add a dry run mode

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## [Unreleased]
+
+### Enhancements
+- Add ability to run the launcher without launching any processes via the `/dryrun` flag
+
 ## [0.7.2] - 2022-10-10
 
 ### Enhancements

README.md

@@ -163,6 +163,7 @@ The following arguments are in addition to the above:
 | /edh4                  | Select Elite Dangerous Horizons 4.0 as the startup product                                                                       |
 | /frontier profile-name | Use this argument to login with a Frontier Store account. Keep the profile name to letters, numbers, dashes and underscores only |
 | /restart delay         | Restart the game after it has closed with _delay_ being the number of seconds given to cancel the restart (i.e `/restart 3`)     |
+| /dryrun                | Prints output without launching any processes                                                                                    |
 
 Note that the restart feature doesn't work with Epic accounts. After Elite launches, it invalidates
 the launcher's auth token and doesn't communicate the new token which then prevents the ability to

src/MinEdLauncher/App.fs

@@ -73,11 +73,11 @@ let printInfo (platform: Platform) productsDir cobraVersion =
     CobraBay Version: %s{cobraVersion}
     Products Dir: %s{productsDir}"""
     
-let rec launchProduct proton processArgs restart productName product =
+let rec launchProduct dryRun proton processArgs restart productName product =
     let args = processArgs()
     Log.info $"Launching %s{productName}"
     
-    match Product.run proton args product with
+    match Product.run dryRun proton args product with
     | Product.RunResult.Ok p ->
         let timeout = restart |> Option.defaultValue 3000L
         let cancelRestart() =
@@ -106,7 +106,10 @@ let rec launchProduct proton processArgs restart productName product =
         Log.info $"Shutdown %s{productName}"
         
         if restart.IsSome && not (cancelRestart()) then
-            launchProduct proton processArgs restart productName product
+            launchProduct dryRun proton processArgs restart productName product
+    | Product.DryRun p ->
+        Console.WriteLine("\tDry run")
+        Console.WriteLine($"\t{p.FileName} {p.Arguments}")
     | Product.RunResult.AlreadyRunning -> Log.info $"%s{productName} is already running"
     | Product.RunResult.Error e -> Log.error $"Couldn't start selected product: %s{e.ToString()}"
   
@@ -495,10 +498,15 @@ let run settings launcherVersion cancellationToken = taskResult {
     
     let gameLanguage = Cobra.getGameLang settings.CbLauncherDir settings.PreferredLanguage
     let processArgs() = Product.createArgString settings.DisplayMode gameLanguage connection.Session machineId (getRunningTime()) settings.WatchForCrashes settings.Platform SHA1.hashFile selectedProduct
-    let processes = Process.launchProcesses settings.Processes
+    settings.Processes |> List.iter (fun p -> Log.info $"Starting process %s{p.FileName}")
+    let processes =
+        if settings.DryRun then
+            []
+        else
+            Process.launchProcesses settings.Processes
     
     if not cancellationToken.IsCancellationRequested then
-        launchProduct settings.CompatTool processArgs settings.Restart selectedProduct.Name p
+        launchProduct settings.DryRun settings.CompatTool processArgs settings.Restart selectedProduct.Name p
         Process.stopProcesses processes
     return 0
 } 

src/MinEdLauncher/Process.fs

@@ -6,7 +6,6 @@ let launchProcesses (processes:ProcessStartInfo list) =
     processes
     |> List.choose (fun p ->
         try
-            Log.info $"Starting process %s{p.FileName}"
             Process.Start(p) |> Some
         with
         | e ->

src/MinEdLauncher/Product.fs

@@ -270,8 +270,8 @@ let createProcessInfo proton args product =
     startInfo.RedirectStandardError <- true
     startInfo
 
-type RunResult = Ok of Process | AlreadyRunning | Error of exn
-let run proton args (product:RunnableProduct)  =
+type RunResult = Ok of Process | AlreadyRunning | DryRun of ProcessStartInfo | Error of exn
+let run dryRun proton args (product:RunnableProduct)  =
     if isRunning product then
         AlreadyRunning
     else
@@ -279,7 +279,10 @@ let run proton args (product:RunnableProduct)  =
         
         Log.debug $"Process: %s{startInfo.FileName} %s{startInfo.Arguments}"
         
-        try
-            Process.Start(startInfo) |> Ok
-        with
-        | e -> Error e
+        if dryRun then
+            DryRun startInfo
+        else
+            try
+                Process.Start(startInfo) |> Ok
+            with
+            | e -> Error e

src/MinEdLauncher/Settings.fs

@@ -25,7 +25,8 @@ let defaults =
       ForceUpdate = Set.empty
       Processes = List.empty
       FilterOverrides = OrdinalIgnoreCaseMap.empty
-      AdditionalProducts = List.empty }
+      AdditionalProducts = List.empty
+      DryRun = false }
     
 [<RequireQualifiedAccess>]
 type FrontierCredResult = Found of string * string * string option | NotFound of string | UnexpectedFormat of string | Error of string
@@ -140,6 +141,7 @@ let parseArgs defaults (findCbLaunchDir: Platform -> Result<string,string>) (arg
             | "/autorun", _                   -> { s with AutoRun = true }
             | "/autoquit", _                  -> { s with AutoQuit = true }
             | "/forcelocal", _                -> { s with ForceLocal = true }
+            | "/dryrun", _                    -> { s with DryRun = true }
             | arg, _ when arg.StartsWith('/')
                           && arg.Length > 1   -> { s with ProductWhitelist = s.ProductWhitelist.Add (arg.TrimStart('/')) }
             | _ -> s) defaults

src/MinEdLauncher/Types.fs

@@ -95,7 +95,8 @@ type LauncherSettings =
       ForceUpdate: string Set
       Processes: ProcessStartInfo list
       FilterOverrides: OrdinalIgnoreCaseMap<string>
-      AdditionalProducts: AuthorizedProduct list }
+      AdditionalProducts: AuthorizedProduct list
+      DryRun: bool }
 type ProductMode = Online | Offline
 type VersionInfo =
     { Name: string

tests/Settings.fs

@@ -79,6 +79,10 @@ let tests =
             let! settings = parse [| "/novr" |]
             Expect.equal settings.DisplayMode Pancake ""
         }
+        testTask "Matches /dryrun" {
+            let! settings = parse [| "/dryrun" |]
+            Expect.isTrue settings.DryRun ""
+        }
         testTask "Matches /autorun" {
             let! settings = parse [| "/autorun" |]
             Expect.equal settings.AutoRun true ""