普罗米修斯仪表指标的单元测试

Question

这是我的指标代码：

from prometheus_client import Gauge

probe = Gauge('probe_success', '1 - probe success, 0 - probe failure'                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
          ['probe_type', 'target', 'timeout', 'service', 'namespace', 'reason'])

如果地址请求成功则最终值为1，如果发生错误则值为0。

def probe_success(probe_type, target, timeout, service, namespace, reason, value):
    probe.labels(probe_type, target, timeout, service, namespace, reason).set(value)

这就是我的指标：

  probe_success{namespace="test",probe_type="http",reason="MissingSchema",service="servicename",target="ddress-test1",timeout="5"} 0.0
probe_success{namespace="test",probe_type="http",reason="ConnectionError",service="servicename",target="http://address-test2",timeout="10"} 0.0
probe_success{namespace="test-2",probe_type="http",reason="",service="servicename",target="https://www.google.com",timeout="5"} 1.0

那么我该如何测试这些指标。我阅读了有关 REGISTRY.get_sample_value 的信息，但我没有看到如何在仪表组方法上使用它。一般来说，我不知道如何构建合适的测试用例。如果有人有建议，我会很乐意阅读。

Answer 1

这是我的解决方案：

from prometheus_client import REGISTRY
from utils.metrics import probe_success



def test_probe_success_metric_when_the_probe_fails():
   
    # calling the metrics function, passing the needed parameters
    # setting the gauges value to be equal to 0 (which means 'False', by default it is 1 'True')
    probe_success(
        'http',
        'http://127.0.0.1:8000/',
        1,
        'test_service',
        'test_namespace',
        'Timeout',
        0,
    )

    # searching in prometheus_client REGISTRY by metrics function name, and certain arguments (passed above)

    after = REGISTRY.get_sample_value(
        'probe_success',
        {
            'probe_type': 'http',
            'target': 'http://127.0.0.1:8000/',
            'timeout': '1',
            'service': 'test_service',
            'namespace': 'test_namespace',
            'reason': 'Timeout',
        },
    )
    
    # assert whether found gauge value of after is equal to 0.0 (the value which we passed above)
    assert 0.0 == after


 # Here the procedure is the same as above, but with the difference that here the gauge value is set to 1 'True'.
def test_probe_success_metric_when_the_probe_success():

    probe_success(
        'http', 'http://127.0.0.1:8000/', 1, 'test_service',
        'test_namespace', '', 1
    )

   after = REGISTRY.get_sample_value(
        'probe_success',
        {
            'probe_type': 'http',
            'target': 'http://127.0.0.1:8000/',
            'timeout': '1',
            'service': 'test_service',
            'namespace': 'test_namespace',
            'reason': '',
        },
    )

assert 1.0 == after

这是一个带有解释但带有计数器指标的示例： https://www.robustperception.io/how-to-unit-test-prometheus-instrumentation

普罗米修斯仪表指标的单元测试

Unittests for prometheus gauge metrics

python

python-unittest

prometheus