CI: Use nixbuild.net

The build takes place on the remote, which takes advantage of Nix's
caching.
The previous workflow used a remote cache but in order to build locally,
all the dependencies needed to be downloaded from the cache everytime.
The dependencies are 462M, downloading took most of the time.

1 files changed, 24 insertions, 8 deletions

diff --git a/shell.nix b/shell.nix
index 8036a5e..1ee5012 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,19 +1,35 @@
 { pkgs ? import <nixpkgs> {
-    config.android_sdk.accept_license = true;
-    config.allowUnfree = true;
-  } }:
+  config.android_sdk.accept_license = true;
+  config.allowUnfree = true;
+} }:
 
 let
-  jdk = pkgs.openjdk8;
-
   android = pkgs.androidenv.composeAndroidPackages {
     buildToolsVersions = [ "30.0.3" ];
     platformVersions = [ "30" ];
     abiVersions = [ "armeabi-v7a" ];
   };
 
-in
-pkgs.mkShell {
-  buildInputs = [ pkgs.findutils jdk android.androidsdk pkgs.fontforge ];
+  buildInputs =
+    [ pkgs.findutils pkgs.openjdk8 android.androidsdk pkgs.fontforge ];
+
+  # Env variable required by the Makefile
   ANDROID_HOME = "${android.androidsdk}/libexec/android-sdk";
+
+  # Build the debug APK. Exposed as an attribute, used in CI
+  debug-apk = pkgs.stdenv.mkDerivation {
+    name = "unexpected-keyboard-debug";
+    src = ./.;
+    inherit buildInputs ANDROID_HOME;
+    buildPhase = ''
+      make
+    '';
+    installPhase = ''
+      mkdir -p $out
+      mv _build/*.apk $out
+    '';
+  };
+
+in pkgs.mkShell { inherit buildInputs ANDROID_HOME; } // {
+  inherit debug-apk;
 }