Refactor SWIFT_HASH_PATH_SUFFIX to be in a config file. Adding new conf file /etc/swift/swift.conf

Author: David Goetz

doc/source/development_saio.rst

@@ -199,6 +199,12 @@ virtual machine will emulate running a four node Swift cluster.
         [filter:cache]
         use = egg:swift#memcache
 
+  #. Create `/etc/swift/swift.conf`::
+
+        [swift-hash]
+        # random unique string that can never change (DO NOT LOSE)
+        swift_hash_path_suffix = changeme
+
   #. Create `/etc/swift/account-server/1.conf`::
 
         [DEFAULT]

etc/swift.conf-sample

@@ -0,0 +1,3 @@
+[swift-hash]
+swift_hash_path_suffix = changeme
+

swift/common/daemon.py

@@ -45,6 +45,7 @@ def run(self, once=False, capture_stdout=True, capture_stderr=True):
             sys.stderr = utils.LoggerFileObject(self.logger)
 
         utils.drop_privileges(self.conf.get('user', 'swift'))
+        utils.validate_configuration()
 
         try:
             os.setsid()

swift/common/utils.py

@@ -31,7 +31,7 @@
 import ctypes.util
 import fcntl
 import struct
-from ConfigParser import ConfigParser
+from ConfigParser import ConfigParser, NoSectionError, NoOptionError
 from tempfile import mkstemp
 import cPickle as pickle
 
@@ -56,12 +56,25 @@
 # Used by hash_path to offer a bit more security when generating hashes for
 # paths. It simply appends this value to all paths; guessing the hash a path
 # will end up with would also require knowing this suffix.
-HASH_PATH_SUFFIX = os.environ.get('SWIFT_HASH_PATH_SUFFIX', 'endcap')
+hash_conf = ConfigParser()
+HASH_PATH_SUFFIX = ''
+if hash_conf.read('/etc/swift/swift.conf'):
+    try:
+        HASH_PATH_SUFFIX = hash_conf.get('swift-hash',
+                                         'swift_hash_path_suffix')
+    except (NoSectionError, NoOptionError):
+        pass
 
 # Used when reading config values
 TRUE_VALUES = set(('true', '1', 'yes', 'True', 'Yes', 'on', 'On'))
 
 
+def validate_configuration():
+    if HASH_PATH_SUFFIX == '':
+        sys.exit("Error: [swift-hash]: swift_hash_path_suffix missing "
+                 "from /etc/swift/swift.conf")
+
+
 def load_libc_function(func_name):
     """
     Attempt to find the function in libc, otherwise return a no-op func.

swift/common/wsgi.py

@@ -34,7 +34,7 @@
 from eventlet.green import socket, ssl
 
 from swift.common.utils import get_logger, drop_privileges, \
-    LoggerFileObject, NullLogger
+    validate_configuration, LoggerFileObject, NullLogger
 
 
 def monkey_patch_mimetools():
@@ -112,6 +112,7 @@ def run_wsgi(conf_file, app_section, *args, **kwargs):   # pragma: no cover
     sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 600)
     worker_count = int(conf.get('workers', '1'))
     drop_privileges(conf.get('user', 'swift'))
+    validate_configuration()
 
     def run_server():
         wsgi.HttpProtocol.default_request_version = "HTTP/1.0"