" {
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req.Header.Set("Authorization", "Bearer "+c.apiKey)
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}
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return c.httpClient.Do(req)
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}
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resp, err := do()
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if err != nil {
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return "", fmt.Errorf("call LLM: %w", err)
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}
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if resp.StatusCode == http.StatusTooManyRequests {
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_ = resp.Body.Close()
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wait := 5 * time.Second
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if ra := resp.Header.Get("Retry-After"); ra != "" {
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if secs, err := strconv.Atoi(ra); err == nil {
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wait = time.Duration(secs) * time.Second
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}
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}
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select {
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case <-ctx.Done():
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return "", ctx.Err()
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case <-time.After(wait):
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}
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resp, err = do()
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if err != nil {
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return "", fmt.Errorf("retry LLM call: %w", err)
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}
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}
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defer resp.Body.Close() //nolint:errcheck
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out, err := io.ReadAll(resp.Body)
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if err != nil {
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return "", fmt.Errorf("read response: %w", err)
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}
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if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("LLM returned %d: %s", resp.StatusCode, out)
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}
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var cr chatResponse
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if err := json.Unmarshal(out, &cr); err != nil {
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return "", fmt.Errorf("parse response: %w", err)
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}
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if len(cr.Choices) == 0 {
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return "", fmt.Errorf("LLM returned no choices")
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}
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return cr.Choices[0].Message.Content, nil
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}
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