feat(dwg): switch to ODA File Converter (libredwg too unstable)

ODA File Converter handles all DWG versions reliably.
Uses xvfb for headless Qt operation in Docker.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dwg2dxf-api/app.py

@@ -1,6 +1,8 @@
-"""Minimal DWG-to-DXF conversion microservice via libredwg."""
+"""DWG-to-DXF conversion microservice via ODA File Converter."""
 
+import glob
 import os
+import shutil
 import subprocess
 import tempfile
 import uuid
@@ -11,15 +13,16 @@ app = Flask(__name__)
 
 MAX_FILE_SIZE = 100 * 1024 * 1024  # 100 MB
 
+# ODA File Converter installs here on Ubuntu
+ODA_BIN = "/usr/bin/ODAFileConverter"
+
 
 @app.route("/health", methods=["GET"])
 def health():
-    """Health check — verifies dwg2dxf binary is callable."""
-    try:
-        subprocess.run(["dwg2dxf", "--version"], capture_output=True, timeout=5)
-        return jsonify({"status": "ok", "dwg2dxf": "available"}), 200
-    except Exception as e:
-        return jsonify({"status": "error", "detail": str(e)}), 503
+    """Health check — verifies ODA File Converter is installed."""
+    if os.path.isfile(ODA_BIN) and os.access(ODA_BIN, os.X_OK):
+        return jsonify({"status": "ok", "converter": "ODAFileConverter"}), 200
+    return jsonify({"status": "error", "detail": "ODAFileConverter not found"}), 503
 
 
 @app.route("/convert", methods=["POST"])
@@ -38,11 +41,13 @@ def convert():
         c if c.isalnum() or c in "._-" else "_" for c in original_name
     )
 
-    tmp_dir = os.path.join(tempfile.gettempdir(), f"dwg-{uuid.uuid4().hex}")
-    os.makedirs(tmp_dir, exist_ok=True)
+    work_dir = os.path.join(tempfile.gettempdir(), f"dwg-{uuid.uuid4().hex}")
+    input_dir = os.path.join(work_dir, "in")
+    output_dir = os.path.join(work_dir, "out")
+    os.makedirs(input_dir, exist_ok=True)
+    os.makedirs(output_dir, exist_ok=True)
 
-    input_path = os.path.join(tmp_dir, safe_name)
-    output_path = input_path.rsplit(".", 1)[0] + ".dxf"
+    input_path = os.path.join(input_dir, safe_name)
 
     try:
         uploaded.save(input_path)
@@ -51,21 +56,30 @@ def convert():
         if file_size > MAX_FILE_SIZE:
             return jsonify({"error": f"File too large ({file_size} bytes)."}), 413
 
+        # ODA File Converter: input_dir output_dir version type recurse audit
+        # ACAD2018 = output DXF version, DXF = output format, 0 = no recurse, 1 = audit
         result = subprocess.run(
-            ["dwg2dxf", input_path],
+            [
+                "xvfb-run", "--auto-servernum", "--server-args=-screen 0 1x1x24",
+                ODA_BIN, input_dir, output_dir, "ACAD2018", "DXF", "0", "1",
+            ],
             capture_output=True,
             timeout=120,
         )
 
-        if not os.path.exists(output_path):
+        # Find the output DXF file
+        dxf_files = glob.glob(os.path.join(output_dir, "*.dxf"))
+        if not dxf_files:
             stderr = result.stderr.decode("utf-8", errors="replace")
-            return jsonify({
-                "error": f"Conversion failed: {stderr or 'no output file'}"
-            }), 500
+            stdout = result.stdout.decode("utf-8", errors="replace")
+            detail = stderr or stdout or "No output file produced"
+            return jsonify({"error": f"Conversion failed: {detail}"}), 500
 
+        dxf_path = dxf_files[0]
         dxf_name = safe_name.rsplit(".", 1)[0] + ".dxf"
+
         return send_file(
-            output_path,
+            dxf_path,
             mimetype="application/dxf",
             as_attachment=True,
             download_name=dxf_name,
@@ -78,15 +92,7 @@ def convert():
         return jsonify({"error": f"Unexpected error: {str(e)}"}), 500
 
     finally:
-        for f in os.listdir(tmp_dir):
-            try:
-                os.unlink(os.path.join(tmp_dir, f))
-            except OSError:
-                pass
-        try:
-            os.rmdir(tmp_dir)
-        except OSError:
-            pass
+        shutil.rmtree(work_dir, ignore_errors=True)
 
 
 if __name__ == "__main__":