drawio-headless: extract from pandoc-drawio-filter

This wrapper is useful independently of pandoc-drawio-filter — it's
useful in any other situation in which somebody might want to use
draw.io diagrams in a build process.

So, make it accessible from the top level to facilitate reuse.

pkgs/applications/graphics/drawio/headless.nix

@@ -0,0 +1,36 @@
+{ lib, writeTextFile, runtimeShell, drawio, xvfb-run }:
+
+writeTextFile {
+  name = "${drawio.pname}-headless-${drawio.version}";
+
+  executable = true;
+  destination = "/bin/drawio";
+  text = ''
+    #!${runtimeShell}
+
+    # Electron really wants a configuration directory to not die with:
+    # "Error: Failed to get 'appData' path"
+    # so we give it some temp dir as XDG_CONFIG_HOME
+    tmpdir=$(mktemp -d)
+
+    function cleanup {
+      rm -rf "$tmpdir"
+    }
+    trap cleanup EXIT
+
+    # Drawio needs to run in a virtual X session, because Electron
+    # refuses to work and dies with an unhelpful error message otherwise:
+    # "The futex facility returned an unexpected error code."
+    XDG_CONFIG_HOME="$tmpdir" ${xvfb-run}/bin/xvfb-run ${drawio}/bin/drawio $@
+  '';
+
+  meta = with lib; {
+    description = "xvfb wrapper around drawio";
+    longDescription = ''
+      A wrapper around drawio for running in headless environments.
+      Runs drawio under xvfb-run, with configuration going to a temporary
+      directory.
+    '';
+    maintainers = with maintainers; [ qyliss tfc ];
+  };
+}

pkgs/tools/misc/pandoc-drawio-filter/default.nix

@@ -1,5 +1,5 @@
 { buildPythonApplication
-, drawio
+, drawio-headless
 , fetchFromGitHub
 , lib
 , pandoc
@@ -21,32 +21,13 @@ let
     sha256 = "sha256-2XJSAfxqEmmamWIAM3vZqi0mZjUUugmR3zWw8Imjadk=";
   };
 
-  wrappedDrawio = writeScriptBin "drawio" ''
-    #!${runtimeShell}
-
-    # Electron really wants a configuration directory to not die with:
-    # "Error: Failed to get 'appData' path"
-    # so we give it some temp dir as XDG_CONFIG_HOME
-    tmpdir=$(mktemp -d)
-
-    function cleanup {
-      rm -rf "$tmpdir"
-    }
-    trap cleanup EXIT
-
-    # Drawio needs to run in a virtual X session, because Electron
-    # refuses to work and dies with an unhelpful error message otherwise:
-    # "The futex facility returned an unexpected error code."
-    XDG_CONFIG_HOME="$tmpdir" ${xvfb-run}/bin/xvfb-run ${drawio}/bin/drawio $@
-  '';
-
   pandoc-drawio-filter = buildPythonApplication {
     pname = "pandoc-drawio-filter";
 
     inherit src version;
 
     propagatedBuildInputs = [
-      wrappedDrawio
+      drawio-headless
       pandocfilters
     ];
 

pkgs/top-level/all-packages.nix

@@ -25860,6 +25860,7 @@ with pkgs;
   drawing = callPackage ../applications/graphics/drawing { };
 
   drawio = callPackage ../applications/graphics/drawio {};
+  drawio-headless = callPackage ../applications/graphics/drawio/headless.nix { };
 
   drawpile = libsForQt5.callPackage ../applications/graphics/drawpile { };
   drawpile-server-headless = libsForQt5.callPackage ../applications/graphics/drawpile {