I just wanted to follow this up with a quick comment that might not have been obvious from the previous posts. I think something like a GpioController is the wrong level of abstraction to be exporting as a service from the board level bundles. Those exports should be configured pin or device services. The only place to configure all the pins/devices for a given implementation remain with the board's bundle. Switch the board you are using and you simply modify the boards pin configuration service exports from that board's bundle to match what is required. All actuator and sensor bundles that use those pins simply work without modification. All the application level bundles that use the exported services from the actuators and sensors continue to work as well.
Configuration details remain consolidated at the levels which require them. -----Original Message----- From: Łukasz Dywicki [mailto:[email protected]] Sent: Wednesday, January 4, 2017 4:25 PM To: [email protected] Subject: Re: Karaf IoT Brad, If you have service dependant on presence of some board you can make it conditional. Just use OSGi service lifecycle to deregister service when device is disconnected. Service consumers should be aware of it or at least should not call injected service any longer. That’s perfect use case for service tracker. While GPIO will physicaly never get disconnected from raspberry the connected device, i2c may go out at any time. Tricky part is how to detect when device goes offline. This can’t be done in general way and I think it needs to be linked with device interactions (tracking link status and when it hangs) or system events, but this brings us back to Kura and native libraries. Cheers, Lukasz -- Apache Karaf Committer & PMC Twitter: @ldywicki Blog: http://dywicki.pl Code-House - http://code-house.org > Wiadomość napisana przez Brad Red Hat <[email protected]> w dniu 4 sty > 2017, o godz. 22:56: > > I'm still doing a bit of head scratching to figure out where I and OSGi > libraries fit in the Kura scheme. Part of the problem is code samples may > not be the best indicator of intended use but they are what's out there. > Here's an example which doesn't fit how I think about OSGi services. If I > switch the board I'm deploy to then my code is broken. If these were injected > as services instead, then this device driver level bundle would be unaware of > the change. Configuring it at the board bundle level also means that all > configuration for pins, numbers and modes is in a single place. > > Well, I guess I've gone off the beaten path here and shouldn't be posting any > of this to the Karaf forum as it is a tangential concern here. More to the > point here is getting a Karaf deployment mechanism in place. > > public void activate(ComponentContext componentContext) { > logger.info("Bundle {} is starting...", APP_ID); //A factory call > across class loaders. Even if this is changed to inject GpioController it > doesn't quite work. > GpioController gpioController = GpioFactory.getInstance(); //Pins and > board devices should be configured and exported as named services at the > board level not in the application bundle. > GpioPinDigitalMultipurpose motionSensor = > gpioController.provisionDigitalMultipurposePin(RaspiPin.GPIO_01, > PinMode.DIGITAL_INPUT); //Ditto > GpioPinDigitalMultipurpose motionStatusLed = > gpioController.provisionDigitalMultipurposePin(RaspiPin.GPIO_05, > PinMode.DIGITAL_OUTPUT); > > .... > } > > > -----Original Message----- > From: Łukasz Dywicki [mailto:[email protected]] > Sent: Wednesday, January 4, 2017 2:54 PM > To: [email protected] > Cc: Markus Rathgeb <[email protected]> > Subject: Re: Karaf IoT > > I am OpenHab (OH) 2 user and I I must say that whole PDE thing is redundant > from my Karaf (as a platform) point of view. But this all comes from past of > project which was launched with Tycho and PDE since early days. There are > multiple entities involved in project and it is not an easy task to redefine > how things should be built. > > Initial apis of OH were quite simple and didn’t require anything strictly > related to physical thing. Starting form OH2 and extraction of Eclipse > SmartHome there is a seperation of concerns. OH2 bindings define Bridge and > Things connected over it and may have Channels associated with every of > these. At this stage it is lowest common denominator. There is no higher > level APIs for representing pumps, boilers or sensors or alarms but from > other hand OH is not a SCADA platform. Maybe at some point there will be > further generalization of code which will allow bindings to gain some > benefits? Many of bindings is pure software integration with vendor bridges > having very little or no hardware involved at all which makes it easier to > develop. > > I haven’t played with Kura so far because I didn’t need such low level > library, but even if I would need something such that I would rather go for > dedicated library handling specific use case instead of Kura which brings too > much. > > Kind regards, > Lukasz > -- > Apache Karaf Committer & PMC > Twitter: @ldywicki > Blog: http://dywicki.pl > Code-House - http://code-house.org > > >> Wiadomość napisana przez [email protected] w dniu 2 sty 2017, o godz. >> 19:56: >> >> I share most of Brad's concerns; at first I was very interested in >> OpenHAB but after playing with it for a bit I began to think about >> designing a new service layer and then seeing if I could fit the >> OpenHAB native libraries to it. >> >> OpenHAB corroborates my "PDE considered harmful" theory; it must be >> possible to use OSGi idioms effectively while developing in Eclipse >> PDE, but it doesn't seem to happen in practice. >> >> So Brad, I am right with you and I would like to help - but I am >> seriously short of time at the moment :-( >> >> >> >> > >
