Stop using a Cabal library to achieve reasonable Docker image sizes

Purr.cabal

@@ -13,26 +13,11 @@ extra-source-files:
     README
     ChangeLog.md
 
-library
+executable Purr
-  exposed-modules:
+  main-is: Main.hs
-      Core.Configuration
-      Core.HTTP
-      Core.SQLite
-      Core.Templates
-      Core.Types
-      Feature.Generation.HTTP
-      Feature.Generation.Links
-      Feature.Generation.Passwords
-      Feature.Generation.Shared
-      Feature.Generation.Templates
-      Feature.Sharing.HTTP
-      Feature.Sharing.SQLite
-      Feature.Sharing.Templates
-      Lib
-  other-modules:
-      Paths_Purr
   hs-source-dirs:
-      src
+      app
+      , src
   default-extensions:
       ConstraintKinds
       DeriveGeneric
@@ -41,6 +26,7 @@ library
       GeneralizedNewtypeDeriving
       OverloadedStrings
       ScopedTypeVariables
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N -optl-pthread -fPIC
   build-depends:
     base >=4.7
     , base64-bytestring >=1.2.0.0
@@ -63,44 +49,19 @@ library
     , utf8-string ==1.0.2
     , wai-extra >=3.1.12.1
     , wai-middleware-static >=0.5
-  default-language: Haskell2010
-
-executable Purr
-  main-is: Main.hs
   other-modules:
-      Paths_Purr
+    Core.Configuration
-  hs-source-dirs:
+    Core.HTTP
-      app
+    Core.SQLite
-  default-extensions:
+    Core.Templates
-      ConstraintKinds
+    Core.Types
-      DeriveGeneric
+    Feature.Generation.HTTP
-      FlexibleContexts
+    Feature.Generation.Links
-      FlexibleInstances
+    Feature.Generation.Passwords
-      GeneralizedNewtypeDeriving
+    Feature.Generation.Shared
-      OverloadedStrings
+    Feature.Generation.Templates
-      ScopedTypeVariables
+    Feature.Sharing.HTTP
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N -optl-pthread -fPIC
+    Feature.Sharing.SQLite
-  build-depends:
+    Feature.Sharing.Templates
-      Purr
+    Lib
-    , base >=4.7
-    , base64-bytestring >=1.2.0.0
-    , blaze-html >=0.9.1.0
-    , bytestring >=0.10.12.1
-    , containers >=0.6.4.1
-    , dhall >=1.40
-    , file-embed ==0.0.15.0
-    , http-types >=0.12.3
-    , iso8601-time >=0.1.5
-    , mtl >=2.2.2
-    , random >=1.2
-    , saltine >=0.2.0.0
-    , scotty >=0.12
-    , shakespeare >=2.0.20
-    , split >=0.2.3.4
-    , sqlite-simple >=0.4.18.0
-    , text >=1.2.5.0
-    , time >=1.9
-    , utf8-string ==1.0.2
-    , wai-extra >=3.1.12.1
-    , wai-middleware-static >=0.5
   default-language: Haskell2010

flake.lock

@@ -18,7 +18,56 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "locked": {
+        "lastModified": 1653893745,
+        "narHash": "sha256-0jntwV3Z8//YwuOjzhV2sgJJPt+HY6KhU7VZUL0fKZQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "1ed9fb1935d260de5fe1c2f7ee0ebaae17ed2fa1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nix2container": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1677791117,
+        "narHash": "sha256-zL4Fc5133KMqX7zCzcPODaBPEblUfgQt2UccNBm34Pc=",
+        "owner": "nlewo",
+        "repo": "nix2container",
+        "rev": "85670cab354f7df69dd4af097c27cf9bc5826cb2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nlewo",
+        "repo": "nix2container",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
+      "locked": {
+        "lastModified": 1677612629,
+        "narHash": "sha256-yC+9LfhfwOd5sXFW8TLnDmqVMNYiHXYPGy9BbdpRqfU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "111ca8e0378e88d9decaa1c6dd7597f35d8bc67f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1683159243,
         "narHash": "sha256-Fh41KQcZTswb4NyYfSsbNEhDS/Im0/Id6m3k7qZ6/Xw=",
@@ -36,7 +85,8 @@
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "nix2container": "nix2container",
+        "nixpkgs": "nixpkgs_2"
       }
     },
     "systems": {

flake.nix

@@ -4,22 +4,29 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs";
     flake-utils.url = "github:numtide/flake-utils";
+    nix2container.url = "github:nlewo/nix2container";
   };
 
-  outputs = { self, nixpkgs, flake-utils }:
+  outputs = { self, nixpkgs, flake-utils, nix2container }:
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs              = nixpkgs.legacyPackages.${system};
         packageName       = "purr";
         dockerPackageName = "${packageName}-docker";
 
+        nix2containerPkgs = nix2container.packages.x86_64-linux;
+
         haskellPackages = pkgs.haskellPackages;
 
         enableSharedExecutables = false;
+        enableSharedLibraries = false;
+
+        purr = pkgs.haskell.lib.justStaticExecutables self.packages.${system}.default;
+
       in {
+
         packages.${packageName} =
-          haskellPackages.callCabal2nix packageName self rec {
+          haskellPackages.callCabal2nix packageName self rec {};
-          };
 
         packages.default = self.packages.${system}.${packageName};
         defaultPackage = self.packages.${system}.default;
@@ -33,17 +40,19 @@
         };
 
         devShell = self.devShells.${system}.default;
+
         packages.${dockerPackageName} = pkgs.dockerTools.buildImage {
           name = "purr";
+
           copyToRoot = pkgs.buildEnv {
             name = "image-root";
-            paths = [ self.packages.${system}.default ];
+            paths = [ purr ];
             pathsToLink = [ "/bin" ];
           };
           tag = "latest";
           config = {
             Cmd = [
-              "/bin/Purr-musl"
+              "/bin/Purr"
             ];
             ExposedPorts = {
               "3000/tcp" = {};