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
|
/*
This file is part of GNU Taler
(C) 2019 GNUnet e.V.
GNU Taler 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, or (at your option) any later version.
TALER 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
GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* Implementation of token bucket throttling.
*/
/**
* Imports.
*/
import {
getTimestampNow,
timestampDifference,
timestampCmp,
} from "../util/time";
import { URL } from "./url";
import { Logger } from "./logging";
const logger = new Logger("RequestThrottler.ts");
/**
* Maximum request per second, per origin.
*/
const MAX_PER_SECOND = 100;
/**
* Maximum request per minute, per origin.
*/
const MAX_PER_MINUTE = 500;
/**
* Maximum request per hour, per origin.
*/
const MAX_PER_HOUR = 2000;
/**
* Throttling state for one origin.
*/
class OriginState {
tokensSecond: number = MAX_PER_SECOND;
tokensMinute: number = MAX_PER_MINUTE;
tokensHour: number = MAX_PER_HOUR;
private lastUpdate = getTimestampNow();
private refill(): void {
const now = getTimestampNow();
if (timestampCmp(now, this.lastUpdate) < 0) {
// Did the system time change?
this.lastUpdate = now;
return;
}
const d = timestampDifference(now, this.lastUpdate);
if (d.d_ms === "forever") {
throw Error("assertion failed");
}
this.tokensSecond = Math.min(
MAX_PER_SECOND,
this.tokensSecond + d.d_ms / 1000,
);
this.tokensMinute = Math.min(
MAX_PER_MINUTE,
this.tokensMinute + d.d_ms / 1000 / 60,
);
this.tokensHour = Math.min(
MAX_PER_HOUR,
this.tokensHour + d.d_ms / 1000 / 60 / 60,
);
this.lastUpdate = now;
}
/**
* Return true if the request for this origin should be throttled.
* Otherwise, take a token out of the respective buckets.
*/
applyThrottle(): boolean {
this.refill();
if (this.tokensSecond < 1) {
logger.warn("request throttled (per second limit exceeded)");
return true;
}
if (this.tokensMinute < 1) {
logger.warn("request throttled (per minute limit exceeded)");
return true;
}
if (this.tokensHour < 1) {
logger.warn("request throttled (per hour limit exceeded)");
return true;
}
this.tokensSecond--;
this.tokensMinute--;
this.tokensHour--;
return false;
}
}
/**
* Request throttler, used as a "last layer of defense" when some
* other part of the re-try logic is broken and we're sending too
* many requests to the same exchange/bank/merchant.
*/
export class RequestThrottler {
private perOriginInfo: { [origin: string]: OriginState } = {};
/**
* Get the throttling state for an origin, or
* initialize if no state is associated with the
* origin yet.
*/
private getState(origin: string): OriginState {
const s = this.perOriginInfo[origin];
if (s) {
return s;
}
const ns = (this.perOriginInfo[origin] = new OriginState());
return ns;
}
/**
* Apply throttling to a request.
*
* @returns whether the request should be throttled.
*/
applyThrottle(requestUrl: string): boolean {
const origin = new URL(requestUrl).origin;
return this.getState(origin).applyThrottle();
}
/**
* Get the throttle statistics for a particular URL.
*/
getThrottleStats(requestUrl: string): Record<string, unknown> {
const origin = new URL(requestUrl).origin;
const state = this.getState(origin);
return {
tokensHour: state.tokensHour,
tokensMinute: state.tokensMinute,
tokensSecond: state.tokensSecond,
maxTokensHour: MAX_PER_HOUR,
maxTokensMinute: MAX_PER_MINUTE,
maxTokensSecond: MAX_PER_SECOND,
};
}
}
|
