Azure Web App Unable to find assembly 'Entity Framework'

Question

I'm trying to publish a project to an Azure Web App via Visual Studio 2015. This is an MVC 4 targeting Framework 4.6.2. The publish procedure claims in VS2015 to have finished successfully, however, when the browser is launched to display the published site, it errors out with a 502 error (bad gateway/proxy) on the favicon.ico file. Obviously, that's not what's really happening.

I downloaded my eventlog.xml file from the Web App and looking at the error being reported, it's claiming that it's unable to find assembly 'EntityFramework, Version=6.0.0.0...'. However, I see the EntityFramework.dll contained within the project bin folder. But, just to see if it made any difference, I tried using Kudu to install EntityFramework from NuGet, as well as doing a nuget restore using the packages.config file that was successfully pushed up to Azure. All that did was restore a ton of files where I didn't need and the same error remains.

Has anyone else seen this issue and have any recommendations on how to resolve it? I'm not sure what else I can post to give a clearer picture of what's going one...it's not like there's any code or source, and the eventlog.xml file shows little more than the YSOD error message for a missing assembly.

Please, any assistance would be greatly appreciated!

Answer 1

I've had this in the past - if you read the error message carefully it says it can't load that assembly or some of its dependencies - so it may well be another dll that's missing from your application.

Use the Console blade in the portal (or the separate Kudu site and console if you prefer) to compare the bin folder contents with that on your dev/test environment and see what's missing - if you stick to using nuget packages then you shouldn't be able to go far wrong, but I think I still had problems a while ago with EF when I didn't reference the EF libraries directly from the web app, but only from a repository assembly that was referenced from the web app.

If you're not using Nuget and referencing the dependencies directly make sure the referenced dll's "copy to output" properties in VS are set correctly, such that the dll's end up being copied to your project's bin folder and included in the package that gets deployed to Azure.

Answer 2

Well, it turns out this one was one of those "that's not the real issue" error messages. Thanks to Russell and Karel. You input led me to verify a few things and make sure I had all things referenced properly.

Here's what I found out...our DEV SQL VM is turned off on the weekends to conserve resources (aka $$$). After sending all files from my local bin directory via FTP, I browsed to the site and received the same error. Downloading the logs, however, showed that I couldn't reach the db server using Named Pipes. Whoops...one of the connection strings (in the repository project) had not been set to the FQDN, so it wasn't using TCP/IP for the connection.

I fixed that, published the site, turned ON the sql server, and now the site is working as expected.

Moral of the story, make sure you have all connection strings set properly.