Make sure the ZEO 5 client works with the ZEO 4 server

Added an option to test the ZEO 5 client against the ZEO 4
server. This involved making a copy of the ZEO 4 server in
ZEO.tests.ZEO4 and disabling tests of ZEO5-specific features.

Testing revealed bugs in support for ZEO 4 servers, which were fixed.

.travis.yml

@@ -14,6 +14,15 @@ matrix:
         - os: linux
           python: 3.5
           env: ZEO_MTACCEPTOR=1
+        - os: linux
+          python: 2.7
+          env: ZEO4_SERVER=1
+        - os: linux
+          python: 3.4
+          env: ZEO4_SERVER=1
+        - os: linux
+          python: 3.5
+          env: ZEO4_SERVER=1
 install:
     - pip install -U setuptools
     - python bootstrap.py

src/ZEO/ClientStorage.py

@@ -949,8 +949,7 @@ class ClientStorage(ZODB.ConflictResolution.ConflictResolvingStorage):
     def serialnos(self, args):
         """Server callback to pass a list of changed (oid, serial) pairs.
         """
-        for oid, s in args:
-            self._tbuf.serial(oid, s)
+        self._tbuf.serialnos(args)
 
     def info(self, dict):
         """Server callback to update the info dictionary."""

src/ZEO/TransactionBuffer.py

@@ -92,3 +92,17 @@ class TransactionBuffer:
         for oid in server_resolved:
             if oid not in seen:
                 yield oid, None, True
+
+
+    # Support ZEO4:
+
+    def serialnos(self, args):
+        for oid in args:
+            if isinstance(oid, bytes):
+                self.server_resolved.add(oid)
+            else:
+                oid, serial = oid
+                if isinstance(serial, Exception):
+                    self.exception = serial
+                elif serial == b'rs':
+                    self.server_resolved.add(oid)

src/ZEO/asyncio/client.py

@@ -599,13 +599,19 @@ class Client(object):
             self.cache.setLastTid(tid)
 
     def serialnos(self, serials):
+        # Method called by ZEO4 storage servers.
+
         # Before delegating, check for errors (likely ConflictErrors)
         # and invalidate the oids they're associated with.  In the
         # past, this was done by the client, but now we control the
         # cache and this is our last chance, as the client won't call
         # back into us when there's an error.
-        for oid, serial in serials:
-            if isinstance(serial, Exception):
+        for oid in serials:
+            if isinstance(oid, bytes):
+                self.cache.invalidate(oid, None)
+            else:
+                oid, serial = oid
+                if isinstance(serial, Exception) or serial == b'rs':
                     self.cache.invalidate(oid, None)
 
         self.client.serialnos(serials)

src/ZEO/tests/ZEO4/README.rst

+======================
+Copy of ZEO 4 server
+======================
+
+This copy was made by first converting the ZEO 4 server code to use
+relative imports.  The code was tested with ZEO 4 before copying.  It
+was unchanged aside from the relative imports.
+
+The ZEO 4 server is used for tests if the ZEO4_SERVER environment
+variable is set to a non-empty value.

src/ZEO/tests/ZEO4/__init__.py

+#

src/ZEO/tests/ZEO4/auth/__init__.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+
+_auth_modules = {}
+
+def get_module(name):
+    if name == 'sha':
+        from auth_sha import StorageClass, SHAClient, Database
+        return StorageClass, SHAClient, Database
+    elif name == 'digest':
+        from .auth_digest import StorageClass, DigestClient, DigestDatabase
+        return StorageClass, DigestClient, DigestDatabase
+    else:
+        return _auth_modules.get(name)
+
+def register_module(name, storage_class, client, db):
+    if name in _auth_modules:
+        raise TypeError("%s is already registred" % name)
+    _auth_modules[name] = storage_class, client, db

src/ZEO/tests/ZEO4/auth/auth_digest.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+"""Digest authentication for ZEO
+
+This authentication mechanism follows the design of HTTP digest
+authentication (RFC 2069).  It is a simple challenge-response protocol
+that does not send passwords in the clear, but does not offer strong
+security.  The RFC discusses many of the limitations of this kind of
+protocol.
+
+Guard the password database as if it contained plaintext passwords.
+It stores the hash of a username and password.  This does not expose
+the plaintext password, but it is sensitive nonetheless.  An attacker
+with the hash can impersonate the real user.  This is a limitation of
+the simple digest scheme.
+
+HTTP is a stateless protocol, and ZEO is a stateful protocol.  The
+security requirements are quite different as a result.  The HTTP
+protocol uses a nonce as a challenge.  The ZEO protocol requires a
+separate session key that is used for message authentication.  We
+generate a second nonce for this purpose; the hash of nonce and
+user/realm/password is used as the session key.
+
+TODO: I'm not sure if this is a sound approach; SRP would be preferred.
+"""
+
+import os
+import random
+import struct
+import time
+
+from .base import Database, Client
+from ..StorageServer import ZEOStorage
+from ZEO.Exceptions import AuthError
+from ..hash import sha1
+
+def get_random_bytes(n=8):
+    try:
+        b = os.urandom(n)
+    except NotImplementedError:
+        L = [chr(random.randint(0, 255)) for i in range(n)]
+        b = b"".join(L)
+    return b
+
+def hexdigest(s):
+    return sha1(s.encode()).hexdigest()
+
+class DigestDatabase(Database):
+    def __init__(self, filename, realm=None):
+        Database.__init__(self, filename, realm)
+
+        # Initialize a key used to build the nonce for a challenge.
+        # We need one key for the lifetime of the server, so it
+        # is convenient to store in on the database.
+        self.noncekey = get_random_bytes(8)
+
+    def _store_password(self, username, password):
+        dig = hexdigest("%s:%s:%s" % (username, self.realm, password))
+        self._users[username] = dig
+
+def session_key(h_up, nonce):
+    # The hash itself is a bit too short to be a session key.
+    # HMAC wants a 64-byte key.  We don't want to use h_up
+    # directly because it would never change over time.  Instead
+    # use the hash plus part of h_up.
+    return (sha1(("%s:%s" % (h_up, nonce)).encode('latin-1')).digest() +
+            h_up.encode('utf-8')[:44])
+
+class StorageClass(ZEOStorage):
+    def set_database(self, database):
+        assert isinstance(database, DigestDatabase)
+        self.database = database
+        self.noncekey = database.noncekey
+
+    def _get_time(self):
+        # Return a string representing the current time.
+        t = int(time.time())
+        return struct.pack("i", t)
+
+    def _get_nonce(self):
+        # RFC 2069 recommends a nonce of the form
+        # H(client-IP ":" time-stamp ":" private-key)
+        dig = sha1()
+        dig.update(str(self.connection.addr).encode('latin-1'))
+        dig.update(self._get_time())
+        dig.update(self.noncekey)
+        return dig.hexdigest()
+
+    def auth_get_challenge(self):
+        """Return realm, challenge, and nonce."""
+        self._challenge = self._get_nonce()
+        self._key_nonce = self._get_nonce()
+        return self.auth_realm, self._challenge, self._key_nonce
+
+    def auth_response(self, resp):
+        # verify client response
+        user, challenge, response = resp
+
+        # Since zrpc is a stateful protocol, we just store the nonce
+        # we sent to the client.  It will need to generate a new
+        # nonce for a new connection anyway.
+        if self._challenge != challenge:
+            raise ValueError("invalid challenge")
+
+        # lookup user in database
+        h_up = self.database.get_password(user)
+
+        # regeneration resp from user, password, and nonce
+        check = hexdigest("%s:%s" % (h_up, challenge))
+        if check == response:
+            self.connection.setSessionKey(session_key(h_up, self._key_nonce))
+        return self._finish_auth(check == response)
+
+    extensions = [auth_get_challenge, auth_response]
+
+class DigestClient(Client):
+    extensions = ["auth_get_challenge", "auth_response"]
+
+    def start(self, username, realm, password):
+        _realm, challenge, nonce = self.stub.auth_get_challenge()
+        if _realm != realm:
+            raise AuthError("expected realm %r, got realm %r"
+                            % (_realm, realm))
+        h_up = hexdigest("%s:%s:%s" % (username, realm, password))
+
+        resp_dig = hexdigest("%s:%s" % (h_up, challenge))
+        result = self.stub.auth_response((username, challenge, resp_dig))
+        if result:
+            return session_key(h_up, nonce)
+        else:
+            return None

src/ZEO/tests/ZEO4/auth/base.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+"""Base classes for defining an authentication protocol.
+
+Database -- abstract base class for password database
+Client -- abstract base class for authentication client
+"""
+from __future__ import print_function
+from __future__ import print_function
+
+import os
+from ..hash import sha1
+
+class Client:
+    # Subclass should override to list the names of methods that
+    # will be called on the server.
+    extensions = []
+
+    def __init__(self, stub):
+        self.stub = stub
+        for m in self.extensions:
+            setattr(self.stub, m, self.stub.extensionMethod(m))
+
+def sort(L):
+    """Sort a list in-place and return it."""
+    L.sort()
+    return L
+
+class Database:
+    """Abstracts a password database.
+
+    This class is used both in the authentication process (via
+    get_password()) and by client scripts that manage the password
+    database file.
+
+    The password file is a simple, colon-separated text file mapping
+    usernames to password hashes. The hashes are SHA hex digests
+    produced from the password string.
+    """
+    realm = None
+    def __init__(self, filename, realm=None):
+        """Creates a new Database
+
+        filename: a string containing the full pathname of
+            the password database file. Must be readable by the user
+            running ZEO. Must be writeable by any client script that
+            accesses the database.
+
+        realm: the realm name (a string)
+        """
+        self._users = {}
+        self.filename = filename
+        self.load()
+        if realm:
+            if self.realm and self.realm != realm:
+                raise ValueError("Specified realm %r differs from database "
+                                 "realm %r" % (realm or '', self.realm))
+            else:
+                self.realm = realm
+
+    def save(self, fd=None):
+        filename = self.filename
+        needs_closed = False
+        if not fd:
+            fd = open(filename, 'w')
+            needs_closed = True
+
+        try:
+            if self.realm:
+                print("realm", self.realm, file=fd)
+
+            for username in sorted(self._users.keys()):
+                print("%s: %s" % (username, self._users[username]), file=fd)
+        finally:
+            if needs_closed:
+                fd.close()
+
+    def load(self):
+        filename = self.filename
+        if not filename:
+            return
+
+        if not os.path.exists(filename):
+            return
+
+        with open(filename) as fd:
+            L = fd.readlines()
+
+        if not L:
+            return
+
+        if L[0].startswith("realm "):
+            line = L.pop(0).strip()
+            self.realm = line[len("realm "):]
+
+        for line in L:
+            username, hash = line.strip().split(":", 1)
+            self._users[username] = hash.strip()
+
+    def _store_password(self, username, password):
+        self._users[username] = self.hash(password)
+
+    def get_password(self, username):
+        """Returns password hash for specified username.
+
+        Callers must check for LookupError, which is raised in
+        the case of a non-existent user specified."""
+        if username not in self._users:
+            raise LookupError("No such user: %s" % username)
+        return self._users[username]
+
+    def hash(self, s):
+        return sha1(s.encode()).hexdigest()
+
+    def add_user(self, username, password):
+        if username in self._users:
+            raise LookupError("User %s already exists" % username)
+        self._store_password(username, password)
+
+    def del_user(self, username):
+        if username not in self._users:
+            raise LookupError("No such user: %s" % username)
+        del self._users[username]
+
+    def change_password(self, username, password):
+        if username not in self._users:
+            raise LookupError("No such user: %s" % username)
+        self._store_password(username, password)

src/ZEO/tests/ZEO4/auth/hmac.py

+"""HMAC (Keyed-Hashing for Message Authentication) Python module.
+
+Implements the HMAC algorithm as described by RFC 2104.
+"""
+from six.moves import map
+from six.moves import zip
+
+def _strxor(s1, s2):
+    """Utility method. XOR the two strings s1 and s2 (must have same length).
+    """
+    return "".join(map(lambda x, y: chr(ord(x) ^ ord(y)), s1, s2))
+
+# The size of the digests returned by HMAC depends on the underlying
+# hashing module used.
+digest_size = None
+
+class HMAC:
+    """RFC2104 HMAC class.
+
+    This supports the API for Cryptographic Hash Functions (PEP 247).
+    """
+
+    def __init__(self, key, msg = None, digestmod = None):
+        """Create a new HMAC object.
+
+        key:       key for the keyed hash object.
+        msg:       Initial input for the hash, if provided.
+        digestmod: A module supporting PEP 247. Defaults to the md5 module.
+        """
+        if digestmod is None:
+            import md5
+            digestmod = md5
+
+        self.digestmod = digestmod
+        self.outer = digestmod.new()
+        self.inner = digestmod.new()
+        self.digest_size = digestmod.digest_size
+
+        blocksize = 64
+        ipad = "\x36" * blocksize
+        opad = "\x5C" * blocksize
+
+        if len(key) > blocksize:
+            key = digestmod.new(key).digest()
+
+        key = key + chr(0) * (blocksize - len(key))
+        self.outer.update(_strxor(key, opad))
+        self.inner.update(_strxor(key, ipad))
+        if msg is not None:
+            self.update(msg)
+
+##    def clear(self):
+##        raise NotImplementedError("clear() method not available in HMAC.")
+
+    def update(self, msg):
+        """Update this hashing object with the string msg.
+        """
+        self.inner.update(msg)
+
+    def copy(self):
+        """Return a separate copy of this hashing object.
+
+        An update to this copy won't affect the original object.
+        """
+        other = HMAC("")
+        other.digestmod = self.digestmod
+        other.inner = self.inner.copy()
+        other.outer = self.outer.copy()
+        return other
+
+    def digest(self):
+        """Return the hash value of this hashing object.
+
+        This returns a string containing 8-bit data.  The object is
+        not altered in any way by this function; you can continue
+        updating the object after calling this function.
+        """
+        h = self.outer.copy()
+        h.update(self.inner.digest())
+        return h.digest()
+
+    def hexdigest(self):
+        """Like digest(), but returns a string of hexadecimal digits instead.
+        """
+        return "".join([hex(ord(x))[2:].zfill(2)
+                        for x in tuple(self.digest())])
+
+def new(key, msg = None, digestmod = None):
+    """Create a new hashing object and return it.
+
+    key: The starting key for the hash.
+    msg: if available, will immediately be hashed into the object's starting
+    state.
+
+    You can now feed arbitrary strings into the object using its update()
+    method, and can ask for the hash value at any time by calling its digest()
+    method.
+    """
+    return HMAC(key, msg, digestmod)

src/ZEO/tests/ZEO4/component.xml

+<component>
+
+  <sectiontype name="zeo">
+
+    <description>
+      The content of a ZEO section describe operational parameters
+      of a ZEO server except for the storage(s) to be served.
+    </description>
+
+    <key name="address" datatype="socket-binding-address"
+         required="yes">
+      <description>
+        The address at which the server should listen.  This can be in
+        the form 'host:port' to signify a TCP/IP connection or a
+        pathname string to signify a Unix domain socket connection (at
+        least one '/' is required).  A hostname may be a DNS name or a
+        dotted IP address.  If the hostname is omitted, the platform's
+        default behavior is used when binding the listening socket (''
+        is passed to socket.bind() as the hostname portion of the
+        address).
+      </description>
+    </key>
+
+    <key name="read-only" datatype="boolean"
+         required="no"
+         default="false">
+      <description>
+        Flag indicating whether the server should operate in read-only
+        mode.  Defaults to false.  Note that even if the server is
+        operating in writable mode, individual storages may still be
+        read-only.  But if the server is in read-only mode, no write
+        operations are allowed, even if the storages are writable.  Note
+        that pack() is considered a read-only operation.
+      </description>
+    </key>
+
+    <key name="invalidation-queue-size" datatype="integer"
+         required="no"
+         default="100">
+      <description>
+        The storage server keeps a queue of the objects modified by the
+        last N transactions, where N == invalidation_queue_size.  This
+        queue is used to speed client cache verification when a client
+        disconnects for a short period of time.
+      </description>
+    </key>
+
+    <key name="invalidation-age" datatype="float" required="no">
+      <description>
+        The maximum age of a client for which quick-verification
+        invalidations will be provided by iterating over the served
+        storage. This option should only be used if the served storage
+        supports efficient iteration from a starting point near the
+        end of the transaction history (e.g. end of file).
+      </description>
+    </key>
+
+    <key name="monitor-address" datatype="socket-binding-address"
+         required="no">
+      <description>
+        The address at which the monitor server should listen.  If
+        specified, a monitor server is started.  The monitor server
+        provides server statistics in a simple text format.  This can
+        be in the form 'host:port' to signify a TCP/IP connection or a
+        pathname string to signify a Unix domain socket connection (at
+        least one '/' is required).  A hostname may be a DNS name or a
+        dotted IP address.  If the hostname is omitted, the platform's
+        default behavior is used when binding the listening socket (''
+        is passed to socket.bind() as the hostname portion of the
+        address).
+      </description>
+    </key>
+
+    <key name="transaction-timeout" datatype="integer"
+         required="no">
+      <description>
+        The maximum amount of time to wait for a transaction to commit
+        after acquiring the storage lock, specified in seconds.  If the
+        transaction takes too long, the client connection will be closed
+        and the transaction aborted.
+      </description>
+    </key>
+
+    <key name="authentication-protocol" required="no">
+      <description>
+        The name of the protocol used for authentication.  The
+        only protocol provided with ZEO is "digest," but extensions
+        may provide other protocols.
+      </description>
+    </key>
+
+    <key name="authentication-database" required="no">
+      <description>
+        The path of the database containing authentication credentials.
+      </description>
+    </key>
+
+    <key name="authentication-realm" required="no">
+      <description>
+        The authentication realm of the server.  Some authentication
+        schemes use a realm to identify the logical set of usernames
+        that are accepted by this server.
+      </description>
+    </key>
+
+    <key name="pid-filename" datatype="existing-dirpath"
+         required="no">
+      <description>
+        The full path to the file in which to write the ZEO server's Process ID
+        at startup. If omitted, $INSTANCE/var/ZEO.pid is used.
+      </description>
+      <metadefault>$INSTANCE/var/ZEO.pid (or $clienthome/ZEO.pid)</metadefault>
+    </key>
+
+    <!-- DM 2006-06-12: added option -->
+    <key name="drop-cache-rather-verify" datatype="boolean"
+         required="no" default="false">
+       <description>
+         indicates that the cache should be dropped rather than
+	 verified when the verification optimization is not
+	 available (e.g. when the ZEO server restarted).
+       </description>
+    </key>
+
+  </sectiontype>
+
+</component>

src/ZEO/tests/ZEO4/hash.py

+##############################################################################
+#
+# Copyright (c) 2008 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+"""In Python 2.6, the "sha" and "md5" modules have been deprecated
+in favor of using hashlib for both. This class allows for compatibility
+between versions."""
+
+try:
+    import hashlib
+    sha1 = hashlib.sha1
+    new = sha1
+except ImportError:
+    import sha
+    sha1 = sha.new
+    new = sha1
+    digest_size = sha.digest_size

src/ZEO/tests/ZEO4/monitor.py

+##############################################################################
+#
+# Copyright (c) 2003 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+"""Monitor behavior of ZEO server and record statistics.
+"""
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+from __future__ import print_function
+
+import asyncore
+import socket
+import time
+import logging
+
+zeo_version = 'unknown'
+try:
+    import pkg_resources
+except ImportError:
+    pass
+else:
+    zeo_dist = pkg_resources.working_set.find(
+        pkg_resources.Requirement.parse('ZODB3')
+        )
+    if zeo_dist is not None:
+        zeo_version = zeo_dist.version
+
+class StorageStats:
+    """Per-storage usage statistics."""
+
+    def __init__(self, connections=None):
+        self.connections = connections
+        self.loads = 0
+        self.stores = 0
+        self.commits = 0
+        self.aborts = 0
+        self.active_txns = 0
+        self.verifying_clients = 0
+        self.lock_time = None
+        self.conflicts = 0
+        self.conflicts_resolved = 0
+        self.start = time.ctime()
+
+    @property
+    def clients(self):
+        return len(self.connections)
+
+    def parse(self, s):
+        # parse the dump format
+        lines = s.split("\n")
+        for line in lines:
+            field, value = line.split(":", 1)
+            if field == "Server started":
+                self.start = value
+            elif field == "Clients":
+                # Hack because we use this both on the server and on
+                # the client where there are no connections.
+                self.connections = [0] * int(value)
+            elif field == "Clients verifying":
+                self.verifying_clients = int(value)
+            elif field == "Active transactions":
+                self.active_txns = int(value)
+            elif field == "Commit lock held for":
+                # This assumes
+                self.lock_time = time.time() - int(value)
+            elif field == "Commits":
+                self.commits = int(value)
+            elif field == "Aborts":
+                self.aborts = int(value)
+            elif field == "Loads":
+                self.loads = int(value)
+            elif field == "Stores":
+                self.stores = int(value)
+            elif field == "Conflicts":
+                self.conflicts = int(value)
+            elif field == "Conflicts resolved":
+                self.conflicts_resolved = int(value)
+
+    def dump(self, f):
+        print("Server started:", self.start, file=f)
+        print("Clients:", self.clients, file=f)
+        print("Clients verifying:", self.verifying_clients, file=f)
+        print("Active transactions:", self.active_txns, file=f)
+        if self.lock_time:
+            howlong = time.time() - self.lock_time
+            print("Commit lock held for:", int(howlong), file=f)
+        print("Commits:", self.commits, file=f)
+        print("Aborts:", self.aborts, file=f)
+        print("Loads:", self.loads, file=f)
+        print("Stores:", self.stores, file=f)
+        print("Conflicts:", self.conflicts, file=f)
+        print("Conflicts resolved:", self.conflicts_resolved, file=f)
+
+class StatsClient(asyncore.dispatcher):
+
+    def __init__(self, sock, addr):
+        asyncore.dispatcher.__init__(self, sock)
+        self.buf = []
+        self.closed = 0
+
+    def close(self):
+        self.closed = 1
+        # The socket is closed after all the data is written.
+        # See handle_write().
+
+    def write(self, s):
+        self.buf.append(s)
+
+    def writable(self):
+        return len(self.buf)
+
+    def readable(self):
+        return 0
+
+    def handle_write(self):
+        s = "".join(self.buf)
+        self.buf = []
+        n = self.socket.send(s.encode('ascii'))
+        if n < len(s):
+            self.buf.append(s[:n])
+
+        if self.closed and not self.buf:
+            asyncore.dispatcher.close(self)
+
+class StatsServer(asyncore.dispatcher):
+
+    StatsConnectionClass = StatsClient
+
+    def __init__(self, addr, stats):
+        asyncore.dispatcher.__init__(self)
+        self.addr = addr
+        self.stats = stats
+        if type(self.addr) == tuple:
+            self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+        else:
+            self.create_socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        self.set_reuse_addr()
+        logger = logging.getLogger('ZEO.monitor')
+        logger.info("listening on %s", repr(self.addr))
+        self.bind(self.addr)
+        self.listen(5)
+
+    def writable(self):
+        return 0
+
+    def readable(self):
+        return 1
+
+    def handle_accept(self):
+        try:
+            sock, addr = self.accept()
+        except socket.error:
+            return
+        f = self.StatsConnectionClass(sock, addr)
+        self.dump(f)
+        f.close()
+
+    def dump(self, f):
+        print("ZEO monitor server version %s" % zeo_version, file=f)
+        print(time.ctime(), file=f)
+        print(file=f)
+
+        L = sorted(self.stats.keys())
+        for k in L:
+            stats = self.stats[k]
+            print("Storage:", k, file=f)
+            stats.dump(f)
+            print(file=f)

src/ZEO/tests/ZEO4/schema.xml

+<schema>
+
+  <!-- note that zeoctl.xml is a closely related schema which should
+       match this schema, but should require the "runner" section -->
+
+  <description>
+    This schema describes the configuration of the ZEO storage server
+    process.
+  </description>
+
+  <!-- Use the storage types defined by ZODB. -->
+  <import package="ZODB"/>
+
+  <!-- Use the ZEO server information structure. -->
+  <import package="ZEO.tests.ZEO4"/>
+
+  <import package="ZConfig.components.logger"/>
+
+  <!-- runner control -->
+  <import package="zdaemon"/>
+
+
+  <section type="zeo" name="*" required="yes" attribute="zeo" />
+
+  <section type="runner" name="*" required="no" attribute="runner" />
+
+  <multisection name="*" type="ZODB.storage"
+                attribute="storages"
+                required="yes">
+    <description>
+      One or more storages that are provided by the ZEO server.  The
+      section names are used as the storage names, and must be unique
+      within each ZEO storage server.  Traditionally, these names
+      represent small integers starting at '1'.
+    </description>
+  </multisection>
+
+  <section name="*" type="eventlog" attribute="eventlog" required="no" />
+
+</schema>

src/ZEO/tests/ZEO4/zrpc/__init__.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+# zrpc is a package with the following modules
+# client -- manages connection creation to remote server
+# connection -- object dispatcher
+# log -- logging helper
+# error -- exceptions raised by zrpc
+# marshal -- internal, handles basic protocol issues
+# server -- manages incoming connections from remote clients
+# smac -- sized message async connections
+# trigger -- medusa's trigger
+
+# zrpc is not an advertised subpackage of ZEO; its interfaces are internal

src/ZEO/tests/ZEO4/zrpc/_hmac.py

+# This file is a slightly modified copy of Python 2.3's Lib/hmac.py.
+# This file is under the Python Software Foundation (PSF) license.
+
+"""HMAC (Keyed-Hashing for Message Authentication) Python module.
+
+Implements the HMAC algorithm as described by RFC 2104.
+"""
+from six.moves import map
+from six.moves import zip
+
+def _strxor(s1, s2):
+    """Utility method. XOR the two strings s1 and s2 (must have same length).
+    """
+    return "".join(map(lambda x, y: chr(ord(x) ^ ord(y)), s1, s2))
+
+# The size of the digests returned by HMAC depends on the underlying
+# hashing module used.
+digest_size = None
+
+class HMAC:
+    """RFC2104 HMAC class.
+
+    This supports the API for Cryptographic Hash Functions (PEP 247).
+    """
+
+    def __init__(self, key, msg = None, digestmod = None):
+        """Create a new HMAC object.
+
+        key:       key for the keyed hash object.
+        msg:       Initial input for the hash, if provided.
+        digestmod: A module supporting PEP 247. Defaults to the md5 module.
+        """
+        if digestmod is None:
+            import md5
+            digestmod = md5
+
+        self.digestmod = digestmod
+        self.outer = digestmod.new()
+        self.inner = digestmod.new()
+        # Python 2.1 and 2.2 differ about the correct spelling
+        try:
+            self.digest_size = digestmod.digestsize
+        except AttributeError:
+            self.digest_size = digestmod.digest_size
+
+        blocksize = 64
+        ipad = "\x36" * blocksize
+        opad = "\x5C" * blocksize
+
+        if len(key) > blocksize:
+            key = digestmod.new(key).digest()
+
+        key = key + chr(0) * (blocksize - len(key))
+        self.outer.update(_strxor(key, opad))
+        self.inner.update(_strxor(key, ipad))
+        if msg is not None:
+            self.update(msg)
+
+##    def clear(self):
+##        raise NotImplementedError("clear() method not available in HMAC.")
+
+    def update(self, msg):
+        """Update this hashing object with the string msg.
+        """
+        self.inner.update(msg)
+
+    def copy(self):
+        """Return a separate copy of this hashing object.
+
+        An update to this copy won't affect the original object.
+        """
+        other = HMAC("")
+        other.digestmod = self.digestmod
+        other.inner = self.inner.copy()
+        other.outer = self.outer.copy()
+        return other
+
+    def digest(self):
+        """Return the hash value of this hashing object.
+
+        This returns a string containing 8-bit data.  The object is
+        not altered in any way by this function; you can continue
+        updating the object after calling this function.
+        """
+        h = self.outer.copy()
+        h.update(self.inner.digest())
+        return h.digest()
+
+    def hexdigest(self):
+        """Like digest(), but returns a string of hexadecimal digits instead.
+        """
+        return "".join([hex(ord(x))[2:].zfill(2)
+                        for x in tuple(self.digest())])
+
+def new(key, msg = None, digestmod = None):
+    """Create a new hashing object and return it.
+
+    key: The starting key for the hash.
+    msg: if available, will immediately be hashed into the object's starting
+    state.
+
+    You can now feed arbitrary strings into the object using its update()
+    method, and can ask for the hash value at any time by calling its digest()
+    method.
+    """
+    return HMAC(key, msg, digestmod)

src/ZEO/tests/ZEO4/zrpc/error.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+from ZODB import POSException
+from ZEO.Exceptions import ClientDisconnected
+
+class ZRPCError(POSException.StorageError):
+    pass
+
+class DisconnectedError(ZRPCError, ClientDisconnected):
+    """The database storage is disconnected from the storage server.
+
+    The error occurred because a problem in the low-level RPC connection,
+    or because the connection was closed.
+    """
+
+    # This subclass is raised when zrpc catches the error.

src/ZEO/tests/ZEO4/zrpc/log.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+import os
+import threading
+import logging
+
+from ZODB.loglevels import BLATHER
+
+LOG_THREAD_ID = 0 # Set this to 1 during heavy debugging
+
+logger = logging.getLogger('ZEO.zrpc')
+
+_label = "%s" % os.getpid()
+
+def new_label():
+    global _label
+    _label = str(os.getpid())
+
+def log(message, level=BLATHER, label=None, exc_info=False):
+    label = label or _label
+    if LOG_THREAD_ID:
+        label = label + ':' + threading.currentThread().getName()
+    logger.log(level, '(%s) %s' % (label, message), exc_info=exc_info)
+
+REPR_LIMIT = 60
+
+def short_repr(obj):
+    "Return an object repr limited to REPR_LIMIT bytes."
+
+    # Some of the objects being repr'd are large strings. A lot of memory
+    # would be wasted to repr them and then truncate, so they are treated
+    # specially in this function.
+    # Also handle short repr of a tuple containing a long string.
+
+    # This strategy works well for arguments to StorageServer methods.
+    # The oid is usually first and will get included in its entirety.
+    # The pickle is near the beginning, too, and you can often fit the
+    # module name in the pickle.
+
+    if isinstance(obj, str):
+        if len(obj) > REPR_LIMIT:
+            r = repr(obj[:REPR_LIMIT])
+        else:
+            r = repr(obj)
+        if len(r) > REPR_LIMIT:
+            r = r[:REPR_LIMIT-4] + '...' + r[-1]
+        return r
+    elif isinstance(obj, (list, tuple)):
+        elts = []
+        size = 0
+        for elt in obj:
+            r = short_repr(elt)
+            elts.append(r)
+            size += len(r)
+            if size > REPR_LIMIT:
+                break
+        if isinstance(obj, tuple):
+            r = "(%s)" % (", ".join(elts))
+        else:
+            r = "[%s]" % (", ".join(elts))
+    else:
+        r = repr(obj)
+    if len(r) > REPR_LIMIT:
+        return r[:REPR_LIMIT] + '...'
+    else:
+        return r

src/ZEO/tests/ZEO4/zrpc/marshal.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+import logging
+
+from ZEO._compat import Unpickler, Pickler, BytesIO, PY3, PYPY
+from .error import ZRPCError
+from .log import log, short_repr
+
+def encode(*args): # args: (msgid, flags, name, args)
+    # (We used to have a global pickler, but that's not thread-safe. :-( )
+
+    # It's not thread safe if, in the couse of pickling, we call the
+    # Python interpeter, which releases the GIL.
+
+    # Note that args may contain very large binary pickles already; for
+    # this reason, it's important to use proto 1 (or higher) pickles here
+    # too.  For a long time, this used proto 0 pickles, and that can
+    # bloat our pickle to 4x the size (due to high-bit and control bytes
+    # being represented by \xij escapes in proto 0).
+    # Undocumented:  cPickle.Pickler accepts a lone protocol argument;
+    # pickle.py does not.
+    if PY3:
+        # XXX: Py3: Needs optimization.
+        f = BytesIO()
+        pickler = Pickler(f, 3)
+        pickler.fast = 1
+        pickler.dump(args)
+        res = f.getvalue()
+        return res
+    else:
+        pickler = Pickler(1)
+        pickler.fast = 1
+        # Only CPython's cPickle supports dumping
+        # and returning in one operation:
+        #   return pickler.dump(args, 1)
+        # For PyPy we must return the value; fortunately this
+        # works the same on CPython and is no more expensive
+        pickler.dump(args)
+        return pickler.getvalue()
+
+
+
+if PY3:
+    # XXX: Py3: Needs optimization.
+    fast_encode = encode
+elif PYPY:
+    # can't use the python-2 branch, need a new pickler
+    # every time, getvalue() only works once
+    fast_encode = encode
+else:
+    def fast_encode():
+        # Only use in cases where you *know* the data contains only basic
+        # Python objects
+        pickler = Pickler(1)
+        pickler.fast = 1
+        dump = pickler.dump
+        def fast_encode(*args):
+            return dump(args, 1)
+        return fast_encode
+    fast_encode = fast_encode()
+
+def decode(msg):
+    """Decodes msg and returns its parts"""
+    unpickler = Unpickler(BytesIO(msg))
+    unpickler.find_global = find_global
+    try:
+        unpickler.find_class = find_global # PyPy, zodbpickle, the non-c-accelerated version
+    except AttributeError:
+        pass
+    try:
+        return unpickler.load() # msgid, flags, name, args
+    except:
+        log("can't decode message: %s" % short_repr(msg),
+            level=logging.ERROR)
+        raise
+
+def server_decode(msg):
+    """Decodes msg and returns its parts"""
+    unpickler = Unpickler(BytesIO(msg))
+    unpickler.find_global = server_find_global
+    try:
+        unpickler.find_class = server_find_global # PyPy, zodbpickle, the non-c-accelerated version
+    except AttributeError:
+        pass
+
+    try:
+        return unpickler.load() # msgid, flags, name, args
+    except:
+        log("can't decode message: %s" % short_repr(msg),
+            level=logging.ERROR)
+        raise
+
+_globals = globals()
+_silly = ('__doc__',)
+
+exception_type_type = type(Exception)
+
+def find_global(module, name):
+    """Helper for message unpickler"""
+    try:
+        m = __import__(module, _globals, _globals, _silly)
+    except ImportError as msg:
+        raise ZRPCError("import error %s: %s" % (module, msg))
+
+    try:
+        r = getattr(m, name)
+    except AttributeError:
+        raise ZRPCError("module %s has no global %s" % (module, name))
+
+    safe = getattr(r, '__no_side_effects__', 0)
+    if safe:
+        return r
+
+    # TODO:  is there a better way to do this?
+    if type(r) == exception_type_type and issubclass(r, Exception):
+        return r
+
+    raise ZRPCError("Unsafe global: %s.%s" % (module, name))
+
+def server_find_global(module, name):
+    """Helper for message unpickler"""
+    try:
+        if module != 'ZopeUndo.Prefix':
+            raise ImportError
+        m = __import__(module, _globals, _globals, _silly)
+    except ImportError as msg:
+        raise ZRPCError("import error %s: %s" % (module, msg))
+
+    try:
+        r = getattr(m, name)
+    except AttributeError:
+        raise ZRPCError("module %s has no global %s" % (module, name))
+
+    return r

src/ZEO/tests/ZEO4/zrpc/server.py

+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+import asyncore
+import socket
+
+# _has_dualstack: True if the dual-stack sockets are supported
+try:
+    # Check whether IPv6 sockets can be created
+    s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+except (socket.error, AttributeError):
+    _has_dualstack = False
+else:
+    # Check whether enabling dualstack (disabling v6only) works
+    try:
+        s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, False)
+    except (socket.error, AttributeError):
+        _has_dualstack = False
+    else:
+        _has_dualstack = True
+    s.close()
+    del s
+
+from .connection import Connection
+from .log import log
+from .log import logger
+import logging
+
+# Export the main asyncore loop
+loop = asyncore.loop
+
+class Dispatcher(asyncore.dispatcher):
+    """A server that accepts incoming RPC connections"""
+    __super_init = asyncore.dispatcher.__init__
+
+    def __init__(self, addr, factory=Connection, map=None):
+        self.__super_init(map=map)
+        self.addr = addr
+        self.factory = factory
+        self._open_socket()
+
+    def _open_socket(self):
+        if type(self.addr) == tuple:
+            if self.addr[0] == '' and _has_dualstack:
+                # Wildcard listen on all interfaces, both IPv4 and
+                # IPv6 if possible
+                self.create_socket(socket.AF_INET6, socket.SOCK_STREAM)
+                self.socket.setsockopt(
+                    socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, False)
+            elif ':' in self.addr[0]:
+                self.create_socket(socket.AF_INET6, socket.SOCK_STREAM)
+                if _has_dualstack:
+                    # On Linux, IPV6_V6ONLY is off by default.
+                    # If the user explicitly asked for IPv6, don't bind to IPv4
+                    self.socket.setsockopt(
+                        socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, True)
+            else:
+                self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+        else:
+            self.create_socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        self.set_reuse_addr()
+        log("listening on %s" % str(self.addr), logging.INFO)
+
+        for i in range(25):
+            try:
+                self.bind(self.addr)
+            except Exception as exc:
+                log("bind failed %s waiting", i)
+                if i == 24:
+                    raise
+                else:
+                    time.sleep(5)
+            else:
+                break
+
+        self.listen(5)
+
+    def writable(self):
+        return 0
+
+    def readable(self):
+        return 1
+
+    def handle_accept(self):
+        try:
+            sock, addr = self.accept()
+        except socket.error as msg:
+            log("accepted failed: %s" % msg)
+            return
+
+
+        # We could short-circuit the attempt below in some edge cases
+        # and avoid a log message by checking for addr being None.
+        # Unfortunately, our test for the code below,
+        # quick_close_doesnt_kill_server, causes addr to be None and
+        # we'd have to write a test for the non-None case, which is
+        # *even* harder to provoke. :/ So we'll leave things as they
+        # are for now.
+
+        # It might be better to check whether the socket has been
+        # closed, but I don't see a way to do that. :(
+
+        # Drop flow-info from IPv6 addresses
+        if addr: # Sometimes None on Mac. See above.
+            addr = addr[:2]
+
+        try:
+            c = self.factory(sock, addr)
+        except:
+            if sock.fileno() in asyncore.socket_map:
+                del asyncore.socket_map[sock.fileno()]
+            logger.exception("Error in handle_accept")
+        else:
+            log("connect from %s: %s" % (repr(addr), c))

src/ZEO/tests/forker.py

@@ -32,6 +32,13 @@ logger = logging.getLogger('ZEO.tests.forker')
 
 DEBUG = os.environ.get('ZEO_TEST_SERVER_DEBUG')
 
+ZEO4_SERVER = os.environ.get('ZEO4_SERVER')
+skip_if_testing_client_against_zeo4 = (
+    (lambda func: None)
+    if ZEO4_SERVER else
+    (lambda func: func)
+    )
+
 class ZEOConfig:
     """Class to generate ZEO configuration file. """
 
@@ -104,21 +111,30 @@ def runner(config, qin, qout, timeout=None,
             ))
 
     try:
-        import ZEO.runzeo, threading
+        import threading
         from six.moves.queue import Empty
 
-        options = ZEO.runzeo.ZEOOptions()
+        if ZEO4_SERVER:
+            from .ZEO4 import runzeo
+        else:
+            from .. import runzeo
+
+        options = runzeo.ZEOOptions()
         options.realize(['-C', config])
-        server = ZEO.runzeo.ZEOServer(options)
+        server = runzeo.ZEOServer(options)
         globals()[(name if name else 'last') + '_server'] = server
         server.open_storages()
         server.clear_socket()
         server.create_server()
         logger.debug('SERVER CREATED')
+        if ZEO4_SERVER:
+            qout.put(server.server.addr)
+        else:
             qout.put(server.server.acceptor.addr)
         logger.debug('ADDRESS SENT')
         thread = threading.Thread(
-            target=server.server.loop, kwargs=dict(timeout=.2),
+            target=server.server.loop,
+            kwargs={} if ZEO4_SERVER else dict(timeout=.2),
             name = None if name is None else name + '-server',
             )
         thread.setDaemon(True)

src/ZEO/tests/test_client_credentials.py

@@ -8,6 +8,9 @@ import unittest
 
 import ZEO.StorageServer
 
+from . import forker
+
+@unittest.skipIf(forker.ZEO4_SERVER, "ZEO4 servers don't support SSL")
 class ClientAuthTests(setupstack.TestCase):
 
     def setUp(self):
@@ -50,7 +53,6 @@ class ClientAuthTests(setupstack.TestCase):
 
         stop()
 
-
 def test_suite():
     return unittest.makeSuite(ClientAuthTests)
 

src/ZEO/tests/test_client_side_conflict_resolution.py

@@ -9,6 +9,7 @@ from ZODB.broken import find_global
 
 import ZEO
 
+from . import forker
 from .utils import StorageServer
 
 class Var(object):
@@ -16,10 +17,10 @@ class Var(object):
         self.value = other
         return True
 
+@unittest.skipIf(forker.ZEO4_SERVER, "ZEO4 servers don't support SSL")
 class ClientSideConflictResolutionTests(zope.testing.setupstack.TestCase):
 
     def test_server_side(self):
-
         # First, verify default conflict resolution.
         server = StorageServer(self, DemoStorage())
         zs = server.zs