openshift-installer-presubmits: Set HOME and USER for bazel-build-tar…

…ball

OpenShift Prow containers execute with arbitrary container-side UIDs
[1] for some security reason I don't understand.  That makes it hard
for Bazel to figure out where to put things, and we'd die with [2]:

  + bazel --output_base=/tmp build tarball
  Error: $USER is not set, and unable to look up name of current user: (error: 0): Success

as Bazel [3]:

1. Checked $USER and found it unset.
2. Fell back to getpwuid(getuid()) and found no entry matching the
   arbitrary container-side UID.

Setting USER is not sufficient; it results in errors like [4]:

  + USER=bazel-testing bazel --output_base=/tmp build tarball
  Error: mkdir('/.cache/bazel/_bazel_bazel-testing'): (error: 13): Permission denied

as Bazel tries to expand its default ~/.cache/bazel [5].  Setting HOME
addresses that, but then actions like tarball creation die with [6]:

  ERROR: /home/prow/go/src/github.com/openshift/installer/BUILD.bazel:106:1: error executing shell command: 'bazel-out/host/bin/external/bazel_tools/tools/build_defs/pkg/build_tar --flagfile=bazel-out/k8-fastbuild/bin/tf_bin.args' failed (Exit 1)
  Traceback (most recent call last):
    File "/usr/lib/python2.7/site.py", line 554, in <module>
      main()
    File "/usr/lib/python2.7/site.py", line 536, in main
      known_paths = addusersitepackages(known_paths)
    File "/usr/lib/python2.7/site.py", line 272, in addusersitepackages
      user_site = getusersitepackages()
    File "/usr/lib/python2.7/site.py", line 247, in getusersitepackages
      user_base = getuserbase() # this will also set USER_BASE
    File "/usr/lib/python2.7/site.py", line 237, in getuserbase
      USER_BASE = get_config_var('userbase')
    File "/usr/lib/python2.7/sysconfig.py", line 582, in get_config_var
      return get_config_vars().get(name)
    File "/usr/lib/python2.7/sysconfig.py", line 533, in get_config_vars
      _CONFIG_VARS['userbase'] = _getuserbase()
    File "/usr/lib/python2.7/sysconfig.py", line 210, in _getuserbase
      return env_base if env_base else joinuser("~", ".local")
    File "/usr/lib/python2.7/sysconfig.py", line 196, in joinuser
      return os.path.expanduser(os.path.join(*args))
    File "/usr/lib/python2.7/posixpath.py", line 262, in expanduser
      userhome = pwd.getpwuid(os.getuid()).pw_dir
  KeyError: 'getpwuid(): uid not found: 1000130000'

This is the same issue we saw for Bazel, but is now because of Python
code [7].  Bazel's build_tar invocation uses run_shell with
use_default_shell_env=True [8], so to get HOME set there as well we
need to use --action_env [9] (I'm updating test-bazel-build-tarball.sh
to pass that argument through to Bazel).

[1]: #1178 (comment)
[2]: https://storage.googleapis.com/origin-ci-test/pr-logs/pull/openshift_installer/123/ci-pull-openshift-installer-bazel-build-tarball/1/build-log.txt
[3]: https://github.com/bazelbuild/bazel/blob/0.16.1/src/main/cpp/blaze_util_posix.cc#L654-L664
[4]: https://storage.googleapis.com/origin-ci-test/pr-logs/pull/openshift_installer/123/ci-pull-openshift-installer-bazel-build-tarball/3/build-log.txt
[5]: https://docs.bazel.build/versions/master/output_directories.html#documentation-of-the-current-bazel-output-directory-layout
[6]: https://storage.googleapis.com/origin-ci-test/pr-logs/pull/openshift_installer/123/ci-pull-openshift-installer-bazel-build-tarball/4/build-log.txt
[7]: https://github.com/python/cpython/blob/1f34aece28d143edb94ca202e661364ca394dc8c/Lib/posixpath.py#L260-L262
[8]: https://github.com/bazelbuild/bazel/blob/0.16.1/tools/build_defs/pkg/pkg.bzl#L82-L89
[9]: https://docs.bazel.build/versions/master/command-line-reference.html#build-options

ci-operator/jobs/openshift/installer/openshift-installer-presubmits.yaml

@@ -166,12 +166,16 @@ presubmits:
       containers:
       - image: quay.io/coreos/tectonic-builder:bazel-v0.3
         env:
+        - name: HOME
+          value: /tmp
         - name: IS_CONTAINER
           value: "TRUE"
+        - name: USER
+          value: bazel
         command:
         - sh
         args:
-        - ./hack/test-bazel-build-tarball.sh
+        - ./hack/test-bazel-build-tarball.sh --action_env=HOME=/tmp
 
   - name: ci-pull-openshift-installer-go-vet
     trigger: "(?m)^/test go-vet"