Improve support for Python 3.

This fixes the messages shown in #97 but does not mean there is proper Python 3 support in all used libraries.

.travis.yml

@@ -2,6 +2,13 @@ language: python
 
 python:
   - "2.7"
+# The way the selection of the Python version is currently made in Makefile
+# leads to travis always picking up Python 2 for the task.
+# All versions of Python are appearantly present in a travis environment.
+# Once the makefile has been adjusted the following lines should be enabled.
+#  - "3.5"
+#  - "3.6"
+#  - "3.7-dev"
 
 notifications:
   email:

Makefile

@@ -1,3 +1,8 @@
+# Once there is Python 3 support in this package and it's dependencies
+# the detection of the used Python version should be changed.
+# The following line prefers `python` as this will allow this to work
+# in CI (e.g. Travis CI) and put up the configured Python version:
+# SYSTEMPYTHON = `which python python3 python2 | head -n 1`
 SYSTEMPYTHON = `which python2 python | head -n 1`
 VIRTUALENV = virtualenv --python=$(SYSTEMPYTHON)
 ENV = ./local

syncserver.wsgi

@@ -6,7 +6,10 @@ import os
 import sys
 import site
 from logging.config import fileConfig
-from ConfigParser import NoSectionError
+try:
+    from ConfigParser import NoSectionError
+except ImportError:
+    from configparser import NoSectionError
 
 # detecting if virtualenv was used in this dir
 _CURDIR = os.path.dirname(os.path.abspath(__file__))

syncserver/__init__.py

@@ -2,9 +2,13 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import binascii
 import os
 import logging
-from urlparse import urlparse, urlunparse, urljoin
+try:
+    from urlparse import urlparse, urlunparse, urljoin
+except ImportError:
+    from urllib.parse import urlparse, urlunparse, urljoin
 
 import requests
 
@@ -31,7 +35,7 @@ def includeme(config):
     """Install SyncServer application into the given Pyramid configurator."""
     # Set the umask so that files are created with secure permissions.
     # Necessary for e.g. created-on-demand sqlite database files.
-    os.umask(0077)
+    os.umask(0o077)
 
     # If PyOpenSSL is available, configure requests to use it.
     # This helps improve security on older python versions.
@@ -50,7 +54,7 @@ def includeme(config):
 
     secret = settings.get("syncserver.secret")
     if secret is None:
-        secret = os.urandom(32).encode("hex")
+        secret = generate_random_hex_key(64)
     sqluri = settings.get("syncserver.sqluri")
     if sqluri is None:
         rootdir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
@@ -138,7 +142,7 @@ def includeme(config):
         # Default to a randomly-generated secret.
         # This setting isn't useful in a self-hosted setup
         # and setting a default avoids scary-sounding warnings.
-        settings["fxa.metrics_uid_secret_key"] = os.urandom(16).encode("hex")
+        settings["fxa.metrics_uid_secret_key"] = generate_random_hex_key(32)
 
     # Include the relevant sub-packages.
     config.scan("syncserver", ignore=["syncserver.wsgi_app"])
@@ -197,6 +201,10 @@ def str_to_bool(value):
     raise ValueError("unable to parse boolean from %r" % (value,))
 
 
+def generate_random_hex_key(length):
+    return binascii.hexlify(os.urandom(length // 2))
+
+
 @subscriber(NewRequest)
 def reconcile_wsgi_environ_with_public_url(event):
     """Event-listener that checks and tweaks WSGI environ based on public_url.

syncserver/staticnode.py

@@ -10,7 +10,12 @@ are implicitly assigned to a single, static node.
 
 """
 import time
-import urlparse
+
+try:
+    from urlparse import urlparse
+except ImportError:
+    from urllib.parse import urlparse
+
 from mozsvc.exceptions import BackendError
 
 from sqlalchemy import Column, Integer, String, BigInteger, Index
@@ -98,7 +103,7 @@ class StaticNodeAssignment(object):
     def __init__(self, sqluri, node_url, **kw):
         self.sqluri = sqluri
         self.node_url = node_url
-        self.driver = urlparse.urlparse(sqluri).scheme.lower()
+        self.driver = urlparse(sqluri).scheme.lower()
         sqlkw = {
             "logging_name": "syncserver",
             "connect_args": {},
@@ -111,7 +116,7 @@ class StaticNodeAssignment(object):
             sqlkw["connect_args"]["check_same_thread"] = False
             # If using a :memory: database, we must use a QueuePool of
             # size 1 so that a single connection is shared by all threads.
-            if urlparse.urlparse(sqluri).path.lower() in ("/", "/:memory:"):
+            if urlparse(sqluri).path.lower() in ("/", "/:memory:"):
                 sqlkw["pool_size"] = 1
                 sqlkw["max_overflow"] = 0
         if "mysql" in self.driver: