This Video Tutorial illustrates how to use Event Handlers in SSIS.
SSIS Executables (Package, Containers, and Tasks) execute in an object hierarchy. An event handler can be defined on any object of the hierarchy. events can be OnPreExecute, OnPostExecute, OnWarning, OnError, .... Each event handler has a design area such as control flow that you can add tasks and containers with precedence constraints.
OnError event handler has two special system variables which is very useful; ErrorCode, and ErrorDescription. You will also learn about SourceName variable in this video that provides the source executable that raises event handler.
In this video with a demo sample you will learn how to log error with OnError event handler. and you will learn how to use system variables to log error message. you will also learn how to consider event hierarchy when you are developing event handlers.