@devintent/verdaccio-prometheus-middleware

verdaccio-prometheus-middleware

A Prometheus metrics middleware plugin for Verdaccio v5. Collects several types of metrics and exposes them at a configurable metrics endpoint (defaults to /-/metrics). The metrics are produced in the standard prometheus metrics text format.

Table of contents

• Metric Types
  • Prometheus Default Metrics
  • HTTP Request Metrics
  • Package Download Metrics
• Installation
• Configuration
• Package Groups
• Contributing
  • Pull Requests

Metric Types

This plugin is capable of collecting three (3) different types of metrics. Further explanation is provided in the sections below.

Prometheus Default Metrics

This plugin will collect default (standard) metrics when the defaultMetrics.enabled configuration option is set to true. More information about default metrics can be found at:

• https://prometheus.io/docs/instrumenting/writing_clientlibs/#standard-and-runtime-collectors
• https://github.com/siimon/prom-client/tree/v14.0.1#default-metrics

HTTP Request Metrics

This plugin will collect metrics related to incoming HTTP requests when the requestMetrics.enabled configuration option is set to true. A counter metric is used to track the number of HTTP requests. The following labels are applied to every request for this metric:

• username - The Verdaccio username of the user attempting to install/download a package. If the request is unauthenticated then the value UNKNOWN is used.
• userAgentName - The name of the user agent the client used to make the request. It is derived from the user-agent header on the request. If no user-agent header is provided it defaults to UNKNOWN.
• httpMethod - The HTTP method used in the request.
• statusCode - The status code of the response from Verdaccio.

Package Download Metrics

This plugin will collect metrics related to package tarball downloads when the packageMetrics.enabled configuration option is set to true. A counter metric is used to track the number of package tarball installs/downloads. The following labels are applied to every request for this metric:

• username - The Verdaccio username of the user attempting to install/download a package. If the request is unauthenticated then the value UNKNOWN is used.
• userAgentName - The name of the user agent the client used to make the request. It is derived from the user-agent header on the request. If no user-agent header is provided it defaults to UNKNOWN.
• statusCode - The status code of the response from Verdaccio.

Optionally, an additional packageGroup label can be applied if a packageMetrics.packageGroups option is added to the plugin configuration. Refer to the Package Groups section of this README for more information.

Installation

Because Verdaccio automatically prefixes the string verdaccio- to the directory it looks for when loading a plugin, this plugin will need to be installed to a directory named verdaccio-metrics IF your middlewares configuration uses metrics as the configuration key for this plugin (as shown in the Configuration example). Below is an example Dockerfile that can be used to build a custom image containing this plugin. The Verdaccio plugins configuration option is assumed to be set to /verdaccio/plugins.

# Docker multi-stage build - https://docs.docker.com/develop/develop-images/multistage-build/
# Use an alpine node image to install the plugin
FROM node:lts-alpine as builder

# Install the metrics middleware plugin. Replace `x.y.z` with the plugin version.
RUN mkdir -p /verdaccio/plugins \
    && cd /verdaccio/plugins \
    && npm install --global-style --no-bin-links --omit=optional @devintent/verdaccio-prometheus-middleware@x.y.z

# The final built image will be based on the standard Verdaccio docker image.
FROM verdaccio/verdaccio:5

# Copy the plugin files over from the 'builder' node image.
# The `$VERDACCIO_USER_UID` env variable is defined in the base `verdaccio/verdaccio` image.
# Refer to: https://github.com/verdaccio/verdaccio/blob/v5.13.3/Dockerfile#L32
COPY --chown=$VERDACCIO_USER_UID:root --from=builder \
  /verdaccio/plugins/node_modules/@devintent/verdaccio-prometheus-middleware \
  /verdaccio/plugins/verdaccio-metrics

Configuration

Complete configuration example with comments:

middlewares:
  metrics:
    ## Optional. Defaults to `/-/metrics`.
    metricsPath: /custom/path/metrics

    ## Optional. If not specified, no default metrics will be collected.
    ## Refer to: https://github.com/siimon/prom-client/tree/v14.0.1#default-metrics
    defaultMetrics:
      ## Optional. Defaults to `false`. Make sure to set this to `true` if you want to collect default metrics.
      enabled: true

    ## Optional. If not specified, no http request metrics will be collected.
    requestMetrics:
      ## Optional. Defaults to `false`. Make sure to set this to `true` if you want to collect request metrics.
      enabled: true

      ## Optional. Defaults to 'registry_http_requests'.
      metricName: 'registry_http_requests'

      ## Optional. An array of regular expressions used to match and exclude request paths. The default list of paths to
      ## exclude are shown below. If you override this array of values these default paths will NOT be included and will
      ## need to be added manually if you still wish to exclude them. The `metricsPath` is **ALWAYS** excluded.
      pathExclusions:
        - '^/$' # root path to web ui
        - '^/[-]/ping' # health endpoint
        - '^/[-]/(static|verdaccio|web)' # web ui related paths
        - '[.]ico$' # requests for icons (e.g. `favicon.ico`)

    ## Optional. If not specified, no package download metrics will be collected.
    packageMetrics:
      ## Optional. Defaults to `false`. Make sure to set this to `true` if you want to collect package download metrics.
      enabled: true

      ## Optional. Defaults to 'registry_package_downloads'.
      metricName: 'registry_package_downloads'

      ## Optional. A map of regular expressions to package grouping names.
      packageGroups:
        ## NOTE: The order of items below matters. The first matched regex is the package grouping that will be applied
        ## to the metric generated for a request.
        '@angular/[^/]*': angular
        'react': react
        '.*': other

Package Groups

The packageMetrics.packageGroups configuration option accepts an object map whose keys are expected to be a regular expression string and the value the name of the package group that should be used for the packageGroup metric label. If no packageMetrics.packageGroups are defined, a packageGroup label will NOT be applied to the packageMetrics counter metric.

The regular expression key is evaluated against the request path in the following manner:

// scoped packages generally have the `/` url encoded to `%2f`
new RegExp(packageGroupRegex).test(decodeURIComponent(request.path));

The order of the keys/values in the object map matters. The regular expressions are evaluated from first to last in the order they are listed under the packageMetrics.packageGroups configuration option and the first matching regex will have the corresponding package grouping value applied when the packageMetrics counter metric is collected.

Given the following example configuration:

# Verdaccio config file
middlewares:
  metrics:
    packageMetrics:
      enabled: true
      packageGroups:
        '@babel/plugin': 'babel-plugin'
        'babel[-]plugin': 'babel-plugin'
        'babel': 'babel'
        '@.*': scoped
        '.*': other

... the following packages would resolve to the packageGroup as listed in the table:

Package Name	Package Group
@babel/core	babel
@babel/parser	babel
@babel/plugin-transform-runtime	babel-plugin
babel-plugin-istanbul	babel-plugin
babel-jest	babel
@angular/core	scoped
@apollo/client	scoped
react	other
apollo-server-express	other

Contributing

This project enforces the Angular commit message format.

A husky prepare-commit-msg hook is used in conjunction with commitzen in order to automatically prompt for all required fields in the commit message. The commitzen prompts can be bypassed and the commit message may still manually be created by interrupting the commitzen prompt using ctrl+c. A valid commit message is still required as each commit message is linted using commitlint and a husky commit-msg hook to ensure the Angular commit message format is followed.

Pull Requests

Prior to opening a pull request, please ensure that you run the command:

npm run release

This will automatically increment the version number in the package.json based on the types of commits contained in the pull request and update the CHANGELOG.md appropriately. If a specific version type needs to be forced, the same command can be executed with an argument passed:

# force incrementing to a new major version
npm run release -- -r major