Merge pull request #1 from metrics-js/remove_global_registry

Remove global registry

Author: digitalsadhu

.eslintrc

@@ -3,16 +3,12 @@
     "parserOptions": {
         "ecmaVersion": 2018
     },
+    "env": {
+        "node": true,
+        "jest": true
+    },
     "rules": {
         "strict": [0, "global"],
         "class-methods-use-this": [0]
-    },
-    "overrides": [
-        {
-            "files": "src/layouts/frontpage/assets/**/*",
-            "env": {
-                "browser": true
-            }
-        }
-    ]
+    }
 }

.travis.yml

@@ -5,7 +5,7 @@ cache:
 notifications:
     email: false
 node_js:
+    - '11'
     - '10'
-    - '9'
     - '8'
 dist: trusty

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+Notable changes to this project will be documented in this file.
+
+The latest version of this document is always available in [releases][releases-url].
+
+## [Unreleased]
+
+## [2.0.0] - 2018-11-22
+
+-   prom-client global state removed
+-   .metrics() method added
+-   .contentType() method added
+-   lint fixing
+
+[unreleased]: https://github.com/metrics-js/prometheus-consumer/compare/v2.0.0...HEAD
+[2.0.0]: https://github.com/metrics-js/prometheus-consumer/compare/v1.0.0...v2.0.0
+[releases-url]: https://github.com/metrics-js/prometheus-consumer/blob/master/CHANGELOG.md

README.md

@@ -52,64 +52,123 @@ const metricsConsumer = new PrometheusConsumer({ client: promClient });
 
 ### Step 2.
 
-Pipe the metrics output stream directly into our consumer
+Pipe the metrics output stream directly into our consumer making sure to add an error handler to avoid uncaught exceptions.
 
 ```js
 const client = new MetricsClient();
 
+metricsConsumer.on('error', err => console.error(err));
+
 client.pipe(metricsConsumer);
 ```
 
+### Step 3.
+
+Render a metrics page for prometheus to scrape.
+In this example we use express (though any framework will work) to render out metrics on the route `/metrics`.
+
+```js
+app.get('/metrics', (req, res) => {
+    res.set('Content-Type', metricsConsumer.contentType()).send(
+        metricsConsumer.metrics(),
+    );
+});
+```
+
 ## API
 
-### new PrometheusConsumer(options)
+-   [constructor](#constructoroptions)
+    -   [override](#overridenameconfig)
+    -   [metrics](#metrics)
+    -   [contentType](#contenttype)
+
+### constructor(options)
 
 Create a new metrics consumer instance ready to have metrics piped into it.
 
-**options**
+_Examples_
+
+```js
+const consumer = new PrometheusConsumer({ client: promClient });
+```
 
-| name             | description                                                                                                                                               | type     | default |
-| ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- | ------- |
-| client           | Prom client dependency. Passed in this way in order to avoid having a hard dependency on a specific version of prom-client which polutes the global space |
-| bucketStepStart  | Value to start bucket generation from. Each step increases from here by `bucketStepFactor`                                                                | `number` | 0.001   |
-| bucketStepFactor | Scaling factor for bucket creation. Must be > 1                                                                                                           | `number` | 1.15    |
-| bucketStepCount  | Number of times `bucketStepFactor` should be applied to `bucketStepStart`                                                                                 | `number` | 45      |
+remember to add an error handler to the consumer to avoid uncaught exception errors.
+
+```js
+consumer.on('error', err => console.error(err));
+```
+
+#### options
+
+| name                                  | description                                                                                | type     | default |
+| ------------------------------------- | ------------------------------------------------------------------------------------------ | -------- | ------- |
+| [client](#client)                     | Prom client module dependency.                                                             |
+| [bucketStepStart](#bucketstepstart)   | Value to start bucket generation from. Each step increases from here by `bucketStepFactor` | `number` | 0.001   |
+| [bucketStepFactor](#bucketstepfactor) | Scaling factor for bucket creation. Must be > 1                                            | `number` | 1.15    |
+| [bucketStepCount](#bucketstepcount)   | Number of times `bucketStepFactor` should be applied to `bucketStepStart`                  | `number` | 45      |
+
+##### client
+
+Prom client module dependency. Passed in this way in order to avoid having a hard dependency on a specific version of prom-client.
 
 _Example_
 
 ```js
-const consumer = new PrometheusConsumer({
-    client: promClient,
-    bucketStepStart: 1,
-    bucketStepFactor: 2,
-    bucketStepCount: 8,
-});
+const consumer = new PrometheusConsumer({ client: promClient });
 ```
 
-This example will use buckets: 1,2,4,8,16,32,64,128,256
+##### bucketStepStart
+
+Value to start bucket generation from. Each step increases from here by `bucketStepFactor`
+
+_Example_
+
+```js
+const consumer = new PrometheusConsumer({ bucketStepStart: 1 });
+```
 
-### instance.override(name, config)
+##### bucketStepFactor
+
+Scaling factor for bucket creation. Must be > 1
+
+_Example_
+
+```js
+const consumer = new PrometheusConsumer({ bucketStepFactor: 2 });
+```
+
+##### bucketStepCount
+
+Number of times `bucketStepFactor` should be applied to `bucketStepStart`
+
+_Example_
+
+```js
+const consumer = new PrometheusConsumer({ bucketStepCount: 8 });
+```
+
+### .override(name, config)
 
 Override handling of a specific metric (by name). This is useful if the defaults
 do not produce the desired result for a given metric. You can change what type
 of prometheus metrics are generated by setting `type` and for histograms, you
 can override bucket handling.
 
-**name**
+#### name
 
 An alpha-numeric (plus the underscore character) string name of metric to be
 overriden. Any metrics that match this name will be processed using the override
 config (see below)
 
-**config**
+#### config
 
 | name    | description                                                                 | type       | default   |
 | ------- | --------------------------------------------------------------------------- | ---------- | --------- |
 | type    | One of `histogram`, `counter`, `gauge` or `summary`                         | `string`   |           |
 | labels  | Array with allowed values: `url`, `method`, `status`, `layout` and `podlet` | `string[]` |           |
 | buckets | An object, see `config.buckets` below                                       | `object`   | see below |
 
-**config.buckets**
+##### buckets
 
 | name             | description                                                                                | type     | default |
 | ---------------- | ------------------------------------------------------------------------------------------ | -------- | ------- |
@@ -148,3 +207,21 @@ consumer.override('my_time_based_metric', {
     },
 });
 ```
+
+### .metrics()
+
+Returns the generated metrics text ready for scraping by prometheus. This should be used in conjunction with [.contentType()](#contenttype)
+
+_Example_
+
+```js
+app.get('/metrics', (req, res) => {
+    res.set('Content-Type', metricsConsumer.contentType()).send(
+        metricsConsumer.metrics(),
+    );
+});
+```
+
+### .contentType()
+
+Returns the correct content type to use when rendering metrics text for scraping by prometheus. See [.metrics()](#metrics) for an express js usage example.

lib/index.js

@@ -1,5 +1,6 @@
 'use strict';
 
+const Joi = require('joi');
 const { Writable } = require('readable-stream');
 const {
     createCounter,
@@ -14,7 +15,7 @@ const {
     overrideConfig,
     constructorOptions,
 } = require('../schemas');
-const Joi = require('joi');
+
 const overrides = new Map();
 const metricTypes = {
     HISTOGRAM: 'histogram',
@@ -29,29 +30,26 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         this.options = Joi.attempt(
             options,
             constructorOptions,
-            'Invalid `options` object given to new FinnPodiumMetrics.'
+            'Invalid `options` object given to new PrometheusMetricsConsumer.',
         );
 
-        const client = this.options.client;
+        const { client } = this.options;
         this.Counter = client.Counter;
         this.Gauge = client.Gauge;
         this.Histogram = client.Histogram;
         this.Summary = client.Summary;
         this.bucketFunction = client.exponentialBuckets;
-        this.register = client.register;
+        this.registry = new client.Registry();
     }
 
     get [Symbol.toStringTag]() {
         return 'PrometheusMetricsConsumer';
     }
 
     labels(metric) {
-        const labelNames = [];
-        const labelValues = [];
-        for (const [key, val] of Object.entries(metric.meta || {})) {
-            labelNames.push(key);
-            labelValues.push(val);
-        }
+        const labelNames = Object.keys(metric.meta || {});
+        const labelValues = Object.values(metric.meta || {});
+
         return { labelNames, labelValues };
     }
 
@@ -63,11 +61,14 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         const { name } = metric;
         const { labelNames, labelValues } = this.labels(metric);
 
-        if (!this.register.getSingleMetric(name)) {
-            createCounter(this.Counter, metric, { labels: labelNames });
+        if (!this.registry.getSingleMetric(name)) {
+            createCounter(this.Counter, metric, {
+                labels: labelNames,
+                registry: this.registry,
+            });
         }
 
-        this.register
+        this.registry
             .getSingleMetric(name)
             .labels(...labelValues)
             .inc(1);
@@ -77,11 +78,14 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         const { name } = metric;
         const { labelNames, labelValues } = this.labels(metric);
 
-        if (!this.register.getSingleMetric(name)) {
-            createGauge(this.Gauge, metric, { labels: labelNames });
+        if (!this.registry.getSingleMetric(name)) {
+            createGauge(this.Gauge, metric, {
+                labels: labelNames,
+                registry: this.registry,
+            });
         }
 
-        this.register
+        this.registry
             .getSingleMetric(name)
             .labels(...labelValues)
             .set(metric.value);
@@ -91,14 +95,15 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         const { name, time } = metric;
         const { labelNames, labelValues } = this.labels(metric);
 
-        if (!this.register.getSingleMetric(name)) {
+        if (!this.registry.getSingleMetric(name)) {
             createHistogram(this.Histogram, this.bucketFunction, metric, {
                 ...this.options,
                 ...this.bucketsForHistogram(name),
                 labels: labelNames,
+                registry: this.registry,
             });
         }
-        this.register
+        this.registry
             .getSingleMetric(name)
             .labels(...labelValues)
             .observe(time);
@@ -108,12 +113,13 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         const { name, time } = metric;
         const { labelNames, labelValues } = this.labels(metric);
 
-        if (!this.register.getSingleMetric(name)) {
+        if (!this.registry.getSingleMetric(name)) {
             createSummary(this.Summary, metric, {
                 labels: labelNames,
+                registry: this.registry,
             });
         }
-        this.register
+        this.registry
             .getSingleMetric(name)
             .labels(...labelValues)
             .observe(time);
@@ -124,13 +130,13 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
             Joi.attempt(
                 name,
                 metricName,
-                'Invalid `name` given to prometheusMetricsConsumer.override.'
+                'Invalid `name` given to prometheusMetricsConsumer.override.',
             ),
             Joi.attempt(
                 config,
                 overrideConfig,
-                'Invalid `config` object given to prometheusMetricsConsumer.override.'
-            )
+                'Invalid `config` object given to prometheusMetricsConsumer.override.',
+            ),
         );
     }
 
@@ -153,13 +159,14 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
     _write(metric, enc, cb) {
         if (this.typeFor(metric) === metricTypes.HISTOGRAM) {
             if (!isHistogram(metric)) {
-                return cb(
+                cb(
                     new Error(
                         `Attempted to plot metric "${
                             metric.name
-                        }" on a histogram, however metric was missing \`time\` value`
-                    )
+                        }" on a histogram, however metric was missing \`time\` value`,
+                    ),
                 );
+                return;
             }
             this.histogram(metric);
         } else if (this.typeFor(metric) === metricTypes.GAUGE) {
@@ -171,4 +178,12 @@ module.exports = class PrometheusMetricsConsumer extends Writable {
         }
         cb();
     }
+
+    metrics() {
+        return this.registry.metrics();
+    }
+
+    contentType() {
+        return this.registry.contentType;
+    }
 };