3410: Add replication attributes (and rules about updating them) to model and docs.

[arvados.git] / sdk / python / tests / run_test_server.py

diff --git a/sdk/python/tests/run_test_server.py b/sdk/python/tests/run_test_server.py
index b5536da77c072653105935df69a2e350d8ddecd5..5fee9eb0ec193d0cd4c3496480bf8b103727ea80 100644 (file)
--- a/sdk/python/tests/run_test_server.py
+++ b/sdk/python/tests/run_test_server.py
@@ -9,6 +9,7 @@ import random
 import re
 import shutil
 import signal
+import socket
 import subprocess
 import string
 import sys
@@ -94,28 +95,22 @@ def kill_server_pid(pidfile, wait=10, passenger_root=False):
         pass
 
 def find_available_port():
-    """Return a port number that is not in use right now.
+    """Return an IPv4 port number that is not in use right now.
+
+    We assume whoever needs to use the returned port is able to reuse
+    a recently used port without waiting for TIME_WAIT (see
+    SO_REUSEADDR / SO_REUSEPORT).
 
     Some opportunity for races here, but it's better than choosing
     something at random and not checking at all. If all of our servers
     (hey Passenger) knew that listening on port 0 was a thing, the OS
     would take care of the races, and this wouldn't be needed at all.
     """
-    port = None
-    while port is None:
-        port = random.randint(20000, 40000)
-        port_hex = ':%04x ' % port
-        try:
-            with open('/proc/net/tcp', 'r') as f:
-                for line in f:
-                    if 0 <= string.find(line, port_hex):
-                        port = None
-                        break
-        except OSError:
-            # This isn't going so well. Just use the random port.
-            pass
-        except IOError:
-            pass
+
+    sock = socket.socket()
+    sock.bind(('0.0.0.0', 0))
+    port = sock.getsockname()[1]
+    sock.close()
     return port
 
 def run(leave_running_atexit=False):
@@ -143,19 +138,22 @@ def run(leave_running_atexit=False):
 
     existing_api_host = os.environ.get('ARVADOS_TEST_API_HOST', my_api_host)
     if existing_api_host and pid_file_ok:
-        try:
-            reset()
-            return
-        except:
-            pass
+        if existing_api_host == my_api_host:
+            try:
+                return reset()
+            except:
+                # Fall through to shutdown-and-start case.
+                pass
+        else:
+            # Server was provided by parent. Can't recover if it's
+            # unresettable.
+            return reset()
 
     # Before trying to start up our own server, call stop() to avoid
     # "Phusion Passenger Standalone is already running on PID 12345".
-    # We want to kill it if it's our own _or_ it's some stale
-    # left-over server. But if it's been deliberately provided to us
-    # by a parent process, we don't want to force-kill it. That'll
-    # just wreck things for the next test suite that tries to use it.
-    stop(force=('ARVADOS_TEST_API_HOST' not in os.environ))
+    # (If we've gotten this far, ARVADOS_TEST_API_HOST isn't set, so
+    # we know the server is ours to kill.)
+    stop(force=True)
 
     restore_cwd = os.getcwd()
     api_src_dir = os.path.join(SERVICES_SRC_DIR, 'api')
@@ -177,7 +175,8 @@ def run(leave_running_atexit=False):
             '-out', 'tmp/self-signed.pem',
             '-keyout', 'tmp/self-signed.key',
             '-days', '3650',
-            '-subj', '/CN=0.0.0.0'])
+            '-subj', '/CN=0.0.0.0'],
+        stdout=sys.stderr)
 
     port = find_available_port()
     env = os.environ.copy()