How to handle mDNS (avahi-daemon) stop

[thunderace]

Hello, how is it possible to handle a stop/start of hte mDNS daemon (avahi-daemon for me on debian).

In case of daemon stop, what can we do to restart the advertising service?
Thx.

[agnat]

Heh, good question. Not sure if it possible at all. I'll look into it.

On Dec 17, 2012, at 15:33, thunder notifications@github.com wrote:

Hello, how is it possible to handle a stop/start of hte mDNS daemon (avahi-daemon for me on debian).

In case of daemon stop, the client crash and need to be restarted.

Thx.

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Reply to this email directly or view it on GitHub.

[thunderace]

It's possible in python for example. Calibre, the e-book library management, handle such thing right. But i don't know how :)

[agnat]

Well, obviously it's possible. What I meant is: It might not be fixable in mdns. If that's the case I'll report it upstream to the node/libuv guys...

On Dec 17, 2012, at 17:37, thunder notifications@github.com wrote:

It's possible in python for example. Calibre, the e-book library management, handle such thing right. But i don't know how :)

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Reply to this email directly or view it on GitHub.

[agnat]

Well, for me it doesn't crash. If the daemon is down while creating a browser I get an exception. When the daemon goes down while browsing I get an error event. Both is easy to handle:

var mdns = require('./lib/mdns');

try {
  var b = mdns.createBrowser(mdns.tcp('http'));
} catch (ex) {
  console.log('something bad happened. we better start over.')
}

b.on('error', function(error) {
  console.log('something bad happened. we better start over.')
});
b.start();

The error is a bit vague though. But I can't change that. mdns only forwards what the underlying library reports. However, in case of an unknown error it is probably best to set up a new browser and start over anyway. The only improvement on the mdns side I can think of is to attach the actual error code to the exception/error object. The source code looks a bit like I've tried that already and it probably wasn't that simple. However, I'll give it another try (See #57)...

Tested on ubuntu 11.10, node 0.8.12, mdns 1.0.0.

[thunderace]

Sorry you arre right : no crash (i missed to attach the 'error' handler). The solution is to restart the browser/createAdvertisement. I will try this. back soon.

Thx

[thunderace]

below code to handle avahi errors :

function createAdvertisement()  {
    try {
        var mdns_txt_record = {
            name: domoConfig.domoConf.svcName,
            port: domoConfig.domoConf.svcPort
    };
    var advert = mdns.createAdvertisement(mdns.tcp(domoConfig.domoConf.svcName) , domoConfig.domoConf.svcPort, {txtRecord: mdns_txt_record});
    advert.on('error', function(error) {
        console.log("advert ERROR ", error);
        setTimeout(createAdvertisement, 30 * 1000);
    });
    advert.start();
    } catch (ex){
        console.log("advert creation ERROR ");
        setTimeout(createAdvertisement, 30 * 1000);
    } 
} 
}

Thx for your help

[agnat]

You're welcome.