Comment 4 for bug 1900126

As to hanging, I'm also unable to reproduce your issue.

I tried substituting various bad ulrs into the WHEELS environment variable. It always exits cleanly with the errro ....

Traceback (most recent call last):
  File "/opt/loci/scripts/fetch_wheels.py", line 155, in <module>
    main()
  File "/opt/loci/scripts/fetch_wheels.py", line 129, in main
    data = get_wheels(wheels)
  File "/opt/loci/scripts/fetch_wheels.py", line 90, in get_wheels
    resp = urllib2.urlopen(r)
  File "/usr/lib64/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib64/python3.6/urllib/request.py", line 526, in open
    response = self._open(req, data)
  File "/usr/lib64/python3.6/urllib/request.py", line 544, in _open
    '_open', req)
  File "/usr/lib64/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/lib64/python3.6/urllib/request.py", line 1346, in http_open
    return self.do_open(http.client.HTTPConnection, req)
  File "/usr/lib64/python3.6/urllib/request.py", line 1320, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [Errno -2] Name or service not known>
The command '/bin/sh -c /opt/loci/scripts/install.sh' returned a non-zero code: 1
Command (docker) failed, attempt 1 of 1.
Max command attempts reached. Aborting...
Failed to build stx-horizon... Aborting
Cleaning loci build container and image:
....
There were 1 failures:
stx-horizon

$echo $?
1