Refactored common rate limit code into separate module

internal/backends/funkwhale/client.go

@@ -23,15 +23,13 @@ package funkwhale
 
 import (
 	"errors"
-	"net/http"
 	"strconv"
-	"time"
 
 	"github.com/go-resty/resty/v2"
+	"go.uploadedlobster.com/scotty/internal/ratelimit"
 )
 
 const MaxItemsPerGet = 50
-const DefaultRateLimitWaitSeconds = 5
 
 type Client struct {
 	HttpClient *resty.Client
@@ -46,25 +44,7 @@ func NewClient(serverUrl string, token string) Client {
 	client.SetHeader("Accept", "application/json")
 
 	// Handle rate limiting (see https://docs.funkwhale.audio/developer/api/rate-limit.html)
-	client.SetRetryCount(5)
+	ratelimit.EnableHTTPHeaderRateLimit(client, "Retry-After")
-	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
-	})
 
 	return Client{
 		HttpClient: client,

internal/backends/listenbrainz/client.go

@@ -23,20 +23,18 @@ package listenbrainz
 
 import (
 	"errors"
-	"net/http"
 	"strconv"
 	"time"
 
 	"github.com/go-resty/resty/v2"
+	"go.uploadedlobster.com/scotty/internal/ratelimit"
 )
 
-const listenBrainzBaseURL = "https://api.listenbrainz.org/1/"
-
 const (
-	DefaultItemsPerGet          = 25
+	listenBrainzBaseURL  = "https://api.listenbrainz.org/1/"
-	MaxItemsPerGet              = 1000
+	DefaultItemsPerGet   = 25
-	MaxListensPerRequest        = 1000
+	MaxItemsPerGet       = 1000
-	DefaultRateLimitWaitSeconds = 5
+	MaxListensPerRequest = 1000
 )
 
 type Client struct {
@@ -52,25 +50,7 @@ func NewClient(token string) Client {
 	client.SetHeader("Accept", "application/json")
 
 	// Handle rate limiting (see https://listenbrainz.readthedocs.io/en/latest/users/api/index.html#rate-limiting)
-	client.SetRetryCount(5)
+	ratelimit.EnableHTTPHeaderRateLimit(client, "X-RateLimit-Reset-In")
-	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("X-RateLimit-Reset-In"))
-			if err != nil {
-				retryAfter = DefaultRateLimitWaitSeconds
-			}
-		}
-		return time.Duration(retryAfter * int(time.Second)), err
-	})
 
 	return Client{
 		HttpClient: client,

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 (
-const MaxItemsPerGet = 50
+	baseURL        = "https://api.spotify.com/v1/"
-const DefaultRateLimitWaitSeconds = 5
+	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(
+	// Handle rate limiting (see https://developer.spotify.com/documentation/web-api/concepts/rate-limits)
-		func(r *resty.Response, err error) bool {
+	ratelimit.EnableHTTPHeaderRateLimit(client, "Retry-After")
-			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
-	})
 	return Client{
 		HttpClient: client,
 	}

internal/ratelimit/httpheader.go

@@ -0,0 +1,52 @@
+/*
+Copyright © 2023 Philipp Wolfer <phw@uploadedlobster.com>
+
+Scotty is free software: you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later version.
+
+Scotty is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+Scotty. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package ratelimit
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/go-resty/resty/v2"
+)
+
+const (
+	RetryCount                  = 5
+	DefaultRateLimitWaitSeconds = 5
+	MaxWaitTimeSeconds          = 60
+)
+
+func EnableHTTPHeaderRateLimit(client *resty.Client, resetInHeader string) {
+	client.SetRetryCount(RetryCount)
+	client.AddRetryCondition(
+		func(r *resty.Response, err error) bool {
+			code := r.StatusCode()
+			return code == http.StatusTooManyRequests || code >= http.StatusInternalServerError
+		},
+	)
+	client.SetRetryMaxWaitTime(time.Duration(MaxWaitTimeSeconds * time.Second))
+	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(resetInHeader))
+			if err != nil {
+				retryAfter = DefaultRateLimitWaitSeconds
+			}
+		}
+		return time.Duration(retryAfter * int(time.Second)), err
+	})
+}