[pve-devel] [RFC storage 2/6] add generalized functions to manage volume attributes
Dominik Csapak
d.csapak at proxmox.com
Fri Sep 24 10:54:47 CEST 2021
On 9/17/21 15:02, Fabian Ebner wrote:
> replacing the ones for handling notes. The generic implementation in
> Plugin.pm will fall back to the methods for notes to ensure backwards
> compatibility with external plugins.
>
> This is mainly done to avoid the need to add new methods every time a
> new attribute is added.
>
> Not adding a timeout parameter like the notes functions have, because
> it was not used and can still be added if it ever is needed in the
> future.
>
> For get_volume_attribute, undef will indicate that the attribute is
> not supported. This makes it possible to distinguish "not supported"
> from "error getting the attribute", which is useful when the attribute
> is important for an operation. For example, free_image checking for
> protection (introduced in a later patch) can abort if getting the
> 'protected' attribute fails.
>
> Suggested-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
> Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
> ---
>
> Hope I didn't miss a way this would break external plugins.
i think it would break a plugin that is not derived from
the bas Plugin.pm no?
an example:
i have a CustomCIFSPlugin that uses CIFSPlugin as base
i have implemented a custom 'get_volume_notes' function
after this patch, 'get_volume_attribute' will be called, which
falls back to the CIFSPlugin version which calls the DirPlugin
'get_volume_attribute' instead of my custom 'get_volume_notes'
since we did not document the custom plugins very well, i am
not sure if that's even a supported scenario, or if a custom
plugin always have to use the 'Plugin' as a base
if it is supported, we could only solve it by either make
it a breaking api change, or by keeping the '*_volume_notes'
around and fall back to *_volume_attribute implmentation
or did i make a mistake anywhere in my assumptions?
>
> Requires an APIAGE+APIVER bump.
>
> The alternative to undef indicating "not supported" would be to add a
> separate method like supports_volume_attribute. Or adapt
> volume_has_feature, but it doesn't really feel like the right fit as
> it's currently intended for features for guest images only.
>
> PVE/API2/Storage/Content.pm | 7 +++---
> PVE/Storage.pm | 12 +++++-----
> PVE/Storage/BTRFSPlugin.pm | 4 ++--
> PVE/Storage/CIFSPlugin.pm | 10 ++++----
> PVE/Storage/CephFSPlugin.pm | 10 ++++----
> PVE/Storage/DirPlugin.pm | 47 +++++++++++++++++++++++--------------
> PVE/Storage/NFSPlugin.pm | 10 ++++----
> PVE/Storage/PBSPlugin.pm | 28 ++++++++++++++--------
> PVE/Storage/Plugin.pm | 36 ++++++++++++++++++++++++++++
> 9 files changed, 113 insertions(+), 51 deletions(-)
>
> diff --git a/PVE/API2/Storage/Content.pm b/PVE/API2/Storage/Content.pm
> index 4d0ceb6..b3dc593 100644
> --- a/PVE/API2/Storage/Content.pm
> +++ b/PVE/API2/Storage/Content.pm
> @@ -321,11 +321,12 @@ __PACKAGE__->register_method ({
> format => $format,
> };
>
> - # not all storages/types support notes, so ignore errors here
> + # keep going if fetching an optional attribute fails
> eval {
> - my $notes = PVE::Storage::get_volume_notes($cfg, $volid);
> + my $notes = PVE::Storage::get_volume_attribute($cfg, $volid, 'notes');
> $entry->{notes} = $notes if defined($notes);
> };
> + warn $@ if $@;
>
> return $entry;
> }});
> @@ -371,7 +372,7 @@ __PACKAGE__->register_method ({
> PVE::Storage::check_volume_access($rpcenv, $authuser, $cfg, undef, $volid);
>
> if (exists $param->{notes}) {
> - PVE::Storage::update_volume_notes($cfg, $volid, $param->{notes});
> + PVE::Storage::update_volume_attribute($cfg, $volid, 'notes', $param->{notes});
> }
>
> return undef;
> diff --git a/PVE/Storage.pm b/PVE/Storage.pm
> index 7b319fe..729c90e 100755
> --- a/PVE/Storage.pm
> +++ b/PVE/Storage.pm
> @@ -215,24 +215,24 @@ sub file_size_info {
> return PVE::Storage::Plugin::file_size_info($filename, $timeout);
> }
>
> -sub get_volume_notes {
> - my ($cfg, $volid, $timeout) = @_;
> +sub get_volume_attribute {
> + my ($cfg, $volid, $attribute) = @_;
>
> my ($storeid, $volname) = parse_volume_id($volid);
> my $scfg = storage_config($cfg, $storeid);
> my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
>
> - return $plugin->get_volume_notes($scfg, $storeid, $volname, $timeout);
> + return $plugin->get_volume_attribute($scfg, $storeid, $volname, $attribute);
> }
>
> -sub update_volume_notes {
> - my ($cfg, $volid, $notes, $timeout) = @_;
> +sub update_volume_attribute {
> + my ($cfg, $volid, $attribute, $value) = @_;
>
> my ($storeid, $volname) = parse_volume_id($volid);
> my $scfg = storage_config($cfg, $storeid);
> my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
>
> - $plugin->update_volume_notes($scfg, $storeid, $volname, $notes, $timeout);
> + return $plugin->update_volume_attribute($scfg, $storeid, $volname, $attribute, $value);
> }
>
> sub volume_size_info {
> diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
> index dbc1244..61bede2 100644
> --- a/PVE/Storage/BTRFSPlugin.pm
> +++ b/PVE/Storage/BTRFSPlugin.pm
> @@ -136,9 +136,9 @@ sub status {
> return PVE::Storage::DirPlugin::status($class, $storeid, $scfg, $cache);
> }
>
> -# TODO: sub get_volume_notes {}
> +# TODO: sub get_volume_attribute {}
>
> -# TODO: sub update_volume_notes {}
> +# TODO: sub update_volume_attribute {}
>
> # croak would not include the caller from within this module
> sub __error {
> diff --git a/PVE/Storage/CIFSPlugin.pm b/PVE/Storage/CIFSPlugin.pm
> index c5f3894..bee6885 100644
> --- a/PVE/Storage/CIFSPlugin.pm
> +++ b/PVE/Storage/CIFSPlugin.pm
> @@ -286,13 +286,15 @@ sub check_connection {
> return 1;
> }
>
> -sub get_volume_notes {
> +sub get_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::get_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::get_volume_attribute($class, @_);
> }
> -sub update_volume_notes {
> +sub update_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::update_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::update_volume_attribute($class, @_);
> }
>
> 1;
> diff --git a/PVE/Storage/CephFSPlugin.pm b/PVE/Storage/CephFSPlugin.pm
> index 3b9a791..2c06804 100644
> --- a/PVE/Storage/CephFSPlugin.pm
> +++ b/PVE/Storage/CephFSPlugin.pm
> @@ -232,14 +232,16 @@ sub deactivate_storage {
> }
> }
>
> -sub get_volume_notes {
> +sub get_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::get_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::get_volume_attribute($class, @_);
> }
>
> -sub update_volume_notes {
> +sub update_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::update_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::update_volume_attribute($class, @_);
> }
>
> 1;
> diff --git a/PVE/Storage/DirPlugin.pm b/PVE/Storage/DirPlugin.pm
> index 0423e5f..6ab9ef2 100644
> --- a/PVE/Storage/DirPlugin.pm
> +++ b/PVE/Storage/DirPlugin.pm
> @@ -87,32 +87,43 @@ sub parse_is_mountpoint {
> return $is_mp; # contains a path
> }
>
> -sub get_volume_notes {
> - my ($class, $scfg, $storeid, $volname, $timeout) = @_;
> +sub get_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute) = @_;
>
> - my $path = $class->filesystem_path($scfg, $volname);
> - $path .= $class->SUPER::NOTES_EXT;
> + my ($vtype) = $class->parse_volname($volname);
> + return if $vtype ne 'backup';
>
> - return PVE::Tools::file_get_contents($path) if -f $path;
> + if ($attribute eq 'notes') {
> + my $path = $class->filesystem_path($scfg, $volname);
> + $path .= $class->SUPER::NOTES_EXT;
>
> - return '';
> -}
> + return PVE::Tools::file_get_contents($path) if -f $path;
>
> -sub update_volume_notes {
> - my ($class, $scfg, $storeid, $volname, $notes, $timeout) = @_;
> + return '';
> + }
>
> - my ($vtype) = $class->parse_volname($volname);
> - die "only backups can have notes\n" if $vtype ne 'backup';
> + return;
> +}
>
> - my $path = $class->filesystem_path($scfg, $volname);
> - $path .= $class->SUPER::NOTES_EXT;
> +sub update_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute, $value) = @_;
>
> - if (defined($notes) && $notes ne '') {
> - PVE::Tools::file_set_contents($path, $notes);
> - } elsif (-e $path) {
> - unlink $path or die "could not delete notes - $!\n";
> + my ($vtype) = $class->parse_volname($volname);
> + die "only backups support attribute '$attribute'\n" if $vtype ne 'backup';
> +
> + if ($attribute eq 'notes') {
> + my $path = $class->filesystem_path($scfg, $volname);
> + $path .= $class->SUPER::NOTES_EXT;
> +
> + if (defined($value) && $value ne '') {
> + PVE::Tools::file_set_contents($path, $value);
> + } elsif (-e $path) {
> + unlink $path or die "could not delete notes - $!\n";
> + }
> + return;
> }
> - return;
> +
> + die "attribute '$attribute' is not supported for storage type '$scfg->{type}'\n";
> }
>
> sub status {
> diff --git a/PVE/Storage/NFSPlugin.pm b/PVE/Storage/NFSPlugin.pm
> index 39bf15a..3a6efe5 100644
> --- a/PVE/Storage/NFSPlugin.pm
> +++ b/PVE/Storage/NFSPlugin.pm
> @@ -188,13 +188,15 @@ sub check_connection {
> return 1;
> }
>
> -sub get_volume_notes {
> +sub get_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::get_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::get_volume_attribute($class, @_);
> }
> -sub update_volume_notes {
> +sub update_volume_attribute {
> my $class = shift;
> - PVE::Storage::DirPlugin::update_volume_notes($class, @_);
> +
> + return PVE::Storage::DirPlugin::update_volume_attribute($class, @_);
> }
>
> 1;
> diff --git a/PVE/Storage/PBSPlugin.pm b/PVE/Storage/PBSPlugin.pm
> index bb1c382..d8e1ac8 100644
> --- a/PVE/Storage/PBSPlugin.pm
> +++ b/PVE/Storage/PBSPlugin.pm
> @@ -782,24 +782,32 @@ sub deactivate_volume {
> return 1;
> }
>
> -sub get_volume_notes {
> - my ($class, $scfg, $storeid, $volname, $timeout) = @_;
> +sub get_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute) = @_;
> +
> + if ($attribute eq 'notes') {
> + my (undef, $name, undef, undef, undef, undef, $format) = $class->parse_volname($volname);
>
> - my (undef, $name, undef, undef, undef, undef, $format) = $class->parse_volname($volname);
> + my $data = run_client_cmd($scfg, $storeid, "snapshot", [ "notes", "show", $name ]);
>
> - my $data = run_client_cmd($scfg, $storeid, "snapshot", [ "notes", "show", $name ]);
> + return $data->{notes} // '';
> + }
>
> - return $data->{notes};
> + return;
> }
>
> -sub update_volume_notes {
> - my ($class, $scfg, $storeid, $volname, $notes, $timeout) = @_;
> +sub update_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute, $value) = @_;
>
> - my (undef, $name, undef, undef, undef, undef, $format) = $class->parse_volname($volname);
> + if ($attribute eq 'notes') {
> + my (undef, $name, undef, undef, undef, undef, $format) = $class->parse_volname($volname);
>
> - run_client_cmd($scfg, $storeid, "snapshot", [ "notes", "update", $name, $notes ], 1);
> + run_client_cmd($scfg, $storeid, "snapshot", [ "notes", "update", $name, $value ], 1);
>
> - return undef;
> + return;
> + }
> +
> + die "attribute '$attribute' is not supported for storage type '$scfg->{type}'\n";
> }
>
> sub volume_size_info {
> diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
> index 417d1fd..1182008 100644
> --- a/PVE/Storage/Plugin.pm
> +++ b/PVE/Storage/Plugin.pm
> @@ -851,18 +851,52 @@ sub file_size_info {
> return wantarray ? ($size, $format, $used, $parent, $st->ctime) : $size;
> }
>
> +# FIXME remove on the next APIAGE reset.
> +# Deprecated, use get_volume_attribute instead.
> sub get_volume_notes {
> my ($class, $scfg, $storeid, $volname, $timeout) = @_;
>
> die "volume notes are not supported for $class";
> }
>
> +# FIXME remove on the next APIAGE reset.
> +# Deprecated, use update_volume_attribute instead.
> sub update_volume_notes {
> my ($class, $scfg, $storeid, $volname, $notes, $timeout) = @_;
>
> die "volume notes are not supported for $class";
> }
>
> +# Returns undef if the attribute is not supported for the volume.
> +# Should die if there is an error fetching the attribute.
> +# Possible attributes:
> +# notes - user-provided comments/notes.
> +sub get_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute) = @_;
> +
> + if ($attribute eq 'notes') {
> + my $notes = eval { $class->get_volume_notes($scfg, $storeid, $volname); };
> + if (my $err = $@) {
> + return if $err =~ m/^volume notes are not supported/;
> + die $err;
> + }
> + return $notes;
> + }
> +
> + return;
> +}
> +
> +# Dies if the attribute is not supported for the volume.
> +sub update_volume_attribute {
> + my ($class, $scfg, $storeid, $volname, $attribute, $value) = @_;
> +
> + if ($attribute eq 'notes') {
> + $class->update_volume_notes($scfg, $storeid, $volname, $value);
> + }
> +
> + die "attribute '$attribute' is not supported for storage type '$scfg->{type}'\n";
> +}
> +
> sub volume_size_info {
> my ($class, $scfg, $storeid, $volname, $timeout) = @_;
> my $path = $class->filesystem_path($scfg, $volname);
> @@ -1098,6 +1132,8 @@ my $get_subdir_files = sub {
> return $res;
> };
>
> +# If attributes are set on a volume, they should be included in the result.
> +# See get_volume_attribute for a list of possible attributes.
> sub list_volumes {
> my ($class, $storeid, $scfg, $vmid, $content_types) = @_;
>
>
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