My ASP.NET web app takes an image file and uploads it to Azure storage as a BLOB. It works fine when ran locally in both debug & release mode. The problem occurs when the app is deployed through its Azure web app. Unfortunately, because I cannot get the stack trace I can't quite figure out what's causing the issue but the only thing I can think of is the Azure storage is blocking it for security reasons, but it's set to allow calls from Azure services so I thought it would allow it.
Here's the function that the site calls to upload the image. This is the only function that's called from the action so it has to be throwing an exception here.
public async Task<bool> UploadFile(IFormFile file, string fileName, Vendor vendor)
{
string storageConnectionString = _config.GetConnectionString("Storage");
CloudStorageAccount storage = CloudStorageAccount.Parse(storageConnectionString);
CloudBlobClient blobClient = storage.CreateCloudBlobClient();
string nameFormatted = vendor.Name.Replace(" ", "").ToLower();
var container = blobClient.GetContainerReference(nameFormatted);
await container.CreateIfNotExistsAsync();
using (var stream = file.OpenReadStream())
{
var blobRef = container.GetBlockBlobReference(fileName);
await blobRef.UploadFromStreamAsync(stream);
}
return true;
}
And here's the error that is thrown when deployed.
Although I could not see any obvious issue in your code, actually you can remote debug your application on Azure WebApp by Visual Studio.
There are three offical blogs introduce how to remote debugging on Azure WebApp.
Introduction to Remote Debugging on Azure Web Sites
Remote debug your Azure App Service Web App
Troubleshoot an app in Azure App Service using Visual Studio
You just need to follow the figure below to enable the Debugging feature of your App Service on Azure portal, then you can follow the blogs above to do it.
Hope it helps.
Related
We have a asp.net web app with "Always on" that is running a long task. To avoid to run this task two or more time simultaneously, at the beggining of the task a flag is set to database. If this task is forced to shutdown the flag is not removed, and the task is not gonna run again without manual intervention.
I've been looking for if the concept of recycle a website is existing in Azure, I didn't find much about it. I found for example https://stackoverflow.com/a/21841469/1081568 it seems that is never executed recycled, but I find some people complaining about web apps with "always on" set that recycles randomly.
I would like to know in which circumstance an app could be Recycled/shutdown in Azure? Just for maintenance? Azure recycle asp.net webs apps? Or is a concept exclusive of On-Premise servers?
And another question, Is there a way to capture this shutdown/recycle from Azure and stop my running task gracefully if it's running.
Thanks
As far as I know, normally azure will not recycled your web app's resource, if you set web apps with "always on".
If web app's “Always On” setting is off, which means the web site will be recycled after period of inactivity (20 minutes).
And another question, Is there a way to capture this shutdown/recycle from Azure and stop my running task gracefully if it's running.
According to your description, I suggest you could send a kudu restapi request to get the current web app's processid.
If the application restarted, the processid will be changed. By comparing the processid, you could capture this web app is recycled.
More details about how to get the current web app's processid, you could refer to below steps:
1.Set a Deployment credentials in your azure web application as below:
Notice:Remember the user name and password, we will use them to generate the access token
2.Send the request to below url to get the process information.
Url:https://yourwebsitename.scm.azurewebsites.net/api/processes
Code sample:
string url = #"https://yourwebsitename.scm.azurewebsites.net/api/processes";
var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
httpWebRequest.Method = "GET";
httpWebRequest.ContentLength = 0;
string logininforation = "username:password";
byte[] byt = System.Text.Encoding.UTF8.GetBytes(logininforation);
string encode = Convert.ToBase64String(byt);
httpWebRequest.Headers.Add(HttpRequestHeader.Authorization, "Basic " + encode);
using (HttpWebResponse response = (HttpWebResponse)httpWebRequest.GetResponse())
{
using (System.IO.StreamReader r = new System.IO.StreamReader(response.GetResponseStream()))
{
string jsonResponse = r.ReadToEnd();
dynamic result = JsonConvert.DeserializeObject(jsonResponse);
dynamic resultList = result.Children();
foreach (var item in resultList)
{
Console.WriteLine(item.name + " : " + item.id);
}
}
}
Result:
You could also find the processid in the portal.
Select your web app --> Process explorer
Image:
Can you give more details of how you ran AppCmd in Azure web app with SignalR as it requires admin rights? I don't think below will work for this reason.
protected void Application_Start()
try
{
var windowsDir = Environment.GetEnvironmentVariable("windir");
var command = System.IO.Path.Combine(windowsDir, #"System32\inetsrv\appcmd.exe set config / section:system.webserver / serverRuntime / appConcurrentRequestLimit:10000");
Process.Start(command);
}
catch (Exception ex)
{
Trace.WriteLine(ex.GetBaseException().Message);
}
}
Azure web app runs in sandbox. We have no permission to write system drive.
System drive access
Applications can read the system drive as controlled by ACLs on the drive. Applications cannot write to any location on the system drive, as implemented in the sandbox (i.e. even if ACLs allowed writing to a location on system drive, the sandbox would restrict it).
However if you choose Azure cloud service, we can use appcmd.exe in startup task. Of course, it will work like a charm if choose Azure VM as web server.
I am working on an ERP asp.net mvc 5 web application deployed under iis7. And now I want to implement a new scanning service, which mainly uses powercli and power shell scripts, and scan our network for servers & vms and get their specifications and their statues.
So I am thinking of the following approach:-
1.Since the scanning should be access by only specific users and requires the hosting server to have powercli and other tools installed, so I want to create a new asp.net mvc 5 web application , and deploy it under iis7 instread of modifying my current ERP syste,. Where the new application will have the following action method which will do the scan as follow:-
public ActionResult ScanServer(string token)
{
// do the scan
//send n email with scanning result
}
2.Now inside my current ERP system I can manually initiating the scan by calling the above action method as follow:-
[HttpPost]
[CheckUserPermissions(Action = "", Model = "Admin")]
public ActionResult Scan()
{
try
{
string currentURL = System.Web.Configuration.WebConfigurationManager.AppSettings["scanningURL"];
using (WebClient wc = new WebClient())
{
string url = currentURL + "home/scanserver?token=*******" ;
var json = wc.DownloadString(url);
TempData["messagePartial"] = string.Format("Scan has been completed. Scan reported generated");
}
}
catch (WebException ex)
{
TempData["messageDangerPartial"] = string.Format("scanningservice can not be accessed");
}
catch (Exception e)
{
TempData["messageDangerPartial"] = string.Format("scan can not be completed");
}
Now I did a quick test where I manually started the scan from the ERP and the scanning service deployed under iis worked well.
But I have these questions:-
The scanning service might take 20-30 minutes to complete. So from an architecture point of view is my current approach considered valid ? I mean to initiate a scan by calling an action method from another application ?
Now can i inside the scanning service web application, to force it to call its action method on a timly basis (for example every 4 hours)?
Thanks
Your best option would be to write a windows service to install on the webserver alongside the web app. This windows service can use threads or a timer to execute a long running task (such as scanning your network) at a specified interval and send an email when finished.
You can talk to your service from the app using the database, a config file, or maybe even a registry entry.
If this will not work for you, you can look into some task scheduling apps such as Quartz.NET. If you do use a windows service, I recommend the excellent TopShelf which makes it easy to create and deploy. Here is a nice blog post I found by Scott Hanselman that may help.
Bellow is my code from asp.net service which is trying to run some external exe. It works fine from my Visual Studio on win 7, but fails on my server (server 2008).
Myapp.exe reports back eror that account under which is runned doesn't have sufficiet priviliges.
List<ProcInfo> allProcesses = new List<ProcInfo>();
ProcessStartInfo pInfo = new ProcessStartInfo();
pInfo.FileName = binPath + #"\myApp.exe";
pInfo.WindowStyle = ProcessWindowStyle.Hidden;
pInfo.CreateNoWindow = true;
pInfo.UseShellExecute = false;
pInfo.RedirectStandardOutput = true;
string exitMsg = "";
int exitCode = 1;
try
{
using (Process proc = Process.Start(pInfo))
{
exitMsg = proc.StandardOutput.ReadToEnd();
proc.WaitForExit(1000);
exitCode = proc.ExitCode;
}
}
Resource pool on the server runs under account with sufficient priviliges and I also tried to use same account in code to start service with those same credentials and still nothing.
I have been told that account under which asp.net worker thread runs impose some additional limitations. So even if resource pool runs under appropriate account, you still won't have sufficient priviligies.
I also found something about using pInvoke and win32 api calls as the only way to run external code from asp.net service. But I don't have any win32 api knowlege nor did I found exples of this.
I would be very grateful for any tip/example how to run external exe under specified account from asp.net service.
If the account the worker process is runnning under lacks sufficient privelages then you have a few options.
You can either use impersonation in your code:
WindowsIdentity.Impersonate Method
Or configure IIS to run the application under a user account with the required privileges.
Here is an article which explains different methods of impersonation security:
Understanding ASP.NET Impersonation Security
If you do not feel confident implementing the user impersonation code yourself, here is a link to a codeproject article:
A small C# Class for impersonating a User
We have a web service running on the server. We want to use the service in local machine. Could some one kindly give all the steps to get the methods availble in the client.
We have created web methods in the server. And trying to access the same thing on the client. I can literally access those methods using the refernce variable of the server. but when I try to run it , it comes up with run time exception unable to connect to remote server.
I have added the web reference to my client class. What else I am missing. Do I need to do any kind of registration of service with client from command prompt.
I am assuming the client is unable to connect to server because the server is not running when I try to access the methods.
Any one with guidance will be helpful.
Thank you
Hari Gillala
I have added web refernce to this below client class using http://ipaddressofwerver/decisionclass/decisionclass.svc
The code:
try
{
DecisionClass ds = new DecisionClass();
string s = ds.Url;
Label1.Text = s;
string [] a = ds.GetList();
foreach (string i in a)
{
Response.Write(i);
}
}
catch (Exception Ex)
{
Response.Write(Ex.Message);
}
I am assuming the client is unable to connect to server because the server is not running when I try to access the methods.
If it's not running, it won't generate a WSDL either. However, it may have been running while you created the web reference, and then stopped.
Here are some things you can try to track down the problem:
Open the web service's URL, as specified in the web reference, in a regular web browser. This should bring up the web service's documentation page, and if you're running locally and haven't changed the web service's web.config, you can even call some simple methods using the provided test forms
See if you can access the web service with SoapUI or a similar tool.
Also, make sure you're running the web service in IIS, not in the Visual Studio development server - IIS will keep running when you close the project or even Visual Studio, but the development server might not.