Add disconnected application instances

[Holger Protzek]

Hi,

I would like to add live and standby instances of one application to the collector server. But unfortunately if I try to add a application with disconnected instances, I am not able to add this application.

Is there a way to allow also disconnected instances in an application?

Regrads

Holger

[evernat]

Hi Holger,

Yes, it's possible.
You can edit directly the applications.properties files in the storage directory (probably /tmp/javamelody/applications.properties in your case).
In this file, you can add an application on a new line after the others, and then restart the collector server.

bye,
Emeric

[bookit]

Hi Emeric,

I tried this, but then if I click on the app link, a error 500 pops up with following stack trace:

java.net.ConnectException: Connection refused

        at java.net.PlainSocketImpl.socketConnect(Native Method)

        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)

        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)

        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)

        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)

        at java.net.Socket.connect(Socket.java:529)

        at sun.net.NetworkClient.doConnect(NetworkClient.java:158)

        at sun.net.www.http.HttpClient.openServer(HttpClient.java:395)

        at sun.net.www.http.HttpClient.openServer(HttpClient.java:530)

        at sun.net.www.http.HttpClient.<init>(HttpClient.java:234)

        at sun.net.www.http.HttpClient.New(HttpClient.java:307)

        at sun.net.www.http.HttpClient.New(HttpClient.java:324)

        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)

        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)

        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)

        at net.bull.javamelody.LabradorRetriever.call(LabradorRetriever.java:151)

        at net.bull.javamelody.RemoteCollector.collectForUrl(RemoteCollector.java:325)

        at net.bull.javamelody.RemoteCollector.collectDataWithUrls(RemoteCollector.java:82)

        at net.bull.javamelody.RemoteCollector.collectData(RemoteCollector.java:75)

        at net.bull.javamelody.CollectorServer.collectForApplication(CollectorServer.java:152)

        at net.bull.javamelody.CollectorServer.collectForApplication(CollectorServer.java:126)

        at net.bull.javamelody.CollectorServer.collectWithoutErrors(CollectorServer.java:102)

        at net.bull.javamelody.CollectorServer$1.run(CollectorServer.java:68)

        at java.util.TimerThread.mainLoop(Timer.java:512)

        at java.util.TimerThread.run(Timer.java:462)

[bookit]

I would like to patch this, what is the best approach? Catch the IOException in LabradorRetriever and only throw a exception when all instances of the application are offline?

[Vernat Emeric]

Hi,

Ah yes. I did not understood well.
In fact, you want to monitor a single application with multiple server instances, and to display data even if some monitored instances of the application are offline in general.
Of course, it would simply work if you add monitoring only for the instances which are online in general, and ignore the others.

Anyway, if you want to change that for offline instances, you can always catch IOException in the methods "call" and "copyTo" of LabradorRetriever.
So if some or all instances of the application are offline, all the ioexceptions will be ignored and the known data will be displayed.

http://code.google.com/p/javamelody/source/browse/trunk/javamelody-core/src/main/java/net/bull/javamelody/LabradorRetriever.java#138

bye,
Emeric