Environment.GetEnvironmentVariable("RoleRoot") returning null when called in a WebRole

Question

I have a method (in a separated class library) which is called by a WebRole and a WorkerRole. This method contains the path of a file, which is returned using Environment.GetEnvironmentVariable("RoleRoot"), as follows:

private string FooPath()    
{
    string appRoot = Environment.GetEnvironmentVariable("RoleRoot");
    return Path.Combine(appRoot + @"\", @"approot\file.foo");
}

When I call this method from a WorkerRole the path is returned normally. But when I call it from a WebRole I get null.

Any ideas?

EDIT: I am using APNS-Sharp to send push messages to iOS and it requires a .p12 certificate in order to work. Currently I have the .p12 in the root of my class library (which is called by both WebRole and WorkerRole). But the point is: Why RoleRoot returns null when I call it from a WebRole but returns the path when I call from a WorkerRole?

Are you sure you need to locate files in `RoleRoot`? It seems to be a wrong idea for me. — Snowbear, May 25 '11 at 21:48
can you make it a little bit more clear what are you going to do with this file? Who will read it and who will write it? Probably all you need is this: http://msdn.microsoft.com/en-us/library/microsoft.windowsazure.serviceruntime.roleenvironment.getlocalresource.aspx — Snowbear, May 25 '11 at 22:02
regarding your question quick googling results in this: http://blogs.msdn.com/b/avkashchauhan/archive/2011/05/25/role-environment-variables-in-full-iis-web-role-and-in-hwc-web-role.aspx — Snowbear, May 26 '11 at 08:40
Thanks! That helped me to understand my problem and I even came with the solution. Can you post as answer? :-) — Davidson Sousa, May 26 '11 at 23:32

score 10 · Accepted Answer · answered May 28 '11 at 10:48

RoleRoot returns false for WebRole because the WebRole uses IIS, just like a normal website. That's why it's difficult to get Environment Variables from a WebRole.

In order to get the path properly I had to use the classic Server.MapPath and reference the bin folder, instead of approot:

private string FooPathWebRole()    
{
    string appRoot = HttpContext.Current.Server.MapPath(@"~\");
    return Path.Combine(appRoot + @"\", @"bin\file.foo");
}

For the WorkerRole nothing has changed:

private string FooPathWorkerRole()    
{
    string appRoot = Environment.GetEnvironmentVariable("RoleRoot");
    return Path.Combine(appRoot + @"\", @"approot\file.foo");
}

In addition, I found out that Azure doesn't import p12 certificates. I would have to transform it into another format, which I don't believe would work for me. So, the best option is to place them on the root of the application and mark its Build Action to Content.

Note you need to add a ref to System.IO for the Path.Combine command. — PapillonUK, Dec 14 '11 at 22:56
See http://blog.toddysm.com/2011/03/what-environment-variables-can-you-use-in-windows-azure.html — Zephyr was a Friend of Mine, Jun 03 '13 at 14:39

score 1 · Answer 2 · answered Dec 16 '11 at 23:42

1

I tried from webrole and it works for me. I place it at the OnStart() code of the web role, which is called by WaIISHost

answered Dec 16 '11 at 23:42

Lingxiao

11
1

score 0 · Answer 3 · edited May 23 '17 at 12:25

0

If you want to load a certificate, you could try the advice in http://blogs.msdn.com/b/jnak/archive/2010/01/29/installing-certificates-in-windows-azure-vms.aspx

Linked from How do I import a public certificate to Windows Azure?

edited May 23 '17 at 12:25

Community

1
1

answered May 25 '11 at 22:12

Stuart

66,722
7
114
165

Environment.GetEnvironmentVariable("RoleRoot") returning null when called in a WebRole

3 Answers3

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