-
Notifications
You must be signed in to change notification settings - Fork 0
/
ratelimiting.go
112 lines (97 loc) · 3.13 KB
/
ratelimiting.go
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
package mvp
import (
"fmt"
"time"
"github.com/andreyvit/mvp/flogger"
"golang.org/x/time/rate"
)
type RateLimitSettings struct {
PerSec rate.Limit
Burst int
}
type RateLimitPreset string
const (
RateLimitPresetNone = RateLimitPreset("none")
RateLimitPresetDefaultWebRead = RateLimitPreset("web.r")
RateLimitPresetDefaultWebWrite = RateLimitPreset("web.w")
RateLimitPresetDefaultAPIRead = RateLimitPreset("api.r")
RateLimitPresetDefaultAPIWrite = RateLimitPreset("api.w")
RateLimitPresetSpam = RateLimitPreset("spam")
RateLimitPresetAuthentication = RateLimitPreset("auth")
RateLimitPresetDangerous = RateLimitPreset("danger")
)
type RateLimitGranularity string
const (
RateLimitGranularityApp = RateLimitGranularity("app")
RateLimitGranularityIP = RateLimitGranularity("ip")
RateLimitGranularityUser = RateLimitGranularity("user")
RateLimitGranularityKey = RateLimitGranularity("key")
)
type RateLimiter struct {
defaultLimiter *rate.Limiter
Preset RateLimitPreset
Settings RateLimitSettings
}
func (limiter *RateLimiter) Limiter(key string) *rate.Limiter {
if key == "" {
return limiter.defaultLimiter
} else {
panic("TODO: add support for per-key limiters")
}
}
func initRateLimiting(app *App) {
app.rateLimiters = make(map[RateLimitPreset]map[RateLimitGranularity]*RateLimiter)
for preset, granSettings := range app.Settings.RateLimits {
granLimiters := make(map[RateLimitGranularity]*RateLimiter)
for gran, settings := range granSettings {
granLimiters[gran] = &RateLimiter{
defaultLimiter: rate.NewLimiter(settings.PerSec, settings.Burst),
Preset: preset,
Settings: settings,
}
}
app.rateLimiters[preset] = granLimiters
}
app.rateLimiters[RateLimitPresetNone] = map[RateLimitGranularity]*RateLimiter{}
}
func (app *App) RateLimiters(preset RateLimitPreset) map[RateLimitGranularity]*RateLimiter {
result := app.rateLimiters[preset]
if result == nil {
panic(fmt.Errorf("rate limiter preset not configured: %q", preset))
}
return result
}
func (app *App) enforceRateLimit(rc *RC) (any, error) {
if app.Settings.DisableRateLimits {
return nil, nil
}
preset := rc.RateLimitPreset
limiters := app.RateLimiters(preset)
var maxDelay time.Duration
var maxGran RateLimitGranularity
enforce := func(gran RateLimitGranularity, key string) error {
if limiter := limiters[gran]; limiter != nil {
now := rc.Now()
rsrv := limiter.Limiter(key).ReserveN(now, 1)
delay := rsrv.DelayFrom(now)
if delay > app.Settings.MaxRateLimitRequestDelay.Value() {
rsrv.CancelAt(now)
flogger.Log(rc, "ratelimit: %s:%s hard rate limit exceeded (refusing to sleep for %d ms)", preset, gran, delay.Milliseconds())
return ErrTooManyRequests
}
if delay > maxDelay {
maxDelay, maxGran = delay, gran
}
}
return nil
}
if err := enforce(RateLimitGranularityApp, ""); err != nil {
return nil, err
}
// TODO: IP, etc -- when we add support for per-key limiters
if maxDelay > 0 {
flogger.Log(rc, "ratelimit: %s:%s soft rate limit exceeded (delay %d ms)", preset, maxGran, maxDelay.Milliseconds())
time.Sleep(maxDelay)
}
return nil, nil
}