Prometheus metric extension

[CarpenterLee]

Signed-off-by: Carpenter Lee [email protected]

Describe what this PR does / why we need it

Sentinel real-time statistics are useful for system monitoring. #730 adds extension interface to Sentinel internal statistics, which provides an implementation independent way to get Sentinel statistics.

This PR provides Prometheus backend implementation of MetricExtension.

Does this pull request fix one issue?

NONE

Describe how you did it

Provides Prometheus backend implementation of MetricExtension.

Describe how to verify it

Run test cases.

Special notes for reviews

[codecov-io]

Codecov Report

Merging #735 into master will increase coverage by 0.31%.
The diff coverage is 94.23%.

@@             Coverage Diff              @@
##             master     #735      +/-   ##
============================================
+ Coverage     41.04%   41.36%   +0.31%     
- Complexity     1338     1349      +11     
============================================
  Files           301      302       +1     
  Lines          8630     8682      +52     
  Branches       1159     1159              
============================================
+ Hits           3542     3591      +49     
- Misses         4663     4666       +3     
  Partials        425      425

Impacted Files	Coverage Δ	Complexity Δ
...xtension/prometheus/PrometheusMetricExtension.java	94.23% <94.23%> (ø)	12 <12> (?)

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[sczyh30]

Related to #211

[anjia0532]

Has there been any progress in this matter?

[CLAassistant]

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[Billzaifei]

Hi, @CarpenterLee
I think the extension still need to improve. It should provide some kind of tags to distinguish from provider metrics from consumer ones.In my practice, the two metrics always make me confused.

[Billzaifei]

Hi, @sczyh30 ! Is my request(#1566 ) closed?

Issue Description
Type: feature request

Describe what happened (or what feature you want)
For the below interface, I used it to export prometheus metrics.
com.alibaba.csp.sentinel.metric.extension.MetricExtension

Take the method[addPass(String resource, int n, Object... args)] for example.
I want to distinguish [in] type from [out] type using it as the prometheus tag. #provider[in]/consumer[out]

So I think I need a feature replacing the input String parameter[resource] with the below class type:

com.alibaba.csp.sentinel.slotchain.ResourceWrapper

[sczyh30]

Hi, @sczyh30 ! Is my request(#1566 ) closed?

Issue Description
Type: feature request

Describe what happened (or what feature you want)
For the below interface, I used it to export prometheus metrics.
com.alibaba.csp.sentinel.metric.extension.MetricExtension

Take the method[addPass(String resource, int n, Object... args)] for example.
I want to distinguish [in] type from [out] type using it as the prometheus tag. #provider[in]/consumer[out]

So I think I need a feature replacing the input String parameter[resource] with the below class type:

com.alibaba.csp.sentinel.slotchain.ResourceWrapper

This PR is outdated. New PRs are welcomed!

[Billzaifei]

Hi, @sczyh30 ! Is my request(#1566 ) closed?
Issue Description
Type: feature request
Describe what happened (or what feature you want)
For the below interface, I used it to export prometheus metrics.
com.alibaba.csp.sentinel.metric.extension.MetricExtension
Take the method[addPass(String resource, int n, Object... args)] for example.
I want to distinguish [in] type from [out] type using it as the prometheus tag. #provider[in]/consumer[out]
So I think I need a feature replacing the input String parameter[resource] with the below class type:
com.alibaba.csp.sentinel.slotchain.ResourceWrapper

This PR is outdated. New PRs are welcomed!

Enhancement/advanced metric extension tagging entrytype #1609 raised for the feature request#1566

[wushengju]

I have try this way to send Metric to prometheus, but i can't find metics like sentinel_pass_requests_total in http://localhost:9527/actuator/prometheus.