fix(robot-server): ensure robot-server starts after mosquitto #14729
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| @@ -4,7 +4,7 @@ Description=Opentrons Robot HTTP Server | |||
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| Requires=nginx.service | |||
| After=nginx.service | |||
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| After=mosquitto.service | |||
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Do we also want to add Wants=mosquitto.service?
If we omit that, and we only have After=mosquitto.service, the sequencing will be correct any time systemd starts both services, but systemd won't necessarily know that it has to start both services. Concretely: if you're in a state where nothing is started, and then you do systemctl start opentrons-robot-server, it won't also start mosquitto.service.
I'm not sure if this will matter in practice, since mosquitto.service is started by multi-user.target.
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Hm, I don't feel strongly about it, but I could see that behavior as being potentially confusing. As long as mosquitto is guaranteed to start on boot (which I believe is always the case), then I think we're good.
If you feel like it should be there, I don't mind adding it.
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Please do also add Wants it's good practice. systemd is a general-purpose constraint solver and so if another, tighter constraint is active this wants will have no effect, but it's always a good idea to express intent in unit files like this.
| @@ -4,7 +4,7 @@ Description=Opentrons Robot HTTP Server | |||
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| Requires=nginx.service | |||
| After=nginx.service | |||
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| After=mosquitto.service | |||
There was a problem hiding this comment.
Please do also add Wants it's good practice. systemd is a general-purpose constraint solver and so if another, tighter constraint is active this wants will have no effect, but it's always a good idea to express intent in unit files like this.
Closes EXEC-351
Overview
@SyntaxColoring brought up the valid point that we should ensure mosquitto starts before the robot server, since the robot-server assumes this is true. This doesn't appear to be an issue in practice (so far), but let's fix it.
Risk assessment
low