1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
package discordgo
import (
"net/http"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
)
// customRateLimit holds information for defining a custom rate limit
type customRateLimit struct {
suffix string
requests int
reset time.Duration
}
// RateLimiter holds all ratelimit buckets
type RateLimiter struct {
sync.Mutex
global *int64
buckets map[string]*Bucket
globalRateLimit time.Duration
customRateLimits []*customRateLimit
}
// NewRatelimiter returns a new RateLimiter
func NewRatelimiter() *RateLimiter {
return &RateLimiter{
buckets: make(map[string]*Bucket),
global: new(int64),
customRateLimits: []*customRateLimit{
&customRateLimit{
suffix: "//reactions//",
requests: 1,
reset: 200 * time.Millisecond,
},
},
}
}
// GetBucket retrieves or creates a bucket
func (r *RateLimiter) GetBucket(key string) *Bucket {
r.Lock()
defer r.Unlock()
if bucket, ok := r.buckets[key]; ok {
return bucket
}
b := &Bucket{
Remaining: 1,
Key: key,
global: r.global,
}
// Check if there is a custom ratelimit set for this bucket ID.
for _, rl := range r.customRateLimits {
if strings.HasSuffix(b.Key, rl.suffix) {
b.customRateLimit = rl
break
}
}
r.buckets[key] = b
return b
}
// GetWaitTime returns the duration you should wait for a Bucket
func (r *RateLimiter) GetWaitTime(b *Bucket, minRemaining int) time.Duration {
// If we ran out of calls and the reset time is still ahead of us
// then we need to take it easy and relax a little
if b.Remaining < minRemaining && b.reset.After(time.Now()) {
return b.reset.Sub(time.Now())
}
// Check for global ratelimits
sleepTo := time.Unix(0, atomic.LoadInt64(r.global))
if now := time.Now(); now.Before(sleepTo) {
return sleepTo.Sub(now)
}
return 0
}
// LockBucket Locks until a request can be made
func (r *RateLimiter) LockBucket(bucketID string) *Bucket {
return r.LockBucketObject(r.GetBucket(bucketID))
}
// LockBucketObject Locks an already resolved bucket until a request can be made
func (r *RateLimiter) LockBucketObject(b *Bucket) *Bucket {
b.Lock()
if wait := r.GetWaitTime(b, 1); wait > 0 {
time.Sleep(wait)
}
b.Remaining--
return b
}
// Bucket represents a ratelimit bucket, each bucket gets ratelimited individually (-global ratelimits)
type Bucket struct {
sync.Mutex
Key string
Remaining int
limit int
reset time.Time
global *int64
lastReset time.Time
customRateLimit *customRateLimit
Userdata interface{}
}
// Release unlocks the bucket and reads the headers to update the buckets ratelimit info
// and locks up the whole thing in case if there's a global ratelimit.
func (b *Bucket) Release(headers http.Header) error {
defer b.Unlock()
// Check if the bucket uses a custom ratelimiter
if rl := b.customRateLimit; rl != nil {
if time.Now().Sub(b.lastReset) >= rl.reset {
b.Remaining = rl.requests - 1
b.lastReset = time.Now()
}
if b.Remaining < 1 {
b.reset = time.Now().Add(rl.reset)
}
return nil
}
if headers == nil {
return nil
}
remaining := headers.Get("X-RateLimit-Remaining")
reset := headers.Get("X-RateLimit-Reset")
global := headers.Get("X-RateLimit-Global")
retryAfter := headers.Get("Retry-After")
// Update global and per bucket reset time if the proper headers are available
// If global is set, then it will block all buckets until after Retry-After
// If Retry-After without global is provided it will use that for the new reset
// time since it's more accurate than X-RateLimit-Reset.
// If Retry-After after is not proided, it will update the reset time from X-RateLimit-Reset
if retryAfter != "" {
parsedAfter, err := strconv.ParseInt(retryAfter, 10, 64)
if err != nil {
return err
}
resetAt := time.Now().Add(time.Duration(parsedAfter) * time.Millisecond)
// Lock either this single bucket or all buckets
if global != "" {
atomic.StoreInt64(b.global, resetAt.UnixNano())
} else {
b.reset = resetAt
}
} else if reset != "" {
// Calculate the reset time by using the date header returned from discord
discordTime, err := http.ParseTime(headers.Get("Date"))
if err != nil {
return err
}
unix, err := strconv.ParseInt(reset, 10, 64)
if err != nil {
return err
}
// Calculate the time until reset and add it to the current local time
// some extra time is added because without it i still encountered 429's.
// The added amount is the lowest amount that gave no 429's
// in 1k requests
delta := time.Unix(unix, 0).Sub(discordTime) + time.Millisecond*250
b.reset = time.Now().Add(delta)
}
// Udpate remaining if header is present
if remaining != "" {
parsedRemaining, err := strconv.ParseInt(remaining, 10, 32)
if err != nil {
return err
}
b.Remaining = int(parsedRemaining)
}
return nil
}
|
