NAME
Shardcache::Client::Fast - Perl extension for the client part of libshardcache
SYNOPSIS
use Shardcache::Client::Fast;
@hosts = ("peer1:localhost:4444", "peer2:localhost:4445", "peer3:localhost:4446" );
$secret = "some_secret";
$c = Shardcache::Client::Fast->new(\@hosts, $secret);
# Set a new value for key "key"
$rc = $c->set("key", "value");
if ($rc != 0) {
die "Error setting key 'key' : " . $c->errstr;
}
# Read the value back
$v = $c->get("key");
if (!$v && $c->errno) {
die "Error getting value for key 'key' : " . $c->errstr;
}
# set the key "key2" and make it expire in 60 seconds
$c->set("key2", "value2", 60);
# evict "key"
$c->evict("key");
# remove "key2" prematurely
$c->del("key2");
# check if "peer3" is alive
if ($c->check("peer3") != 0) {
warn "peer3 is not responding";
}
# get the index of keys existing on "peer2"
$index = $c->index("peer2");DESCRIPTION
Perl bindings to libshardcache-client. This library is a replacement for the pure-perl Sharcache::Client allowing faster access to shardcache nodes by using libshardcache directly instead of reimplementing the protocol and handling connections on the perl side.
EXPORT
None by default.
METHODS
new ( %params )
REQUIRED PARAMS
- me
-
A 'address:port' string describing the current node - storage
-
A valid Shardcache::Storage subclass, implementing the underlying storage
OPTIONAL PARAMS
- nodes
-
An arrayref containing the nodes in our shardcache 'cloud' - secret
-
A secret used to compute the signature used for internal communication. If not specified the string 'default' will be used
tcp_timeout ( $new_value )
Set/Get the tcp timeout (in milliseconds) used for all operations on a tcp socket (such as connect(), read(), write()). A value of 0 means no-timeout (system-wide timeouts might still apply). If $new_value is negative, no new value will be set but the current value will be returned. If $new_value is positive it will set as new tcp timeout and the old value will be returned.use_random_node ( $new_value )
Set the internal shardcache client flag which determines if using the consistent hashing to always query the node responsible for a given key, or select any random node among the available ones when executing a get/set/del/evict command. If $new_value is true a random node will be used, if false the node responsible for the specific key will be selected. Note that the 'stats', the 'index' and the 'migration*' commands are not affected by this flagget ( $key )
Get the value for $key. If found in the cache it will be returned immediately, if this node is responsible for $key, the underlying storage will be queried for the value, otherwise a request to the responsible node in the shardcache 'cloud' will be done to obtain the value (and the local cache will be populated)get_async ( $key, $coderef, [ $priv ] )
Get the value for $key asynchronously. This function will block and call the provided callback as soon as a chunk of data is read from the node. The control will be returned to the caller when there is no more data to read or an error occurred $coderef must be a reference to a perl SUB which will get as arguments the tuple : ($node, $key, $data, $priv) $priv will be the same scalar value passed to get_async() as last argument If the $coderef, called at each chunk of data being received, returns a NON-TRUE value the fetch will be interrupted and the coderef won't be called anymore. Returning a TRUE value will make it go ahead until completed.exists ( $key )
Check existence of the key on the node responsible for it. Returns 1 if the key exists, 0 if doesn't exist, -1 on errorstouch ( $key )
For loading of a key into the cache if not loaded already, otherwise updates the loaded-timestamp for the cached key. Returns 0 on success, -1 on errors.set ( $key, $value, [ $expire ] )
Set a new value for $key in the underlying storage.add ( $key, $value, [ $expire ] )
Set a new value for $key in the underlying storage if it doesn't exists. Returns 0 if successfully stored, 1 if already existsing, -1 in case of errors.del ( $key )
Remove the value associated to $key from the underlying storage (note the cache of all nodes will be evicted as well).evict ( $key )
Evict the value associated to $key from the cache (note this will not remove the value from the underlying storage).stats ( [ $node ] )
Retrieve the stats for a given node (or all nodes if none is provided as parameter).index ( [ $node ] )
Retrieve the index for a given node (or all nodes if none is provided as parameter).check ( [ $node ] )
Checks the status of a given node (or all nodes if none is provided as parameter).get_multi ( @$keys )
Get multiple keys at once. The @$keys parameter is expected to be an ARRAYREF containing the keys to retrieve. Returns an arrayref containing the values for the requested keys. Values are stored at the same index of the corresponding key in the input array. Empty or unretrieved values will be returned as undef. Note that multi-commands are not all-or-nothing, some operations may succeed, while others may fail.set_multi ( %$pairs )
Get multiple keys at once. The %$pairs parameter is expected to be an HASHREF containing the key/value pairs to set. Returns an hashref containing the same keys of the input hashref as keys and the status of the operation as values (1 if successfully set, 0 otherwise). Note that multi-commands are not all-or-nothing, some operations may succeed, while others may fail.
Exportable functions
shardcache_client_t *shardcache_client_create(shardcache_node_t *nodes, int num_nodes, char *auth)
int shardcache_client_del(shardcache_client_t *c, void *key, size_t klen)
void shardcache_client_destroy(shardcache_client_t *c)
int shardcache_client_evict(shardcache_client_t *c, void *key, size_t klen)
size_t shardcache_client_get(shardcache_client_t *c, void *key, size_t klen, void **data)
int shardcache_get_async(shardcache_t *cache, void *key, size_t klen, shardcache_get_async_callback_t cb, void *priv);
int shardcache_client_exists(shardcache_client_t *c, void *key, size_t klen)
int shardcache_client_touch(shardcache_client_t *c, void *key, size_t klen)
int shardcache_client_set(shardcache_client_t *c, void *key, size_t klen, void *data, size_t dlen, uint32_t expire)
int shardcache_client_add(shardcache_client_t *c, void *key, size_t klen)
int shardcache_client_stats(shardcache_client_t *c, char *node, char **buf, size_t *len);
int shardcache_client_check(shardcache_client_t *c, char *node);
int shardcache_client_tcp_timeout(shardcache_client_t *c, int new_value);
int shardcache_client_use_random_node(shardcache_client_t *c, int new_value);
shardcache_storage_index_t *shardcache_client_index(shardcache_client_t *c, char *node);
int shardcache_client_errno(shardcache_client_t *c)
char *shardcache_client_errstr(shardcache_client_t *c)SEE ALSO
Mention other useful documentation such as the documentation of related modules or operating system documentation (such as man pages in UNIX), or any relevant external documentation such as RFCs or standards.
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AUTHOR
xant, <xant@xant.net>
COPYRIGHT AND LICENSE
Copyright (C) 2013 by xant
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.12.4 or, at your option, any later version of Perl 5 you may have available.