Add Sentinel MetricExtension, which provides extension to Sentinel internal statistics.
This extension provides callbacks when a request passes rule checking, 
blocked by flow control, successfully end or exception occurred. 
Accompanied by these events, response time and current thread number 
will be recorded too.

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- Refactor the semantics and logic for blockHandler and fallback
- Add `fallbackClass` support for fallback in global classes
- Add `defaultFallback` support
- Update test cases and demo

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- The `appType` can be retrieved from `csp.sentinel.app.type` field. It's useful to identify the service type (e.g. API gateway).

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

* Add unit test for com.alibaba.csp.sentinel.util.IdUtil
* Add unit tests for com.alibaba.csp.sentinel.util.StringUtil

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

to avoid affecting normal logic of users

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

* De-duplicate rules automatically when loading rules
* Update rule managers

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

* Rename: MetricsLeapArray -> BucketLeapArray
* Add implementation for `FutureBucketLeapArray`, a kind of `BucketLeapArray` that only reserves for future buckets, which is used for calculating occupied future tokens.
* Add OccupiableBucketLeapArray that combines common BucketLeapArray with FutureBucketLeapArray. The rollingNumberInSecond in StatisticNode now uses OccupiableBucketLeapArray by default.
* Add OccupySupport interface. Node now implements OccupySupport interface.
* Add occupy-related methods in Metric and ArrayMetric.
* Handle prioritized requests in default traffic shaping controller.
* Update default occupyTimeout to 500ms

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- Update test cases (use assertEquals(e, a, delta) instead)
- Also add `totalPass` method in Node interface

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

This reverts commit 35371c1

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

- Regard the total inbound as a "virtual node" with the name `__total_inbound_traffic__`

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- `Entry` class now implements `AutoCloseable` so it supports try-with-resources (`close` method adapts to `exit`)

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

close → open: use `compareAndSet` to update for `cut` attribute (changed to an `AtomicBoolean`)

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

* Extract getRule in BlockException and refine override methods in subclasses

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- Apply awaitility to core tests
- Cache maven local repo in Travis

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

- reuse old map size to avoid rearrange and rehash the map