Ensure build steps use non-interactive package installs.

[Alexhuszagh]

Fixes #589. Some libraries, such as tzdata, can ask for user input
during installation, which is problematic when building a Docker image,
since it prevents automatation and stdin i typically not attached. This
has also been an issue upgrading Docker images to the latest Ubuntu
versions.

[reitermarkus]

Does it make sense to set this in lib.sh instead?

[Alexhuszagh]

Does it make sense to set this in lib.sh instead?

That should work, I'll redo this PR then. Seems like a much "drier" approach. One of the issues though is it's not only the command install_packages that installs packages. Other scripts do too, such as:

• android-ndk.sh
• android-system.sh

And a lot of the Dockerfiles, such as Dockerfile.i686-pc-windows-gnu, Dockerfile.asmjs-unknown-emscripten, and Dockerfile.aarch64-unknown-linux-gnu, do as well. Just for resilience reasons, it would be good to ensure they're all using non-interactive prompts. RPM packages never ask for user input with -y, so at least we only have to worry about Ubuntu-based Docker images here.

So I'm not sure what the best solution is here.

[Alexhuszagh]

Currently, merely updating install_packages to use DEBIAN_FRONTEND=noninteractive is insufficient. I've attempted the following patch, but this causes other steps to fail:

--- a/docker/lib.sh
+++ b/docker/lib.sh
@@ -6,7 +6,8 @@ install_packages() {
 
         for pkg in "${@}"; do
             if ! dpkg -L "${pkg}" >/dev/null 2>/dev/null; then
-                apt-get install --assume-yes --no-install-recommends "${pkg}"
+                DEBIAN_FRONTEND=noninteractive apt-get install --assume-yes \
+                    --no-install-recommends "${pkg}"
 
                 purge_list+=( "${pkg}" )
             fi

Here, we have the failing step of Dockerfile.armv5te-unknown-linux-gnueabi, which produces the tzdata error above.

RUN apt-get update && apt-get install --assume-yes --no-install-recommends \
    g++-arm-linux-gnueabi \
    crossbuild-essential-armel \
    libc6-dev-armel-cross && \
    /qemu.sh arm

We could export this only in Dockerfiles that currently require non-interactive tzdata, but this seems to be a fragile solution. The currently affected Dockerfiles are:

• armv5te-unknown-linux-gnueabi
• i686-pc-windows-gnu

[Emilgardis]

bors r+

[bors]

Build failed:

• conclusion

[Emilgardis]

oh yeah, need someone else to r+ #690

[Emilgardis]

bors r+

[bors]

Build failed (retrying...):

• conclusion

[Emilgardis]

bors cancel

#695

[bors]

Canceled.

[Emilgardis]

bors r+

[bors]

Build succeeded:

• conclusion