When you attempt to deploy an ASP.NET Core project to App Service on Linux, you may run into an error during the build process – Object reference not set to an instance of an object. When you try to deploy the project to App Service on Windows, everything works, so where is the issue?
I am sure you have heard of App Service’s feature called Local Cache, which allows to cache all the files locally on the instance instead of pulling them from the shared storage which can lower the application’s load times – especially when using just-in-time compiled code like PHP. This great feature however, is only available currently on App Service on Windows, and in this article, we are going to explore the options of having something similar on App Service on Linux powered by Docker.
During Build 2017, Microsoft announced bunch of new features for App Service on Linux. One of those features announced was support for SSH support directly into the web worker instance. Based on my previous article about building a custom image for ASL, I have updated the HHVM image both on GitHub and Docker hub to have SSH support as well.
In this article we are going to take a look at options on how to deploy a standard PHP application to Azure App Service. This article is split into two parts – classical App Service running Windows and the new Docker-based App Service on Linux which recently got some really nice improvements towards PHP support.
When I was writing a web application with ASP.NET Core with Azure AD and Microsoft Graph, I ran into a very interesting issue – the identity cookies would get really large (8 kB or more in chunked authentication cookies) and therefore all the requests to the site would contain this much data in headers. This was bearable because it just “worked” but then I tried accessing the site from Safari on a MacBook or an iPhone and the server would return errors when trying to rebuild the user’s identity.
Recently I have been working on a project in ASP.NET Core and DotVVM accompanied by a WebJob using Azure WebJob SDK. The idea behind publishing was that whenever I push code to the repository (VSTS in my case), App Service would pull the code, build it and deploy it automatically (this is achieved by setting up Continuous Deployment). This method works just great for ASP.NET Core application, however when accompanied by a WebJob, things weren’t as smooth as I was expecting them to be.
If you have been watching Connect(); or if you read the Azure blog, you should be aware by now, that Azure has recently introduced a pretty cool service called App Service on Linux. It is probably also not going to be a surprise to you if I tell you that it is being powered by Docker. And that is not the only great thing about it – you can also bring your own Docker image into App Service on Linux!