Use tmpdir for coordination file

pyproject.toml

@@ -27,6 +27,7 @@ dependencies = [
     "tomlkit>=0.14.0",
     "pillow>=11.0,<12.0", # compatibility with mflux
     "mflux==0.15.5",
+    "python-multipart>=0.0.21",
     "msgspec>=0.19.0",
     "zstandard>=0.23.0",
 ]

src/exo/worker/engines/mlx/utils_mlx.py

@@ -2,6 +2,7 @@ import json
 import os
 import re
 import sys
+import tempfile
 import time
 from pathlib import Path
 from typing import Any, cast
@@ -98,14 +99,13 @@ def mlx_distributed_init(
     rank = bound_instance.bound_shard.device_rank
     logger.info(f"Starting initialization for rank {rank}")
 
-    coordination_file = None
-    try:
+    with tempfile.TemporaryDirectory() as tmpdir:
+        coordination_file = str(
+            Path(tmpdir) / f"hosts_{bound_instance.instance.instance_id}_{rank}.json"
+        )
         # TODO: singleton instances
         match bound_instance.instance:
             case MlxRingInstance(hosts_by_node=hosts_by_node, ephemeral_port=_):
-                coordination_file = (
-                    f"./hosts_{bound_instance.instance.instance_id}_{rank}.json"
-                )
                 hosts_for_node = hosts_by_node[bound_instance.bound_node_id]
                 hosts_json = HostList.from_hosts(hosts_for_node).model_dump_json()
 
@@ -128,9 +128,6 @@ def mlx_distributed_init(
                     jaccl_devices[i][i] is None for i in range(len(jaccl_devices))
                 )
                 # Use RDMA connectivity matrix
-                coordination_file = (
-                    f"./hosts_{bound_instance.instance.instance_id}_{rank}.json"
-                )
                 jaccl_devices_json = json.dumps(jaccl_devices)
 
                 with open(coordination_file, "w") as f:
@@ -150,10 +147,6 @@ def mlx_distributed_init(
         logger.info(f"Rank {rank} mlx distributed initialization complete")
 
         return group
-    finally:
-        with contextlib.suppress(FileNotFoundError):
-            if coordination_file:
-                os.remove(coordination_file)
 
 
 def initialize_mlx(

uv.lock

@@ -385,6 +385,7 @@ dependencies = [
     { name = "pillow", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "psutil", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "pydantic", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
+    { name = "python-multipart", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "rustworkx", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "tiktoken", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
     { name = "tomlkit", marker = "sys_platform == 'darwin' or sys_platform == 'linux'" },
@@ -423,6 +424,7 @@ requires-dist = [
     { name = "pillow", specifier = ">=11.0,<12.0" },
     { name = "psutil", specifier = ">=7.0.0" },
     { name = "pydantic", specifier = ">=2.11.7" },
+    { name = "python-multipart", specifier = ">=0.0.21" },
     { name = "rustworkx", specifier = ">=0.17.1" },
     { name = "tiktoken", specifier = ">=0.12.0" },
     { name = "tomlkit", specifier = ">=0.14.0" },
@@ -1882,6 +1884,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/ec/57/56b9bcc3c9c6a792fcbaf139543cee77261f3651ca9da0c93f5c1221264b/python_dateutil-2.9.0.post0-py2.py3-none-any.whl", hash = "sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427", size = 229892, upload-time = "2024-03-01T18:36:18.57Z" },
 ]
 
+[[package]]
+name = "python-multipart"
+version = "0.0.21"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/78/96/804520d0850c7db98e5ccb70282e29208723f0964e88ffd9d0da2f52ea09/python_multipart-0.0.21.tar.gz", hash = "sha256:7137ebd4d3bbf70ea1622998f902b97a29434a9e8dc40eb203bbcf7c2a2cba92", size = 37196, upload-time = "2025-12-17T09:24:22.446Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/aa/76/03af049af4dcee5d27442f71b6924f01f3efb5d2bd34f23fcd563f2cc5f5/python_multipart-0.0.21-py3-none-any.whl", hash = "sha256:cf7a6713e01c87aa35387f4774e812c4361150938d20d232800f75ffcf266090", size = 24541, upload-time = "2025-12-17T09:24:21.153Z" },
+]
+
 [[package]]
 name = "pyyaml"
 version = "6.0.3"