The ASP.NET Exception Reporter is an exception handling and reporting tool developed by Orbit One. It is based on the ELMAH open source project and adds rich reporting and notification possibilities as well as strong exception aggregation and classification. The application is open source and can be found on http://aspexceptionreporter.codeplex.com/

1. www.orbitone.com
Raas van Gaverestraat 83
B-9000 GENT, Belgium
E-mail info@orbitone.com
Website www.orbitone.com
Tel. +32 9 265 74 20
Fax +32 9 265 74 10
VAT BE 456.457.353
Bank 442-7059001-50 (KBC)
6 October, 2009 ASP.NET Exception Reporter
by Mel Gerats & Wim De Coninck

2. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck
In this presentation
 What is ELMAH
 Why use it
 ASP.NET Exception Reporter

3. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck3
What is ELMAH
Open source project
http://code.google.com/p/elmah/
Error Logging Modules And Handlers
Plug and play

4. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck4

5. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck5
Why use ELMAH
 Track and analyze unhandled exceptions
 Solve errors before they are reported
 Keep track of errors over time
 Can be added to existing web sites without changing code
 Show friendly error page but save the error somewhere
 Compatible with
web sites
web services
.net 1.x, 2.0, 3.x
SharePoint

6. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck6
Limitations
 One instance web application
 Overview through HttpHandler (elmah.axd)
 Only limited reporting

7. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck7
What we needed
 Exceptions always saved!
 Central reporting website for all applications
 Notifications
 Additional filters and classification
 Installation on remote servers with no direct access to our database

8. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck8

9. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck9
Architecture
SQL server
ELMAH
Database
Developers
Administrators
ELMAH notification server
SEP
13
Windows scheduled task
Starts the email notifier
command line application:
- every 30 minutes
- daily at 20 PM
Intelligent Error Filter
- Error level (0-5)
-Error type (Infrastructure / Code)
ELMAH web service
ELMAH Web server
Web interface
ELMAH HttpModule
XML Folder
Web server(s)
Exceptions Exceptions Exceptions Exceptions Exceptions Exceptions
Custom error Page
Redirect to
Exceptions
In XML format
Filesystem
Directory watcher
Agent
OleDb
OleDbHttps
OleDb
Email
http
Consulting webpages
OleDb

10.  HttpModule deployed per
application or server wide
 Configured in web.config or
machine.config
 Error files to central folder on file
system
 Agents monitor file system folder.
6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck10
Web Server

11.  Web Service receives error
 Add classification, levels, metadata
 Save to database
 Receive heartbeats from agents
6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck11
Web service
Intelligent Error Filter
- Error level (0-5)
-Error type (Infrastructure / Code)
ELMAH web service
ELMAH Web server
Web interface OleDb
Https
OleDb
http
Consulting webpages

12. Applications
12 ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck
6 October, 2009
Web site
Notifications
Rss feeds
…

13. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck13
ELMAH HttpModule
When an error happens:
Save all information
Server variables
Client information
Form variables
The original error page
Saved as xml to a “Logs” folder
Redirect to custom error page

14. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck14
Agent
 Installed on web server as a windows service
 Monitors the “Logs” folder on the file system
 Sends errors to the web service for processing
 Saves errors that cannot be processed to an “invalid errors” folder
 Sends a heartbeat every x minutes

15. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck15
Web service
 Receives errors from all agents
 Calculate error level, based on rules
Final level = average level of all applied rules
Example: “user agent contains “robot” => level 0
 Give error a classification, based on rules
Example: “remote address contains “192.168” => internal user
 Saves the error to the database
 Keeps track of the status of each agent based on heartbeats

16. Web Site
16 ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck
6 October, 2009
 Last 100 Errors
 Search
Error id
Time frame
Application
Error message
 Filters
Level
Type
User type
 Application health status
 Agents status

17. Demo
17 ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck
6 October, 2009
Demo website

18. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck18
Notifications
 Daily report:
overview of latest errors
Applications with the most errors
 Possibilities:
 Instant notifications when certain events occur
Lots of errors at a short interval
Same error over and over
Patterns

19. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck19
Technologies used
 SQL Server
Data store
 LinqToSQL
Data access
 ASP.NET, JQuery
Website
 Web Services
Central access point
 Windows services
Agents
 Scheduled Tasks
Notifications

20. Database
6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck20

21. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck21
Data Access
 OrbitOne.Base, ORM built on top of Nhibernate
Custom
Slow
No Linq support
 Nhibernate 2.1, with Linq provider
Unfinished
Strange results
 LinqToSQL
Fast!
Easy

22. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck22
Technologies used
 XML Data Type in SQL server
 index on xml fields

23. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck23
Error filter rules
 Xpath selector
/error[@detail[contains(.,'General network error')]]
 Error Filter Rule
Level = 0
Type = Infrastructure
 Rule can have multiple selectors, is applied when one is applicable
 All rules are applied on all errors
 Final level is the average level

24. 6 October, 2009
ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck24
Resources
 Orbit One ASP.NET Exception Reporter on Codeplex
http://aspexceptionreporter.codeplex.com
 ELMAH on Google Code
http://code.google.com/p/elmah/
 Documentation
http://aspexceptionreporter.codeplex.com/documentation
 ELMAH @ StackOverflow
http://stackoverflow.com/questions/tagged/elmah

25. www.orbitone.com
25 ELMAH Asp.NET exception logging, by Mel Gerats & Wim De Coninck
6 October, 2009