java-client/README.md

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# Pegasus Java Client

[![Test - java client](https://github.com/apache/incubator-pegasus/actions/workflows/test_java-client.yml/badge.svg)](https://github.com/apache/incubator-pegasus/actions/workflows/test_java-client.yml)

## Build

```
mvn clean package -DskipTests
```

## Install

```
mvn clean install -DskipTests
```

## Test

To run test, you should start pegasus onebox firstly, and run test as:

```
mvn clean package
```

or specify one test:

```
mvn clean package -Dtest=TestPing
```

## Configuration

Configure client by "pegasus.properties", for example:

```
meta_servers = 127.0.0.1:34601,127.0.0.1:34602,127.0.0.1:34603
operation_timeout = 1000
async_workers = 4
enable_perf_counter = true
perf_counter_tags = k1=v1,k2=v2,k3=v3
push_counter_interval_secs = 10
```

You can provide a parameter of 'configPath' when creating a client instance.

The format of 'configPath' should be one of these:
* zk path: zk://host1:port1,host2:port2,host3:port3/path/to/config
* local file path: file:///path/to/config
* resource path: resource:///path/to/config

## PerfCounter(Metrics)

Pegasus Java Client supports QPS and latency statistics of requests.

The related configurations are:

```
enable_perf_counter = true
perf_counter_tags = k1=v1,k2=v2,k3=v3
push_counter_interval_secs = 10
```

For each type of request(get, set, multiset, etc.), we collect 8 metrics:
1. cps-1sec: the request's qps
2. cps-1min: the request's queries per 1 minute
3. cps-5min: the request's queries per 5 minutes
4. cps-15min: the request's queries per 15 minutes
5. latency-p50: the moving median of request's queries
6. latency-p99: the moving p99 of request's queries
7. lantecy-p999: the moving p999 of request's queries
8: latency-max: the moving max of request's queries

We use io.dropwizard.metrics library to calculate the request count.

Currently, metrics are integrated with open-falcon(https://open-falcon.org/),
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which push counters to local http agent http://127.0.0.1:1988/push/v1.
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If you'd like to integrate pegasus client with other monitor system, please let us know ASAP.