Configure debconf to be always non-interactive

[SimonSapin]

See for example http://travis-ci.org/#!/Kozea/WeasyPrint/jobs/1895338/L208

Even though DEBIAN_FRONTEND=noninteractive is passed explicitly, debconf still tries to ask questions with a ncurses-based interactive interface. Apparently, sudo does not preserve environment variables.

A more permanent fix could be to set Frontend noninteractive near the top of /etc/debconf.conf.

[michaelklishin]

We already configure apt to "assume yes" and that has been sufficient for now. How does your project use debconf?

[michaelklishin]

I think we also need to configure sudo to preserve DEBIAN_FRONTEND, otherwise there will be 10 other tools we need to configured in a similar way.

[SimonSapin]

My project needs python3-gi-cairo which does not exist in Ubuntu 11.10, so I’m installing it from 12.04.

From .travis.yml:

 - sudo sed -i s/oneiric/precise/ /etc/apt/sources.list
 - sudo apt-get -qy update
 - DEBIAN_FRONTEND=noninteractive sudo apt-get -qy install python3-gi python3-gi-cairo

Doing so also upgrades libc6. debconf then tries to ask "interactively" whether PostgreSQL should be restarted. I don’t care about Postgres though.

[Mezzle]

sudo doesn't provide environment - but if you pass it -E it'll pass the environment - as sudo is only ever called by your code, not the internals of travis for this - using -E on sudo should suffice.

[michaelklishin]

It will take some time to upgrade all VM images to have updates sudoers, I think in the meantime if you copy the same file we install in fa89acd in a before_install step and make sure it has permissions 0440 and owned by root, it will be sufficient for now.

So, /etc/sudoers.d/env_keep, owned by root, 0440 with this content:

Defaults        env_keep += "DEBIAN_FRONTEND CI TRAVIS"

[SimonSapin]

Both of these worked for me: sudo env DEBIAN_FRONTEND=noninteractive apt-get ... or sudo -E apt-get ....

[llucax]

Or a la make: sudo DEBIAN_FRONTEND=noninteractive apt-get ...