Elm make fails inside alpine docker container

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It looks like a DNS issue.

elm binary will use the DNS nameservers from /etc/resolv.conf to resolve domain names, and IIRC TCP queries are not supported. So maybe first check that this works fine:

You could open a shell inside your container, install dig and test that package.elm-lang.org resolution always works correctly in UDP:

docker run -it --rm alpine:3.11.2 /bin/ash

then inside the container:

apk update
apk add bind-tools

then

# Replace 192.168.100.1 by the nameserver defined in your /etc/resolv.conf
dig @192.168.100.1 +noall +answer +notcp +retry=0 package.elm-lang.org

You should get:

package.elm-lang.org.	14116	IN	A	45.55.106.189

Run it several times to check that it is reliable (maybe in a loop).

Also to be sure it’s not linked to your local DNS resolution, try to add the following command in your Dockerfile before the elm make one:

RUN echo "nameserver 8.8.8.8" > /etc/resolv.conf

Then try to build again.