[PATCH OSSTEST v2 3/4] Add support for selecting resources based on their properties.

[Ian Campbell <ian.campbell@citrix.com>]

In particular for allocating hosts based on host properties.

To do this we extend the hostflags syntax with "condition:arg1:arg2".
This specifies that the candidate host must pass the condition given
the arguments.

Each "condition" is a new module in the Osstest::ResourceCondition
namespace. For each condition an object is constructed using the given
arguments (split on ':') and stored in $hid.

When allocating for each candidate host the object's ->check method is
called giving $restype and $resname and will return true or false
depending on whether the given host meets the condition.

Only a single condition is implemented here "PropMinVer" which
requires that a given property on the resource has at least the given
value when compared as a version string. Enforce that the database and
the resource property both use the canonical CamelCase naming through
the use of the newly added here propname_check function. Lack of the
property being compared is taken a "no restriction" and hence is
allowed.

Osstest::cfgvar_re is exported for use in the new propname_check
function.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
v2:
  - ">=(v)" in stringify.
  - s/required minimum/maximum minimum/
  - Require cond name to match \w+ (avoiding spaces or other meta character
    magic and associated pitfalls)
  - Spaces inside various @{ ... }
  - Add and use propname_check
---
 Osstest.pm                              |  6 +--
 Osstest/ResourceCondition/PropMinVer.pm | 77 +++++++++++++++++++++++++++++++++
 Osstest/TestSupport.pm                  | 16 ++++++-
 ts-hosts-allocate-Executive             | 25 +++++++++--
 4 files changed, 117 insertions(+), 7 deletions(-)
 create mode 100644 Osstest/ResourceCondition/PropMinVer.pm

diff --git a/Osstest.pm b/Osstest.pm
index 1fe16fc..4a763c6 100644
--- a/Osstest.pm
+++ b/Osstest.pm
@@ -40,7 +40,7 @@ BEGIN {
                       db_begin_work db_prepare
                       ensuredir get_filecontents_core_quiet system_checked
                       nonempty visible_undef show_abs_time
-                      %arch_debian2xen %arch_xen2debian
+                      %arch_debian2xen %arch_xen2debian $cfgvar_re
                       );
     %EXPORT_TAGS = ( );
 
@@ -62,6 +62,8 @@ our %arch_debian2xen = qw(i386 x86_32
 our %arch_xen2debian;
 $arch_xen2debian{$arch_debian2xen{$_}} = $_ foreach keys %arch_debian2xen;
 
+our $cfgvar_re = '[A-Z][0-9a-zA-Z-_]*';
+
 #---------- static default config settings ----------
 
 our %c = qw(
@@ -121,8 +123,6 @@ sub readglobalconfig () {
     $c{AuthorizedKeysFiles} = '';
     $c{AuthorizedKeysAppend} = '';
 
-    my $cfgvar_re = '[A-Z][0-9a-zA-Z-_]*';
-
     my $cfgfiles = $ENV{'OSSTEST_CONFIG'} || "$ENV{'HOME'}/.xen-osstest/config";
 
     my $readcfg;
diff --git a/Osstest/ResourceCondition/PropMinVer.pm b/Osstest/ResourceCondition/PropMinVer.pm
new file mode 100644
index 0000000..155aefb
--- /dev/null
+++ b/Osstest/ResourceCondition/PropMinVer.pm
@@ -0,0 +1,77 @@
+# This is part of "osstest", an automated testing framework for Xen.
+# Copyright (C) 2015 Citrix Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package Osstest::ResourceCondition::PropMinVer;
+
+use strict;
+use warnings;
+
+use Osstest;
+use Osstest::TestSupport;
+
+use Sort::Versions;
+
+use overload '""' => 'stringify';
+
+BEGIN {
+    use Exporter ();
+    our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
+    $VERSION     = 1.00;
+    @ISA         = qw(Exporter);
+    @EXPORT      = qw();
+    %EXPORT_TAGS = ( );
+
+    @EXPORT_OK   = qw();
+}
+
+sub new {
+    my ($class, $name, $prop, $val) = @_;
+
+    die "propname: $prop?" unless propname_check($prop);
+
+    return bless {
+	Prop => $prop,
+	MinVal => $val
+    }, $class;
+}
+
+sub stringify {
+    my ($pmv) = @_;
+    return "$pmv->{MinVal} >=(v) property $pmv->{Prop}";
+}
+
+sub check {
+    my ($pmv, $restype, $resname) = @_;
+
+    # Using _cached avoids needing to worry about $dbh_tests being
+    # closed/reopened between invocations
+    my $hpropq = $dbh_tests->prepare_cached(<<END);
+       SELECT val FROM resource_properties
+	WHERE restype = ? AND resname = ? AND name = ?
+END
+    $hpropq->execute($restype, $resname, $pmv->{Prop});
+
+    my $row= $hpropq->fetchrow_arrayref();
+    $hpropq->finish();
+
+    return 1 unless $row; # No prop == no restriction.
+
+    # If the maximum minimum is >= to the resource's minimum then the
+    # resource meets the requirement.
+    return versioncmp($pmv->{MinVal}, $row->[0]) >= 0;
+}
+
+1;
diff --git a/Osstest/TestSupport.pm b/Osstest/TestSupport.pm
index 0afaeab..8032fac 100644
--- a/Osstest/TestSupport.pm
+++ b/Osstest/TestSupport.pm
@@ -71,7 +71,7 @@ BEGIN {
                       get_target_property get_host_native_linux_console
                       power_state power_cycle power_cycle_sleep
                       serial_fetch_logs
-                      propname_massage
+                      propname_massage propname_check
          
                       get_stashed open_unique_stashfile compress_stashed
                       dir_identify_vcs build_clone built_stash built_stash_file
@@ -933,6 +933,20 @@ sub propname_massage ($) {
     return $prop;
 }
 
+sub propname_check ($) {
+    # ensure propname is valid and in the canonical WordWordWord form
+    # (rather than, say, one of the legacy forms described in
+    # propname_massage).
+    my ($prop) = @_;
+
+    # Check only valid characters
+    return 0 if $prop !~ m|^${cfgvar_re}$|;
+    # Check canonical form
+    return 0 if propname_massage($prop) ne $prop;
+    # Is ok
+    return 1;
+}
+
 # It is fine to call this on a guest object too, in which case it will
 # always return $defval.
 sub get_host_property ($$;$) {
diff --git a/ts-hosts-allocate-Executive b/ts-hosts-allocate-Executive
index 294395d..35a9347 100755
--- a/ts-hosts-allocate-Executive
+++ b/ts-hosts-allocate-Executive
@@ -213,7 +213,7 @@ sub compute_hids () {
     our %equivs;
 
     foreach my $ident (@ARGV) {
-        my $hid= { };
+        my $hid= { Conds => { host => [] } };
         my $override_use;
         if ($ident =~ m/\=/) {
             $hid->{OverrideUse}= $'; #'
@@ -251,11 +251,23 @@ sub compute_hids () {
                 my $equiv= $hid->{Equiv}= $equivs{$formalclass};
                 print DEBUG "HID $ident FLAG $flag EQUIV $equiv->{Wanted}\n";
                 next;
-            }
+            } elsif ($flag =~ m/^\w+:/) {
+		my (@c) = split /:/, $flag;
+		my $o;
+		eval ("use Osstest::ResourceCondition::$c[0];".
+		      "\$o = Osstest::ResourceCondition::$c[0]->new(\@c);")
+		    or die "get ResourceCondition $@";
+
+		push @{ $hid->{Conds}{host} }, $o;
+
+		print DEBUG "HID $ident FLAG $flag HCOND $o\n";
+		next;
+	    }
             $flags{$flag}= 1;
         }
         $hid->{Flags}= \%flags;
-        print DEBUG "HID $ident FLAGS ".(join ',', sort keys %flags)."\n";
+        print DEBUG "HID $ident FLAGS ".(join ',', sort keys %flags).
+	    " + ".scalar @{ $hid->{Conds}{host} }." host conditions(s)\n";
         push @hids, $hid;
     }
 }
@@ -363,6 +375,13 @@ END
             push @{ $candrow->{Warnings} },
                 "specified host lacks flags @missingflags";
         }
+
+	foreach my $c (@{ $hid->{Conds}{$candrow->{restype}} }) {
+	    if (!$c->check($candrow->{restype}, $candrow->{resname})) {
+		print DEBUG "$dbg failed $c condition\n";
+		next CANDIDATE unless defined $use;
+	    }
+	}
         $any++;
 
         print DEBUG "$dbg GOOD\n";
-- 
2.5.1