Hi. Welcome to cyber-dojo 😄

cyber-dojo is where programmers meet to practice TDD
this video explains how to use it for group TDD practice: https://youtu.be/OGGk-iFVOPQ
this video explains how to use it for individual TDD practice: https://youtu.be/lIRF8MgyXho
cyber-dojo is not an IDE, an Individual Development Environment
cyber-dojo is an IDE, an Interactive Dojo Environment!
cyber-dojo is about shared learning
in a cyber-dojo you practice by going slower and focusing on improving rather than finishing
cyber-dojo foundation is a registered Scottish Charitable Incorporated Organisation
How can I contribute to developing cyber-dojo?

Running a server
- on docker
- on docker swarm
- on Kubernetes (no-longer-maintained)
Versioning
Overriding the default...
Misc

running a server on docker

Follow these instructions to install the cyber-dojo bash script and to prepare your server.

$ cyber-dojo up
...
$ cyber-dojo version
Version: 0.1.462
   Type: public
...

running a server on docker swarm

This is exploratory only and may be dropped without notice. Follow these instructions to install the cyber-dojo bash script and to prepare your server.

$ export CYBER_DOJO_SWARM=true
$ cyber-dojo up

running a server on Kubernetes

Follow these instructions

listing the current version

$ cyber-dojo version
Version: 0.1.462
   Type: public

listing installed versions

$ cyber-dojo version ls
0.1.462      2026-02-15 20:27:03 +0000 UTC
...
0.1.21       2019-08-07 11:51:48 +0000 UTC
...

updating the server to the latest version

$ cyber-dojo update latest
$ cyber-dojo version
Version: 0.1.462
   Type: public
...
# Now make it live...
$ cyber-dojo up
Using version=0.1.462 (public)
...

setting the server to a specific version

$ cyber-dojo update 0.1.555
$ cyber-dojo version
Version: 0.1.555
   Type: public
...
# Now make it live...
$ cyber-dojo up
Using version=0.1.555 (public)
...

overriding the default port

By default your cyber-dojo server will be on port 80.

Override this port using the command-line argument --port. Eg
```
$ cyber-dojo up --port=8000
...
Using port=8000
...
```

overriding the default start-point images

The cyber-dojo up command uses three default start-point images (tagged appropriately)
- --custom=cyberdojo/custom-start-points
- --exercises=cyberdojo/exercises-start-points
- --languages=cyberdojo/languages-start-points-common
You can create and use your own alternative start-point images in place of these defaults if you wish.
- Read how to create them by running:
```
cyber-dojo start-point create --help
```
- Read how to use them by running:
```
cyber-dojo up --help
```

overriding the default nginx image

By default your cyber-dojo server will use cyberdojo/nginx as its nginx service image (tagged appropriately).

You can override this by exporting two environment variables. Eg

$ export CYBER_DOJO_NGINX_IMAGE=cucumber/nginx
$ export CYBER_DOJO_NGINX_TAG=efd7e37
$ cyber-dojo up ...
...
Using nginx=cucumber/nginx:efd7e37
...

overriding the default rails web image

By default your cyber-dojo server will use cyberdojo/web as its web service image (tagged appropriately).

You can override this by exporting two environment variables. Eg

$ export CYBER_DOJO_WEB_IMAGE=turtlesec/web
$ export CYBER_DOJO_WEB_TAG=84d6d0e
$ cyber-dojo up ...
...
Using web=turtlesec/web:84d6d0e
...

overriding the default dot env files

There are default .env files for the web and nginx services.

You can override these by exporting two environment variables set to the absolute path of your own .env file. Eg

$ export CYBER_DOJO_NGINX_ENV=/home/fred/my_nginx.env
$ export CYBER_DOJO_WEB_ENV=/home/fred/my_web.env
$ cyber-dojo up
...
Using nginx.env=/home/fred/my_nginx.env (custom)
Using web.env=/home/fred/my_web.env (custom)
...

When an exercise starts a welcome dialog displays traffic-light information. You can turn off this dialog with the following web.env entry:

STARTING_INFO_DIALOG=off

You can turn off the review page's [fork] button with the following web.env entry:

FORK_BUTTON=off

You can turn off the [dashboard] button from the info toolbar with the following web.env entry:

DASHBOARD_BUTTON=off

You can turn off traffic-light prediction with the following web.env entry:

PREDICT=off

Micro Services

Each repo in the github cyber-dojo organization builds a single docker image.
The main Amazon ECS backed https://cyber-dojo.org uses:

custom-start-points
serves the custom start-points.
exercises-start-points
serves the exercises start-points.
languages-start-points
serves the languages start-points.
differ
diffs two sets of files.
nginx
web-proxy, security, images (jpg) cache, and service routing.
runner
runs the tests and returns [stdout,stderr,status,timed_out,colour].
saver
API to GET/POST group/kata data, e.g., for individual traffic-lights.
creator Gitlab
UI to configure and create (or re-enter) a group-exercise or an individual-exercise.
dashboard
UI for a group session dashboard of all traffic-lights.
web
main UX for coding, testing, and reviewing.