Displaying Docker containers and their history with Go

Programming Snapshot – Go Docker Monitor

© Lead Image © Erik Reis, 123RF.com

© Lead Image © Erik Reis, 123RF.com

Article from Issue 231/2020
Author(s):

With a monitoring system implemented in Go, Mike Schilli displays the Docker containers that have been launched and closed on his system.

Even in the age of newfangled buzzwords like "Kubernetes," veteran system administrators still appreciate command-line tools like good old top, which displays running processes in real time. Since I also want to keep up with the young bloods (even at my age, which can already be described as advanced), I recently created a small, terminal-based monitor that shows Docker containers coming and going on a system.

The standard Docker client, docker, is written in Go and communicates via a web interface with the Docker daemon to query the status of running containers, start new ones, or terminate existing ones. In addition to a Python interface, Docker also offers a Go SDK. Since Go also has excellent libraries for displaying in the terminal, it was my choice for implementing the dockertop monitor in this Programming Snapshot column.

The idea is simple: The program asks the Docker daemon at regular intervals for all the containers running on the system, displays their names in a list, and refreshes them every second – just like top. As an additional treat, the monitor in the right part of the split screen also displays a rolling history of the containers. Each time it detects a new one, the program writes New: <Name> into it. If a container has been lost since the last call – for example, because it has died in the meantime – the log entry reads: Gone: <Name> (Figure 1).

[...]

Use Express-Checkout link below to read the full article (PDF).

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

SINGLE ISSUES
 
SUBSCRIPTIONS
 
TABLET & SMARTPHONE APPS
Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Tutorials – Docker

    You might think Docker is a tool reserved for gnarly sys admins, useful only to service companies that run complicated SaaS applications, but that is not true: Docker is useful for everybody.

  • Ansible Container Auto Deploy

    Streamline software deployment with Ansible and Docker containers.

  • Docker with OwnCloud

    Run your application smoothly and portably in the cloud with the Docker container system. This workshop takes a practical look deploying Docker with the OwnCloud cloud environment.

  • Perl: Testing Modules with Docker

    If you want to distribute your programs across multiple platforms, you need to prepare them to run in foreign environments from the start. Linux container technology and the resource-conserving Docker project let you test your own Perl modules on several Linux distributions in one fell swoop.

  • Docker Appoints Steve Singh CEO

    The new CEO comes from a very strong SaaS background.

comments powered by Disqus

Direct Download

Read full article as PDF:

Price $2.95

News