feat(dwg): DWG→DXF via sidecar microservice (libredwg)

Add dedicated dwg2dxf container (Debian slim + libredwg-tools + Flask)
instead of modifying the Alpine base image. The ArchiTools API route
proxies to the sidecar over Docker internal network.

- dwg2dxf-api/: Dockerfile + Flask app (POST /convert, GET /health)
- docker-compose.yml: dwg2dxf service, healthcheck, depends_on
- route.ts: rewritten from local exec to HTTP proxy
- .dockerignore: exclude sidecar from main build context

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

src/app/api/dwg-convert/route.ts

@@ -1,18 +1,12 @@
 import { NextRequest, NextResponse } from "next/server";
-import { writeFile, readFile, unlink, mkdir } from "fs/promises";
-import { exec } from "child_process";
-import { promisify } from "util";
-import { randomUUID } from "crypto";
-import { join } from "path";
-import { tmpdir } from "os";
 
-const execAsync = promisify(exec);
+const DWG2DXF_URL = process.env.DWG2DXF_URL ?? "http://localhost:5001";
 
 export async function POST(req: NextRequest) {
-  const tmpDir = join(tmpdir(), `dwg-${randomUUID()}`);
   try {
     const formData = await req.formData();
     const file = formData.get("fileInput") as File | null;
+
     if (!file) {
       return NextResponse.json(
         { error: "Lipsește fișierul DWG." },
@@ -28,20 +22,29 @@ export async function POST(req: NextRequest) {
       );
     }
 
-    await mkdir(tmpDir, { recursive: true });
+    // Re-package for sidecar (field name: "file")
+    const sidecarForm = new FormData();
+    sidecarForm.append("file", file, name);
 
-    const inputPath = join(tmpDir, name);
-    const outputPath = inputPath.replace(/\.dwg$/i, ".dxf");
+    const res = await fetch(`${DWG2DXF_URL}/convert`, {
+      method: "POST",
+      body: sidecarForm,
+    });
 
-    const buffer = Buffer.from(await file.arrayBuffer());
-    await writeFile(inputPath, buffer);
+    if (!res.ok) {
+      const data = await res.json().catch(() => ({ error: res.statusText }));
+      const errorMsg =
+        typeof data === "object" && data !== null && "error" in data
+          ? String((data as Record<string, unknown>).error)
+          : `Eroare sidecar DWG: ${res.status}`;
+      return NextResponse.json({ error: errorMsg }, { status: res.status });
+    }
 
-    await execAsync(`dwg2dxf "${inputPath}"`, { timeout: 60_000 });
-
-    const dxfBuffer = await readFile(outputPath);
+    const blob = await res.blob();
+    const buffer = Buffer.from(await blob.arrayBuffer());
     const dxfName = name.replace(/\.dwg$/i, ".dxf");
 
-    return new NextResponse(dxfBuffer, {
+    return new NextResponse(buffer, {
       status: 200,
       headers: {
         "Content-Type": "application/dxf",
@@ -50,35 +53,24 @@ export async function POST(req: NextRequest) {
     });
   } catch (err) {
     const message = err instanceof Error ? err.message : "Unknown error";
+
     if (
-      message.includes("ENOENT") ||
-      message.includes("not found") ||
-      message.includes("not recognized")
+      message.includes("ECONNREFUSED") ||
+      message.includes("fetch failed") ||
+      message.includes("ENOTFOUND")
     ) {
       return NextResponse.json(
         {
           error:
-            "Conversia DWG→DXF este disponibilă doar pe server (Docker). Local nu este instalat dwg2dxf (libredwg).",
+            "Serviciul de conversie DWG nu este disponibil. Verificați că containerul dwg2dxf este pornit.",
         },
-        { status: 501 },
+        { status: 503 },
       );
     }
+
     return NextResponse.json(
       { error: `Eroare la conversie DWG→DXF: ${message}` },
       { status: 500 },
     );
-  } finally {
-    // Clean up temp files
-    try {
-      const { readdir } = await import("fs/promises");
-      const files = await readdir(tmpDir);
-      for (const f of files) {
-        await unlink(join(tmpDir, f)).catch(() => {});
-      }
-      const { rmdir } = await import("fs/promises");
-      await rmdir(tmpDir).catch(() => {});
-    } catch {
-      // temp cleanup failure is non-critical
-    }
   }
 }