[pve-devel] [RFC pve-storage 08/36] plugin: dir: move helper subs of directory plugin to common modules

[Max Carrara <m.carrara@proxmox.com>]

Because the directory plugin's subroutines are frequently used by
other plugins, it's best to factor these helpers into the common
module. This is a first step in making other plugins not depend on the
directory plugin anymore.

Simultaneously this commit also introduces the `Common::Path` module,
which ought to provide shared subroutines for operations on paths.

The changes of this commit are backwards-compatible; the old subs act
as mere wrappers and will emit a warning when used.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---
 src/PVE/Storage/Common.pm       | 31 ++++++++++++++++++++
 src/PVE/Storage/Common/Makefile |  1 +
 src/PVE/Storage/Common/Path.pm  | 51 +++++++++++++++++++++++++++++++++
 src/PVE/Storage/DirPlugin.pm    | 38 ++++++++++++------------
 4 files changed, 101 insertions(+), 20 deletions(-)
 create mode 100644 src/PVE/Storage/Common/Path.pm

diff --git a/src/PVE/Storage/Common.pm b/src/PVE/Storage/Common.pm
index f828c8c..a2ae979 100644
--- a/src/PVE/Storage/Common.pm
+++ b/src/PVE/Storage/Common.pm
@@ -3,10 +3,13 @@ package PVE::Storage::Common;
 use strict;
 use warnings;
 
+use PVE::JSONSchema;
+
 use parent qw(Exporter);
 
 our @EXPORT_OK = qw(
     get_deprecation_warning
+    storage_parse_is_mountpoint
 );
 
 =pod
@@ -29,10 +32,19 @@ be grouped in a submodule can also be found here.
 
 =over
 
+=item C<PVE::Storage::Common::Path>
+
+Utilities concerned with working with paths.
+
 =back
 
 =head1 FUNCTIONS
 
+B<Note:> Functions prefixed with C<storage_> are related to the C<PVE::Storage>
+API and usually expect an C<$scfg> ("storage config") hash. This hash is
+expected to contain the configuration for I<one> storage, which is (usually)
+acquired via C<PVE::Storage::storage_config>.
+
 =cut
 
 =pod
@@ -56,4 +68,23 @@ sub get_deprecation_warning : prototype($) {
 	. "the future. Please use '$new_sub_name' instead.";
 }
 
+=head3 storage_parse_is_mountpoint
+
+    $path = storage_parse_is_mountpoint($scfg)
+
+Helper that tries to return a path if the given I<storage config> hash C<$scfg>
+contains an C<is_mountpoint> property. Returns C<undef> if it can't.
+
+=cut
+
+sub storage_parse_is_mountpoint : prototype($) {
+    my ($scfg) = @_;
+    my $is_mp = $scfg->{is_mountpoint};
+    return undef if !defined $is_mp;
+    if (defined(my $bool = PVE::JSONSchema::parse_boolean($is_mp))) {
+	return $bool ? $scfg->{path} : undef;
+    }
+    return $is_mp; # contains a path
+}
+
 1;
diff --git a/src/PVE/Storage/Common/Makefile b/src/PVE/Storage/Common/Makefile
index 0c4bba5..9455b81 100644
--- a/src/PVE/Storage/Common/Makefile
+++ b/src/PVE/Storage/Common/Makefile
@@ -1,4 +1,5 @@
 SOURCES = \
+	  Path.pm \
 
 
 .PHONY: install
diff --git a/src/PVE/Storage/Common/Path.pm b/src/PVE/Storage/Common/Path.pm
new file mode 100644
index 0000000..7535dda
--- /dev/null
+++ b/src/PVE/Storage/Common/Path.pm
@@ -0,0 +1,51 @@
+package PVE::Storage::Common::Path;
+
+use strict;
+use warnings;
+
+use Cwd;
+
+use PVE::ProcFSTools;
+
+use parent qw(Exporter);
+
+our @EXPORT_OK = qw(
+    path_is_mounted
+);
+
+=pod
+
+=head1 NAME
+
+PVE::Storage::Common::Path - Shared functions and utilities for manipulating paths
+
+=head1 FUNCTIONS
+
+=cut
+
+=pod
+
+=head3 path_is_mounted
+
+    $is_mounted = path_is_mounted($mountpoint)
+    $is_mounted = path_is_mounted($mountpoint, $mountdata)
+
+Checks if the given path in C<$mountpoint> is actually mounted. Optionally takes
+a C<$mountdata> hash returned by C<PVE::ProcFSTools::parse_proc_mounts> in
+order to avoid repeatedly reading and parsing C</proc/mounts>.
+
+=cut
+
+# NOTE: should ProcFSTools::is_mounted accept an optional cache like this?
+sub path_is_mounted {
+    my ($mountpoint, $mountdata) = @_;
+
+    $mountpoint = Cwd::realpath($mountpoint); # symlinks
+    return 0 if !defined($mountpoint); # path does not exist
+
+    $mountdata = PVE::ProcFSTools::parse_proc_mounts() if !$mountdata;
+    return 1 if grep { $_->[1] eq $mountpoint } @$mountdata;
+    return undef;
+}
+
+1;
diff --git a/src/PVE/Storage/DirPlugin.pm b/src/PVE/Storage/DirPlugin.pm
index 2efa8d5..ac0d365 100644
--- a/src/PVE/Storage/DirPlugin.pm
+++ b/src/PVE/Storage/DirPlugin.pm
@@ -3,12 +3,16 @@ package PVE::Storage::DirPlugin;
 use strict;
 use warnings;
 
-use Cwd;
 use Encode qw(decode encode);
 use File::Path;
 use IO::File;
 use POSIX;
 
+use PVE::Storage::Common qw(
+    get_deprecation_warning
+    storage_parse_is_mountpoint
+);
+use PVE::Storage::Common::Path;
 use PVE::Storage::Plugin;
 use PVE::JSONSchema qw(get_standard_option);
 
@@ -86,26 +90,20 @@ sub options {
 # Storage implementation
 #
 
-# NOTE: should ProcFSTools::is_mounted accept an optional cache like this?
 sub path_is_mounted {
-    my ($mountpoint, $mountdata) = @_;
+    warn get_deprecation_warning(
+	"PVE::Storage::Common::Path::path_is_mounted"
+    );
 
-    $mountpoint = Cwd::realpath($mountpoint); # symlinks
-    return 0 if !defined($mountpoint); # path does not exist
-
-    $mountdata = PVE::ProcFSTools::parse_proc_mounts() if !$mountdata;
-    return 1 if grep { $_->[1] eq $mountpoint } @$mountdata;
-    return undef;
+    return PVE::Storage::Common::Path::path_is_mounted(@_);
 }
 
 sub parse_is_mountpoint {
-    my ($scfg) = @_;
-    my $is_mp = $scfg->{is_mountpoint};
-    return undef if !defined $is_mp;
-    if (defined(my $bool = PVE::JSONSchema::parse_boolean($is_mp))) {
-	return $bool ? $scfg->{path} : undef;
-    }
-    return $is_mp; # contains a path
+    warn get_deprecation_warning(
+	"PVE::Storage::Common::storage_parse_is_mountpoint"
+    );
+
+    return storage_parse_is_mountpoint(@_);
 }
 
 # FIXME move into 'get_volume_attribute' when removing 'get_volume_notes'
@@ -211,11 +209,11 @@ sub update_volume_attribute {
 sub status {
     my ($class, $storeid, $scfg, $cache) = @_;
 
-    if (defined(my $mp = parse_is_mountpoint($scfg))) {
+    if (defined(my $mp = PVE::Storage::Common::storage_parse_is_mountpoint($scfg))) {
 	$cache->{mountdata} = PVE::ProcFSTools::parse_proc_mounts()
 	    if !$cache->{mountdata};
 
-	return undef if !path_is_mounted($mp, $cache->{mountdata});
+	return undef if !PVE::Storage::Common::Path::path_is_mounted($mp, $cache->{mountdata});
     }
 
     return $class->SUPER::status($storeid, $scfg, $cache);
@@ -227,8 +225,8 @@ sub activate_storage {
 
     my $path = $scfg->{path};
 
-    my $mp = parse_is_mountpoint($scfg);
-    if (defined($mp) && !path_is_mounted($mp, $cache->{mountdata})) {
+    my $mp = storage_parse_is_mountpoint($scfg);
+    if (defined($mp) && !PVE::Storage::Common::Path::path_is_mounted($mp, $cache->{mountdata})) {
 	die "unable to activate storage '$storeid' - " .
 	    "directory is expected to be a mount point but is not mounted: '$mp'\n";
     }
-- 
2.39.2



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