feat: Global app data via environment variable

Specify `RECYCLARR_APP_DATA` so that every command inherits and uses
that path for its application data. This behaves the same as if you had
specified the `--app-data` option for every invocation of Recyclarr.

CHANGELOG.md

@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Docker support! Image name is `ghcr.io/recyclarr/recyclarr`. See the [Docker] wiki page for more
   information.
+- Global app data path support via environment variable named `RECYCLARR_APP_DATA`. The path
+  specified here will be used as the app data path for every invocation of `recyclarr` as if
+  `--app-data` were specified.
 
 ### Fixed
 

src/Common/DefaultEnvironment.cs

@@ -11,4 +11,9 @@ internal class DefaultEnvironment : IEnvironment
     {
         return Environment.GetFolderPath(folder, option);
     }
+
+    public string? GetEnvironmentVariable(string variable)
+    {
+        return Environment.GetEnvironmentVariable(variable);
+    }
 }

src/Common/IEnvironment.cs

@@ -4,4 +4,5 @@ public interface IEnvironment
 {
     public string GetFolderPath(Environment.SpecialFolder folder);
     string GetFolderPath(Environment.SpecialFolder folder, Environment.SpecialFolderOption option);
+    string? GetEnvironmentVariable(string variable);
 }

src/Recyclarr.Tests/Command/Initialization/DefaultAppDataSetupTest.cs

@@ -1,3 +1,5 @@
+using System.IO.Abstractions;
+using System.IO.Abstractions.Extensions;
 using System.IO.Abstractions.TestingHelpers;
 using AutoFixture.NUnit3;
 using Common;
@@ -22,6 +24,8 @@ public class DefaultAppDataSetupTest
         [Frozen] IAppPaths paths,
         DefaultAppDataSetup sut)
     {
+        env.GetEnvironmentVariable(default!).ReturnsForAnyArgs((string?) null);
+
         paths.DefaultAppDataDirectoryName.Returns("app_data");
         env.GetFolderPath(Arg.Any<Environment.SpecialFolder>(), Arg.Any<Environment.SpecialFolderOption>())
             .Returns(FileUtils.NormalizePath("base/path"));
@@ -49,6 +53,8 @@ public class DefaultAppDataSetupTest
         [Frozen] IEnvironment env,
         DefaultAppDataSetup sut)
     {
+        env.GetEnvironmentVariable(default!).ReturnsForAnyArgs((string?) null);
+
         sut.SetupDefaultPath(null, false);
 
         env.Received().GetFolderPath(Environment.SpecialFolder.ApplicationData, Environment.SpecialFolderOption.None);
@@ -59,8 +65,46 @@ public class DefaultAppDataSetupTest
         [Frozen] IEnvironment env,
         DefaultAppDataSetup sut)
     {
+        env.GetEnvironmentVariable(default!).ReturnsForAnyArgs((string?) null);
+
         sut.SetupDefaultPath(null, true);
 
         env.Received().GetFolderPath(Environment.SpecialFolder.ApplicationData, Environment.SpecialFolderOption.Create);
     }
+
+    [Test, AutoMockData]
+    public void Use_environment_variable_if_override_not_specified(
+        [Frozen(Matching.ImplementedInterfaces)] MockFileSystem fs,
+        [Frozen] IEnvironment env,
+        DefaultAppDataSetup sut)
+    {
+        var expectedPath = fs.CurrentDirectory()
+            .SubDirectory("env")
+            .SubDirectory("var")
+            .SubDirectory("path").FullName;
+
+        env.GetEnvironmentVariable(default!).ReturnsForAnyArgs(expectedPath);
+
+        sut.SetupDefaultPath(null, true);
+
+        env.Received().GetEnvironmentVariable("RECYCLARR_APP_DATA");
+        fs.AllDirectories.Should().Contain(expectedPath);
+    }
+
+    [Test, AutoMockData]
+    public void Explicit_override_takes_precedence_over_environment_variable(
+        [Frozen(Matching.ImplementedInterfaces)] MockFileSystem fs,
+        [Frozen] IEnvironment env,
+        DefaultAppDataSetup sut)
+    {
+        var expectedPath = fs.CurrentDirectory()
+            .SubDirectory("env")
+            .SubDirectory("var")
+            .SubDirectory("path").FullName;
+
+        sut.SetupDefaultPath(expectedPath, true);
+
+        env.DidNotReceiveWithAnyArgs().GetEnvironmentVariable(default!);
+        fs.AllDirectories.Should().Contain(expectedPath);
+    }
 }

src/Recyclarr/Command/Initialization/DefaultAppDataSetup.cs

@@ -20,6 +20,9 @@ public class DefaultAppDataSetup : IDefaultAppDataSetup
 
     public void SetupDefaultPath(string? appDataDirectoryOverride, bool forceCreate)
     {
+        // If a specific app data directory is not provided, use the following environment variable to find the path.
+        appDataDirectoryOverride ??= _env.GetEnvironmentVariable("RECYCLARR_APP_DATA");
+
         // If the user did not explicitly specify an app data directory, perform some system introspection to verify if
         // the user has a home directory.
         if (string.IsNullOrEmpty(appDataDirectoryOverride))
@@ -49,8 +52,8 @@ public class DefaultAppDataSetup : IDefaultAppDataSetup
         else
         {
             // Ensure user-specified app data directory is created and use it.
-            _fs.Directory.CreateDirectory(appDataDirectoryOverride);
-            _paths.SetAppDataPath(appDataDirectoryOverride);
+            var dir = _fs.Directory.CreateDirectory(appDataDirectoryOverride);
+            _paths.SetAppDataPath(dir.FullName);
         }
     }
 }

wiki/Command-Line-Reference.md

@@ -97,6 +97,10 @@ Overrides the normal, default location of the [[application data directory|File-
 that this option is mainly intended for usage in the official Docker image. It is not intended for
 normal use outside of that.
 
+If you'd like this behavior globally for all commands without having to specify this option, define
+an environment variable named `RECYCLARR_APP_DATA` with the same path. Note that if you have both
+set, `--app-data` always takes precedence.
+
 ## Sonarr
 
 ### `--list-release-profiles`