Sometimes I found that it was frustrating to not know what exception detail was when an exception was thrown from a production website. At that point, the all-mighty Elmah error logging and exception handling plug-in came to my mind. But all my previous Elmah plug-in was added during web project development and deployed along with the project to hosting server. How to go about plugging in an Elmah when my website is already up there and running? Here were the steps I went through the other day to accomplish exactly that:

1. Downloaded the elmah sql script file from https://code.google.com/p/elmah/downloads/detail?name=ELMAH-1.2-db-SQLServer.sql&can=2&q= and executed it against the sql database ProdDB on the host. It went through and created the Elmah_Error table and related stored procs inside ProdDB database
2. Now let’s manually add elmah.dll and configure the web.config to register elmah.
3. Copied elmah.dll from one of my old projects that had Elmah already working to the target bin folder.
4. Added to <configuration><configSections> the following:

   <sectionGroup name="elmah"><section name="security" type="Elmah.SecuritySectionHandler, Elmah" />
   <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah" />
   <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah" /></sectionGroup>

5. Added to <httpHandlers>:

   <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah"/>

6. Added to <httpModules>:

   <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
   <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" />
   <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />

7. Added <elmah> to <configuration> right after </system.web> and before <system.net>

   <elmah>
   <!--<errorLog type="Elmah.XmlFileErrorLog, Elmah" logPath="~/App_Data/Errors" />-->
   <errorLog applicationName="AppName" connectionStringName="connToProdDb" type="Elmah.SqlErrorLog, Elmah" />
   <errorMail subject="Website error via Elmah" to="stevey@yangsoft.com" from="webmaster@yangsoft.com" aysnc="true" />
   
   <security allowRemoteAccess="no" />
   
   </elmah>

8. Last, but not least, in order to get the alert email sent out automatically to me, I needed to add the SMTP parameters to the mailSettings section in the <system.net>

   <mailSettings>
   <smtp deliveryMethod="Network">
   <network host="mail.domainname.com" userName="webmaster@domainname.com" password="password" port="numberthatworks" />
   
   </smtp>
   
   </mailSettings>

   (there was no <system.net>, so just created one)

9. Added the following right after </system.net> and before <system.webserver>

   <!--deny annonymous access to error log-->
   <location path="elmah.axd">
   <system.web>
   
   <authorization>
   <allow users="*"/>
   <!--<deny users="?" />-->
   </authorization>
   </system.web>
   
   </location>

10. Added to <system.webserver><modules>:

    <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
    <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" preCondition="managedHandler" />
    <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />

11. Added to <system.webserver><handlers>

    <add name="Elmah" path="elmah.axd" verb="POST,GET,HEAD" type="Elmah.ErrorLogPageFactory, Elmah" preCondition="integratedMode" />

12. Finally, it is completed! Now browsed to the site and manually generated some errors; immediately, I got an email alert; then I browsed to the elmah.axd, and it also rendered all the errors in a tabulated format nice and neat. Of course, more detail info is obtained by clicking on the detail link and you will be surprised how much exception stack trace has been caught.