Something + add comments to proto

internal/provider/musicbrainz/client.go

@@ -17,8 +17,10 @@ import (
 )
 
 const (
-	baseURL   = "https://musicbrainz.org/ws/2"
-	userAgent = "MetadataAggregator/0.1.0 (https://github.com/metadata-agregator)"
+	baseURL     = "https://musicbrainz.org/ws/2"
+	userAgent   = "MetadataAggregator/0.1.0 (https://github.com/metadata-agregator)"
+	maxRetries  = 3
+	baseBackoff = 2 * time.Second
 )
 
 type client struct {
@@ -36,16 +38,45 @@ func newClient() *client {
 }
 
 func (c *client) get(ctx context.Context, endpoint string, params url.Values) ([]byte, error) {
-	if err := c.waitForRateLimit(ctx); err != nil {
-		return nil, err
+	var lastErr error
+
+	for attempt := 0; attempt <= maxRetries; attempt++ {
+		if err := c.waitForRateLimit(ctx); err != nil {
+			return nil, err
+		}
+
+		req, err := c.buildRequest(ctx, endpoint, params)
+		if err != nil {
+			return nil, err
+		}
+
+		data, err := c.executeAndRead(ctx, req, endpoint)
+		if err == nil {
+			return data, nil
+		}
+
+		if err != ErrRateLimited {
+			return nil, err
+		}
+
+		lastErr = err
+		if attempt < maxRetries {
+			backoff := baseBackoff * time.Duration(1<<attempt)
+			zerolog.Ctx(ctx).Info().
+				Int("attempt", attempt+1).
+				Int("max_retries", maxRetries).
+				Dur("backoff", backoff).
+				Msg("rate limited, waiting before retry")
+
+			select {
+			case <-ctx.Done():
+				return nil, ctx.Err()
+			case <-time.After(backoff):
+			}
+		}
 	}
 
-	req, err := c.buildRequest(ctx, endpoint, params)
-	if err != nil {
-		return nil, err
-	}
-
-	return c.executeAndRead(ctx, req, endpoint)
+	return nil, lastErr
 }
 
 func (c *client) waitForRateLimit(ctx context.Context) error {