[systemd-devel] Antw: Re: Explain status "Loaded: not-found (Reason: No such file or directory)"

[Ulrich Windl]

>>> Lennart Poettering <lennart at poettering.net> schrieb am 09.05.2019 um 17:08
in
Nachricht <20190509150818.GA5854 at gardel-login>:
> On Do, 09.05.19 12:25, Ulrich Windl (Ulrich.Windl at rz.uni-regensburg.de) 
> wrote:
> 
>> Hi!
>>
>> I'm developing a service and getting the status of my target gives:
>> ● iotwatch.target
>>    Loaded: not-found (Reason: No such file or directory)
>>    Active: active since Thu 2019-05-09 12:00:56 CEST; 18min ago
>>
>> I guess it's not a file named "Reason" that's missing. Despite of my
>> recommendation to create helpful error messages, can you explain what it 
> means?
>> Even after an strace I could not find out what is missing.
> 
> "Loaded" is a field that indicates whether the unit definition was
> properly loaded from the unit file. Here, it's shown as "not-found",
> which is the value indicating that no unit file by the name
> "iotwatch.target" could be found. Then, in brackets you get some
> additional information: here "Reason:" is the field that indicates the
> reason why the unit file wasn't found, and this usually gives you a
> UNIX error code, i.e. the text string associated with an "errno"
> code. "No such file or directory" is the string for ENOENT, i.e. it's
> the simplest of cases here: there really just was no file found by the
> name you requested.
> 
> Typically, when you see "not-found" as "Loaded" value, you'll also see
> "No such file or directory" as "Reason" value, but there are some
> other cases, since units are not always synthesized from unit files on
> disk, but from other concepts too.
> 

Thanks for the explanation; it's more clear now. However I'd prefer a message
like "Loaded: iotwatch.target could not be found", so
* name what is missing, and
* use an "errno message" only for specific system calls (not to summarize
several)

Regards,
Ulrich

> Lennart
> 
> --
> Lennart Poettering, Berlin