lib: add escape-hatch exporting mechanism

1 files changed, 36 insertions, 0 deletions

diff --git a/nix/lib.nix b/nix/lib.nix
index e152df9..179223b 100644
--- a/nix/lib.nix
+++ b/nix/lib.nix
@@ -84,6 +84,42 @@ rec {
       }) // { inherit policies preferences; };
     in wrapped;
 
+  # This attempts to provide a start for deploying Nix-configured profiles to
+  # systems which do not have Nix installed, and where /nix/store is undesired.
+  # It does this by bundling all referenced store items into $out, and rewriting
+  # references to those store items.
+  export = { selfPath, policies ? {}, preferences ? {} }: pkgs.stdenv.mkDerivation rec {
+    name = "firefox-profile-export";
+    nativeBuildInputs = [ pkgs.jq ];
+
+    allowedRequisites = [];
+
+    buildCommand =
+      let
+        policyFile = mkPolicies policies;
+        prefsFile = mkPrefs preferences;
+
+        closure = pkgs.closureInfo {
+          rootPaths = [
+            policyFile prefsFile
+          ];
+        };
+      in ''
+      mkdir $out $out/store
+
+      storePaths=$(cat ${closure}/store-paths)
+      for p in $storePaths; do
+        cp -a "$p" $out/store/"$(basename "$p" | sed -e 's|\([a-z0-9]\{32\}\)-||')"
+      done
+
+      mv $out/store/prefs.js $out/
+      jq < $out/store/policies.json > $out/policies.json
+
+      find $out -type f -print0 |
+        xargs -0I{} -- sed -i -e "s|$NIX_STORE/\\([a-z0-9]\{32\}\\)-|${selfPath}/store/|g" "{}"
+    '';
+  };
+
   launcher = firefox: pkgs.writeShellScriptBin "firefox" ''
     # FF doesn't accept ro profiles, tries to create lockfile
     TMP_PROFILE="$(mktemp -d)"