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    @plastdev/metrics
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    1.1.1 • Public • Published

    Metrics

    A small express middleware to get base metrics for any node.js app.

    Installation

    • npm install --save @plastdev/metrics

    Usage

    import { Metrics, MetricType } from '@plastdev/metrics'
    let metrics = new Metrics(options)

    Note: The options Part may be omitted, as all parts are optional.

    Before your Routes:
    router.use(metrics.collect)

    And to enable the _metrics-Endpoint:
    router.get('/_metrics', metrics.endpoint)

    Custom Metrics

    To Add your own custom Metrics: metrics.addCustomMetric({ name: 'test', help: 'Some Test Metric' }, TYPE)

    where TYPE is one of:

    • MetricType.COUNTER
    • MetricType.GAUGE
    • MetricType.HISTOGRAM
    • MetricType.SUMMARY

    All metrics can take a labelNames property in the configuration object. All labelNames that the metric support needs to be declared here. There are 2 ways to add values to the labels

    metrics.addCustomMetric({
      name: 'metric_name',
      help: 'metric_help',
      labelNames: ['method', 'statusCode'],
    }, MetricType.GAUGE);
    
    metrics.customMetrics["NAME"].set({ method: 'GET', statusCode: '200' }, 100); // 1st version, Set value 100 with method set to GET and statusCode to 200
    metrics.customMetrics["NAME"].labels('GET', '200').set(100); // 2nd version, Same as above

    It is also possible to use timers with labels, both before and after the timer is created:

    const end = metrics.customMetrics["NAME"].startTimer({ method: 'GET' }); // Set method to GET, we don't know statusCode yet
    xhrRequest(function (err, res) {
      if (err) {
        end({ statusCode: '500' }); // Sets value to xhrRequest duration in seconds with statusCode 500
      } else {
        end({ statusCode: '200' }); // Sets value to xhrRequest duration in seconds with statusCode 200
      }
    });

    Counter

    Counters go up, and reset when the process restarts.

    • metrics.customMetrics["NAME"].inc(); // Inc with 1
    • metrics.customMetrics["NAME"].inc(10); // Inc with 10

    Gauge

    Gauges are similar to Counters but Gauges value can be decreased.

    • metrics.customMetrics["NAME"].set(10); // Set to 10
    • metrics.customMetrics["NAME"].inc(); // Inc with 1
    • metrics.customMetrics["NAME"].inc(10); // Inc with 10
    • metrics.customMetrics["NAME"].dec(); // Dec with 1
    • metrics.customMetrics["NAME"].dec(10); // Dec with 10

    Histograms

    Histograms track sizes and frequency of events.

    metrics.customMetrics["NAME"].observe(10); // Observe value in histogram

    Utility to observe request durations

    const end = metrics.customMetrics["NAME"].startTimer();
    xhrRequest(function (err, res) {
      const seconds = end(); // Observes and returns the value to xhrRequests duration in seconds
    });

    Summary

    Summaries calculate percentiles of observed values.

    metrics.customMetrics["NAME"].observe(10);

    Utility to observe request durations

    const end = metrics.customMetrics["NAME"].startTimer();
    xhrRequest(function (err, res) {
      end(); // Observes the value to xhrRequests duration in seconds
    });

    Options

    The Following Options may be used to configure the behaviour.

    • ignore: A String Array with routes to ignore, e.g. ['/foo'] . Default: []. Important: /_metrics and /favicon.ico are always ignored
    • disableErrorCounter: Disable the Error Counter. Default: false
    • disableRouteCounter: Disable the Route Counter. Default: false
    • disableDurationCounter: Disable the Duration Counter. Default: false
    • disableDefaultMetrics: Disable the Collection of default metrics. Default: false

    Default Metrics

    • process_cpu_user_seconds_total Total user CPU time spent in seconds.
    • process_cpu_system_seconds_total Total system CPU time spent in seconds.
    • process_cpu_seconds_total Total user and system CPU time spent in seconds.
    • process_start_time_seconds Start time of the process since unix epoch in seconds.
    • process_resident_memory_bytes Resident memory size in bytes.
    • nodejs_eventloop_lag_seconds Lag of event loop in seconds.
    • nodejs_eventloop_lag_min_seconds The minimum recorded event loop delay.
    • nodejs_eventloop_lag_max_seconds The maximum recorded event loop delay.
    • nodejs_eventloop_lag_mean_seconds The mean of the recorded event loop delays.
    • nodejs_eventloop_lag_stddev_seconds The standard deviation of the recorded event loop delays.
    • nodejs_eventloop_lag_p50_seconds The 50th percentile of the recorded event loop delays.
    • nodejs_eventloop_lag_p90_seconds The 90th percentile of the recorded event loop delays.
    • nodejs_eventloop_lag_p99_seconds The 99th percentile of the recorded event loop delays.
    • nodejs_active_handles Number of active libuv handles grouped by handle type. Every handle type is C++ class name.
    • nodejs_active_handles_total Total number of active handles.
    • nodejs_active_requests Number of active libuv requests grouped by request type. Every request type is C++ class name.
    • nodejs_active_requests_total Total number of active requests.
    • nodejs_heap_size_total_bytes Process heap size from Node.js in bytes.
    • nodejs_heap_size_used_bytes Process heap size used from Node.js in bytes.
    • nodejs_external_memory_bytes Node.js external memory size in bytes.
    • nodejs_heap_space_size_total_bytes Process heap space size total from Node.js in bytes.
    • nodejs_heap_space_size_used_bytes Process heap space size used from Node.js in bytes.
    • nodejs_heap_space_size_available_bytes Process heap space size available from Node.js in bytes.
    • nodejs_version_info Node.js version info.

    Examples

    You can find prebuilt examples in the fitting folder.

    Just call node examples/dist/server.js 3000 to start a Test-Server on Port 3000.

    Then use your Browser to call the Endpoints:

    • /foo
    • /bar
    • /404
    • /401

    And check the results on the Endpoint /_metrics

    Install

    npm i @plastdev/metrics

    DownloadsWeekly Downloads

    10

    Version

    1.1.1

    License

    Unlicense

    Unpacked Size

    37.4 kB

    Total Files

    13

    Last publish

    Collaborators

    • sigmundd