docker thrift-build tags

["James E. King, III" <jk...@apache.org>]

How do the images in

I modified the build scripts for travis to use build stages:

Stage 1 is docker, and we build trusty, xenial, and artful images.
Stage 2 is testing, and we are supposed to use those images.

The script that triggers this looks like:

---
pushd ${SCRIPT_DIR}/$DISTRO
if dockerfile_changed; then
  echo Dockerfile has not changed.  No need to rebuild.
  exit 0
fi
popd

echo Dockerfile has changed.  Rebuilding docker image $DISTRO.
docker build --tag $SRC_IMG build/docker/$DISTRO
---

Once the docker image is built and tagged, with "build --tag", shouldn't it
show up in the repository at
https://hub.docker.com/r/thrift/thrift-build/tags/ automatically?  It
isn't, and I don't know how that part of the build process works or is
supposed to work.

If someone tries to build in travis CI on a fork, I assume they would not
have the right permissions to tag or re-tag images, however for an official
apache/thrift generated build, shouldn't that build be able to tag directly?

Here's PR I submitted: https://github.com/apache/thrift/pull/1387
Here's the Travis CI job:
https://travis-ci.org/apache/thrift/builds/283720518
Note how build jobs 3+ rebuilt the docker image, even though build job 2
was supposed to have built and tagged it?  And the tag in
https://hub.docker.com/r/thrift/thrift-build/tags/ hasn't been updated for
whatever reason?  How do I find out why?

Thanks,

Jim