All HELIOS services are monitored by the HELIOS Service Controller. If a program aborts due to a major problem, the Service Controller will log errors and restart the service. The “wostarter.so” (WOStarter) is a plug-in for the Service Controller to constantly monitor its whole web service. If a web service gets stuck and is not responding correctly to HTTP requests from the WOStarter, the Service Controller will restart the service. This adds an additional level of availability auditing to the Service Controller.
The file “wostarter.so” is located in “HELIOSDIR/lib”. The HELIOS Service Controller can use this plug-in to start/stop and monitor the WebShare Web Server (“websharewoa”). It can be activated for the WebShare Web Server via the following preference:
# prefvalue -k 'Services/websharewoa/ServiceStarter' -t str "de.helios.servicestarter.wostarter"
WOStarter periodically checks whether the “websharewoa” service is still alive. WOStarter can detect the following web service failures:
HTTP response does not contain an expected keyword
HTTP response contains a keyword that is not expected
HTTP error occurs
HTTP response is incomplete
No HTTP response at all
When WOStarter detects a problem with its monitored web service, it will log detailed errors and restart the web service. Custom WOStarter settings can be configured via preferences.
WatchdogInterval preference specifies the timeout in
# prefvalue -k 'Programs/websharewoa/WatchdogInterval' -t int [value]
WOHost preference specifies the hostname or the IP
address of the web service (default=
# prefvalue -k 'Programs/websharewoa/WOHost' -t str [value]
WOPort preference specifies the port of the web service
# prefvalue -k 'Programs/websharewoa/WOPort' -t int [value]
ResponsePositive preference specifies optional strings
that must be contained in the HTTP response (no default).
# prefvalue -k 'Programs/websharewoa/ResponsePositive' -t strlist [value]
ResponseNegative preference specifies optional strings
that must be contained in the HTTP response and which
indicate an error (no default).
# prefvalue -k 'Programs/websharewoa/ResponseNegative' -t strlist [value]