DaCHS on Docker

Update:

Recently the Dachs-on-Docker images repository -- on DockerHub -- have been changed from chbrandt to gavodachsorganisation. The documentation is being reviewed and updated accordingly, but if/whenever you see a chbrandt/dachs, read, change it to gavodachs/dachs.

Here you'll find recipes for building and running GAVO DaCHS in Docker containers (https://hub.docker.com/u/gavodachs).

ToC:

• Quick Dachs
  1. Run a published image
  2. Build your own image
  3. Container flavors

Quick Dachs

DaCHS service is composed by two daemons: PostgreSQL and the Dachs server. Postgres stores the data, while Dachs-server interfaces the user (web, api) and manages the astro/planetary data accordingly. By default, Dachs provides its (api) endpoints at port 8080 on localhost.

For fine details about DaCHS, refer to the official docs: soft.g-vo.org.

Run a published image

If all you wanna do now is to see Dachs-on-Docker running:

[~/]$ docker run -it -p 8080:8080 --name dachs gavodachs/dachs

Which should print a help/intro message like the following, and land you in a terminal session inside the container:

==========================================================
This image provides dachs & postgresql bundled together,
same scenario as you would have if installed the package,
gavodachs-server, on your own linux box

To start DaCHS (and Postgres), type:
--------------------
 $ /dachs.sh start
--------------------
It is just a convenience script to start/stop the services.
See its '--help' for further information about its usage.

After starting DaCHS, you should see it working at:
 - http://localhost[:8080]

Use 'gavo/dachs' as usual:
--------------------
 $ dachs --help
--------------------
DaCHS documents are available at:
 - http://dachs-doc.rtfd.io/tutorial.html

DaCHS version: 2.7.3
PSQL version: 13.11
==========================================================

root@a3035ad36500:/$

At this point, you can run and use DaCHS as you would in any "normal" operating system. For instance, you can start DaCHS and PostgreSQL in debug mode:

root@a3035ad36500:/$ service postgresql start
Starting PostgreSQL 13 database server: main.
root@a3035ad36500:/$
root@a3035ad36500:/$ dachs serve debug
<date> [-] Log opened.
<date> [-] Site starting on 8080
<date> [-] Starting factory <twisted.web.server.Site object at 0x7fb33c844fd0>
Starting VO server: dachs.
(...)

Or -- as per the help message (above) -- you can start Dachs service with /dachs.sh start:

root@a3035ad36500:/$ /dachs.sh start
13/main (port 5432): down
Starting PostgreSQL 13 database server: main.
Starting VO server: dachs.
root@a3035ad36500:/$ 

Docker run will instantiate the container and hand you a bash session from inside the container. Then we start Postgres to finally start Dachs (in debug mode to have it verbose).

The /dachs.sh you will find in the container is a simple script to start/stop the servers for your convenience (eg, /dachs.sh start will do the above steps).

You go to http://localhost:8080 and you should see Dachs frontpage:

Build your own image

On the other hand, if you want to build your own iamge (the latest dachs image), you'll do:

[~/]$ cd dockerfiles
[~/dockerfiles]$ docker build -t my_dachs dachs/
(...)
=> => exporting layers
=> => writing image sha256:ddb02867...
=> => naming to docker.io/library/my_dachs

This will create a new image -- my_dachs -- for you (you can check it with docker images). You can then run my_dachs as we did before in "Run a published image".

For more details on building images, go to dockerfiles/README.md

Container flavors

The containers are built on top of Debian Bullseye image, which GAVO/DaCHS package is part of the main (and backports) repository (current Dachs version: 2.3). For the latest images we use also GAVO repositories, where updates go first (current Dachs version: 2.5).

There are three images in our context: dachs, server, postgres. Those three images are to provide two different running setup: using just one image, dachs, like we just did; Or as a pair of containers, postgres and (dachs) server, talking to each other.

The single-container setup:

• gavodachs/dachs[:tag] provides a "one-shot" solution for having Dachs running in its simple; Dachs-server and Postgres run inside the same container.

The other two images provide Dachs and Postgres in their individual containers:

• gavodachs/server[:tag] provides gavodachs-server, depends on postgres.

• gavodachs/postgres[:tag] provides PostgreSQL for use by dachs-server.

  How to run server/postgres is covered in page 'individual_containers.md'.

Tags

The tags reflect the apt repositories set up in there:

• latest,gavo: uses all repositories (Debian and Gavo)
• backports: uses all Debian repositories
• main: uses only Debian's stable/main

See etc/apt_sources.list for the actual list of repositories used (they are enabled-or-not during the building of the image, according to building arguments).

Check the documents directory (docs/) for more content.

/.\