Use mod_version to clean-up apache version matching

This change uses mod_version (shipped by default on everything we care
about) to set-up version-specific config within apache rather than
within devstack scripts.

Clean up the horizon and keystone config file generation to use the
internal apache matching.

Since I6478db385fda2fa1c75ced12d3e886b2e1152852 the apache matching in
'functions' is actually duplicated.  just leave get_apache_version in
lib/apache as it is used for config-file name matching in there.

Change-Id: I6478db385fda2fa1c75ced12d3e886b2e1152852

files/apache-horizon.template

@@ -17,10 +17,16 @@
 
     <Directory %HORIZON_DIR%/>
         Options Indexes FollowSymLinks MultiViews
-        %HORIZON_REQUIRE%
         AllowOverride None
-        Order allow,deny
-        allow from all
+        # Apache 2.4 uses mod_authz_host for access control now (instead of
+        #  "Allow")
+        <IfVersion < 2.4>
+            Order allow,deny
+            Allow from all
+        </IfVersion>
+        <IfVersion >= 2.4>
+            Require all granted
+        </IfVersion>
     </Directory>
 
     ErrorLog /var/log/%APACHE_NAME%/horizon_error.log

files/apache-keystone.template

@@ -6,7 +6,9 @@ Listen %ADMINPORT%
     WSGIProcessGroup keystone-public
     WSGIScriptAlias / %PUBLICWSGI%
     WSGIApplicationGroup %{GLOBAL}
-    %ERRORLOGFORMAT%
+    <IfVersion >= 2.4>
+      ErrorLogFormat "%{cu}t %M"
+    </IfVersion>
     ErrorLog /var/log/%APACHE_NAME%/keystone.log
     CustomLog /var/log/%APACHE_NAME%/access.log combined
 </VirtualHost>
@@ -16,7 +18,9 @@ Listen %ADMINPORT%
     WSGIProcessGroup keystone-admin
     WSGIScriptAlias / %ADMINWSGI%
     WSGIApplicationGroup %{GLOBAL}
-    %ERRORLOGFORMAT%
+    <IfVersion >= 2.4>
+      ErrorLogFormat "%{cu}t %M"
+    </IfVersion>
     ErrorLog /var/log/%APACHE_NAME%/keystone.log
     CustomLog /var/log/%APACHE_NAME%/access.log combined
 </VirtualHost>

functions

@@ -21,18 +21,6 @@ function function_exists {
     declare -f -F $1 > /dev/null
 }
 
-# Checks if installed Apache is <= given version
-# $1 = x.y.z (version string of Apache)
-function check_apache_version {
-    local cmd="apachectl"
-    if ! [[ -x $(which apachectl 2>/dev/null) ]]; then
-        cmd="/usr/sbin/apachectl"
-    fi
-
-    local version=$($cmd -v | grep version | grep -Po 'Apache/\K[^ ]*')
-    expr "$version" '>=' $1 > /dev/null
-}
-
 
 # Cleanup anything from /tmp on unstack
 # clean_tmp

lib/apache

@@ -59,6 +59,11 @@ function install_apache_wsgi {
     else
         exit_distro_not_supported "apache installation"
     fi
+
+    # ensure mod_version enabled for <IfVersion ...>.  This is
+    # built-in statically on anything recent, but precise (2.2)
+    # doesn't have it enabled
+    sudo a2enmod version || true
 }
 
 # get_apache_version() - return the version of Apache installed

lib/horizon

@@ -120,12 +120,6 @@ function init_horizon {
     # Create an empty directory that apache uses as docroot
     sudo mkdir -p $HORIZON_DIR/.blackhole
 
-    # Apache 2.4 uses mod_authz_host for access control now (instead of "Allow")
-    local horizon_require=''
-    if check_apache_version "2.4" ; then
-        horizon_require='Require all granted'
-    fi
-
     local horizon_conf=$(apache_site_config_for horizon)
 
     # Configure apache to run horizon
@@ -135,7 +129,6 @@ function init_horizon {
         s,%HORIZON_DIR%,$HORIZON_DIR,g;
         s,%APACHE_NAME%,$APACHE_NAME,g;
         s,%DEST%,$DEST,g;
-        s,%HORIZON_REQUIRE%,$horizon_require,g;
     \" $FILES/apache-horizon.template >$horizon_conf"
 
     if is_ubuntu; then

lib/keystone

@@ -125,12 +125,6 @@ function _config_keystone_apache_wsgi {
     local keystone_apache_conf=$(apache_site_config_for keystone)
     local apache_version=$(get_apache_version)
 
-    if [[ ${apache_version#*\.} -ge 4 ]]; then
-        # Apache 2.4 supports custom error log formats
-        # this should mirror the original log formatting.
-        local errorlogformat='ErrorLogFormat "%{cu}t %M"'
-    fi
-
     # copy proxy vhost and wsgi file
     sudo cp $KEYSTONE_DIR/httpd/keystone.py $KEYSTONE_WSGI_DIR/main
     sudo cp $KEYSTONE_DIR/httpd/keystone.py $KEYSTONE_WSGI_DIR/admin
@@ -143,7 +137,6 @@ function _config_keystone_apache_wsgi {
         s|%PUBLICWSGI%|$KEYSTONE_WSGI_DIR/main|g;
         s|%ADMINWSGI%|$KEYSTONE_WSGI_DIR/admin|g;
         s|%USER%|$STACK_USER|g
-        s|%ERRORLOGFORMAT%|$errorlogformat|g;
     " -i $keystone_apache_conf
     enable_apache_site keystone
 }