Add stack/nix integration

Relates to #4

.gitignore

@@ -22,3 +22,6 @@ cabal.project.local~
 .HTF/
 .ghc.environment.*
 .ghci
+
+### Nix ###
+/result*

default.nix

@@ -0,0 +1,18 @@
+{ system ? builtins.currentSystem
+, crossSystem ? null
+, config ? {}
+
+# Import IOHK common nix lib
+, iohkLib ? import ./nix/iohk-common.nix
+# Pin nixpkgs to a revision on the nixos-19.03 channel
+, nixpkgs ? iohkLib.fetchNixpkgs ./nix/nixpkgs-src.json
+, pkgs ? import nixpkgs { inherit system crossSystem config; }
+
+# Keep this argument even if unused.
+# It will prevent Hydra from caching the evaluation.
+, gitrev ? iohkLib.commitIdFromGitRepo ./.
+}:
+
+{
+  inherit pkgs;
+}

nix/iohk-common.nix

@@ -0,0 +1,15 @@
+# Imports the iohk-nix library.
+# The version can be overridden for debugging purposes by setting
+# NIX_PATH=iohk_nix=/path/to/iohk-nix
+
+import (
+  let try = builtins.tryEval <iohk_nix>;
+  in if try.success
+  then builtins.trace "using host <iohk_nix>" try.value
+  else
+    let
+      spec = builtins.fromJSON (builtins.readFile ./iohk-nix.json);
+    in builtins.fetchTarball {
+      url = "${spec.url}/archive/${spec.rev}.tar.gz";
+      inherit (spec) sha256;
+    }) {}

nix/iohk-nix.json

@@ -0,0 +1,7 @@
+{
+  "url": "https://github.com/input-output-hk/iohk-nix",
+  "rev": "f20ab3940d3ec5d5a3d92e1f0544f501316adc43",
+  "date": "2019-02-15T19:35:36+10:00",
+  "sha256": "07hla7d0l91is5m5mwa86vq51fdxkjvbjv7176ipdg1z59wy21bj",
+  "fetchSubmodules": false
+}

nix/nixpkgs-src.json

@@ -0,0 +1,7 @@
+{
+  "url": "https://github.com/NixOS/nixpkgs.git",
+  "rev": "07e2b59812de95deeedde95fb6ba22d581d12fbc",
+  "date": "2019-02-26T15:31:33+01:00",
+  "sha256": "1yxmv04v2dywk0a5lxvi9a2rrfq29nw8qsm33nc856impgxadpgf",
+  "fetchSubmodules": false
+}

nix/stack-shell.nix

@@ -0,0 +1,20 @@
+# This is the derivation used by "stack --nix".
+# It provides the system dependencies required for a stack build.
+{ system ? builtins.currentSystem
+, config ? {}
+, walletPackages ? import ./.. { inherit config system; }
+, pkgs ? walletPackages.pkgs
+}:
+with pkgs;
+
+haskell.lib.buildStackProject {
+  name = "cardano-wallet-stack-env";
+  ghc = haskell.compiler.ghc863;
+
+  buildInputs = [
+    zlib gmp ncurses lzma openssl git
+  ] ++ (lib.optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [ Cocoa CoreServices libcxx libiconv ]));
+
+  phases = ["nobuildPhase"];
+  nobuildPhase = "mkdir -p $out";
+}

stack.yaml

@@ -8,3 +8,6 @@ extra-deps:
 
 - git: https://github.com/input-output-hk/cardano-crypto
   commit: 3c5db489c71a4d70ee43f5f9b979fcde3c797f2a
+
+nix:
+  shell-file: nix/stack-shell.nix