Merge "Use python3 as default python command"
diff --git a/inc/python b/inc/python
index cf61389..52ad565 100644
--- a/inc/python
+++ b/inc/python
@@ -450,6 +450,31 @@
     fi
 }
 
+# Provide requested python version and sets PYTHON variable
+function install_python {
+    # NOTE: install_python function should finally just do what install_python3
+    # does as soon Python 2 support has been dropped
+    if python3_enabled; then
+        install_python3
+        export PYTHON=$(which python${PYTHON3_VERSION} 2>/dev/null ||
+                        which python3 2>/dev/null)
+        if [[ "${DISTRO}" =~ (rhel8) ]]; then
+            # Use Python 3 as default python command so that we have only one
+            # python alternative to use on the system for either python and
+            # python3
+            sudo alternatives --set python "${PYTHON}"
+        else
+            # Install anyway Python 2 for legacy scripts that still requires
+            # python instead of python3 command
+            install_package python
+        fi
+    else
+        echo "WARNING - Python 2 support has been deprecated in favor of Python 3"
+        install_package python
+        export PYTHON=$(which python 2>/dev/null)
+    fi
+}
+
 # Install python3 packages
 function install_python3 {
     if is_ubuntu; then
diff --git a/stack.sh b/stack.sh
index 0f9d57b..7119e5f 100755
--- a/stack.sh
+++ b/stack.sh
@@ -415,11 +415,8 @@
 
 # Ensure python is installed
 # --------------------------
-install_python3
+install_python
 
-if ! python3_enabled; then
-    is_package_installed python || install_package python
-fi
 
 # Configure Logging
 # -----------------
@@ -497,14 +494,14 @@
             _of_args="$_of_args --no-timestamp"
         fi
         # Set fd 1 and 2 to write the log file
-        exec 1> >( $TOP_DIR/tools/outfilter.py $_of_args -o "${LOGFILE}" ) 2>&1
+        exec 1> >( $PYTHON $TOP_DIR/tools/outfilter.py $_of_args -o "${LOGFILE}" ) 2>&1
         # Set fd 6 to summary log file
-        exec 6> >( $TOP_DIR/tools/outfilter.py -o "${SUMFILE}" )
+        exec 6> >( $PYTHON $TOP_DIR/tools/outfilter.py -o "${SUMFILE}" )
     else
         # Set fd 1 and 2 to primary logfile
-        exec 1> >( $TOP_DIR/tools/outfilter.py -o "${LOGFILE}" ) 2>&1
+        exec 1> >( $PYTHON $TOP_DIR/tools/outfilter.py -o "${LOGFILE}" ) 2>&1
         # Set fd 6 to summary logfile and stdout
-        exec 6> >( $TOP_DIR/tools/outfilter.py -v -o "${SUMFILE}" >&3 )
+        exec 6> >( $PYTHON $TOP_DIR/tools/outfilter.py -v -o "${SUMFILE}" >&3 )
     fi
 
     echo_summary "stack.sh log $LOGFILE"
@@ -521,7 +518,7 @@
         exec 1>/dev/null 2>&1
     fi
     # Always send summary fd to original stdout
-    exec 6> >( $TOP_DIR/tools/outfilter.py -v >&3 )
+    exec 6> >( $PYTHON $TOP_DIR/tools/outfilter.py -v >&3 )
 fi
 
 # Basic test for ``$DEST`` path permissions (fatal on error unless skipped)
@@ -557,9 +554,9 @@
             generate-subunit $DEVSTACK_START_TIME $SECONDS 'fail' >> ${SUBUNIT_OUTPUT}
         fi
         if [[ -z $LOGDIR ]]; then
-            $TOP_DIR/tools/worlddump.py
+            ${PYTHON} $TOP_DIR/tools/worlddump.py
         else
-            $TOP_DIR/tools/worlddump.py -d $LOGDIR
+            ${PYTHON} $TOP_DIR/tools/worlddump.py -d $LOGDIR
         fi
     else
         # If we error before we've installed os-testr, this will fail.
diff --git a/tests/test_worlddump.sh b/tests/test_worlddump.sh
index f407d40..9196525 100755
--- a/tests/test_worlddump.sh
+++ b/tests/test_worlddump.sh
@@ -8,7 +8,7 @@
 
 OUT_DIR=$(mktemp -d)
 
-$TOP/tools/worlddump.py -d $OUT_DIR
+${PYTHON} $TOP/tools/worlddump.py -d $OUT_DIR
 
 if [[ $? -ne 0 ]]; then
     fail "worlddump failed"
diff --git a/tools/generate-devstack-plugins-list.py b/tools/generate-devstack-plugins-list.py
index 3ac9c4d..1cacd06 100644
--- a/tools/generate-devstack-plugins-list.py
+++ b/tools/generate-devstack-plugins-list.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 # Copyright 2016 Hewlett Packard Enterprise Development Company, L.P.
 #
diff --git a/tools/install_prereqs.sh b/tools/install_prereqs.sh
index da59093..a7c03d2 100755
--- a/tools/install_prereqs.sh
+++ b/tools/install_prereqs.sh
@@ -81,12 +81,6 @@
     fi
 fi
 
-if python3_enabled; then
-    install_python3
-    export PYTHON=$(which python${PYTHON3_VERSION} 2>/dev/null || which python3 2>/dev/null)
-else
-    export PYTHON=$(which python 2>/dev/null)
-fi
 
 # Mark end of run
 # ---------------
diff --git a/tools/outfilter.py b/tools/outfilter.py
old mode 100755
new mode 100644
index cf09124..e910f79
--- a/tools/outfilter.py
+++ b/tools/outfilter.py
@@ -1,5 +1,5 @@
-#!/usr/bin/env python
-#
+#!/usr/bin/env python3
+
 # Copyright 2014 Hewlett-Packard Development Company, L.P.
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
diff --git a/tools/update_clouds_yaml.py b/tools/update_clouds_yaml.py
index 9187c66..7be995e 100755
--- a/tools/update_clouds_yaml.py
+++ b/tools/update_clouds_yaml.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
diff --git a/tools/worlddump.py b/tools/worlddump.py
old mode 100755
new mode 100644
index d5ff5d1..1e6e176
--- a/tools/worlddump.py
+++ b/tools/worlddump.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright 2014 Hewlett-Packard Development Company, L.P.
 #
@@ -23,8 +23,8 @@
 import datetime
 from distutils import spawn
 import fnmatch
+import io
 import os
-import os.path
 import shutil
 import subprocess
 import sys
@@ -109,9 +109,10 @@
 # This method gets max version searching 'OpenFlow versions 0x1:0x'.
 # And return a version value converted to an integer type.
 def _get_ofp_version():
-    process = subprocess.Popen(['ovs-ofctl', '--version'], stdout=subprocess.PIPE)
+    process = subprocess.Popen(['ovs-ofctl', '--version'],
+                               stdout=subprocess.PIPE)
     stdout, _ = process.communicate()
-    find_str = 'OpenFlow versions 0x1:0x'
+    find_str = b'OpenFlow versions 0x1:0x'
     offset = stdout.find(find_str)
     return int(stdout[offset + len(find_str):-1]) - 1
 
@@ -206,7 +207,7 @@
 
 def compute_consoles():
     _header("Compute consoles")
-    for root, dirnames, filenames in os.walk('/opt/stack'):
+    for root, _, filenames in os.walk('/opt/stack'):
         for filename in fnmatch.filter(filenames, 'console.log'):
             fullpath = os.path.join(root, filename)
             _dump_cmd("sudo cat %s" % fullpath)
@@ -234,12 +235,22 @@
         # tools out there that can do that sort of thing though.
         _dump_cmd("ls -ltrah /var/core")
 
+
+def disable_stdio_buffering():
+    # re-open STDOUT as binary, then wrap it in a
+    # TextIOWrapper, and write through everything.
+    binary_stdout = io.open(sys.stdout.fileno(), 'wb', 0)
+    sys.stdout = io.TextIOWrapper(binary_stdout, write_through=True)
+
+
 def main():
     opts = get_options()
     fname = filename(opts.dir, opts.name)
     print("World dumping... see %s for details" % fname)
-    sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
-    with open(fname, 'w') as f:
+
+    disable_stdio_buffering()
+
+    with io.open(fname, 'w') as f:
         os.dup2(f.fileno(), sys.stdout.fileno())
         disk_space()
         process_list()