dbuild: try to pull image if not present locally
dbuild: try to pull image if not present locally

Pekka Enberg <penberg@scylladb.com> wrote:
> Image might not be present, but the subsequent "docker run" command will automatically pull it.

Just letting "docker run" fail produces kinda confusing error message,
referring to docker help, but the we want to provide the user
with our own help, so still fail early, just also try to pull the image
if "docker image inspect" failed, indicating it's not present locally.

Signed-off-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>
Message-Id: <20191223085219.1253342-4-23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>

scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla