Nchan Prometheus Exporter

Nchan Prometheus exporter makes it possible to monitor Nchan using Prometheus.

Overview

Nchan is a scalable, flexible pub/sub server for the modern web, built as a module for the Nginx web server. It provides metrics via de nchan_stub_status page. Nchan Prometheus exporter fetches the metrics from a single Nchan, converts the metrics into appropriate Prometheus metrics types and finally exposes them via an HTTP server to be collected by Prometheus.

Getting Started

In this section, we show how to quickly run Nchan Prometheus Exporter for Nchan.

Prerequisites

We assume that you have already installed Prometheus and Nchan. Additionally, you need to:

• Expose the built-in metrics in Nchan:
  • For NCHAN, expose the nchan_stub_status page at /nchan_stub_status on port 8080
  • (optional): For NGINX, expose the stub_status page at /nginx_stub_status on port 8080.
• Configure Prometheus to scrape metrics from the server with the exporter. Note that the default scrape port of the exporter is 9113 and the default metrics path -- /metrics.

Running the Exporter in a Docker Container

To start the exporter we use the docker run command.

• To export Nchan metrics, run:

  $ docker run -p 9113:9113 platanus/nchan-prometheus-exporter:0.1.0 -scrape-uri http://<nchan>:8080/nchan_stub_status
  

• (optional): To additionaly export Nginx metrics, run:

  $ docker run -p 9113:9113 platanus/nchan-prometheus-exporter:0.1.0 -scrape-uri http://<nchan>:8080/nchan_stub_status -nginx -nginx.scrape-uri http://<nchan>:8080/nginx_stub_status
  

where <nchan> is the IP address/DNS name, through which Nchan is available.

Running the Exporter Binary

• To export Nchan metrics, run:

  $ nchan-prometheus-exporter -nchan.scrape-uri http://<nchan>:8080/nchan_stub_status
  

• (optional): To additionaly export Nginx metrics, run:

  $ nchan-prometheus-exporter -nchan.scrape-uri http://<nchan>:8080/nchan_stub_status -nginx -nginx.scrape-uri http://<nchan>:8080/nginx_stub_status
  

where <nchan> is the IP address/DNS name, through which Nchan is available.

Note. The nchan-prometheus-exporter is not a daemon. To run the exporter as a system service (daemon), configure the init system of your Linux server (such as systemd or Upstart) accordingly. Alternatively, you can run the exporter in a Docker container.

Usage

Command-line Arguments

Usage of ./nchan-prometheus-exporter:
  -scrape-uri string
        A URI for scraping Nchan metrics.
        The nchan_stub_status page must be available through the URI. The default value can be overwritten by SCRAPE_URI environment variable. (default "http://127.0.0.1:8080/nchan_stub_status")
  -nginx bool
        Start the exporter with NGINX metrics support. The default value can be overwritten by NGINX environment variable.
  -nginx.scrape-uri string
        A URI for scraping NGINX metrics.
        For NGINX, the stub_status page must be available through the URI. The default value can be overwritten by NGINX_SCRAPE_URI environment variable. (default "http://127.0.0.1:8080/nginx_stub_status")
  -ssl-verify
        Perform SSL certificate verification. The default value can be overwritten by SSL_VERIFY environment variable.
  -web.listen-address string
        An address to listen on for web interface and telemetry. The default value can be overwritten by LISTEN_ADDRESS environment variable. (default ":9113")
  -web.telemetry-path string
        A path under which to expose metrics. The default value can be overwritten by TELEMETRY_PATH environment variable. (default "/metrics")

Exported Metrics

• For Nchan, all nchan_stub_status metrics are exported. Connect to the /metrics page of the running exporter to see the complete list of metrics along with their descriptions.

• For NGINX, all stub_status metrics are exported. Connect to the /metrics page of the running exporter to see the complete list of metrics along with their descriptions.

Troubleshooting

The exporter logs errors to the standard output. When using Docker, if the exporter doesn’t work as expected, check its logs using docker logs command.

Releases

For each release, we publish the corresponding Docker image at platanus/nchan-prometheus-exporter DockerHub repo and the binaries on the GitHub releases page.

Building the Exporter

You can build the exporter using the provided Makefile. Before building the exporter, make sure the following software is installed on your machine:

• make
• git
• Docker for building the container image
• Go for building the binary

Building the Docker Image

To build the Docker image with the exporter, run:

$ make container

Note: go is not required, as the exporter binary is built in a Docker container. See the Dockerfile.

Building the Binary

To build the binary, run:

$ make

Note: the binary is built for the OS/arch of your machine. To build binaries for other platforms, see the Makefile.

The binary is built with the name nchan-prometheus-exporter.

Credits

Thank you contributors!

Nchan Prometheus Exporter is maintained by platanus.

License

Cordova Plugin Flavors is © 2017 platanus, spa. It is free software and may be redistributed under the terms specified in the LICENSE file.