import datetime import errno import socket import threading import time import warnings from itertools import chain from redis.exceptions import ConnectionError, ResponseError, InvalidResponse from redis.exceptions import RedisError, AuthenticationError class ConnectionPool(threading.local): "Manages a list of connections on the local thread" def __init__(self): self.connections = {} def make_connection_key(self, host, port, db): "Create a unique key for the specified host, port and db" return '%s:%s:%s' % (host, port, db) def get_connection(self, host, port, db, password, socket_timeout): "Return a specific connection for the specified host, port and db" key = self.make_connection_key(host, port, db) if key not in self.connections: self.connections[key] = Connection( host, port, db, password, socket_timeout) return self.connections[key] def get_all_connections(self): "Return a list of all connection objects the manager knows about" return self.connections.values() class Connection(object): "Manages TCP communication to and from a Redis server" def __init__(self, host='localhost', port=6379, db=0, password=None, socket_timeout=None): self.host = host self.port = port self.db = db self.password = password self.socket_timeout = socket_timeout self._sock = None self._fp = None def connect(self, redis_instance): "Connects to the Redis server if not already connected" if self._sock: return try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((self.host, self.port)) except socket.error, e: # args for socket.error can either be (errno, "message") # or just "message" if len(e.args) == 1: error_message = "Error connecting to %s:%s. %s." % \ (self.host, self.port, e.args[0]) else: error_message = "Error %s connecting %s:%s. %s." % \ (e.args[0], self.host, self.port, e.args[1]) raise ConnectionError(error_message) sock.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, 1) sock.settimeout(self.socket_timeout) self._sock = sock self._fp = sock.makefile('r') redis_instance._setup_connection() def disconnect(self): "Disconnects from the Redis server" if self._sock is None: return try: self._sock.close() except socket.error: pass self._sock = None self._fp = None def send(self, command, redis_instance): "Send ``command`` to the Redis server. Return the result." self.connect(redis_instance) try: self._sock.sendall(command) except socket.error, e: if e.args[0] == errno.EPIPE: self.disconnect() raise ConnectionError("Error %s while writing to socket. %s." % \ e.args) def read(self, length=None): """ Read a line from the socket is length is None, otherwise read ``length`` bytes """ try: if length is not None: return self._fp.read(length) return self._fp.readline() except socket.error, e: self.disconnect() if e.args and e.args[0] == errno.EAGAIN: raise ConnectionError("Error while reading from socket: %s" % \ e.args[1]) return '' def list_or_args(command, keys, args): # returns a single list combining keys and args # if keys is not a list or args has items, issue a # deprecation warning oldapi = bool(args) try: i = iter(keys) # a string can be iterated, but indicates # keys wasn't passed as a list if isinstance(keys, basestring): oldapi = True except TypeError: oldapi = True keys = [keys] if oldapi: warnings.warn(DeprecationWarning( "Passing *args to Redis.%s has been deprecated. " "Pass an iterable to ``keys`` instead" % command )) keys.extend(args) return keys def timestamp_to_datetime(response): "Converts a unix timestamp to a Python datetime object" if not response: return None try: response = int(response) except ValueError: return None return datetime.datetime.fromtimestamp(response) def string_keys_to_dict(key_string, callback): return dict([(key, callback) for key in key_string.split()]) def dict_merge(*dicts): merged = {} [merged.update(d) for d in dicts] return merged def parse_info(response): "Parse the result of Redis's INFO command into a Python dict" info = {} def get_value(value): if ',' not in value: return value sub_dict = {} for item in value.split(','): k, v = item.split('=') try: sub_dict[k] = int(v) except ValueError: sub_dict[k] = v return sub_dict for line in response.splitlines(): key, value = line.split(':') try: info[key] = int(value) except ValueError: info[key] = get_value(value) return info def pairs_to_dict(response): "Create a dict given a list of key/value pairs" return dict(zip(response[::2], response[1::2])) def zset_score_pairs(response, **options): """ If ``withscores`` is specified in the options, return the response as a list of (value, score) pairs """ if not response or not options['withscores']: return response return zip(response[::2], map(float, response[1::2])) def int_or_none(response): if response is None: return None return int(response) def float_or_none(response): if response is None: return None return float(response) class Redis(threading.local): """ Implementation of the Redis protocol. This abstract class provides a Python interface to all Redis commands and an implementation of the Redis protocol. Connection and Pipeline derive from this, implementing how the commands are sent and received to the Redis server """ RESPONSE_CALLBACKS = dict_merge( string_keys_to_dict( 'AUTH DEL EXISTS EXPIRE EXPIREAT HDEL HEXISTS HMSET MOVE MSETNX ' 'RENAMENX SADD SISMEMBER SMOVE SETEX SETNX SREM ZADD ZREM', bool ), string_keys_to_dict( 'DECRBY HLEN INCRBY LLEN SCARD SDIFFSTORE SINTERSTORE ' 'SUNIONSTORE ZCARD ZREMRANGEBYRANK ZREMRANGEBYSCORE ZREVRANK', int ), string_keys_to_dict( # these return OK, or int if redis-server is >=1.3.4 'LPUSH RPUSH', lambda r: isinstance(r, int) and r or r == 'OK' ), string_keys_to_dict('ZSCORE ZINCRBY', float_or_none), string_keys_to_dict( 'FLUSHALL FLUSHDB LSET LTRIM MSET RENAME ' 'SAVE SELECT SET SHUTDOWN', lambda r: r == 'OK' ), string_keys_to_dict('BLPOP BRPOP', lambda r: r and tuple(r) or None), string_keys_to_dict('SDIFF SINTER SMEMBERS SUNION', lambda r: set(r) ), string_keys_to_dict('ZRANGE ZRANGEBYSCORE ZREVRANGE', zset_score_pairs), { 'BGREWRITEAOF': lambda r: \ r == 'Background rewriting of AOF file started', 'BGSAVE': lambda r: r == 'Background saving started', 'HGETALL': lambda r: r and pairs_to_dict(r) or {}, 'INFO': parse_info, 'LASTSAVE': timestamp_to_datetime, 'PING': lambda r: r == 'PONG', 'RANDOMKEY': lambda r: r and r or None, 'TTL': lambda r: r != -1 and r or None, 'ZRANK': int_or_none, } ) # commands that should NOT pull data off the network buffer when executed SUBSCRIPTION_COMMANDS = set([ 'SUBSCRIBE', 'UNSUBSCRIBE', 'PSUBSCRIBE', 'PUNSUBSCRIBE' ]) def __init__(self, host='localhost', port=6379, db=0, password=None, socket_timeout=None, connection_pool=None, charset='utf-8', errors='strict'): self.encoding = charset self.errors = errors self.connection = None self.subscribed = False self.connection_pool = connection_pool and connection_pool or ConnectionPool() self.select(db, host, port, password, socket_timeout) #### Legacty accessors of connection information #### def _get_host(self): return self.connection.host host = property(_get_host) def _get_port(self): return self.connection.port port = property(_get_port) def _get_db(self): return self.connection.db db = property(_get_db) def pipeline(self, transaction=True): """ Return a new pipeline object that can queue multiple commands for later execution. ``transaction`` indicates whether all commands should be executed atomically. Apart from multiple atomic operations, pipelines are useful for batch loading of data as they reduce the number of back and forth network operations between client and server. """ return Pipeline( self.connection, transaction, self.encoding, self.errors ) def lock(self, name, timeout=None, sleep=0.1): """ Return a new Lock object using key ``name`` that mimics the behavior of threading.Lock. If specified, ``timeout`` indicates a maximum life for the lock. By default, it will remain locked until release() is called. ``sleep`` indicates the amount of time to sleep per loop iteration when the lock is in blocking mode and another client is currently holding the lock. """ return Lock(self, name, timeout=timeout, sleep=sleep) #### COMMAND EXECUTION AND PROTOCOL PARSING #### def _execute_command(self, command_name, command, **options): subscription_command = command_name in self.SUBSCRIPTION_COMMANDS if self.subscribed and not subscription_command: raise RedisError("Cannot issue commands other than SUBSCRIBE and " "UNSUBSCRIBE while channels are open") try: self.connection.send(command, self) if subscription_command: return None return self.parse_response(command_name, **options) except ConnectionError: self.connection.disconnect() self.connection.send(command, self) if subscription_command: return None return self.parse_response(command_name, **options) def execute_command(self, *args, **options): "Sends the command to the redis server and returns it's response" cmd_count = len(args) cmds = [] for i in args: enc_value = self.encode(i) cmds.append('$%s\r\n%s\r\n' % (len(enc_value), enc_value)) return self._execute_command( args[0], '*%s\r\n%s' % (cmd_count, ''.join(cmds)), **options ) def _parse_response(self, command_name, catch_errors): conn = self.connection response = conn.read()[:-2] # strip last two characters (\r\n) if not response: self.connection.disconnect() raise ConnectionError("Socket closed on remote end") # server returned a null value if response in ('$-1', '*-1'): return None byte, response = response[0], response[1:] # server returned an error if byte == '-': if response.startswith('ERR '): response = response[4:] raise ResponseError(response) # single value elif byte == '+': return response # int value elif byte == ':': return int(response) # bulk response elif byte == '$': length = int(response) if length == -1: return None response = length and conn.read(length) or '' conn.read(2) # read the \r\n delimiter return response # multi-bulk response elif byte == '*': length = int(response) if length == -1: return None if not catch_errors: return [self._parse_response(command_name, catch_errors) for i in range(length)] else: # for pipelines, we need to read everything, # including response errors. otherwise we'd # completely mess up the receive buffer data = [] for i in range(length): try: data.append( self._parse_response(command_name, catch_errors) ) except Exception, e: data.append(e) return data raise InvalidResponse("Unknown response type for: %s" % command_name) def parse_response(self, command_name, catch_errors=False, **options): "Parses a response from the Redis server" response = self._parse_response(command_name, catch_errors) if command_name in self.RESPONSE_CALLBACKS: return self.RESPONSE_CALLBACKS[command_name](response, **options) return response def encode(self, value): "Encode ``value`` using the instance's charset" if isinstance(value, str): return value if isinstance(value, unicode): return value.encode(self.encoding, self.errors) # not a string or unicode, attempt to convert to a string return str(value) #### CONNECTION HANDLING #### def get_connection(self, host, port, db, password, socket_timeout): "Returns a connection object" conn = self.connection_pool.get_connection( host, port, db, password, socket_timeout) # if for whatever reason the connection gets a bad password, make # sure a subsequent attempt with the right password makes its way # to the connection conn.password = password return conn def _setup_connection(self): """ After successfully opening a socket to the Redis server, the connection object calls this method to authenticate and select the appropriate database. """ if self.connection.password: if not self.execute_command('AUTH', self.connection.password): raise AuthenticationError("Invalid Password") self.execute_command('SELECT', self.connection.db) def select(self, db, host=None, port=None, password=None, socket_timeout=None): """ Switch to a different Redis connection. If the host and port aren't provided and there's an existing connection, use the existing connection's host and port instead. Note this method actually replaces the underlying connection object prior to issuing the SELECT command. This makes sure we protect the thread-safe connections """ if host is None: if self.connection is None: raise RedisError("A valid hostname or IP address " "must be specified") host = self.connection.host if port is None: if self.connection is None: raise RedisError("A valid port must be specified") port = self.connection.port self.connection = self.get_connection( host, port, db, password, socket_timeout) #### SERVER INFORMATION #### def bgrewriteaof(self): "Tell the Redis server to rewrite the AOF file from data in memory." return self.execute_command('BGREWRITEAOF') def bgsave(self): """ Tell the Redis server to save its data to disk. Unlike save(), this method is asynchronous and returns immediately. """ return self.execute_command('BGSAVE') def dbsize(self): "Returns the number of keys in the current database" return self.execute_command('DBSIZE') def delete(self, *names): "Delete one or more keys specified by ``names``" return self.execute_command('DEL', *names) __delitem__ = delete def flush(self, all_dbs=False): warnings.warn(DeprecationWarning( "'flush' has been deprecated. " "Use Redis.flushdb() or Redis.flushall() instead")) if all_dbs: return self.flushall() return self.flushdb() def flushall(self): "Delete all keys in all databases on the current host" return self.execute_command('FLUSHALL') def flushdb(self): "Delete all keys in the current database" return self.execute_command('FLUSHDB') def info(self): "Returns a dictionary containing information about the Redis server" return self.execute_command('INFO') def lastsave(self): """ Return a Python datetime object representing the last time the Redis database was saved to disk """ return self.execute_command('LASTSAVE') def ping(self): "Ping the Redis server" return self.execute_command('PING') def save(self): """ Tell the Redis server to save its data to disk, blocking until the save is complete """ return self.execute_command('SAVE') #### BASIC KEY COMMANDS #### def append(self, key, value): """ Appends the string ``value`` to the value at ``key``. If ``key`` doesn't already exist, create it with a value of ``value``. Returns the new length of the value at ``key``. """ return self.execute_command('APPEND', key, value) def decr(self, name, amount=1): """ Decrements the value of ``key`` by ``amount``. If no key exists, the value will be initialized as 0 - ``amount`` """ return self.execute_command('DECRBY', name, amount) def exists(self, name): "Returns a boolean indicating whether key ``name`` exists" return self.execute_command('EXISTS', name) __contains__ = exists def expire(self, name, time): "Set an expire flag on key ``name`` for ``time`` seconds" return self.execute_command('EXPIRE', name, time) def expireat(self, name, when): """ Set an expire flag on key ``name``. ``when`` can be represented as an integer indicating unix time or a Python datetime object. """ if isinstance(when, datetime.datetime): when = int(time.mktime(when.timetuple())) return self.execute_command('EXPIREAT', name, when) def get(self, name): """ Return the value at key ``name``, or None of the key doesn't exist """ return self.execute_command('GET', name) __getitem__ = get def getset(self, name, value): """ Set the value at key ``name`` to ``value`` if key doesn't exist Return the value at key ``name`` atomically """ return self.execute_command('GETSET', name, value) def incr(self, name, amount=1): """ Increments the value of ``key`` by ``amount``. If no key exists, the value will be initialized as ``amount`` """ return self.execute_command('INCRBY', name, amount) def keys(self, pattern='*'): "Returns a list of keys matching ``pattern``" return self.execute_command('KEYS', pattern) def mget(self, keys, *args): """ Returns a list of values ordered identically to ``keys`` * Passing *args to this method has been deprecated * """ keys = list_or_args('mget', keys, args) return self.execute_command('MGET', *keys) def mset(self, mapping): "Sets each key in the ``mapping`` dict to its corresponding value" items = [] [items.extend(pair) for pair in mapping.iteritems()] return self.execute_command('MSET', *items) def msetnx(self, mapping): """ Sets each key in the ``mapping`` dict to its corresponding value if none of the keys are already set """ items = [] [items.extend(pair) for pair in mapping.iteritems()] return self.execute_command('MSETNX', *items) def move(self, name, db): "Moves the key ``name`` to a different Redis database ``db``" return self.execute_command('MOVE', name, db) def randomkey(self): "Returns the name of a random key" return self.execute_command('RANDOMKEY') def rename(self, src, dst, **kwargs): """ Rename key ``src`` to ``dst`` * The following flags have been deprecated * If ``preserve`` is True, rename the key only if the destination name doesn't already exist """ if kwargs: if 'preserve' in kwargs: warnings.warn(DeprecationWarning( "preserve option to 'rename' is deprecated, " "use Redis.renamenx instead")) if kwargs['preserve']: return self.renamenx(src, dst) return self.execute_command('RENAME', src, dst) def renamenx(self, src, dst): "Rename key ``src`` to ``dst`` if ``dst`` doesn't already exist" return self.execute_command('RENAMENX', src, dst) def set(self, name, value, **kwargs): """ Set the value at key ``name`` to ``value`` * The following flags have been deprecated * If ``preserve`` is True, set the value only if key doesn't already exist If ``getset`` is True, set the value only if key doesn't already exist and return the resulting value of key """ if kwargs: if 'getset' in kwargs: warnings.warn(DeprecationWarning( "getset option to 'set' is deprecated, " "use Redis.getset() instead")) if kwargs['getset']: return self.getset(name, value) if 'preserve' in kwargs: warnings.warn(DeprecationWarning( "preserve option to 'set' is deprecated, " "use Redis.setnx() instead")) if kwargs['preserve']: return self.setnx(name, value) return self.execute_command('SET', name, value) __setitem__ = set def setex(self, name, value, time): """ Set the value of key ``name`` to ``value`` that expires in ``time`` seconds """ return self.execute_command('SETEX', name, time, value) def setnx(self, name, value): "Set the value of key ``name`` to ``value`` if key doesn't exist" return self.execute_command('SETNX', name, value) def substr(self, name, start, end=-1): """ Return a substring of the string at key ``name``. ``start`` and ``end`` are 0-based integers specifying the portion of the string to return. """ return self.execute_command('SUBSTR', name, start, end) def ttl(self, name): "Returns the number of seconds until the key ``name`` will expire" return self.execute_command('TTL', name) def type(self, name): "Returns the type of key ``name``" return self.execute_command('TYPE', name) #### LIST COMMANDS #### def blpop(self, keys, timeout=0): """ LPOP a value off of the first non-empty list named in the ``keys`` list. If none of the lists in ``keys`` has a value to LPOP, then block for ``timeout`` seconds, or until a value gets pushed on to one of the lists. If timeout is 0, then block indefinitely. """ if isinstance(keys, basestring): keys = [keys] else: keys = list(keys) keys.append(timeout) return self.execute_command('BLPOP', *keys) def brpop(self, keys, timeout=0): """ RPOP a value off of the first non-empty list named in the ``keys`` list. If none of the lists in ``keys`` has a value to LPOP, then block for ``timeout`` seconds, or until a value gets pushed on to one of the lists. If timeout is 0, then block indefinitely. """ if isinstance(keys, basestring): keys = [keys] else: keys = list(keys) keys.append(timeout) return self.execute_command('BRPOP', *keys) def lindex(self, name, index): """ Return the item from list ``name`` at position ``index`` Negative indexes are supported and will return an item at the end of the list """ return self.execute_command('LINDEX', name, index) def llen(self, name): "Return the length of the list ``name``" return self.execute_command('LLEN', name) def lpop(self, name): "Remove and return the first item of the list ``name``" return self.execute_command('LPOP', name) def lpush(self, name, value): "Push ``value`` onto the head of the list ``name``" return self.execute_command('LPUSH', name, value) def lrange(self, name, start, end): """ Return a slice of the list ``name`` between position ``start`` and ``end`` ``start`` and ``end`` can be negative numbers just like Python slicing notation """ return self.execute_command('LRANGE', name, start, end) def lrem(self, name, value, num=0): """ Remove the first ``num`` occurrences of ``value`` from list ``name`` If ``num`` is 0, then all occurrences will be removed """ return self.execute_command('LREM', name, num, value) def lset(self, name, index, value): "Set ``position`` of list ``name`` to ``value``" return self.execute_command('LSET', name, index, value) def ltrim(self, name, start, end): """ Trim the list ``name``, removing all values not within the slice between ``start`` and ``end`` ``start`` and ``end`` can be negative numbers just like Python slicing notation """ return self.execute_command('LTRIM', name, start, end) def pop(self, name, tail=False): """ Pop and return the first or last element of list ``name`` * This method has been deprecated, use Redis.lpop or Redis.rpop instead * """ warnings.warn(DeprecationWarning( "Redis.pop has been deprecated, " "use Redis.lpop or Redis.rpop instead")) if tail: return self.rpop(name) return self.lpop(name) def push(self, name, value, head=False): """ Push ``value`` onto list ``name``. * This method has been deprecated, use Redis.lpush or Redis.rpush instead * """ warnings.warn(DeprecationWarning( "Redis.push has been deprecated, " "use Redis.lpush or Redis.rpush instead")) if head: return self.lpush(name, value) return self.rpush(name, value) def rpop(self, name): "Remove and return the last item of the list ``name``" return self.execute_command('RPOP', name) def rpoplpush(self, src, dst): """ RPOP a value off of the ``src`` list and atomically LPUSH it on to the ``dst`` list. Returns the value. """ return self.execute_command('RPOPLPUSH', src, dst) def rpush(self, name, value): "Push ``value`` onto the tail of the list ``name``" return self.execute_command('RPUSH', name, value) def sort(self, name, start=None, num=None, by=None, get=None, desc=False, alpha=False, store=None): """ Sort and return the list, set or sorted set at ``name``. ``start`` and ``num`` allow for paging through the sorted data ``by`` allows using an external key to weight and sort the items. Use an "*" to indicate where in the key the item value is located ``get`` allows for returning items from external keys rather than the sorted data itself. Use an "*" to indicate where int he key the item value is located ``desc`` allows for reversing the sort ``alpha`` allows for sorting lexicographically rather than numerically ``store`` allows for storing the result of the sort into the key ``store`` """ if (start is not None and num is None) or \ (num is not None and start is None): raise RedisError("``start`` and ``num`` must both be specified") pieces = [name] if by is not None: pieces.append('BY') pieces.append(by) if start is not None and num is not None: pieces.append('LIMIT') pieces.append(start) pieces.append(num) if get is not None: pieces.append('GET') pieces.append(get) if desc: pieces.append('DESC') if alpha: pieces.append('ALPHA') if store is not None: pieces.append('STORE') pieces.append(store) return self.execute_command('SORT', *pieces) #### SET COMMANDS #### def sadd(self, name, value): "Add ``value`` to set ``name``" return self.execute_command('SADD', name, value) def scard(self, name): "Return the number of elements in set ``name``" return self.execute_command('SCARD', name) def sdiff(self, keys, *args): "Return the difference of sets specified by ``keys``" keys = list_or_args('sdiff', keys, args) return self.execute_command('SDIFF', *keys) def sdiffstore(self, dest, keys, *args): """ Store the difference of sets specified by ``keys`` into a new set named ``dest``. Returns the number of keys in the new set. """ keys = list_or_args('sdiffstore', keys, args) return self.execute_command('SDIFFSTORE', dest, *keys) def sinter(self, keys, *args): "Return the intersection of sets specified by ``keys``" keys = list_or_args('sinter', keys, args) return self.execute_command('SINTER', *keys) def sinterstore(self, dest, keys, *args): """ Store the intersection of sets specified by ``keys`` into a new set named ``dest``. Returns the number of keys in the new set. """ keys = list_or_args('sinterstore', keys, args) return self.execute_command('SINTERSTORE', dest, *keys) def sismember(self, name, value): "Return a boolean indicating if ``value`` is a member of set ``name``" return self.execute_command('SISMEMBER', name, value) def smembers(self, name): "Return all members of the set ``name``" return self.execute_command('SMEMBERS', name) def smove(self, src, dst, value): "Move ``value`` from set ``src`` to set ``dst`` atomically" return self.execute_command('SMOVE', src, dst, value) def spop(self, name): "Remove and return a random member of set ``name``" return self.execute_command('SPOP', name) def srandmember(self, name): "Return a random member of set ``name``" return self.execute_command('SRANDMEMBER', name) def srem(self, name, value): "Remove ``value`` from set ``name``" return self.execute_command('SREM', name, value) def sunion(self, keys, *args): "Return the union of sets specifiued by ``keys``" keys = list_or_args('sunion', keys, args) return self.execute_command('SUNION', *keys) def sunionstore(self, dest, keys, *args): """ Store the union of sets specified by ``keys`` into a new set named ``dest``. Returns the number of keys in the new set. """ keys = list_or_args('sunionstore', keys, args) return self.execute_command('SUNIONSTORE', dest, *keys) #### SORTED SET COMMANDS #### def zadd(self, name, value, score): "Add member ``value`` with score ``score`` to sorted set ``name``" return self.execute_command('ZADD', name, score, value) def zcard(self, name): "Return the number of elements in the sorted set ``name``" return self.execute_command('ZCARD', name) def zincr(self, key, member, value=1): "This has been deprecated, use zincrby instead" warnings.warn(DeprecationWarning( "Redis.zincr has been deprecated, use Redis.zincrby instead" )) return self.zincrby(key, member, value) def zincrby(self, name, value, amount=1): "Increment the score of ``value`` in sorted set ``name`` by ``amount``" return self.execute_command('ZINCRBY', name, amount, value) def zinter(self, dest, keys, aggregate=None): warnings.warn(DeprecationWarning( "Redis.zinter has been deprecated, use Redis.zinterstore instead" )) return self.zinterstore(dest, keys, aggregate) def zinterstore(self, dest, keys, aggregate=None): """ Intersect multiple sorted sets specified by ``keys`` into a new sorted set, ``dest``. Scores in the destination will be aggregated based on the ``aggregate``, or SUM if none is provided. """ return self._zaggregate('ZINTERSTORE', dest, keys, aggregate) def zrange(self, name, start, end, desc=False, withscores=False): """ Return a range of values from sorted set ``name`` between ``start`` and ``end`` sorted in ascending order. ``start`` and ``end`` can be negative, indicating the end of the range. ``desc`` indicates to sort in descending order. ``withscores`` indicates to return the scores along with the values. The return type is a list of (value, score) pairs """ if desc: return self.zrevrange(name, start, end, withscores) pieces = ['ZRANGE', name, start, end] if withscores: pieces.append('withscores') return self.execute_command(*pieces, **{'withscores': withscores}) def zrangebyscore(self, name, min, max, start=None, num=None, withscores=False): """ Return a range of values from the sorted set ``name`` with scores between ``min`` and ``max``. If ``start`` and ``num`` are specified, then return a slice of the range. ``withscores`` indicates to return the scores along with the values. The return type is a list of (value, score) pairs """ if (start is not None and num is None) or \ (num is not None and start is None): raise RedisError("``start`` and ``num`` must both be specified") pieces = ['ZRANGEBYSCORE', name, min, max] if start is not None and num is not None: pieces.extend(['LIMIT', start, num]) if withscores: pieces.append('withscores') return self.execute_command(*pieces, **{'withscores': withscores}) def zrank(self, name, value): """ Returns a 0-based value indicating the rank of ``value`` in sorted set ``name`` """ return self.execute_command('ZRANK', name, value) def zrem(self, name, value): "Remove member ``value`` from sorted set ``name``" return self.execute_command('ZREM', name, value) def zremrangebyrank(self, name, min, max): """ Remove all elements in the sorted set ``name`` with ranks between ``min`` and ``max``. Values are 0-based, ordered from smallest score to largest. Values can be negative indicating the highest scores. Returns the number of elements removed """ return self.execute_command('ZREMRANGEBYRANK', name, min, max) def zremrangebyscore(self, name, min, max): """ Remove all elements in the sorted set ``name`` with scores between ``min`` and ``max``. Returns the number of elements removed. """ return self.execute_command('ZREMRANGEBYSCORE', name, min, max) def zrevrange(self, name, start, num, withscores=False): """ Return a range of values from sorted set ``name`` between ``start`` and ``num`` sorted in descending order. ``start`` and ``num`` can be negative, indicating the end of the range. ``withscores`` indicates to return the scores along with the values as a dictionary of value => score """ pieces = ['ZREVRANGE', name, start, num] if withscores: pieces.append('withscores') return self.execute_command(*pieces, **{'withscores': withscores}) def zrevrank(self, name, value): """ Returns a 0-based value indicating the descending rank of ``value`` in sorted set ``name`` """ return self.execute_command('ZREVRANK', name, value) def zscore(self, name, value): "Return the score of element ``value`` in sorted set ``name``" return self.execute_command('ZSCORE', name, value) def zunion(self, dest, keys, aggregate=None): warnings.warn(DeprecationWarning( "Redis.zunion has been deprecated, use Redis.zunionstore instead" )) return self.zunionstore(dest, keys, aggregate) def zunionstore(self, dest, keys, aggregate=None): """ Union multiple sorted sets specified by ``keys`` into a new sorted set, ``dest``. Scores in the destination will be aggregated based on the ``aggregate``, or SUM if none is provided. """ return self._zaggregate('ZUNIONSTORE', dest, keys, aggregate) def _zaggregate(self, command, dest, keys, aggregate=None): pieces = [command, dest, len(keys)] if isinstance(keys, dict): items = keys.items() keys = [i[0] for i in items] weights = [i[1] for i in items] else: weights = None pieces.extend(keys) if weights: pieces.append('WEIGHTS') pieces.extend(weights) if aggregate: pieces.append('AGGREGATE') pieces.append(aggregate) return self.execute_command(*pieces) #### HASH COMMANDS #### def hdel(self, name, key): "Delete ``key`` from hash ``name``" return self.execute_command('HDEL', name, key) def hexists(self, name, key): "Returns a boolean indicating if ``key`` exists within hash ``name``" return self.execute_command('HEXISTS', name, key) def hget(self, name, key): "Return the value of ``key`` within the hash ``name``" return self.execute_command('HGET', name, key) def hgetall(self, name): "Return a Python dict of the hash's name/value pairs" return self.execute_command('HGETALL', name) def hincrby(self, name, key, amount=1): "Increment the value of ``key`` in hash ``name`` by ``amount``" return self.execute_command('HINCRBY', name, key, amount) def hkeys(self, name): "Return the list of keys within hash ``name``" return self.execute_command('HKEYS', name) def hlen(self, name): "Return the number of elements in hash ``name``" return self.execute_command('HLEN', name) def hset(self, name, key, value): """ Set ``key`` to ``value`` within hash ``name`` Returns 1 if HSET created a new field, otherwise 0 """ return self.execute_command('HSET', name, key, value) def hsetnx(self, name, key, value): """ Set ``key`` to ``value`` within hash ``name`` if ``key`` does not exist. Returns 1 if HSETNX created a field, otherwise 0. """ return self.execute_command("HSETNX", name, key, value) def hmset(self, name, mapping): """ Sets each key in the ``mapping`` dict to its corresponding value in the hash ``name`` """ items = [] [items.extend(pair) for pair in mapping.iteritems()] return self.execute_command('HMSET', name, *items) def hmget(self, name, keys): "Returns a list of values ordered identically to ``keys``" return self.execute_command('HMGET', name, *keys) def hvals(self, name): "Return the list of values within hash ``name``" return self.execute_command('HVALS', name) # channels def psubscribe(self, patterns): "Subscribe to all channels matching any pattern in ``patterns``" if isinstance(patterns, basestring): patterns = [patterns] response = self.execute_command('PSUBSCRIBE', *patterns) # this is *after* the SUBSCRIBE in order to allow for lazy and broken # connections that need to issue AUTH and SELECT commands self.subscribed = True return response def punsubscribe(self, patterns=[]): """ Unsubscribe from any channel matching any pattern in ``patterns``. If empty, unsubscribe from all channels. """ if isinstance(patterns, basestring): patterns = [patterns] return self.execute_command('PUNSUBSCRIBE', *patterns) def subscribe(self, channels): "Subscribe to ``channels``, waiting for messages to be published" if isinstance(channels, basestring): channels = [channels] response = self.execute_command('SUBSCRIBE', *channels) # this is *after* the SUBSCRIBE in order to allow for lazy and broken # connections that need to issue AUTH and SELECT commands self.subscribed = True return response def unsubscribe(self, channels=[]): """ Unsubscribe from ``channels``. If empty, unsubscribe from all channels """ if isinstance(channels, basestring): channels = [channels] return self.execute_command('UNSUBSCRIBE', *channels) def publish(self, channel, message): """ Publish ``message`` on ``channel``. Returns the number of subscribers the message was delivered to. """ return self.execute_command('PUBLISH', channel, message) def listen(self): "Listen for messages on channels this client has been subscribed to" while self.subscribed: r = self.parse_response('LISTEN') if r[0] == 'pmessage': msg = { 'type': r[0], 'pattern': r[1], 'channel': r[2], 'data': r[3] } else: msg = { 'type': r[0], 'pattern': None, 'channel': r[1], 'data': r[2] } if r[0] == 'unsubscribe' and r[2] == 0: self.subscribed = False yield msg class Pipeline(Redis): """ Pipelines provide a way to transmit multiple commands to the Redis server in one transmission. This is convenient for batch processing, such as saving all the values in a list to Redis. All commands executed within a pipeline are wrapped with MULTI and EXEC calls. This guarantees all commands executed in the pipeline will be executed atomically. Any command raising an exception does *not* halt the execution of subsequent commands in the pipeline. Instead, the exception is caught and its instance is placed into the response list returned by execute(). Code iterating over the response list should be able to deal with an instance of an exception as a potential value. In general, these will be ResponseError exceptions, such as those raised when issuing a command on a key of a different datatype. """ def __init__(self, connection, transaction, charset, errors): self.connection = connection self.transaction = transaction self.encoding = charset self.errors = errors self.subscribed = False # NOTE not in use, but necessary self.reset() def reset(self): self.command_stack = [] def _execute_command(self, command_name, command, **options): """ Stage a command to be executed when execute() is next called Returns the current Pipeline object back so commands can be chained together, such as: pipe = pipe.set('foo', 'bar').incr('baz').decr('bang') At some other point, you can then run: pipe.execute(), which will execute all commands queued in the pipe. """ # if the command_name is 'AUTH' or 'SELECT', then this command # must have originated after a socket connection and a call to # _setup_connection(). run these commands immediately without # buffering them. if command_name in ('AUTH', 'SELECT'): return super(Pipeline, self)._execute_command( command_name, command, **options) else: self.command_stack.append((command_name, command, options)) return self def _execute_transaction(self, commands): # wrap the commands in MULTI ... EXEC statements to indicate an # atomic operation all_cmds = ''.join([c for _1, c, _2 in chain( (('', 'MULTI\r\n', ''),), commands, (('', 'EXEC\r\n', ''),) )]) self.connection.send(all_cmds, self) # parse off the response for MULTI and all commands prior to EXEC for i in range(len(commands)+1): _ = self.parse_response('_') # parse the EXEC. we want errors returned as items in the response response = self.parse_response('_', catch_errors=True) if len(response) != len(commands): raise ResponseError("Wrong number of response items from " "pipeline execution") # Run any callbacks for the commands run in the pipeline data = [] for r, cmd in zip(response, commands): if not isinstance(r, Exception): if cmd[0] in self.RESPONSE_CALLBACKS: r = self.RESPONSE_CALLBACKS[cmd[0]](r, **cmd[2]) data.append(r) return data def _execute_pipeline(self, commands): # build up all commands into a single request to increase network perf all_cmds = ''.join([c for _1, c, _2 in commands]) self.connection.send(all_cmds, self) data = [] for command_name, _, options in commands: data.append( self.parse_response(command_name, catch_errors=True, **options) ) return data def execute(self): "Execute all the commands in the current pipeline" stack = self.command_stack self.reset() if self.transaction: execute = self._execute_transaction else: execute = self._execute_pipeline try: return execute(stack) except ConnectionError: self.connection.disconnect() return execute(stack) def select(self, *args, **kwargs): raise RedisError("Cannot select a different database from a pipeline") class Lock(object): """ A shared, distributed Lock. Using Redis for locking allows the Lock to be shared across processes and/or machines. It's left to the user to resolve deadlock issues and make sure multiple clients play nicely together. """ LOCK_FOREVER = 2**31+1 # 1 past max unix time def __init__(self, redis, name, timeout=None, sleep=0.1): """ Create a new Lock instnace named ``name`` using the Redis client supplied by ``redis``. ``timeout`` indicates a maximum life for the lock. By default, it will remain locked until release() is called. ``sleep`` indicates the amount of time to sleep per loop iteration when the lock is in blocking mode and another client is currently holding the lock. Note: If using ``timeout``, you should make sure all the hosts that are running clients are within the same timezone and are using a network time service like ntp. """ self.redis = redis self.name = name self.acquired_until = None self.timeout = timeout self.sleep = sleep def __enter__(self): return self.acquire() def __exit__(self, exc_type, exc_value, traceback): self.release() def acquire(self, blocking=True): """ Use Redis to hold a shared, distributed lock named ``name``. Returns True once the lock is acquired. If ``blocking`` is False, always return immediately. If the lock was acquired, return True, otherwise return False. """ sleep = self.sleep timeout = self.timeout while 1: unixtime = int(time.time()) if timeout: timeout_at = unixtime + timeout else: timeout_at = Lock.LOCK_FOREVER if self.redis.setnx(self.name, timeout_at): self.acquired_until = timeout_at return True # We want blocking, but didn't acquire the lock # check to see if the current lock is expired existing = long(self.redis.get(self.name) or 1) if existing < unixtime: # the previous lock is expired, attempt to overwrite it existing = long(self.redis.getset(self.name, timeout_at) or 1) if existing < unixtime: # we successfully acquired the lock self.acquired_until = timeout_at return True if not blocking: return False time.sleep(sleep) def release(self): "Releases the already acquired lock" if self.acquired_until is None: raise ValueError("Cannot release an unlocked lock") existing = long(self.redis.get(self.name) or 1) # if the lock time is in the future, delete the lock if existing >= self.acquired_until: self.redis.delete(self.name) self.acquired_until = None