Improve getting user name for Yugabyte DB builds

Summary:
Added logic to get user name from whoami if there is no USER environment (try for docker).
Same was made for get_version_info.py by copy-pasting get_username from run_tests_on_spark.py as there is no simple way to re-use.

Test Plan:
- unset USER
- build Yugabyte locally with yb_build.sh - it passes with this patch and fails without it

Reviewers: mikhail, bogdan, jharveysmith, steve.varnau

Reviewed By: steve.varnau

Subscribers: jharveysmith, steve.varnau, #devops

Differential Revision: https://phabricator.dev.yugabyte.com/D9788

.arclint

@@ -32,7 +32,8 @@
       "type": "pep8",
       "include": "(\\.py$)",
       "exclude": "(^thirdparty/|^[.]ycm_extra_conf[.]py$)",
-      "bin": "pycodestyle"
+      "bin": "pycodestyle",
+      "flags": ["--max-line-length=100"]
     },
     "googlecpplint": {
       "type": "googlecpplint",

build-support/compiler-wrappers/compiler-wrapper.sh

@@ -601,6 +601,14 @@ if command -v ccache >/dev/null && ! "$compiling_pch" && [[ -z ${YB_NO_CCACHE:-}
   export CCACHE_SLOPPINESS="file_macro,pch_defines,time_macros"
   export CCACHE_BASEDIR=$YB_SRC_ROOT
 
+  if [ -z "${USER:-}" ]; then
+    if whoami &> /dev/null; then
+      USER="$(whoami)"
+    else
+      fatal_error "No USER variable in env and no whoami to detect it"
+    fi
+  fi
+
   # Ensure CCACHE puts temporary files on the local disk.
   export CCACHE_TEMPDIR=${CCACHE_TEMPDIR:-/tmp/ccache_tmp_$USER}
   if [[ -n ${YB_CCACHE_DIR:-} ]]; then

build-support/gen_version_info.py

@@ -39,6 +39,7 @@
 import argparse
 import os
 import re
+import pwd
 import subprocess
 import sys
 import time
@@ -92,7 +93,29 @@ def main():
 
     hostname = socket.gethostname()
     build_time = "%s %s" % (strftime("%d %b %Y %H:%M:%S", localtime()), time.tzname[0])
-    username = os.getenv("USER")
+
+    logging.info('Get user name')
+    try:
+        username = os.getlogin()
+    except OSError as ex:
+        logging.warning(("Got an OSError trying to get the current user name, " +
+                         "trying a workaround: {}").format(ex))
+        # https://github.com/gitpython-developers/gitpython/issues/39
+        try:
+            username = pwd.getpwuid(os.getuid()).pw_name
+        except KeyError:
+            username = os.getenv('USER')
+            if not username:
+                id_output = subprocess.check_output('id').strip()
+                ID_OUTPUT_RE = re.compile(r'^uid=\d+[(]([^)]+)[)]\s.*')
+                match = ID_OUTPUT_RE.match(id_output)
+                if match:
+                    username = match.group(1)
+                else:
+                    logging.warning(
+                        "Couldn't get user name from the environment, either parse 'id' output: %s",
+                        id_output)
+                    raise
 
     git_repo_dir = get_yb_src_root_from_build_root(os.getcwd(), must_succeed=False, verbose=True)
     clean_repo = bool(git_repo_dir) and is_git_repo_clean(git_repo_dir)