[discovery.mdns] Devices may apply a grace period for removal from the Inbox

[andrewfg]

BACKGROUND

Some types of OpenHAB bindings have devices that can sometimes be a bit late in sending their mDNS renewal announcements, which means that such devices are repeatedly removed from, and (re)added to, the InBox. This leads to confusion in the UI, and repeated logger messages. This is an exact analog to the UPNP Discovery issue that was solved by #2144

SOLUTION

The solution is an exact analog to the solution in #2144
Resolves #1835

DOCUMENTATION

The binding developer guide will also be updated via this PR openhab/openhab-docs#1708

Signed-off-by: Andrew Fiddian-Green [email protected]

[andrewfg]

Resolves #1835 in general.
And in combination with openhab/openhab-addons#11834 it resolves the specific Miele issue.

[jlaur]

@andrewfg - link #1835 to this PR?

[andrewfg]

^
Yes. See my post above yours.

[jlaur]

^ Yes. See my post above yours.

Ah, well, I meant reference it here to be able to directly cross-navigate and have issue auto-closed when PR is merged:

[andrewfg]

AFAIK the keyword “Resolves” (or “Fixes”, “Solves” etc.) followed by the issue number should indeed cause Git to auto close the issue.

[jlaur]

AFAIK the keyword “Resolves” (or “Fixes”, “Solves” etc.) followed by the issue number should indeed cause Git to auto close the issue.

Yes, if you write it like "Fixes #1835" in the PR description, it will be linked correctly.

[jlaur]

I have tested this PR in combination with openhab/openhab-addons#11834 and it works as expected - no more constant removal and readding of the Miele XGW 3000 gateway. From code perspective it also looks fine to me. Thanks again for this fix @andrewfg. Now will leave it to core maintainers to review.

[kaikreuzer]

lgtm, thanks!

[cweitkamp]

I am afraid we missed one place in the manual scan where we have to cancel the removal task.

openhab-core/bundles/org.openhab.core.config.discovery.mdns/src/main/java/org/openhab/core/config/discovery/mdns/internal/MDNSDiscoveryService.java

Lines 152 to 172 in 670c64b

	private void scan(boolean isBackground) {
	for (MDNSDiscoveryParticipant participant : participants) {
	long start = System.currentTimeMillis();
	ServiceInfo[] services;
	if (isBackground) {
	services = mdnsClient.list(participant.getServiceType());
	} else {
	services = mdnsClient.list(participant.getServiceType(), FOREGROUND_SCAN_TIMEOUT);
	}
	logger.debug("{} services found for {}; duration: {}ms", services.length, participant.getServiceType(),
	System.currentTimeMillis() - start);
	for (ServiceInfo service : services) {
	DiscoveryResult result = participant.createResult(service);
	if (result != null) {
	final DiscoveryResult resultNew = getLocalizedDiscoveryResult(result,
	FrameworkUtil.getBundle(participant.getClass()));
	thingDiscovered(resultNew);
	}
	}
	}
	}

I will provide a follow-up PR with a fix and some minor code refactoring.

[andrewfg]

Ok. Thanks.

[cweitkamp]

See #2647