Patch for race condition with filesystem and process cleanup

api/src/job.js

@@ -219,9 +219,14 @@ class Job {
 
             for (const file of contents) {
                 const file_path = path.join(clean_path, file);
-                const stat = await fs.stat(file_path);
+                try{
-                if(stat.uid == this.uid)
+                    const stat = await fs.stat(file_path);
-                    await fs.rm(file_path,  { recursive: true, force: true });
+                    if(stat.uid == this.uid)
+                        await fs.rm(file_path,  { recursive: true, force: true });
+                }catch(e){
+                    // File was somehow deleted in the time that we read the dir to when we checked the file
+                    logger.warn(`Error removing file ${file_path}: ${e}`)
+                }
             }
 
         }

tests/multi_request.py

@@ -0,0 +1,49 @@
+"""
+    Description
+        Running multiple requests in parallel can cause the whole container to crash.
+        This happens due to a race condition within the cleanup, where killing the
+        process removes the file, but before this happens we have already marked 
+        the file for deletion
+    
+    Resolution
+        Catching any errors resulting from individual file deletes in the
+        filesystem cleanup.
+    
+"""
+import aiohttp
+import asyncio
+
+def get_request_data(message):
+    return {
+        'language': 'java',
+        'version': '15.0.2',
+        'files': [
+            {
+                'name': 'Test.java',
+                'content': 'public class HelloWorld { public static void main(String[] args) { System.out.print("' + message + '"); }}'
+            }
+        ],
+        'stdin': '',
+        'args': [],
+        'compile_timeout': 10000,
+        'run_timeout': 3000
+    }
+
+async def post_request(session, data):
+    async with session.post('http://127.0.0.1:2000/api/v2/execute', json=data) as resp:
+        response = await resp.json()
+        return response
+
+async def run_many_requests(number):
+    async with aiohttp.ClientSession() as session:
+        tasks = []
+        for i in range(number):
+            request_data = get_request_data(f"Request #{i}")
+            tasks.append(asyncio.ensure_future(post_request(session, request_data)))
+
+        results = await asyncio.gather(*tasks)
+        for result in results:
+            print(result)
+            
+
+asyncio.run(run_many_requests(5))