If we fail to reload Nginx, write to temporary files instead of pipin…

…g output (#4333) (#4400)

Due to issues with piping and Nginx on Arch.
(cherry picked from commit 5fa2080)

certbot-nginx/certbot_nginx/configurator.py

@@ -5,6 +5,7 @@
 import shutil
 import socket
 import subprocess
+import tempfile
 import time
 
 import OpenSSL
@@ -829,22 +830,22 @@ def nginx_restart(nginx_ctl, nginx_conf="/etc/nginx.conf"):
 
     """
     try:
-        proc = subprocess.Popen([nginx_ctl, "-c", nginx_conf, "-s", "reload"],
-                                stdout=subprocess.PIPE,
-                                stderr=subprocess.PIPE)
-        stdout, stderr = proc.communicate()
+        proc = subprocess.Popen([nginx_ctl, "-c", nginx_conf, "-s", "reload"])
+        proc.communicate()
 
         if proc.returncode != 0:
             # Maybe Nginx isn't running
-            nginx_proc = subprocess.Popen([nginx_ctl, "-c", nginx_conf],
-                                          stdout=subprocess.PIPE,
-                                          stderr=subprocess.PIPE)
-            stdout, stderr = nginx_proc.communicate()
-
-            if nginx_proc.returncode != 0:
-                # Enter recovery routine...
-                raise errors.MisconfigurationError(
-                    "nginx restart failed:\n%s\n%s" % (stdout, stderr))
+            # Write to temporary files instead of piping because of communication issues on Arch
+            # https://github.com/certbot/certbot/issues/4324
+            with tempfile.TemporaryFile() as out:
+                with tempfile.TemporaryFile() as err:
+                    nginx_proc = subprocess.Popen([nginx_ctl, "-c", nginx_conf],
+                        stdout=out, stderr=err)
+                    nginx_proc.communicate()
+                    if nginx_proc.returncode != 0:
+                        # Enter recovery routine...
+                        raise errors.MisconfigurationError(
+                            "nginx restart failed:\n%s\n%s" % (out.read(), err.read()))
 
     except (OSError, ValueError):
         raise errors.MisconfigurationError("nginx restart failed")