move example unikernel building from shell.nix to example.nix

Author: mazunki

example.nix

@@ -1,12 +1,24 @@
-{ withCcache ? false,
+{
 
-  doCheck ? true, # boot unikernel after building it
-  includeos ? import ./default.nix { inherit withCcache; },
+  # The unikernel to build
+  unikernel ? ./example,
+
+  # Boot unikernel after building it
+  doCheck ? true,
+
+  # Enable multicore suport.
+  smp ? false,
+
+  # Enable ccache support. See overlay.nix for details.
+  withCcache ? false,
+
+  # The includeos library to build and link against
+  includeos ? import ./default.nix { inherit withCcache; inherit smp; },
 }:
 
 includeos.stdenv.mkDerivation rec {
   pname = "includeos_example";
-  src = includeos.pkgs.lib.cleanSource ./example;
+  src = includeos.pkgs.lib.cleanSource "${unikernel}";
   dontStrip = true;
   inherit doCheck;
 
@@ -20,13 +32,22 @@ includeos.stdenv.mkDerivation rec {
     includeos.chainloader
   ];
 
+  cmakeFlags = [
+    "-DARCH=x86_64"
+    "-DINCLUDEOS_PACKAGE=${includeos}"
+    "-DCMAKE_MODULE_PATH=${includeos}/cmake"
+    "-DFOR_PRODUCTION=OFF"
+  ];
+
   nativeCheckInputs = [
     includeos.vmrunner
     includeos.pkgs.qemu
   ];
 
   checkPhase = ''
+    runHook preCheck
     boot *.elf.bin
+    runHook postCheck
   '';
 
   version = "dev";

shell.nix

@@ -3,9 +3,6 @@
   # nix-shell --argstr buildpath .
   buildpath ? "",
 
-  # The unikernel to build
-  unikernel ? "./example",
-
   # vmrunner path, for vmrunner development
   vmrunner ? "",
 
@@ -16,7 +13,6 @@
   smp ? false,
 
   includeos ? import ./default.nix { inherit withCcache; inherit smp; }
-
 }:
 
 includeos.pkgs.mkShell.override { inherit (includeos) stdenv; } rec {
@@ -48,31 +44,7 @@ includeos.pkgs.mkShell.override { inherit (includeos) stdenv; } rec {
   ];
 
   shellHook = ''
-
-    unikernel=$(realpath ${unikernel})
-    echo -e "Attempting to build unikernel: \n$unikernel"
-    if [ ! -d "$unikernel" ]; then
-        echo "$unikernel is not a valid directory"
-        exit 1
-    fi
-    export BUILDPATH=${buildpath}
-    if [ -z "${buildpath}" ]; then
-        export BUILDPATH="$(mktemp -d)"
-        pushd "$BUILDPATH"
-    else
-        mkdir -p "$BUILDPATH"
-        pushd "$BUILDPATH"
-    fi
-    cmake "$unikernel" -DARCH=x86_64 -DINCLUDEOS_PACKAGE=${includeos} -DCMAKE_MODULE_PATH=${includeos}/cmake \
-                     -DFOR_PRODUCTION=OFF
-    make -j $NIX_BUILD_CORES
     echo -e "\n====================== IncludeOS nix-shell ====================="
-    if [ -z "${buildpath}" ]; then
-        echo -e "\nWorking directory, generated by this script:"
-        echo $BUILDPATH
-        echo -e "\nTo use another directory pass in 'buildpath' to nix:"
-        echo "nix-shell --argstr buildpath you/build/path"
-    fi
     echo -e "\nThe C++ compiler set to:"
     echo $(which $CXX)
     echo -e "\nIncludeOS package:"