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Web application end - how to determine why has stopped

Sa spunem ca avem o aplicatie web care se afla pe IIS. Observam ca aplicatia uneori moare si nu reusimg sa ne dam seama din ce cauza. Din anumite motive "exceptia" care se intampla in aplicatie nu poate sa fie prinsa si aplicația moare fără sa logeze nici o informație. De ce spun "exceptie", deoarece uneori poate sa fie vorba de un pool recycle care sa genereze acest comportament( cauza nu este mereu o exceptie in adevaratul sens al cuvântului).
Ce putem face? O solutie este ca in Global.asax.cs, in metoda Application_End sa obtinem date despre motivul pentru care aplicatie se termina si sa scriem aceste date in trace sau sa le logam undeva. Aceasta metoda o sa fie apelata de fiecare data cand aplicatia este oprita. Din pacate informatiile pentru care aplicatia este oprita se pot obtine doar prin intermedul reflection. Nu avem o alta modalitate sa obtinem aceste date. Daca aplicatia primeste un semnal din exterior ca trebuie sa se opreasca metoda Application_Error nu o sa fie apelata.
Mai jos gasiti un exemplu de implementare a metodei Application_End:
 public void Application_End()
        {
            HttpRuntime runtime = (HttpRuntime)typeof(System.Web.HttpRuntime).InvokeMember("_theRuntime",
                                                                                             BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.GetField,
                                                                                             null, null, null);
            if (runtime == null)
            {
                return;
            }

            string message = (string)runtime.GetType().InvokeMember("_shutDownMessage",
                                                                                 BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField,
                                                                                 null, runtime, null);

            string stackTrace = (string)runtime.GetType().InvokeMember("_shutDownStack",
                                                                           BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField,
                                                                           null, runtime, null);

            Trace.WriteLine(string.Format("Application_End: {0} {1}", message, stackTrace));

        }
Enjoy!

Comments

  1. Un mic dezavantaj : datorita folosirii reflection pentru a citi membrii privati/protejati, codul de mai sus nu va rula in medium trust.

    ReplyDelete
    Replies
    1. Sticumva o alta solutie la aceasta problema fara sa folosim reflection?

      Delete

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