Often when starting a new F# app, there comes a time when I want to read some configuration settings from a file, which can be overridden by environmental variables when running in production. This is closely followed by head-scratching as I try to remember how ConfigurationBuilder works and what NuGet packages I need.
The below example should set you straight until Microsoft changes the API again, which should be just before the next time I type dotnet new ...
Code:
#r "nuget: Microsoft.Extensions.Configuration, 6.0.0"
#r "nuget: Microsoft.Extensions.Configuration.Json, 6.0.0"
#r "nuget: Microsoft.Extensions.Configuration.EnvironmentVariables, 6.0.0"
#r "nuget: Microsoft.Extensions.Configuration.Binder, 6.0.0"
open Microsoft.Extensions.Configuration
[<CLIMutable>]
type Config =
{ Setting1: string
Setting2: string
Setting3: string }
member x.Evaluate =
{ Setting1 = x.Setting1
Setting2 = x.Setting2
Setting3 = x.Setting3 }
let GetHostSettings =
ConfigurationBuilder()
.AddJsonFile("appsettings.json")
.AddEnvironmentVariables()
.Build()
.Get<Config>()
Settings file:
{
"Setting1": "xxxxxx",
"Setting2": "xxxxxx",
"Setting3": "xxxxxx"
}