FSharp.DI 1.0.0

FSharp.DI

Lightweight functional helpers for Microsoft dependency injection and logging in F#.

Quick Start

• Target framework: .NET 10.0
• Install the package (when published):

dotnet add package FSharp.DI

Configure Logging in Program.fs

This is a minimal example of an F# app configuring Microsoft.Extensions.Logging, initializing FSharp.DI, and then calling a module that has a lazy logger bound with let:

open Microsoft.Extensions.DependencyInjection
open Microsoft.Extensions.Logging
open FSharp.DI
open LazyLoggerSample.SampleModule

[<EntryPoint>]
let main _ =
 let services =
 ServiceCollection()
 .AddLogging(fun logging ->
 logging.ClearProviders() |> ignore
 logging.SetMinimumLevel(LogLevel.Information) |> ignore
 logging.AddSimpleConsole(fun options ->
 options.TimestampFormat <- "HH:mm:ss "
 options.SingleLine <- true
 ) |> ignore
 )
 .BuildServiceProvider()

 DI.init services
 run 42
 0

Module-Level Lazy Logger Example

The sample module keeps a lazy logger in a normal module-level let binding:

module LazyLoggerSample.SampleModule

open FSharp.DI

type SampleModuleLog = class end

let private log = DI.loggerLazy<SampleModuleLog>()

let run orderId =
 log.Value.info $"Starting work for order {orderId}"
 log.Value.warn "Logger created on first use"

The let binding is created when the module loads, but the actual logger is not resolved until the first log.Value access. That means the pattern is safe as long as DI.init runs before run is called.

A runnable version of this example is included in samples/LazyLoggerSample/.

License

This project is licensed under the MIT License — see the file for details.

Author

Faisal Waris — © 2026