109 lines
3.5 KiB
Go
109 lines
3.5 KiB
Go
package alertnotification
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import (
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"bytes"
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"context"
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"crypto/hmac"
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"crypto/sha256"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"strconv"
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"strings"
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"time"
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"data-terminal-cloud/internal/outbox"
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)
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const maxErrorBody = 1024
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type webhookEnvelope struct {
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EventID string `json:"event_id"`
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EventType string `json:"event_type"`
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Data json.RawMessage `json:"data"`
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}
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type Processor struct {
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endpoint string
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secret []byte
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client *http.Client
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now func() time.Time
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}
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func NewProcessor(endpoint, secret string, timeout time.Duration) (*Processor, error) {
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endpoint = strings.TrimSpace(endpoint)
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secret = strings.TrimSpace(secret)
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if timeout <= 0 {
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return nil, errors.New("alert webhook timeout must be positive")
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}
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if endpoint == "" {
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return &Processor{client: &http.Client{Timeout: timeout}, now: time.Now}, nil
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}
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parsed, err := url.Parse(endpoint)
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if err != nil || parsed.Host == "" || (parsed.Scheme != "http" && parsed.Scheme != "https") {
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return nil, errors.New("alert webhook URL must be an absolute HTTP(S) URL")
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}
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if len(secret) < 32 {
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return nil, errors.New("alert webhook secret must contain at least 32 characters")
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}
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return &Processor{endpoint: endpoint, secret: []byte(secret), client: &http.Client{Timeout: timeout}, now: time.Now}, nil
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}
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func (p *Processor) Handle(ctx context.Context, event outbox.Event) error {
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if p.endpoint == "" {
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if event.EventType == "alert.webhook_test_requested" {
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return errors.New("alert webhook delivery is not configured")
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}
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return nil
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}
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if event.ID == "" || !supportedEventType(event.EventType) || !json.Valid(event.Payload) {
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return errors.New("invalid alert webhook event")
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}
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body, err := json.Marshal(webhookEnvelope{EventID: event.ID, EventType: event.EventType, Data: event.Payload})
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if err != nil {
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return fmt.Errorf("encode alert webhook: %w", err)
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}
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timestamp := strconv.FormatInt(p.now().UTC().Unix(), 10)
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, p.endpoint, bytes.NewReader(body))
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if err != nil {
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return fmt.Errorf("build alert webhook request: %w", err)
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}
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req.Header.Set("Content-Type", "application/json")
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req.Header.Set("User-Agent", "voice-platform-alert-webhook/1.0")
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req.Header.Set("X-Voice-Event-ID", event.ID)
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req.Header.Set("X-Voice-Timestamp", timestamp)
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req.Header.Set("X-Voice-Signature", sign(p.secret, timestamp, body))
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resp, err := p.client.Do(req)
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if err != nil {
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return outbox.Retryable(fmt.Errorf("deliver alert webhook: %w", err))
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}
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defer resp.Body.Close()
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if resp.StatusCode >= 200 && resp.StatusCode < 300 {
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_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, maxErrorBody))
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return nil
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}
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responseBody, _ := io.ReadAll(io.LimitReader(resp.Body, maxErrorBody))
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requestErr := fmt.Errorf("alert webhook returned HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(responseBody)))
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if resp.StatusCode == http.StatusRequestTimeout || resp.StatusCode == http.StatusTooEarly || resp.StatusCode == http.StatusTooManyRequests || resp.StatusCode >= 500 {
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return outbox.Retryable(requestErr)
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}
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return requestErr
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}
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func supportedEventType(eventType string) bool {
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return eventType == "alert.webhook_requested" || eventType == "alert.webhook_test_requested"
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}
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func sign(secret []byte, timestamp string, body []byte) string {
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mac := hmac.New(sha256.New, secret)
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_, _ = mac.Write([]byte(timestamp))
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_, _ = mac.Write([]byte("."))
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_, _ = mac.Write(body)
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return "v1=" + hex.EncodeToString(mac.Sum(nil))
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}
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