Dockerhub is going to rate limit unauthenticated pulls.
Use our HashiCorp internal mirror for builds run through CircleCI.
Co-authored-by: Mahmood Ali <mahmood@hashicorp.com>
Pulling large docker containers can take longer than the default
context timeout. Without a way to change this it is very hard for
users to utilise Nomad properly without hacky work arounds.
This change adds an optional pull_timeout config parameter which
gives operators the possibility to account for increase pull times
where needed. The infra docker image also has the option to set a
custom timeout to keep consistency.
Due to https://github.com/tsenart/deadcode/issues/3 we can't specify
these consts on their own. This moves them into the _platform_test.go
files to avoid creating a package that only exposes a couple of values.
