Dockerfile apps

Building from a Dockerfile is the default. On each push, Jokku builds the Dockerfile at the root of the repo with BuildKit, turns the image into a root filesystem for its microVMs, and rolls the new version out.

The port#

Your app should listen on $PORT. Jokku sets it to the first of these that applies:

1. The PORT config var, if you set one: jokku config:set myapp PORT=3000.
2. The port the image EXPOSEs. An image inherits its base image's ports (nginx's 80, say), so when there are several, the ones from the newest EXPOSE step win.
3. The image's own PORT environment variable.
4. Otherwise, 5000.

Each deploy tells you which it used:

remote: -----> $PORT is 3000, from EXPOSE 3000/tcp

Another Dockerfile or directory#

To build a different Dockerfile, or build from a subdirectory of the repo:

jokku builder:dockerfile myapp docker/prod.Dockerfile   # relative to the build dir
jokku builder:set myapp build-dir api                   # build from api/ in the repo
jokku builder:report myapp                              # how the app is built

builder:dockerfile is also how you switch an app back to building from git after it ran a compose file or a registry image.

Process types#

Without a Procfile, the app has a single web process that runs the image's ENTRYPOINT and CMD. To run more than one kind of process, add a Procfile to your repo:

web: bin/server
worker: bin/jobs

Only web runs at first; scale the others to start them. See Processes & scaling.

For a Procfile somewhere else, relative to the build dir:

jokku builder:set myapp procfile Procfile.prod

Private base images#

If your Dockerfile starts FROM an image in a private registry, log in once and every build can pull it:

echo $TOKEN | jokku registry:login ghcr.io you

Rebuild without a push#

ps:rebuild builds the last pushed source again and deploys it, for example to pick up a newer base image:

jokku ps:rebuild myapp

Git settings#

jokku git:set myapp deploy-branch production
jokku git:report myapp

Not supported yet#

• Build args. docker-options:add ... build is planned.
• Buildpacks. Herokuish, Cloud Native Buildpacks, nixpacks and railpack aren't supported for now: Jokku builds Dockerfiles, compose files and registry images.