This may seem like a silly question, but we are having an issue debugging IIS in a shared test environment and I'm hoping that someone out there can give us an answer.
We have a Windows Server 2003 that is running IIS 6 and sharepoint 2007. We are debugging locally on the server with visual studio 2008.
When someone attaches the debugger and steps through the code, we find that all users are affected. In essence the web server stops handling all requests from all users.
Our question is whether this is a typical situation and is to be expected? Or is there some configuration that we can change that would allow the one user's session to be debugged but leave the other's unaffected.
Kev's on the right track. You need to make sure that the project you want to debug separate from the others is in its own application pool. This will isolate it to its own process and allow that process to be stopped/debugged without affecting the other applications which can remain in a different pool.
Setup
Start -> Run -> inetmgr
Right Click on Application Pools
Click New -> Application Pool
Name the new pool
Right Click on the application you want to isolate
Click Properties
Click on the Home Directory tab
In the application pool drop-down list select your new pool
Click OK
If there are any requests queued in the old process, they may take a few minutes to terminate before all requests are being diverted to the new process.
Debugging
To figure out which instance of w3wp.exe you need to attach the debugger to:
Start -> Run -> cmd
Type iisapp
You may be prompted to register CScript, if so click yes and run it again
The only gotcha you may still find is that if multiple applications are using the aspnet_state service you may run into blocking issues if you need to debug that process as well.
Links
MSDN
Developer.com
"When someone attaches the debugger
and steps through the code, we find
that all users are affected. In
essence the web server stops handling
all requests from all users."
This is normal, once you attach a debugger to a process such as inetinfo.exe or w3wp.exe and set a break point, every request/thread will be blocked until you allow the debugger to continue, until the next break-point.
I've never found a way around it. Is there some reason you can't debug on each developer's workstation?
Set up a parallel project on the server and try using that. You could use debug.mydomain.com and then just use that for testing. The only reason that I personally can think of to debug on your live servers is if there is a significant difference in the functioning of your app due to either hardware or software configuration.
Ideally you want to have a separate server/instance of your system in as similar an environment as possible so that you don't have to debug on your live machine. Also you might want to consider writing all errors to the event log or at least checking the log since asp.net usually get logged there. This way you can see where your errors are and use that to help you solve your problem in the development environment.
I believe in visual studio you can set the debugger to break only the process being debugged, and not all the processes. Depending on how your system is set up, YMMV with this.
It can't be changed AFAIK. But that's a normal practice to set up separate web-node or web-application for development/debugging purposes. If that's necessary to know exact values of some vars in certain situations you can always use debug logging.
Related
We are developing an (internal) web service based on asp.net 4.8, with a fairly extensive REACT SPA front end.
For debugging purposes during development, we run an IIS server on the local (development) machine, and we do something separate to run a proxy web server for debugging the .js front end SPA (not relevant to the question at hand).
When we start up a Debug session in Visual Studio (2019), VS starts with "Contacting web server to start debugging" and then locks for a time. It clearly does something to start the web server (w3wp.exe), and waits for some reply, before doing what it is told to do in the "Start Action" section of the Web tab on the project properties page.
This is problematic behaviour because it does not attach to w3wp.exe until after it finishes it's "contacting web server to start debugging" operation. This is a huge problem, as our w3wp.exe starts doing all kinds of things that we have no visibility into.
So, can anyone explain to me:
What does VS actually do to "contact the web server"?
Can this be controlled? If so, how?
Can I get the debugger to attach to w3wp.exe right away?
Why does w3wp.exe start up and load its collection of binaries, only unload them and reload them, sometime multiple times?
In short, what the actual heck is going on under the covers at startup?
This (Identity Server 3 Contacting the web server hangs when launching debug mode) question and answer seem irrelevant to my situation
I note the field Override application root URL in the Servers section of the Web tab of the project properties and had hoped this might have something to do with it, but I cannot see any relation.
Partial answers that I will either edit as I find more info, or modify if others correct me, or delete if someone answers completely. The answers to (1) and (2) above are this:
VS obtains the URL of the target web site (I will call this targetServer) from the Project URL entry in the Servers section, Web tab, of the Properties page for the web project. This actually comes from the <webProjectName>.csproj.user file in the project directory. Depending on the selection of the drop down specifying the server type to use, it comes from:
IIS server (<UseIIS>true): the <IISUrl> element
External Host (<UseCustomServer>true): the <CustomServerUrl>
IIS Express: unknown
WARNING: When opening a project with <UseIIS>true, Visual Studio has the very nasty habit of interfering in the setup of your IIS server: it insists on changing the "Physical Location" attribute of the IIS server (that is, the server or virtual app, however you have it set up) to point to the project directory of the web project. Using the "External Host" option avoids this - see https://stackoverflow.com/a/48753054/1082063. (All other discussions of this issue that I have seen incorrectly say this cannot be controlled.)
VS then issues a request to the url <targetServer>/debugAttach.aspx, and the request shows as neither a "GET" nor a "POST", but a "DEBUG", whatever that is. Not sure what VS expects back from this before doing the specified Start Action
Presumably after VS gets some reply from its DEBUG request, it will attach to the process that resulted from this request. Not sure how it knows which process to attach to - perhaps the debugAttach.aspx returns process information?
VS finally executes whatever Start Action is specified in the section of that name on the Web tab of the project Properties.
I strongly suspect that the answer to (3) above is that one cannot get VisualStudio to attach any earlier than it does because it must use the information returned from the debugAttach.aspx request to know which process to attach to. However, putting the line System.Diagnostics.Debugger.Launch(); at the start of Application_Start will allow you to attach the debugger earlier when necessary. (In practice, once you get Application_Start correct, you seldom need to debug it.) See this: https://weblog.west-wind.com/posts/2011/Dec/15/Debugging-ApplicationStart-and-Module-Initialization-with-IIS-and-Visual-Studio for a very good article on the subject.
(4) was a result of quirks in our Visual Studio setup. The initial "hack" used to get around the WARNING in answer (2) just above, was to have a web site with a dummy "virtual path" and have the IISUrl element in Visual Studio point to this virtual path. Then VS could change the Physical path of this virtual path, and we didn't really care, because our Start Action was to start a proxy server for debugging .js in any case. The issue was that this resulted in two calls to Application_start, running on two separate threads: one for the main server and one for the virtual server. Because one of these was happening before the attach happened, we never knew it was happening and it was never caught in a break point. When our application_start became long (timewise - this is not a web server for public consumption...), the two executions of application_start became a nightmare.
The issue you're seeing in IIS is that VS is not launching w3wp.exe, but rather Attaching to Process. In order for VS to attach though the EXE has to be running first, and the time between starting up and attaching (if not already running) ends up being too late to catch the ASP.NET app initialization logic in Application_Start and Module initialization.
As mentioned in my old post there are several ways you can get this to work:
Restarting the application when the debugger is already attached
(by making a change in web.config to trigger an AppDomain reload)
Adding an explicit Debugger.Break() call in Application_Start
Use IIS Express to debug startup code
Did anyone encounter an error with ASP.NET debugging? I've made a really simple, empty MVC page, I've tried returning /Home/Index.cshtml and a string, and each time I get a windows jingle and the browser can't find the server. It doesn't happen when I run it without debugging though, then the website runs just fine.
I've also tried the default MVC template, with Bootstrap etc, and it's the same - runs without debugging, doesn't run with debugging.
It's probably important: I'm running Visual Studio 2017 on up-to-date Windows 10. I've reinstalled the system several weeks ago, really wouldn't want to do that again :/
Generally we could debug an app with the normal user, but sometimes we need to use the admin, for example, as far as I know, if we want to use the attach to process tool for remote debugging, we often run the VS as the admin or others.
This document share us the tasks we need administrator permissions to complete：
https://msdn.microsoft.com/en-us/library/jj662724.aspx?f=255&MSPPError=-2147217396
If possible, you could refer to it especially "Debugging" area in above link.
Hope it could help you:)
It may be a silly question but why one would like to attach debugger to IIS instance?
These SOs
Attach Debugger to IIS instance
How do I attach the debugger to IIS instead of ASP.NET Development Server?
show you how to do it but could you let me know what are the benefits of doing this?
One time, in my entire career, we had a web app that started getting strange errors that had us baffled. We tried a dozen things to try and figure out what was wrong, but we were panicking and needed an answer immediately. So, we attached a debugger to the production instance and set up a few watch/break points. It helped us track down the errors and fix the problem.
Naturally, it hung the server during our debugging session, and made people mad, but no more mad than they already were, because of the problem we had.
It would not have been necessary if the code had been written better, with error logging and diagnostic points. I don't expect to ever do it again.
Apart from TimG's post a couple of reasons I can think of are:
To debug the application in a closer representation of its
production environment
To debug on a remote machine
Example, like #TonE #1 -- in order to test a deployed website (with web.config transformations) locally, like if you can't remote debug a live website or just need to test config transforms (since you can't run them in-place):
Open site project from C:\Dev\AwesomeWebSite\AwesomeWebSite.sln
Publish the site to a local folder C:\Webs in Release mode (or Whatever mode)
Set up a local IIS website pointing at the published project
Do stuff on the locally-deployed version (e.g. browse pages, make webservice calls, etc)
Attach VS to w3p.exe (appropriate instance) in order to debug the deployed version
You might be able to effectively do the same thing by instead pointing the Project at your IIS website per this answer.
I have an application that runs perfectly fine locally using the VS 2010 application server, however, when I deploy to our web app machine startup just spins and spins and never loads. We have other apps on this same machine that load just fine (this is a debug deployment of same app in product).
I have been spinning my wheels on this for days and I am at a loss as the problem could be.
Here is what I did
Create a new directory (same level as other apps)
Copied over our existing test (www.domain/test/) and it works fine
Build and publish new debug app (www.domain/test/) and it just spins trying to load first form.
I know the diretory is "working" as the 'test' application I put there works fine.
If it's killing the App pool, you might get something in the event log. Fiddler (www.fiddlertool.com) is great http debug tool which let you see if you're in a redirect loop. Also Firefox shows a more meaningful error, something about exceeding the max redirect count.
It does sound like something is looping, but not quick enough to cause a stack overflow, which is odd, because you'd expect it to fail every time.
Simon
Do you have the ability to remote desktop into the machine? If so try running process explorer and look at the process details for the worker process that is giving you issues. Definitely look at the TCP connections being created. If your processor is pegged at 100%, and memory usage is rising then you probably have an endless loop running.
It sounds like it's more related to IIS than ASP.NET. What about the identity that the website is running under? Is it possible that the user the site's running under a bad user, or maybe the password needs to be re-entered?
I did a quick Bing search
There are a lot of postings regarding the error message you described above. Most if not all point to code in your app that is crashing. I know I had a similar problem when I used an automated/threaded daemon utility in my web application. Make sure your code is not bringing down the server, sometimes the VS2010 web server is a little more foregiving than an actual IIS deployment.
If that doesn't work try running a Remote Debugging Session to try and catch any errors being thrown but not handled.
Lastly you could try to setup a new local IIS server to see if you have the same problems. Scott Gu has a nice article about using IIS Express to do this.
Can anyone help me with this error?
alt text http://abbeylegal.com/downloads/parsererror.jpg
full image here
It happens usually once a day when trying to load any one of a number of custom asp.net pages in my sharepoint web site. If I recycle my application pool the error disappears (usually for the day).
So far this is what I’ve tried to eliminate the error (which has helped reduce the number of occurrences, but not solved it)
Set the IIS_WPG, Local Service and Network Service account to Full Control permission
on the folder
%windir%\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files
Added
<machineKey validationKey="AutoGenerate,IsolateApps" decryptionKey="AutoGenerate,IsolateApps" validation="3DES" decryption="3DES"/>
to the web.config file section.
Recycle the application pool every two hours
My gut feeling is some sort of file locking issue. Have you tried running Process Monitor and having a look at the trace when this error occurs? Be warned that running it may sap some resources on your server.
To use, follow these steps. (You may also find Mark Russinovich's blog useful.)
Set the filter so that it only displays the w3wp.exe process. This will reduce noise. The simplest way is to right-click on 'w3wp.exe' in the list and select Include 'w3wp.exe'.
The monitor should have automatically started so now just wait until you receive the ASP.NET error. Make a note of the time the error occurs! It may also be reported in the SharePoint ULS log.
Stop Process Monitor from capturing events (File, Capture Events) and narrow down to the time of the error.
Look for the word 'FAIL' or 'ERROR' (you can use the program's find feature) and see if you can work out what's happening. You may need to remove the filter as the problem might have occurred with another process besides w3wp.exe.
There may also be interference with an anti-virus program as I've seen these lock files and cause problems on SharePoint before. Can you try disabling it to check if the error disappears? Alternatively, here are details of locations that need to be excluded so that SharePoint can operate correctly with a file-level virus scanner. You may need to add others, I don't believe that list is comprehensive.
I can see why the app pool recycle works, the dll's get recopied to the Temporary ASP.NET files folder.
The question here is, why are they not there anymore? It could be that the files were locked when the app pool recycled overnight, the files were not overwritten with a new version and remain in a locked state. Maybe search crawl was running when the app pool tried to recycle, visiting that page at the time?
P.S. Is your custom page build as part of a "Visual Studio Web Site" or a "Visual Studio Web Site Project"?