Refactored common rate limit code into separate module

internal/backends/spotify/client.go

@@ -25,17 +25,18 @@ package spotify
 import (
 	"context"
 	"errors"
-	"net/http"
 	"strconv"
 	"time"
 
 	"github.com/go-resty/resty/v2"
+	"go.uploadedlobster.com/scotty/internal/ratelimit"
 	"golang.org/x/oauth2"
 )
 
-const baseURL = "https://api.spotify.com/v1/"
-const MaxItemsPerGet = 50
-const DefaultRateLimitWaitSeconds = 5
+const (
+	baseURL        = "https://api.spotify.com/v1/"
+	MaxItemsPerGet = 50
+)
 
 type Client struct {
 	HttpClient *resty.Client
@@ -47,25 +48,10 @@ func NewClient(token oauth2.TokenSource) Client {
 	client := resty.NewWithClient(httpClient)
 	client.SetBaseURL(baseURL)
 	client.SetHeader("Accept", "application/json")
-	client.SetRetryCount(5)
-	client.AddRetryCondition(
-		func(r *resty.Response, err error) bool {
-			code := r.StatusCode()
-			return code == http.StatusTooManyRequests || code >= http.StatusInternalServerError
-		},
-	)
-	client.SetRetryMaxWaitTime(time.Duration(1 * time.Minute))
-	client.SetRetryAfter(func(client *resty.Client, resp *resty.Response) (time.Duration, error) {
-		var err error
-		var retryAfter int = DefaultRateLimitWaitSeconds
-		if resp.StatusCode() == http.StatusTooManyRequests {
-			retryAfter, err = strconv.Atoi(resp.Header().Get("Retry-After"))
-			if err != nil {
-				retryAfter = DefaultRateLimitWaitSeconds
-			}
-		}
-		return time.Duration(retryAfter * int(time.Second)), err
-	})
+
+	// Handle rate limiting (see https://developer.spotify.com/documentation/web-api/concepts/rate-limits)
+	ratelimit.EnableHTTPHeaderRateLimit(client, "Retry-After")
+
 	return Client{
 		HttpClient: client,
 	}