Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

A DHIS2 from chap-devops, with a chap-core elsewhere

For chap-core development with the Modeling App in front of it: chap-devops runs a DHIS2 (and any models), and chap-core runs somewhere else, usually from its own checkout on this machine.

  1. Start chap-core and make sure that it answers at http://localhost:8000.

    • From its checkout: make it listen on 0.0.0.0:8000, not only on the loopback.
    • From a second chap-devops deployment: run the commands below.
    chap-devops init core --only chap-core --models none --api-port 8000
cd core
chap-devops up
chap-devops status                 # wait for the chap-core line to say up
cd ..

  2. Make the DHIS2 deployment and connect it to that chap-core:

    chap-devops init lab --chap-core-url http://localhost:8000 --with dhis2
cd lab
chap-devops up
chap-devops status                 # wait for the dhis2 line to say up
chap-devops dhis2 connect
chap-devops open dhis2

If chap-core is a container (the second deployment above, or make restart in the chap-core checkout), init gives this warning:

warning: chap-core at http://localhost:8000 is the container `core-f380cb-chap-1`, so it calls the models back at host.docker.internal; if it is a process on this machine instead, run `chap-devops components enable chap-core --url http://localhost:8000 --models-host localhost`

The warning is about models only. chap-devops found the container, so the models register with the correct address. A deployment with no models can ignore it.

chap-devops up returns after some seconds, before DHIS2 answers. The first chap-devops up pulls the DHIS2 images, about 2 GB, and downloads the seed dump. Then DHIS2 needs some seconds to some minutes before it answers. Until then, chap-devops status shows dhis2 starting.

With --chap-core-url, init enables no model unless you name one. Add --models ID,ID to start models that register with that chap-core. If a model cannot register with a chap-core elsewhere, init gives a warning that names it.

--chap-core-url records the chap-core elsewhere (see chap-core from its checkout, with the models), and for the DHIS2 beside it:

  • The route goes to that chap-core as the DHIS2 container reaches it. A localhost URL becomes host.docker.internal, and the DHIS2 service maps that name to the host gateway.
  • dhis2/dhis.conf allows it. A scaffolded file allows every http and https target in route.remote_servers_allowed, so the chap-core elsewhere is covered wherever it runs.
  • chap-core has to listen on more than the loopback (0.0.0.0), since the route arrives from a container. A chap-core in a container publishes its port on all addresses already.

On the seed database, chap-devops dhis2 connect printed this:

DHIS2 2.42.6 at http://localhost:8780, as `admin`
repointed the `chap` route at http://host.docker.internal:8000/**; chap-core answered through it
installed Modeling App 7.3.0
installed DHIS2 Climate App 1.16.2
analytics finished in 20 seconds (job AyL1NbEW3ot)
the Modeling App can reach Chap; open DHIS2 with `chap-devops open dhis2`

The seed database has a chap route already, so the second line says repointed. On a DHIS2 with no chap route, it says created.

If chap-core does not answer, connect still sets the route, but it gives a warning and ends with another line:

warning: the `chap` route is in place but nothing answered through it: HTTP 500 Internal Server Error: finishConnect(..) failed with error(-111): Connection refused: host.docker.internal/192.168.65.254:8000; run `chap-devops status` to see whether chap-core is up
...
run `chap-devops dhis2 show` to see what is still missing

If you see this warning, start chap-core and run chap-devops dhis2 connect again. See The route is there but nothing answers through it.

chap-devops open dhis2 opens DHIS2 in the browser; with --no-browser, it prints the address. Log in as admin with the password district. The Modeling App is Modeling in the apps menu.

It worked when chap-devops dhis2 connect says chap-core answered through it and ends with the Modeling App can reach Chap. In the Modeling App, the Settings page then shows the chap-core version and Connected.

More: DHIS2, A chap-core elsewhere.

All shapes: Use cases.