# SnowJena
**Repository Path**: dingjunjun_codeSpace/SnowJena
## Basic Information
- **Project Name**: SnowJena
- **Description**: 基于令牌桶算法和漏桶算法实现的分布式无锁限流框架，支持嵌入SpringBoot、SpringCloud应用，支持接口限流、方法限流、系统限流、IP限流、用户限流等规则，支持熔断降级，支持流量塑形，支持可视化QPS监控，支持支持设置系统启动保护时间（保护时间内不允许访问），提供快速失败与匀速器两种限流方案，开箱即用。
- **Primary Language**: Java
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: https://www.yueshutong.cn/SnowJena/
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 1
- **Created**: 2022-10-14
- **Last Updated**: 2022-10-14
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
# SnowJean Documentation
## Maven
```xml
cn.yueshutong
snowjena-core
1.0.0.RELEASE
```
## A single point of current limit
This project provides an easy-to-use API. For a single point of current limitation, it is only necessary to produce the current limiter through factory mode and call the tryAcquire() method before the code that needs to be limited runs.
```java
public class AppTest {
Logger logger = LoggerFactory.getLogger(getClass());
@Test
public void test1(){
// 1.configuration rule
LimiterRule limiterRule = new LimiterRule();
limiterRule.setQps(1); //Concurrency per second
// 2.Factory mode production of current limiter
RateLimiter limiter = RateLimiterFactory.of(limiterRule);
// 3.use
while (true){
if (limiter.tryAcquire()){
logger.info("ok");
}
}
}
}
```
View console print :
```verilog
15:10:06.670 [main] INFO com.example.springbootdemo.AppTest - ok
15:10:07.651 [main] INFO com.example.springbootdemo.AppTest - ok
15:10:08.653 [main] INFO com.example.springbootdemo.AppTest - ok
15:10:09.652 [main] INFO com.example.springbootdemo.AppTest - ok
```
## blacklist and whitelist
Black and white list function: black list is not allowed to pass, or only allow the white list to pass (either).
```java
public class AppTest {
Logger logger = LoggerFactory.getLogger(getClass());
/**
* blacklist and whitelist
*/
@Test
public void test2(){
// 1.configuration rule
LimiterRule limiterRule = new LimiterRule();
limiterRule.setQps(1);
limiterRule.setRuleAuthority(RuleAuthority.AUTHORITY_BLACK);
limiterRule.setLimitApp(new String[]{"user1","user2"});
// 2.Factory mode production of current limiter
RateLimiter limiter = RateLimiterFactory.of(limiterRule);
// 3.use
while (true){
if (limiter.tryAcquire("user1")){
logger.info("user1");
}
if (limiter.tryAcquire("user2")){
logger.info("user2");
}
if (limiter.tryAcquire("user3")){
logger.info("user3");
}
}
}
}
```
View console print
```verilog
15:19:22.506 [main] INFO com.example.springbootdemo.AppTest - user3
15:19:23.522 [main] INFO com.example.springbootdemo.AppTest - user3
15:19:24.484 [main] INFO com.example.springbootdemo.AppTest - user3
```
## Distributed current limiting
Distributed current limiting function is more powerful than single point current limiting function, which supports fusing degradation, flow shaping, dynamic configuration rules and visual monitoring, out of the box.
You need to:
1. start Redis
In this example, Redis is enabled locally by default, with default port 6379 and no password.
2. start TicketServer
Download the ticketserver.jar and run on the default port 8521.
Interface after launching TicketServer: 
Client-Side Code
```java
public class AppTest {
Logger logger = LoggerFactory.getLogger(getClass());
@Test
public void test4() {
// 1.Current limiting configuration
LimiterRule limiterRule = new LimiterRule();
limiterRule.setApp("Application");
limiterRule.setId("myId");
limiterRule.setQps(1);
limiterRule.setLimiterModel(LimiterModel.CLOUD);
// 2.configuration TicketServer location（Support for clustering and weighting）
Map map = new HashMap<>();
map.put("127.0.0.1:8521",1);
// 3.Global Configuration
RateLimiterConfig config = RateLimiterConfig.getInstance();
config.setTicketServer(map);
// 4.Factory mode production of current limiter
RateLimiter limiter = RateLimiterFactory.of(limiterRule, config);
// 5.use
while (true) {
if (limiter.tryAcquire()) {
logger.info("ok");
}
}
}
}
```
View console print
```verilog
16:07:08.694 [main] INFO com.example.springbootdemo.AppTest - ok
16:07:09.660 [main] INFO com.example.springbootdemo.AppTest - ok
16:07:10.643 [main] INFO com.example.springbootdemo.AppTest - ok
```
## Deshboard
At this point, open your browser and go to localhost:8521 to see the console view
You can modify QPS in real time, control behavior, current limiting algorithm, black and white list, it should be noted that the list list in English, comma separated.
You can also view the system load online by monitoring the view. (QPS: request received, PASS: request allowed)
## Current limiting rules
Some functions have been briefly mentioned above, while the LimiterRule is explained in detail below.
| parameter | explain |
| ------------- | --------------------------------------------- |
| initialDelay | The initial time delay |
| acquireModel | Control behavior: fast failure/constant speed |
| algorithm | Algorithm: token bucket/leak bucket |
| limiterModel | Deployment mode: single point/distributed |
| ruleAuthority | Blacklist/whitelist/none |
| limitApp | Black and white list |
> Documentation continues to improve. Please submit Issues.