3 Installing cosNotification
3.1 Installation Process
This chapter describes how to install cosNotificationApp in an Erlang Environment.
Preparation
Before starting the installation process for cosNotification, the application Orber must be running.
Configuration
When using the Notification Service the cosNotification application first must be installed using cosNotificationApp:install() or cosNotificationApp:install(Seconds), followed by cosNotificationApp:start().
Then the Event Channel Factory must be started:
- cosNotificationApp:start_global_factory() - starts and returns a reference to a factory using default configuration parameters. This operation should be used for a multi-node Orber.
- cosNotificationApp:start_global_factory(Options) - starts and returns a reference to a factory using given configuration parameters. This operation should be used for a multi-node Orber.
- cosNotificationApp:start_factory() - starts and returns a reference to a factory using default configuration parameters.
- cosNotificationApp:start_factory(Options) - starts and returns a reference to a factory using given configuration parameters.
The following options exist:
- {pullInterval, Seconds} - determine how often Proxy Pull Consumers will check for new events with the client application. The default value is 20 seconds.
- {filterOp, OperationType} - determine which type of Administrator objects should be started, i.e., 'OR_OP' or 'AND_OP'. The default value is 'OR_OP'.
- {timeService, TimeServiceObj | 'undefined'} - to be able to use Start and/or Stop QoS this option must be used. See the function start_time_service/2 in the cosTime application. The default value is 'undefined'.
- {filterOp, OperationType} - determine which type of Administrator objects should be started, i.e., 'OR_OP' or 'AND_OP'. The default value is 'OR_OP'.
- {gcTime, Seconds} - this option determines how often, for example, proxies will garbage collect expired events. The default value is 60.
- {gcLimit, Amount} - determines how many events will be stored before, for example, proxies will garbage collect expired events. The default value is 50. This option is tightly coupled with the QoS property MaxEventsPerConsumer, i.e., the gcLimit should be less than MaxEventsPerConsumer and greater than 0.
It is possible to define a set of global configuration parameters:
| Key | Range | Default |
| type_check | true | false | true |
| notify | atom() | false | false |
| max_events | integer() > 0 | 50 |
| interval_events | integer() > 0 | 10000 milliseconds |
| timeout_events | integer() > interval_events | 3000000 milliseconds |
Table 3.1: Global Configuration Parameters
Comments on the table 'Global Configuration Parameters':
- type_check
- Determine if supplied IOR:s shall be type checked, i.e. invoking corba_object:is_a/2, or not.
- notify
- The given value shall point to an existing module exporting a function (arity 1) called terminated. This operation is invoked when a proxy terminates and the argument is a list containing {proxy, IOR}, {client, IOR} and {reason, term()}. The return value is ignored.
- max_events
- If a supplier proxy has not been able to push events to a consumer and the queue exceeds this limit, then the proxy will terminate. For this option to have any effect, the EventReliability and ConnectionReliability QoS parameters must be set to Persistent. For more information, see also the QoS chapter.
- interval_events
- The same requirements as for max_events. When a supplier proxy detects problems when trying to push events, this parameter determines how often it should try to call the consumer.
- timeout_events
- The same requirements as for max_events. If the proxy has not been able to contact the consumer and this time-limit is reached, then the proxy will terminate.
The Factory is now ready to use. For a more detailed description see Examples.