client: allow setting rate limiter for requests

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/sirupsen/logrus v1.9.4
 	github.com/stretchr/testify v1.11.1
 	golang.org/x/exp v0.0.0-20220414153411-bcd21879b8fd
+	golang.org/x/time v0.5.0
 	gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637
 )
 

go.sum

@@ -29,6 +29,8 @@ golang.org/x/net v0.25.0 h1:d/OCCoBEUq33pjydKrGQhw7IlUPI2Oylr+8qLx49kac=
 golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
 golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
 golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
+golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637 h1:yiW+nvdHb9LVqSHQBXfZCieqV4fzYhNBql77zY0ykqs=

rest/client.go

@@ -5,18 +5,25 @@ import (
 	"fmt"
 	"net/http"
 	"os"
-	"time"
 	"reflect"
+	"time"
+
+	"golang.org/x/time/rate"
 
 	"github.com/massive-com/client-go/v3/rest/gen"
 )
 
+const (
+	rateLimiterSleepInterval = 100 * time.Millisecond
+)
+
 type Client struct {
 	*gen.ClientWithResponses
 	httpClient *http.Client
 	apiKey     string
 	trace      bool
 	pagination bool
+	limiter    *rate.Limiter
 }
 
 type Option func(*Client)
@@ -29,6 +36,14 @@ func WithPagination(enabled bool) Option {
 	return func(c *Client) { c.pagination = enabled }
 }
 
+// WithLimiter sets a rate limiter for the request rate.
+// limiter is checked before
+func WithLimiter(limiter *rate.Limiter) Option {
+	return func(c *Client) {
+		c.limiter = limiter
+	}
+}
+
 // New is backward-compatible (no options = trace=false, pagination=true)
 func New(apiKey string) *Client {
 	return NewWithOptions(apiKey)
@@ -66,8 +81,9 @@ func NewWithOptions(apiKey string, opts ...Option) *Client {
 
 	var err error
 	c.ClientWithResponses, err = gen.NewClientWithResponses("https://api.massive.com",
-		gen.WithHTTPClient(c.httpClient),   // ← THIS makes the FIRST request traced
+		gen.WithHTTPClient(c.httpClient), // ← THIS makes the FIRST request traced
 		gen.WithRequestEditorFn(c.addHeaders),
+		gen.WithRequestEditorFn(c.rateLimit),
 	)
 	if err != nil {
 		panic(err)
@@ -76,18 +92,31 @@ func NewWithOptions(apiKey string, opts ...Option) *Client {
 	return c
 }
 
+// rateLimit enforces the rate limit on the client that was
+// set by WithLimiter during creation time.
+func (c *Client) rateLimit(_ context.Context, _ *http.Request) error {
+	if c.limiter != nil {
+		for !c.limiter.Allow() {
+			time.Sleep(rateLimiterSleepInterval)
+			continue
+		}
+	}
+
+	return nil
+}
+
 func (c *Client) addHeaders(_ context.Context, req *http.Request) error {
 	req.Header.Set("Authorization", "Bearer "+c.apiKey)
 	req.Header.Set("User-Agent", "massive-go-test")
 	return nil
 }
 
 // === Pointer helpers ===
-func String(v string) *string { return &v }
-func Int(v int) *int         { return &v }
-func Int64(v int64) *int64   { return &v }
+func String(v string) *string    { return &v }
+func Int(v int) *int             { return &v }
+func Int64(v int64) *int64       { return &v }
 func Float64(v float64) *float64 { return &v }
-func Bool(v bool) *bool      { return &v }
+func Bool(v bool) *bool          { return &v }
 
 // Generic Ptr (used for everything else, including custom enums)
 func Ptr[T any](v T) *T { return &v }

rest/iterator.go

@@ -57,6 +57,9 @@ func (it *Iterator) fetchNextPage(urlStr string) ([]map[string]any, *string, err
 	if err != nil {
 		return nil, nil, err
 	}
+
+	it.client.rateLimit(req.Context(), req)
+
 	if err := it.client.addHeaders(context.Background(), req); err != nil {
 		return nil, nil, err
 	}