LCOV - code coverage report
Current view: top level - examples - notificationReload.c (source / functions) Hit Total Coverage
Test: coverage-filtered.info Lines: 0 83 0.0 %
Date: 2019-09-12 12:28:41 Functions: 0 5 0.0 %

          Line data    Source code
       1             : /**
       2             :  * @file
       3             :  *
       4             :  * @brief Example for notification library which reloads KDB when Elektra's
       5             :  * configuration (e.g. mount points or global plugins) has changed.
       6             :  * This example also shows how to pass user data using elektraIo*GetData().
       7             :  *
       8             :  * Requires:
       9             :  *   - io_glib binding
      10             :  *   - Transport plugins (e.g. kdb global-mount zeromqsend zeromqrecv && kdb run-hub-zeromq)
      11             :  *
      12             :  * Relevant keys for this example:
      13             :  *   - /sw/example/notification/#0/current/value: Set to any integer value
      14             :  *   Add additional transport plugins and remove the original pair afterwards or
      15             :  *   mount a file which sets the key above to a different value and unmount it again
      16             :  *
      17             :  * @copyright BSD License (see LICENSE.md or https://www.libelektra.org)
      18             :  *
      19             :  */
      20             : 
      21             : #include <kdb.h>
      22             : #include <kdbhelper.h>       // elektraFree
      23             : #include <kdbio.h>           // I/O binding functions (elektraIo*)
      24             : #include <kdbio/glib.h>      // I/O binding constructor for glib (elektraIoGlibNew)
      25             : #include <kdbnotification.h> // notification functions
      26             : 
      27             : #include <glib-unix.h> // g_unix_signal_add()
      28             : #include <glib.h>      // glib functions
      29             : 
      30             : #include <signal.h> // signal()
      31             : #include <stdio.h>  // printf() & co
      32             : #include <stdlib.h> // exit()
      33             : 
      34             : #define TWO_SECONDS 2000
      35             : #define RELOAD_INTERVAL 100
      36             : 
      37             : /**
      38             :  * Data container for this example to demo
      39             :  * usage of the elektraIo*GetData() functions.
      40             :  *
      41             :  * Members could also be globals.
      42             :  */
      43             : typedef struct ExampleUserData
      44             : {
      45             :         GMainLoop * loop;
      46             :         KDB * kdb;
      47             :         Key * parentKey;
      48             :         KeySet * config;
      49             :         ElektraIoInterface * binding;
      50             :         Key * intKeyToWatch;
      51             :         int valueToPrint;
      52             :         ElektraIoTimerOperation * timer;
      53             :         ElektraIoTimerOperation * reload;
      54             : } ExampleUserData;
      55             : 
      56             : static void elektraChangedCallback (Key * changedKey ELEKTRA_UNUSED, void * context);
      57             : 
      58             : /**
      59             :  * Initializes KDB on first call and performs cleanup before initialization on
      60             :  * subsequent calls.
      61             :  *
      62             :  * @param timerOp unused
      63             :  */
      64           0 : static void initKdb (ElektraIoTimerOperation * timerOp ELEKTRA_UNUSED)
      65             : {
      66           0 :         ExampleUserData * data = (ExampleUserData *) elektraIoTimerGetData (timerOp);
      67             : 
      68           0 :         int didReload = 0;
      69             : 
      70             :         // Stop reload task
      71           0 :         elektraIoTimerSetEnabled (data->reload, 0);
      72           0 :         elektraIoBindingUpdateTimer (data->reload);
      73             : 
      74           0 :         if (data->kdb != NULL)
      75             :         {
      76             :                 // Cleanup notifications and close KDB
      77           0 :                 elektraNotificationClose (data->kdb);
      78           0 :                 kdbClose (data->kdb, data->parentKey);
      79           0 :                 didReload = 1;
      80             :         }
      81             : 
      82           0 :         data->kdb = kdbOpen (data->parentKey);
      83           0 :         if (data->kdb == NULL)
      84             :         {
      85           0 :                 printf ("could not open KDB, aborting\n");
      86           0 :                 exit (1);
      87             :         }
      88             : 
      89           0 :         elektraIoSetBinding (data->kdb, data->binding);
      90             : 
      91           0 :         int result = elektraNotificationOpen (data->kdb);
      92           0 :         if (!result)
      93             :         {
      94           0 :                 printf ("could not init notification, aborting\n");
      95           0 :                 exit (1);
      96             :         }
      97             : 
      98           0 :         result = elektraNotificationRegisterInt (data->kdb, data->intKeyToWatch, &data->valueToPrint);
      99           0 :         if (!result)
     100             :         {
     101           0 :                 printf ("could not register variable, aborting\n");
     102           0 :                 exit (1);
     103             :         }
     104             : 
     105           0 :         Key * elektraKey = keyNew ("/elektra", KEY_END);
     106           0 :         if (!elektraNotificationRegisterCallbackSameOrBelow (data->kdb, elektraKey, elektraChangedCallback, data))
     107             :         {
     108           0 :                 printf ("could not register for changes to Elektra's configuration, aborting\n");
     109           0 :                 exit (1);
     110             :         }
     111           0 :         keyDel (elektraKey);
     112             : 
     113             :         // Get configuration
     114           0 :         kdbGet (data->kdb, data->config, data->parentKey);
     115             : 
     116           0 :         if (didReload)
     117             :         {
     118           0 :                 printf ("KDB reloaded.\n");
     119             :         }
     120           0 : }
     121             : 
     122           0 : static gboolean onSIGNAL (gpointer user_data)
     123             : {
     124           0 :         ExampleUserData * data = (ExampleUserData *) user_data;
     125             :         // Cleanup
     126           0 :         elektraIoBindingRemoveTimer (data->timer);
     127           0 :         elektraFree (data->timer);
     128           0 :         elektraIoBindingRemoveTimer (data->reload);
     129           0 :         elektraFree (data->reload);
     130           0 :         elektraNotificationClose (data->kdb);
     131           0 :         kdbClose (data->kdb, data->parentKey);
     132           0 :         elektraIoBindingCleanup (data->binding);
     133             : 
     134           0 :         g_main_loop_quit (data->loop);
     135           0 :         return FALSE;
     136             : }
     137             : 
     138             : /**
     139             :  * This function is called whenever Elektra's configuration has changed.
     140             :  * Since cannot call elektraNotificationClose() here we start a timer operation
     141             :  * which allows us to reload KDB in the next main loop iteration.
     142             :  *
     143             :  * @param changedKey unused
     144             :  * @param context unused
     145             :  */
     146           0 : static void elektraChangedCallback (Key * changedKey ELEKTRA_UNUSED, void * context)
     147             : {
     148           0 :         printf ("\nElektra's configuration has changed.\n");
     149             : 
     150             :         // Enable operation to reload KDB as soon as possible
     151           0 :         ExampleUserData * data = (ExampleUserData *) context;
     152           0 :         elektraIoTimerSetEnabled (data->reload, 1);
     153           0 :         elektraIoBindingUpdateTimer (data->reload);
     154           0 : }
     155             : 
     156           0 : static void printVariable (ElektraIoTimerOperation * timerOp)
     157             : {
     158             :         // int value = *(int *) elektraIoTimerGetData (timerOp);
     159           0 :         ExampleUserData * data = (ExampleUserData *) elektraIoTimerGetData (timerOp);
     160           0 :         printf ("\nMy integer value is %d\n", data->valueToPrint);
     161           0 : }
     162             : 
     163           0 : int main (void)
     164             : {
     165           0 :         ExampleUserData * data = elektraCalloc (sizeof (*data));
     166           0 :         if (data == NULL)
     167             :         {
     168           0 :                 printf ("elektraCalloc failed");
     169           0 :                 return 1;
     170             :         }
     171             : 
     172             :         // Create glib main loop
     173           0 :         GMainContext * context = NULL; // use default context
     174           0 :         data->loop = g_main_loop_new (context, 0);
     175           0 :         data->binding = elektraIoGlibNew (context);
     176             : 
     177             :         // Signal Handling
     178           0 :         g_unix_signal_add (SIGINT, onSIGNAL, data);
     179             : 
     180           0 :         data->config = ksNew (20, KS_END);
     181           0 :         data->parentKey = keyNew ("/sw/example/notification/#0/current", KEY_END);
     182           0 :         data->intKeyToWatch = keyNew ("/sw/example/notification/#0/current/value", KEY_END);
     183             : 
     184             :         // Setup timer that repeatedly prints the variable
     185           0 :         data->timer = elektraIoNewTimerOperation (TWO_SECONDS, 1, printVariable, data);
     186           0 :         elektraIoBindingAddTimer (data->binding, data->timer);
     187             : 
     188             :         // Setup timer for reloading Elektra's configuration
     189           0 :         data->reload = elektraIoNewTimerOperation (RELOAD_INTERVAL, 0, initKdb, data);
     190           0 :         elektraIoBindingAddTimer (data->binding, data->reload);
     191             : 
     192           0 :         printf ("Reloading Notification Example Application\n");
     193           0 :         printf ("Please note that notification transport plugins are required see\n"
     194             :                 " https://www.libelektra.org/tutorials/notifications#notification-configuration!\n");
     195           0 :         printf ("- Set \"%s\" to any integer value\n", keyName (data->intKeyToWatch));
     196           0 :         printf ("- Try to add additional transport plugins and remove the original pair afterwards\n");
     197           0 :         printf ("- Mount a file which sets the key above to a different value and unmount it\n");
     198           0 :         printf ("Send SIGINT (Ctl+C) to exit.\n\n");
     199             : 
     200             :         // Initialize KDB
     201           0 :         initKdb (data->reload);
     202           0 :         printVariable (data->timer); // "value" was automatically updated
     203             : 
     204           0 :         g_main_loop_run (data->loop);
     205             : 
     206           0 :         g_main_loop_unref (data->loop);
     207             : 
     208           0 :         ksDel (data->config);
     209           0 :         keyDel (data->intKeyToWatch);
     210           0 :         keyDel (data->parentKey);
     211           0 :         elektraFree (data);
     212           0 :         printf ("cleanup done!\n");
     213             : }

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