®

BP312: Trap and Manage Your Errors Easily, Efficiently and Reliably Rob McDonagh

Julian Robichaux

ATTENTION

This is a Lotusphere presentation.

If you did not mean to attend Lotusphere, you are in the wrong room.

Let's start with one

embarrassing truth...

...errors happen

Look at all the eraser marks

But there's hope

Welcome to the 1-Step

Program for

Error Recovery

We like to call it...

Logging

Okay, maybe it's

really 2 steps

Log

Trap

So how do you know

that there are errors

in your code?

Because you wrote it

All code is error-prone

Here's an example:

Function AddOne (i As Integer) As IntegerAddOne = i + 1

End Function

Why do we need error-trapping

for something measly like that?

Try this:

Print "32,768 = " & AddOne(32767)

Function AddOne (i As Integer) As IntegerAddOne = i + 1

End Function

You may realize that

you could simply “fix”

the function to return

a Long instead

But how would you know

it had to be fixed?

Because a USER

calls you?

Maybe the CEO?

Or maybe it just keeps

failing silently and

causing weird problems

What do we recommend?

STEP 1:Trap your errors

Function AddOne (i As Integer) As IntegerOn Error Goto trapErrorAddOne = i + 1Exit Function

trapError:Messagebox "Sorry, bad number"

End Function

What happened?

What's this “No Resume” stuff?

An error block is like

its own separate chunk

of code.

You have to tell it what

to do when it's done.

Options:Exit Function/SubResume <block>Resume NextResume 0End (usually a bad idea)

So, let's say we convinced you.

You add error-handling to all of

your code.

You go, girl!

But what good does that

really do you?

Now instead of this when

an error happens...

... your users get this:

Great... thanks...

This hasn't helped at all!!!

We still have a bunch

of errors to deal with.

Don't worry.

Help is on the way.

STEP 2:Log your errors

Not this kind of log

What if...?

Instead of displaying the error

we wrote it to a database...

Using a NotesLog

is the “native” way

to do this:

LogActionLogErrorLogEvent

It works, but it's a little...

ugly

Well, pretty basic anyway

It's not a bad system,

but think of the important

information that's missing

User nameUser ACL accessFunction nameError line numberDatabase nameServer nameNotes client versionEtc.

That's okay, we can just

add it to our error block

Function AddOne (i As Integer) As IntegerOn Error Goto trapErrorAndLogEverythingAddOne = i + 1Exit Function

trapErrorAndLogEverything:Dim session As New NotesSessionDim db As NotesDatabaseSet db = session.CurrentDatabase

Call currentLog.LogError(Err, "Error on line " & Erl & _": " & Error & Chr(10) & _"User name: " & session.CommonUserName & _Chr(10) & "Function name: ThisFunctionName" & _Chr(10) & "Database name: " & db.Title & _Chr(10) & "Server name: " & db.Server & _Chr(10) & "ACL Access Level: " & db.CurrentAccessLevel & _Chr(10) & "Roles: " & Join(Evaluate("@UserRoles"), "; ") & _Chr(10) & "Notes client version: " & session.NotesBuildVersion)

End Function

That would be useful, but a tad...

long-winded...

and annoying to type

What if...?

We could just add a single

line of code, like this:

Function AddOne (i As Integer) As IntegerOn Error Goto trapErrorAddOne = i + 1Exit Function

trapError:Call LogError()Exit Function

End Function

And get output like this:

APPLAUSE

So how do we get from

here:

to there?

OpenLog

It's free.

It's open-source.

It's waiting for you.

http://www.openntf.org

How do you get it?

How do you use it?

DownloadCopy to serverAdjust ACLCopy Script LibraryAdd “LogError”

Too tough?

Let's do a quick demo.

DEMO

Where can I use this?

Anywhere you can typeLotusScript or Java

LotusScriptAgents

JavaAgents

FormsScript

Libraries

Views

Buttons

Actions

DEMO

Even JavaScript!

(psst. Think

“Web 2.0”) NEW!

DEMO

Great, I'm logging errors.

Now what?

How do I know they happened?

Notifications!

RSS Feeds!

NEW!

DEMO

DDM!

Ask your Admin, or read the Redbook:

http://www.redbooks.ibm.com/abstracts/REDP4089.html

Advanced topics:

Using with local/offline database replicasDealing with multiple servers and directoriesExtending and customizing

DEMO

We're out of time

Quick FAQ:Does it work on the client AND the server?What if the log database isn't there? Does my application break?Is it really free?Does anyone use this?How do you guys make money on it?Why don't I just write my own?

Look us up online:

Rob McDonagh = www.CaptainOblivious.com

Julian Robichaux = www.nsftools.com

Thanks!

© IBM Corporation 2007. All Rights Reserved.

The workshops, sessions and materials have been prepared by IBM or the session speakers and reflect their own views. They are provided for informational purposes only, and are neither intended to, nor shall have the effect of being, legal or other guidance or advice to any participant. While efforts were made to verify the completeness and accuracy of the information contained in this presentation, it is provided AS IS without warranty of any kind, express or implied. IBM shall not be responsible for any damages arising out of the use of, or otherwise related to, this presentation or any other materials. Nothing contained in this presentation is intended to, nor shall have the effect of, creating any warranties or representations from IBM or its suppliers or licensors, or altering the terms and conditions of the applicable license agreement governing the use of IBM software.

References in this presentation to IBM products, programs, or services do not imply that they will be available in all countries in which IBM operates. Product release dates and/or capabilities referenced in this presentation may change at any time at IBM’s sole discretion based on market opportunities or other factors, and are not intended to be a commitment to future product or feature availability in any way. Nothing contained in these materials is intended to, nor shall have the effect of, stating or implying that any activities undertaken by you will result in any specific sales, revenue growth or other results.

Performance is based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput or performance that any user will experience will vary depending upon many factors, including considerations such as the amount of multiprogramming in the user's job stream, the I/O configuration, the storage configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve results similar to those stated here.

All customer examples described are presented as illustrations of how those customers have used IBM products and the results they may have achieved. Actual environmental costs and performance characteristics may vary by customer.

IBM, the IBM logo, Lotus, Lotus Notes, Notes, Domino, Domino.Doc, Domino Designer, Lotus Enterprise Integrator, Lotus Workflow, Lotusphere, QuickPlace, Sametime, WebSphere, Workplace, Workplace Forms, Workplace Managed Client, Workplace Web Content Management, AIX, AS/400, DB2, DB2 Universal Database, developerWorks, eServer, EasySync, i5/OS, IBM Virtual Innovation Center, iSeries, OS/400, Passport Advantage, PartnerWorld, Rational, Redbooks, Software as Services, System z, Tivoli, xSeries, z/OS and zSeries are trademarks of International Business Machines Corporation in the United States, other countries, or both.

Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both.

Microsoft and Windows are trademarks of Microsoft Corporation in the United States, other countries, or both.

Intel and Pentium are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries.

UNIX is a registered trademark of The Open Group in the United States and other countries.

Linux is a registered trademark of Linus Torbvalds in the United States, other countries, or both.

Other company, product, or service names may be trademarks or service marks of others.

All references to Acme, Renovations and Zeta Bank refer to a fictitious company and are used for illustration purposes only.