Data Transformation Engine Intelligent Business Integration Reference Guide

Chapter 3 - Methods of Execution Event-Driven Execution Model

Intelligent Business Integration Reference Guide

♦ The output from ErrorLog is delivered to a file. Each time a map fails, an entry

is appended to this file. An alternative to this file-based method is to use the

Mercator SNMP Agent to issue traps, which trigger alerts in SNMP-enabled

network management software (such as HP OpenView, Tivoli NetView, and

BMC Patrol).

♦ Every single map thread execution is logged to an execution history database

through the ExecutionHistoryDB output. Finally, output 5 (PutToEmail),

sends the audit log data to another map for reformatting and dispatch to an

operator’s email account with information on exactly which map failed in its

execution and detailed reasons for the map failure.

It should be stressed that this is only an example of the type of audit logging,

execution logging, and error and exception handling that you can develop with

Mercator products. It is possible to construct a logging and management system

as simple or as sophisticated as is required for the purposes of the enterprise

concerned.

Event Agent

The Event Agent, available for both the Windows and UNIX platforms, is a light-

footprint solution designed to receive external Web requests (high-volume

capable) through the Event Server. The Event Agent is a utility that listens for

incoming HTTP requests and passes them onto the Mercator Event Server to

trigger coordinated systems of maps. The difference between handling HTTP

requests using the Event Agent as compared to a servlet is that the Event Server

can process an entire asynchronous system of maps by a single HTTP request.

Unlike the servlet, which is essentially one map invocation per servlet (although

there are ways to call additional maps in the same session), the Event Agent can

trigger many maps in a coordinated fashion via the Event Server. Also, unlike the

servlet where the map that received the initial HTTP request has to be the map

that sends the resulting HTTP response, the Event Agent and Event Server-based

invocation permits any map in the triggered system, or associated systems, to

send the HTTP response to the Event Agent and forwarded to the point of origin.

This capability not only allows conventional HTTP processing scenarios to be

implemented (such as browser-based access to enterprise resources via the

Internet or Intranet), but also supports a growing trend for using HTTP as the

primary transport for intra-enterprise application-to-application (A2A) and inter-

enterprise business-to-business (B2B) integration. The Event Agent works in

conjunction with the HTTP adapter enabling the Event Server to directly process

HTTP input events without compromising the integrity of the firewall. The Event

Agent can be deployed outside the corporate firewall in the demilitarized zone

(DMZ) for business-to-consumer (B2C) or B2B integration, or inside the firewall

for A2A integration, or in both places.