[pve-devel] [PATCH qemu-server] fix #1934: add qemu fw_cfg variables via 'tags'

[Dominik Csapak]

On 9/2/19 2:14 PM, Fabian Grünbichler wrote:
> On August 23, 2019 2:03 pm, Dominik Csapak wrote:
>> this add the 'tags' property to vms, which has the format:
> 
> why 'tags'? seems rather generic for what it does ;)

because the request in the bugreport was a more general one
(users wanted to simply set some tags for the vm
which are not in the description)

i just wanted to also use them besides simply having them in
the config ;)

> 
>>
>> key=value(;key=value)*
>>
>> each value will be set as
>>
>> -fw_cfg 'name=opt/com.proxmox/$key,string=$value'
>> (qemu recommends using a unique rfqdn)
>>
>> this way, users can tag the vm with that information available inside
>> e.g. under linux the value can be read under
>>
>> /sys/firmware/qemu_fw_cfg/by_name/opt/com.proxmox./$key/raw
>>
>> see the file docs/specs/fw_cfg.txt in the qemu repository for more
>> details
> 
> if we introduce this, wouldn't it also make sense to allow to pass in
> snippet files via this interface (via file=$path instead of string=$value)?

yeah one possibility would be to add a seperate config entry, such as
'tags-files' (or $name-files if tags is not wanted)
which would be a 'key=<volid>' syntax

i just wanted to keep it simple for now, because afaics this
would already satisfy the need for most of the users in the bugreport

> 
>>
>> maybe we can also use this in the future to show/set in the gui
>> e.g. some grouping/ordering etc.
>>
>> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
>> ---
>>   PVE/QemuServer.pm | 37 +++++++++++++++++++++++++++++++++++++
>>   1 file changed, 37 insertions(+)
>>
>> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
>> index 9f5bf56..d55a1ae 100644
>> --- a/PVE/QemuServer.pm
>> +++ b/PVE/QemuServer.pm
>> @@ -232,6 +232,29 @@ my $watchdog_fmt = {
>>   };
>>   PVE::JSONSchema::register_format('pve-qm-watchdog', $watchdog_fmt);
>>   
>> +PVE::JSONSchema::register_format('pve-qm-tags', \&verify_tag_format);
>> +sub verify_tag_format {
>> +    my ($tagstring, $noerr) = @_;
>> +
>> +    if (!$tagstring) {
>> +	return '';
>> +    }
>> +
>> +    # forbid all characters not in range 0x20-0x7E
>> +    for my $tag (split(';', $tagstring)) {
>> +	my ($key, $value) = ($tag =~ m/^(.*)=(.*)$/);
>> +	if ($key =~ m/[\x00-\x1F\x7F-\xFF]/) {
>> +	    die "invalid character in tag key\n" if !$noerr;
>> +	    return undef;
>> +	}
>> +	if ($value =~ m/[\x00-\x1F\x7F-\xFF]/) {
>> +	    die "invalid character in tag value\n" if !$noerr;
>> +	    return undef;
>> +	}
>> +    }
>> +
>> +    return $tagstring;
>> +}
>>   my $agent_fmt = {
>>       enabled => {
>>   	description => "Enable/disable Qemu GuestAgent.",
>> @@ -672,6 +695,13 @@ EODESCR
>>   	description => "Configure a audio device, useful in combination with QXL/Spice.",
>>   	optional => 1
>>       },
>> +    tags => {
>> +	description => "Specify key/value pairs to be added to qemu fw_cfg.",
>> +	type => 'string',
>> +	maxLength => 4096,
>> +	format => 'pve-qm-tags',
>> +	optional => 1,
>> +    },
>>   };
>>   
>>   my $cicustom_fmt = {
>> @@ -4152,6 +4182,13 @@ sub config_to_command {
>>   	push @$cmd, '-loadstate', $statepath;
>>       }
>>   
>> +    if ($conf->{tags}) {
>> +	for my $tag (split(';', $conf->{tags})) {
>> +	    my ($key, $value) = ($tag =~ m/^(.*)=(.*)$/);
>> +	    push @$cmd, '-fw_cfg', "name=opt/com.proxmox/$key,string=$value";
>> +	}
>> +    }
>> +
>>       # add custom args
>>       if ($conf->{args}) {
>>   	my $aa = PVE::Tools::split_args($conf->{args});
>> -- 
>> 2.20.1
>>
>>
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>>
>>
> 
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