/prometheus-api-metrics

API and process monitoring with Prometheus for Node.js micro-service

Primary LanguageJavaScriptApache License 2.0Apache-2.0

Prometheus API Monitoring

NPM Version NPM Downloads Build Status Test Coverage Apache 2.0 License

Goal

API and process monitoring with Prometheus for Node.js micro-service

Note: Prometheus (prom-client) is a peer defendecy since 1.x version

Features

Usage

const apiMetrics = require('prometheus-api-metrics');
app.use(apiMetrics())

Options

  • metricsPath - Path to access the metrics. default: /metrics
  • defaultMetricsInterval - the inverval to collect the process metrics in milliseconds. default: 10000
  • durationBuckets - Buckets for response time in seconds. default: [0.001, 0.005, 0.015, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5]
  • requestSizeBuckets - Buckets for request size in bytes. default: [5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000]
  • responseSizeBuckets - Buckets for response size in bytes. default: [5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000]
  • useUniqueHistogramName - Add to metrics names the project name as a prefix (from package.json)
  • metricsPrefix - A custom matrics names prefix, the package will add underscode between your prefix to the metric name.
  • excludeRoutes - Array of routes to exclude. Routes should be in your framework syntax.

Access the metrics

To get the metrics in Prometheus format use:

curl http[s]://<host>:[port]/metrics

To get the metrics in JSON format use:

curl http[s]://<host>:[port]/metrics.json

Note:

  1. If you pass to the middleware the metricsPath option the path will be the one that you chose.

  2. If you are using express framework and no route was found for the request (e.g: 404 status code), the request will not be collected. that's because we'll risk memory leak since the route is not a pattern but a hardcoded string.

Custom Metrics

You can expand the API metrics with more metrics that you would like to expose. All you have to do is:

Require prometheus client

const Prometheus = require('prom-client');

Create new metric from the kind that you like

const checkoutsTotal = new Prometheus.Counter({
  name: 'checkouts_total',
  help: 'Total number of checkouts',
  labelNames: ['payment_method']
});

Update it:

checkoutsTotal.inc({
  payment_method: paymentMethod
})

The custom metrics will be exposed under the same endpoint as the API metrics.

For more info about the Node.js Prometheus client you can read here

Note

This will work only if you use the default Prometheus registry - do not use new Prometheus.Registry()

Request.js HTTP request duration collector

This feature enbales you to easily process the result of Request.js timings feature.

Usage

####Initialize You can choose to initialozed this functionality as a Class or not

Class:

const HttpMetricsCollector = require('prometheus-api-metrics').HttpMetricsCollector;
const collector = new HttpMetricsCollector();
collector.init();

Singelton:

const HttpMetricsCollector = require('prometheus-api-metrics').HttpMetricsCollector;
HttpMetricsCollector.init();

Options

  • durationBuckets - the histogram buckets for request duration.
  • countClientErrors - Boolean that indicates whether to collect client errors as Counter, this counter will have target and error code labels.
  • useUniqueHistogramName - Add to metrics names the project name as a prefix (from package.json)
  • prefix - A custom matrics names prefix, the package will add underscode between your prefix to the metric name.

For Example:

request

request({ url: 'http://www.google.com', time: true }, (err, response) => {
    Collector.collect(err || response);
});

request-promise-native

return requestPromise({ method: 'POST', url: 'http://www.mocky.io/v2/5bd9984b2f00006d0006d1fd', route: 'v2/:id', time: true, resolveWithFullResponse: true }).then((response) => {
    Collector.collect(response);
}).catch((error) => {
    Collector.collect(error);
});

Notes:

  1. In order to use this feature you must use { time: true } as part of your request configuration and then pass to the collector the response or error you got.
  2. In order to use the timing feature in request-promise/request-promise-native you must also use resolveWithFullResponse: true
  3. Override - you can override the route and target attribute instead of taking them from the request object. In order to do that you should set a metrics object on your request with those attribute:
request({ method: 'POST', url: 'http://www.mocky.io/v2/5bd9984b2f00006d0006d1fd', metrics: { target: 'www.google.com', route: 'v2/:id' }, time: true }, (err, response) => {...};
});

Test

npm test

Prometheus Examples Queries

Apdex

(sum(rate(http_request_duration_seconds_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>">, route="<ROUTE_NAME>", le="0.05"}[10m])) by (<SERVICE_LABLE_FIELD>) + sum(rate(http_request_duration_seconds_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>", route="<ROUTE_NAME>", le="0.1"}[10m])) by (<SERVICE_LABLE_FIELD>)) / 2 / sum(rate(http_request_duration_seconds_count{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>", route="<ROUTE_NAME>"}[10m])) by (<SERVICE_LABLE_FIELD>)

95th Response Time by specific route and status code

histogram_quantile(0.95, sum(rate(http_request_duration_seconds_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>", route="<ROUTE_NAME>", code="200"}[10m])) by (le))

Median Response Time Overall

histogram_quantile(0.50, sum(rate(http_request_duration_seconds_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>"}[10m])) by (le))

Median Request Size Overall

histogram_quantile(0.50, sum(rate(http_request_size_bytes_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>"}[10m])) by (le))

Median Response Size Overall

histogram_quantile(0.50, sum(rate(http_response_size_bytes_bucket{<SERVICE_LABLE_FIELD>="<SERVICE_LABEL>"}[10m])) by (le))

Avarage Memory Usage - All services

avg(nodejs_external_memory_bytes / 1024 / 1024) by (<SERVICE_LABLE_FIELD)

Avarage Eventloop Latency - All services

avg(nodejs_eventloop_lag_seconds) by (<SERVICE_LABLE_FIELD)