Re: [OE-core] [PATCH] systemd.bbclass: support template files with dots

["Bills, Jason M" <jason.m.bills@linux.intel.com>]

On 10/22/2025 4:40 AM, Ross Burton wrote:
> On 15 Oct 2025, at 15:59, Bills, Jason M via lists.openembedded.org <jason.m.bills=linux.intel.com@lists.openembedded.org> wrote:
>>
>> If the SYSTEMD_SERVICE variable contains a template instance that has
>> dots in the name such as "xyz.openbmc_project.my@instance.service", the
>> regex splits on all the dots resulting in the following python
>> exception:
>>
>> Exception: ValueError: too many values to unpack (expected 3)
>>
>> To continue to support service files with dots in the name, this changes
>> to first split only on the '@' to isolate the name, then split the
>> second half on the dot to get the remaining two parameters.
>>
>> Confirmed when building that the three parameters for template instances
>> without dots came out the same and that template instances with dots
>> include the full name with dots in the first parameter.
>>
>> Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
>> ---
>> meta/classes-recipe/systemd.bbclass | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/meta/classes-recipe/systemd.bbclass b/meta/classes-recipe/systemd.bbclass
>> index 5a0550b287..fcd47809b2 100644
>> --- a/meta/classes-recipe/systemd.bbclass
>> +++ b/meta/classes-recipe/systemd.bbclass
>> @@ -247,7 +247,8 @@ python systemd_populate_packages() {
>>                  if not systemd_service_exists(service, user, d):
>>                      continue
>>                  if '@' in service and '@.' not in service:
>> -                    (servicename, instance, service_type) = re.split('[@.]', service)
>> +                    (servicename, postfix) = service.split('@')
>> +                    (instance, service_type) = postfix.split('.')
> 
> The assumption here is that the service name only contains a single dot and the instance isn’t something like foo.bar, right?  Are we certain that is the case?
> 
> Ross
> 

This splits first on the '@', so the assumption is the whole thing 
contains only one '@' and the service name can have many dots.  But the 
instance is assumed to have no dots which is currently the case in 
OpenBMC, but I don't know is guaranteed in systemd.

The documentation ([1]) isn't explicit, but assuming "instance name" 
allows the same characters as "unit name prefix", then it looks like 
it's possible.

I will rework the second split to split on the last dot to allow for the 
case where someone may use an instance with dots.

[1]: 
https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html

-Jason