refactor(build): share the buildinfo stamp between the two builders

Both builders wrote the same six fields beside a published repository --
VERSION, RELEASE, BUILD_TIME, BUILD_MACHINE, COMMIT_ID, COMMIT_ID_LONG -- each
assembling them by hand, and each shelling out to hostname to do it.

builddebs.pl also ran git rev-parse a second time to get the commit, although
it had already derived the same value into $GITINFO earlier in the file. It now
uses that.

The filenames and the time formats stay as they were. deploy.sh copies
builddebs.pl's buildinfo verbatim and cluster-test.pl parses buildrpms.pl's
buildinfo.txt, so both are a contract with consumers outside this repository;
the shared helper takes the format from its caller rather than picking one.
Confirmed byte for byte that each builder's stamp is unchanged.

Covered by tests: the field names and their order, the seven-character short
commit, and that the two callers' formats still differ.

Signed-off-by: Daniel Hilst <392820+dhilst@users.noreply.github.com>

BuildUtils.pm

@@ -33,6 +33,7 @@ our @EXPORT_OK = qw(
     backup_file restore_file
     sh usage
     read_file write_file rewrite_file
+    buildinfo_text
 );
 
 # Both builders echo the commands they run under --verbose.  Set once, after
@@ -42,6 +43,27 @@ our $VERBOSE = 0;
 # The xCAT-probe helpers. xcat-probe reuses functions shipped by xCAT; they are COPIED
 # rather than symlinked because a symlink does not survive packaging, and rather than
 # maintained twice because they would drift. Both builders stage them the same way.
+# The stamp both builders write beside a published repository. deploy.sh copies
+# the file verbatim and cluster-test.pl parses it, so the field names and their
+# order are a contract; each builder passes its own time format and writes to
+# its own filename, which are part of that contract too.
+sub buildinfo_text {
+    my (%args) = @_;
+    my $commit = $args{commit} // 'unknown';
+    my $host   = $args{host};
+    unless (defined $host) {
+        $host = `hostname 2>/dev/null` || 'unknown';
+        chomp $host;
+    }
+    return join('', map { "$_\n" }
+        "VERSION=$args{version}",
+        "RELEASE=$args{release}",
+        "BUILD_TIME=" . strftime($args{time_format}, gmtime($args{epoch})),
+        "BUILD_MACHINE=$host",
+        "COMMIT_ID=" . substr($commit, 0, 7),
+        "COMMIT_ID_LONG=$commit");
+}
+
 # Whole-file read and write.  Deliberately plain open/close rather than
 # File::Slurper, so that loading this module does not oblige a deb build to
 # install a module it otherwise does not need.

builddebs.pl

@@ -36,7 +36,7 @@ use BuildUtils qw(
     pin_control_version rewrite_changelog_header
     reprepro_distributions reprepro_options
     lock_id_for take_build_lock sh_quote
-    sh usage read_file write_file rewrite_file
+    sh usage read_file write_file rewrite_file buildinfo_text
 );
 
 # The xcat-core packages that ship as debs. xCAT-openbmc-py, xCAT-rmc and xCAT-release
@@ -338,17 +338,9 @@ SCRIPT
     close $m;
     chmod 0775, "$repodir/mklocalrepo.sh";
 
-    my $commit = `git -C @{[ sh_quote($ROOT) ]} rev-parse HEAD 2>/dev/null` || 'unknown';
-    chomp $commit;
-    my $host = `hostname 2>/dev/null` || 'unknown'; chomp $host;
-    open my $b, '>', "$repodir/buildinfo" or die "Cannot write buildinfo: $!\n";
-    print {$b} "VERSION=$VERSION\n",
-               "RELEASE=$RELEASE\n",
-               "BUILD_TIME=@{[ strftime('%a %b %d %H:%M:%S %Y', gmtime($EPOCH)) ]}\n",
-               "BUILD_MACHINE=$host\n",
-               "COMMIT_ID=@{[ substr($commit, 0, 7) ]}\n",
-               "COMMIT_ID_LONG=$commit\n";
-    close $b;
+    write_file("$repodir/buildinfo", buildinfo_text(
+        version => $VERSION, release => $RELEASE, epoch => $EPOCH,
+        commit => $GITINFO, time_format => '%a %b %d %H:%M:%S %Y'));
     return;
 }
 

buildrpms.pl

@@ -43,7 +43,7 @@ use File::Slurper qw(read_text write_text);
 use File::Temp qw(tempdir tempfile);
 use FindBin qw($Bin);
 use lib $Bin;
-use BuildUtils qw(git_revision source_date_epoch sh usage);
+use BuildUtils qw(git_revision source_date_epoch sh usage buildinfo_text);
 use Fcntl qw(:flock);           # per-target build lock (concurrency guard; see main())
 use Getopt::Long qw(GetOptions);
 use POSIX qw(strftime);
@@ -811,17 +811,9 @@ EOF2
     chmod 0775, "$repodir/mklocalrepo.sh";
 
     # BUILD_TIME from SOURCE_DATE_EPOCH keeps buildinfo reproducible across rebuilds.
-    my $build_time = strftime("%a %b %e %H:%M:%S %Z %Y", gmtime($SOURCE_DATE_EPOCH));
-    my $build_machine = `hostname`; chomp $build_machine;
-    my $commit_short = substr($GITINFO, 0, 7);
-    write_text("$repodir/buildinfo.txt", <<"EOF");
-VERSION=$VERSION
-RELEASE=$RELEASE
-BUILD_TIME=$build_time
-BUILD_MACHINE=$build_machine
-COMMIT_ID=$commit_short
-COMMIT_ID_LONG=$GITINFO
-EOF
+    write_text("$repodir/buildinfo.txt", buildinfo_text(
+        version => $VERSION, release => $RELEASE, epoch => $SOURCE_DATE_EPOCH,
+        commit => $GITINFO, time_format => "%a %b %e %H:%M:%S %Z %Y"));
 }
 
 # Assemble the flat MULTI-ARCH core from per-arch build outputs and sign it, in the upstream

xCAT-test/unit/build_utils.t

@@ -308,6 +308,31 @@ is( git_revision( git => sub { "\n" }, read_file => sub { "  \n" } ),
 isnt( git_revision( git => sub { '' }, read_file => sub { '' } ), '',
     'the one thing it must never return is empty' );
 
+# ------------------------------------------------------- buildinfo_text --
+# deploy.sh copies this file verbatim and cluster-test.pl parses it, so the
+# field names and their order are a contract, not a presentation choice.
+{
+    my $text = BuildUtils::buildinfo_text(
+        version => '2.18.1', release => 'snap1', epoch => 0,
+        commit => 'abcdef1234567890', host => 'builder',
+        time_format => '%Y-%m-%d',
+    );
+    is_deeply( [ map { (split /=/, $_, 2)[0] } split /\n/, $text ],
+        [qw(VERSION RELEASE BUILD_TIME BUILD_MACHINE COMMIT_ID COMMIT_ID_LONG)],
+        'the fields appear in the order the consumers expect' );
+    like( $text, qr/^COMMIT_ID=abcdef1\n/m, 'the short commit is seven characters' );
+    like( $text, qr/^COMMIT_ID_LONG=abcdef1234567890\n/m, 'and the long one is whole' );
+    like( $text, qr/^BUILD_TIME=1970-01-01\n/m,
+        "the caller's own time format is used" );
+
+    # The two builders stamp different formats, and both are consumed.
+    my %common = (version => '1', release => '2', epoch => 0,
+                  commit => 'c', host => 'h');
+    isnt( BuildUtils::buildinfo_text(%common, time_format => '%a %b %d %H:%M:%S %Y'),
+          BuildUtils::buildinfo_text(%common, time_format => '%a %b %e %H:%M:%S %Z %Y'),
+          'each builder keeps the format its own consumers parse' );
+}
+
 # -------------------------------------------------- whole-file helpers --
 {
     my $dir = tempdir(CLEANUP => 1);