How do I setup a systemd service to be started by a non root user as a user daemon?

Question

I told myself to never ask common sense or novice questions if I can look it up on the web and to resort to asking people as the last resort. This will probably be a fundamental question but please do enlighten me!

My code :

obj = pm.ls (selection=True,sn=True,o=True)       # get selection = obj 
shapes = pm.listRelatives(obj)                    # get obj shapeNode name
cpmNode = pm.createNode('closestPointOnMesh')     # create 
closestPointOnMesh Node
pm.setAttr(shapes+".outMesh",cpmNode + ".inMesh") # setattr selection 
shapeNode to cpmNode inMesh

Error :

# Can only concatenate list (not "str") to list

I don't understand how pm.setAttr(shapes+".outMesh",cpmNode + ".inMesh") is making into a list. Isn't it a command with strings now?

And by putting shapes into pm.setAttr(shapes+".outMesh",cpmNode + ".inMesh") is giving me errors where .outmesh is a string?

Is pm.setAttr(shapes+".outMesh",cpmNode + ".inMesh") a list then?

How should I make my current selection shapeNode to change pCubeShape1 if given example (below):

pm.setAttr("pCubeShape1.outMesh",cpmNode + ".inMesh")

Solution

systemd normally does not allow ordinary users to start system services. While it does support giving access via polkit, that part is still somewhat lacking, and you cannot yet allow only one specific service.

(Edit: Later systemd versions do support it, but only with polkit v106 or later.)

Since rtorrent is not actually a system service, and because you want every user to have their own instance of rtorrent, experiment with systemd's "user" mode.

When you log in, the system will start a user@<uid>.service system unit for you, which will launch a separate "--user" instance of systemd. The new user-systemd will read unit files (starting with default.target) from ~/.config/systemd/user/, /etc/systemd/user/ and /usr/lib/systemd/user/.

Comments

[Hans]

I realize that one could create a separate service file per user, and simply enable it. However I just want to know if it could be possible the way I have described it above.

[Hans]

Fair enough, I could simple setup sudo for the users and have them, as mentioned in my comment above, control their own service file. However this solution would allow the user to control most other services as well...

[user1686]

It wouldn't, if you had read sudo's documentation – sudoers(5) has many examples on restricting a command's arguments.

[bla]

shapes = pm.listRelatives(obj) probably returns a list. And [] + 'any_string' gives me the same error you are having.

[Elson Kwek]

well i do know we cant do list and string together. What i dont understand is where the hell is the list coming from lol. From what i understand, shapes = pm.listRelatives(obj) should be a string. i am trying to insert this "string" into "pm.setAttr(shapes+".outMesh",cpmNode + ".inMesh")" where this is a list if i am nt wrong

[warcholprzemo]

maybe you try print type(shapes), type(cpmNode) so you figure out if objects are string or list. You can use pdb module too for trying possibilities on running code.

[Elson Kwek]

While perhaps the suggestion by @warcholprzemo is great, print type(shapes) tells me that shapes is a list. Perhaps I should rephrase my question to get a straight route to what i want to achieve. cmds.connectAttr("polyShape.outMesh", cpmNode + ".inMesh") #replace polyShape with your shapeNode's name Code from https://www.aganimator.com/tutorials/2016/3/1/cpointmesh-npo‌​intcurve How or what ways should i approach changing the shapeNode name with my current selection given that "polyShape.outMesh" is being unicoded?

[Hans]

Thanks grawity, that was basically what I was missing. However it also turns out to have been a DBus problem as well: there seems to be a bug in dbuse that doesn't set the correct global variable DBUS_SESSION_BUS_ADDRESS for a given user, so systemctl can't access the user session, it errors our. Once I figured out this small problem, everything else works beautifully!

[Elson Kwek]

Thank you @Green Cell. This is the solution I have been looking for! Looks like there's a difference between set and connect Attr. I will study more on it and most appreciated for the kind explaination! Pardon me for the limited knowledge i have atm XD

[Green Cell]

Think of setAttr as a one time operation, where connectAttr would be something that sticks and calculates during playback (a connection between the two nodes). Generally if it needs to be done in the connection editor then it's connectAttr

[Bojan P.]

@Hans and what was the solution to setting DBUS_SESSION_BUS_ADDRESS? This problem still persist...

[Hans]

@BojanP. see my UPDATE2 in the question, basically DBUS_SESSION_BUS_ADDRESS should be set to a user specific dbus socket.