Make PostgreSQL::Test::Cluster::init_from_backup handle tablespaces.

This commit doesn't use this infrastructure for anything new, although
it does adapt 010_pg_basebackup.pl to use it. However, a future commit
will use this to improve test coverage for pg_combinebackup.

Patch by me, reviewed (but not fully endorsed) by Andres Freund.

Discussion: http://postgr.es/m/CA+TgmoYdXTjo9iQeoipTccDpWZzvBNS6EndY2uARM+T4yG_yDg@mail.gmail.com

Author: robertmhaas

src/bin/pg_basebackup/t/010_pg_basebackup.pl

@@ -407,25 +407,12 @@
 
 	my $node2 = PostgreSQL::Test::Cluster->new('replica');
 
-	# Recover main data directory
-	$node2->init_from_backup($node, 'tarbackup2', tar_program => $tar);
-
-	# Recover tablespace into a new directory (not where it was!)
-	my $repTsDir = "$tempdir/tblspc1replica";
-	my $realRepTsDir = "$real_sys_tempdir/tblspc1replica";
-	mkdir $repTsDir;
-	PostgreSQL::Test::Utils::system_or_bail($tar, 'xf', $tblspc_tars[0],
-		'-C', $repTsDir);
-
-	# Update tablespace map to point to new directory.
-	# XXX Ideally pg_basebackup would handle this.
+	# Recover the backup
 	$tblspc_tars[0] =~ m|/([0-9]*)\.tar$|;
 	my $tblspcoid = $1;
-	my $escapedRepTsDir = $realRepTsDir;
-	$escapedRepTsDir =~ s/\\/\\\\/g;
-	open my $mapfile, '>', $node2->data_dir . '/tablespace_map' or die $!;
-	print $mapfile "$tblspcoid $escapedRepTsDir\n";
-	close $mapfile;
+	my $realRepTsDir = "$real_sys_tempdir/tblspc1replica";
+	$node2->init_from_backup($node, 'tarbackup2', tar_program => $tar,
+		'tablespace_map' => { $tblspcoid => $realRepTsDir });
 
 	$node2->start;
 	my $result = $node2->safe_psql('postgres', 'SELECT * FROM test1');

src/test/perl/PostgreSQL/Test/Cluster.pm

@@ -777,7 +777,7 @@ sub backup_fs_cold
 
 =pod
 
-=item $node->init_from_backup(root_node, backup_name)
+=item $node->init_from_backup(root_node, backup_name, %params)
 
 Initialize a node from a backup, which may come from this node or a different
 node. root_node must be a PostgreSQL::Test::Cluster reference, backup_name the string name
@@ -787,8 +787,13 @@ Does not start the node after initializing it.
 
 By default, the backup is assumed to be plain format.  To restore from
 a tar-format backup, pass the name of the tar program to use in the
-keyword parameter tar_program.  Note that tablespace tar files aren't
-handled here.
+keyword parameter tar_program.
+
+If there are tablespace present in the backup, include tablespace_map as
+a keyword parameter whose values is a hash. When tar_program is used, the
+hash keys are tablespace OIDs; otherwise, they are the tablespace pathnames
+used in the backup. In either case, the values are the tablespace pathnames
+that should be used for the target cluster.
 
 To restore from an incremental backup, pass the parameter combine_with_prior
 as a reference to an array of prior backup names with which this backup
@@ -843,24 +848,98 @@ sub init_from_backup
 		}
 
 		local %ENV = $self->_get_env();
-		PostgreSQL::Test::Utils::system_or_bail('pg_combinebackup', '-d',
-			@prior_backup_path, $backup_path, '-o', $data_path);
+		my @combineargs = ('pg_combinebackup', '-d');
+		if (exists $params{tablespace_map})
+		{
+			while (my ($olddir, $newdir) = each %{$params{tablespace_map}})
+			{
+				push @combineargs, "-T$olddir=$newdir";
+			}
+		}
+		push @combineargs, @prior_backup_path, $backup_path, '-o', $data_path;
+		PostgreSQL::Test::Utils::system_or_bail(@combineargs);
 	}
 	elsif (defined $params{tar_program})
 	{
-		mkdir($data_path);
+		mkdir($data_path) || die "mkdir $data_path: $!";
 		PostgreSQL::Test::Utils::system_or_bail($params{tar_program}, 'xf',
 			$backup_path . '/base.tar',
 			'-C', $data_path);
 		PostgreSQL::Test::Utils::system_or_bail(
 			$params{tar_program}, 'xf',
 			$backup_path . '/pg_wal.tar', '-C',
 			$data_path . '/pg_wal');
+
+		# We need to generate a tablespace_map file.
+		open(my $tsmap, ">", "$data_path/tablespace_map")
+			|| die "$data_path/tablespace_map: $!";
+
+		# Extract tarfiles and add tablespace_map entries
+		my @tstars = grep { /^\d+.tar/ }
+			PostgreSQL::Test::Utils::slurp_dir($backup_path);
+		for my $tstar (@tstars)
+		{
+			my $tsoid = $tstar;
+			$tsoid =~ s/\.tar$//;
+
+			die "no tablespace mapping for $tstar"
+				if !exists $params{tablespace_map} ||
+				   !exists $params{tablespace_map}{$tsoid};
+			my $newdir = $params{tablespace_map}{$tsoid};
+
+			mkdir($newdir) || die "mkdir $newdir: $!";
+			PostgreSQL::Test::Utils::system_or_bail($params{tar_program}, 'xf',
+				$backup_path . '/' . $tstar, '-C', $newdir);
+
+			my $escaped_newdir = $newdir;
+			$escaped_newdir =~ s/\\/\\\\/g;
+			print $tsmap "$tsoid $escaped_newdir\n";
+		}
+
+		# Close tablespace_map.
+		close($tsmap);
 	}
 	else
 	{
+		my @tsoids;
 		rmdir($data_path);
-		PostgreSQL::Test::RecursiveCopy::copypath($backup_path, $data_path);
+
+		# Copy the main backup. Exclude tablespace links, but remember them.
+		PostgreSQL::Test::RecursiveCopy::copypath($backup_path, $data_path,
+			'filterfn' => sub {
+				my ($path) = @_;
+				if ($path =~ /^pg_tblspc\/(\d+)$/ && -l "$backup_path/$path")
+				{
+					push @tsoids, $1;
+					return 0;
+				}
+				return 1;
+			});
+
+		# We need to generate a tablespace_map file.
+		open(my $tsmap, ">", "$data_path/tablespace_map")
+			|| die "$data_path/tablespace_map: $!";
+
+		# Now use the list of tablespace links to copy each tablespace.
+		for my $tsoid (@tsoids)
+		{
+			my $olddir = readlink("$backup_path/pg_tblspc/$tsoid")
+				|| die "readlink $backup_path/pg_tblspc/$tsoid: $!";
+
+			die "no tablespace mapping for $olddir"
+				if !exists $params{tablespace_map} ||
+				   !exists $params{tablespace_map}{$olddir};
+
+			my $newdir = $params{tablespace_map}{$olddir};
+			PostgreSQL::Test::RecursiveCopy::copypath($olddir, $newdir);
+
+			my $escaped_newdir = $newdir;
+			$escaped_newdir =~ s/\\/\\\\/g;
+			print $tsmap "$tsoid $escaped_newdir\n";
+		}
+
+		# Close tablespace_map.
+		close($tsmap);
 	}
 	chmod(0700, $data_path) or die $!;