doc/examples/trigger-on-event/README.md

   1 # Trigger notification exemple
   2
   3 ## Description
   4 This exemple is made-up of three executables.
   5
   6 ### `notification-client`
   7
   8 ```
   9 Usage: notification-client TRIGGER_NAME
  10 ```
  11
  12 A simple client that subscribes to the notifications emitted by the `TRIGGER_NAME` trigger.
  13
  14 ### `instrumented-app`
  15
  16 An application that emits the `trigger_exemple:my_event` event every 2 seconds.
  17
  18 ### `demo.sh`
  19
  20 This script adds a trigger named `demo_trigger` which emits a notification when the user-space `trigger_exemple:my_event` event occurs.
  21
  22 Once the trigger has been setup, the notification-client is launched to print all notifications emitted by the `demo_trigger` trigger.
  23
  24 ## Building
  25
  26 Simply run the included Makefile.
  27
  28 ## Running the exemple
  29
  30 1) Launch a session daemon using:
  31         ```
  32         $ lttng-sessiond
  33         ```
  34 2) Launch the `demo.sh` script
  35 3) Launch the `instrumented-app`
  36
  37 The following output should be produced:
  38
  39 ```
  40 $ ./demo.sh
  41 Registering a notification trigger named "demo_trigger" for the trigger_exemple:my_event user-space event
  42 Trigger registered successfully.
  43 Subscribed to notifications of trigger "demo_trigger"
  44 [02-14-2020] 18:13:34.779766 - Received notification of event rule trigger "demo_trigger"
  45 [02-14-2020] 18:13:36.779888 - Received notification of event rule trigger "demo_trigger"
  46 [02-14-2020] 18:13:38.780514 - Received notification of event rule trigger "demo_trigger"
  47 [02-14-2020] 18:13:40.780656 - Received notification of event rule trigger "demo_trigger"
  48 ```
  49
  50 ```
  51 $ ./instrumented-app
  52 [02-14-2020] 18:13:34.779433 - Tracing event "trigger_exemple:my_event"
  53 [02-14-2020] 18:13:36.779693 - Tracing event "trigger_exemple:my_event"
  54 [02-14-2020] 18:13:38.780010 - Tracing event "trigger_exemple:my_event"
  55 [02-14-2020] 18:13:40.780286 - Tracing event "trigger_exemple:my_event"
  56 ```