Databases Reference
In-Depth Information
Once we have populated our
$body
variable with the appropriate SOAP Fault, we
would then use a Reply action as before to return it to the client.
This ensures that any client of the proxy service will only have to deal with the
business faults defined in the WSDL of the service and a handful of pre-defined
system faults that any of the proxy services could return.
If we look at a BPEL process, this approach makes it very simple
to write a fault policy for managing a small, well defined set of
system faults, and within the BPEL process define fault handlers
for the known business faults.
Generating alerts
When a permanent fault occurs, it may indicate that we have an underlying problem
in the system. Therefore, in addition to returning a SOAP Fault to the client, we may
wish to notify someone of the problem.
One way to do this would be through the report action we looked at earlier, but
in some cases, we may have an issue that requires more immediate attention. For
example, if we have an attempted security violation or if there is an error in the
actual logic of a recently deployed proxy service.
For these situations, we can use the
Alert
action to publish an alert to an
appropriate destination, which could be a JMS Queue, E-mail, SNMP Trap, or
Reporting Data Stream.
To add an alert, click
Add an Action
|
Reporting
|
Alert
. This will insert an Alert
action into our error handler, like the one shown in the following screenshot:
To specify the content of the alert, click on
<Expression>
. This will launch the
XQuery expression editor, where we can define the alert body as required. We
can also specify an optional
alert-summary
, which is presented according to the
destination. For example, it will form the subject line for an e-mail notification.
If this is left blank, then it defaults to
Oracle Service Bus Alert
.
The severity level can take a value of Normal, Warning, Minor, Major, Critical, or
Fatal. These don't have specific meanings, so you can attach your definitions to each
of these values. When we configure alerting for the proxy service (see below), we can
opt to filter out alerts based on their severity level.
