Azure Application Settings not overriding my appsettings.json file values

I just had a similar problem (the problem was with PostgreSQL connection string type, I had to change it to custom) and now it works for me, so these are the pieces:

1. This is my appsettings.json file. I have a value for 'Psql' set in my appsettings.Development.json, but in the appsettings.json it is left empty.
2. These are the settings which are set in the Azure portal. Please note, that there are two ways to override the connection string.
3. This is the part of my Startup.cs file. Pay attention to the order of how the settings are applied in the Startup constructor and the way I get the connection string in the ConfigureServices method (GetConnectionString is a standard extension method).

Additional info from my comments below:

Azure GUI (Connection strings, Application settings) uses environment variables internally, so the appsettings.json will stay the same.

If there is a need for an appsettings.json's value to be overwritten during VSTS release activity (before it will be published to Azure), Colin's ALM Corner Build & Release Tools can be used. Here are the links to Colin's ALM Corner Build & Release Tools and tutorial.

Thanks @pasul, your help was much appreciated and helped me find an alternative solution. In order to deploy using VSTS task and replace application settings, you will need to add variables to the release task and pass into the task the json file in question for variable substitution.

When in "Deploy Azure App Service" release task you should see a "File Transforms and Variable Substitution" section. In here you will supply the path to the json file you want to swap variable values.

Then you will need to click on the options button on the release environment. You will see an option to configure variables in the pop out menu.

From here you can add the json property you want to modify as a variable. In my case the connection string. Which will look like the following:

"ConnectionStrings.DefaultConnection"

Then just put in your connection string value. VSTS will then swap out these values for you when deploying.