Can't set build --no-cache option as "--no-cache=true"

[dirkschneemann]

With regular Docker commands, I can do:
docker build --no-cache .
or
docker build --no-cache=true .

In docker-compose, however, this one works
docker-compose build --no-cache
while this one
docker-compose build --no-cache=true
fails with

Build or rebuild services.

Services are built once and then tagged as `project_service`,
e.g. `composetest_db`. If you change a service's `Dockerfile` or the
contents of its build directory, you can run `docker-compose build` to rebuild it.

Usage: build [options] [SERVICE...]

Options:
    --force-rm  Always remove intermediate containers.
    --no-cache  Do not use cache when building the image.
    --pull      Always attempt to pull a newer version of the image.

Is there a specific reason for this inconsistency? Using the more explicit form would be useful for me in the context of a Jenkins job with a "boolean parameter" which is a checkbox, setting a bash variable to "true" or "false".

[MichaelPereira]

This inconsistency comes from the current implementation of the command which doesn't take those cases into account:

compose/compose/cli/main.py

Line 235 in 962ba5b

no_cache=bool(options.get('--no-cache', False)),

I'm not sure how to properly change it to support the following supported version by the docker command:

• --no-cache=true
• --no-cache=false
• --no-cache=1
• --no-cache=0

[shin-]

We use a different command-line parser because docker-compose is written in a different language (Python versus Go).

[dirkschneemann]

That makes sense, thank you for the clarification, @MichaelPereira and @shin- . Would it be possible to align docker-compose's behaviour to that of the docker command? Or is this not possible with docopt (which is used in docker-compose as far as I understand)?

[shin-]

I don't believe docopt supports it. If they release a new version that does, we'll be happy to include it, but I don't really see us spending any time on this otherwise.

[dirkschneemann]

Alright, don't worry, this is certainly not the most important issue and one can easily work around it. Cheers

[nise]

What are the workarounds for this? How can I prohibit caching in docker-compose or in the Dockerfile?