Iterating over Predis\Connection\Aggregate\RedisCluster returns all
the connections currently mapped in the slots map instead of just the
ones initialized in the pool.
When the slots map is retrieved from Redis (which by default is done
automatically) this allows to iterate over all of the current master
nodes of the cluster. When the underlying use of "CLUSTER SLOTS" is
disabled the iteration returns only connections with a slots range
associated in their parameters or initialized by `-MOVED` responses
to make the behaviour of the iteration consistent between the two
modes of operation.
When various nodes in the configuration are unreachable while trying
to send a command, we should attempt to contact a reachable node to
fetch an updated slots map up to $retryLimit times or until there are
no more servers in the pool before giving up.
It is possible that the slots map fetched from Redis contains stale
data and points to a dead server, this happens when the nodes still
have to agree that a master server is down before promoting a slave
to the role of master. In this case no further attempts to execute
the command are performed and an exception is thrown.
This still needs some more testing and will delay v1.0.4 a few days
past its scheduled release.
This prevents an early failure of the command execution on the client
when one slave gets back online but is still loading the dataset from
disk (when this happens, Redis returns the -LOADING error response).
This commit fixes#280.
When the connection to a node in the cluster fails in the attempt to
execute a command, Predis now removes the failed connection from the
cluster pool and contacts a random node to ask for a fresh slots map
and tries to execute the command once again.
When the cluster is configured to have each master replicated to one
or more slaves, one the slaves is automatically promoted to the role
of master by redis-cluster with this change being reflected in the
output of CLUSTER SLOTS, so the next execution should run just fine.
Our current approach is relatively naive as CLUSTER SLOTS is executed
against a random master node, meaning that the client must open a new
connection and execute one more roundtrip only to fetch the new slots
map. For now it is enough, it is still better than having the client
fail when you actually have somes slaves in your redis-cluster setup,
but one improvement could consist in caching the list of slaves for
each master returned in the response of CLUSTER SLOTS so that when a
connection fails the client can try to guess which connection should
use for the next attempt.
This commit closes#173, closes#215, and closes#314.
When using redis-cluster it is now also possible to pass one slot or
non-contiguous ranges of slots via connection parameters in order to
improve the ability to pre-configure the slots map on the client.
Here is an example:
$parameters = [
'tcp://10.0.0.1:6379?slots=0-5460,5500-5600,11000',
'tcp://10.0.0.2:6379?slots=5461-5499,5600-10921',
'tcp://10.0.0.3:6379?slots=10922-10999,11001-16383',
];
This commit fixes#312 (props to @kenotr0n for the original PR).
Common failures are the use of SELECT with a database index outside
the bound of the configured number of databases in redis.conf or the
use of a wrong password for authentication with AUTH.
This resolves#322.
Now the client can discover the whole replication configuration by
asking to one of the servers (master has the precedence) using the
INFO REPLICATION command. This is obviously a best-effort fallback
and there is no strong guarantee about reliability and efficiency.
By enabling auto-discovery, the client automates this process when
the execution of a command fails because one of the target servers
is unreachable. The replication connection requires an instance of
connection factory associated to it in order to be able to create
new connections on the fly.
It is possible to enable the auto-discovery procedure easily via
client options:
$client = new Predis\Client($servers, [
'replication' => true,
'autodiscovery' => true,
]);
Internally the replication class uses this order to pick which server
it should connect to: current connection, one of the slaves, master.
If there is at least 1 slave, connect() will not fail even if master
is undefined. If there are no slaves, connect() will pick master. If
there are no connections registered for replication, connect() will
fail immediatly.
Using IPv6 with Predis was basically impossible due to various inconsistencies
and bugs through the library, now it is supported by all the connection classes.
Following the standard for IPv6 literal addresses in URI strings, the IP literal
must be enclosed within square brackets when passing the parameters as a string:
$parameters = 'tcp://[2001:db8:0:f101::1]:6379';
See https://tools.ietf.org/html/rfc3986#section-3.2.2 for further details.
This commit also fixes#239 making redis-cluster usable with nodes using IPv6.
Instead of using "unix://" you should just use "unix:":
$old = 'unix:///path/to/redis.sock';
$new = 'unix:/path/to/redis.sock';
The old format should be considered obsolete and will not be supported
starting from the next major release of Predis.
Meh
This is handy for accessing remote Redis instances over a secure SSL connection
which is currently a popular option or even requirement with many cloud hosting
environments.
In order to configure the client to use an SSL-encrypted connection the scheme
in the connection parameters must be either "tsl" or "rediss" and a set of SSL
options (see http://php.net/manual/en/context.ssl.php) must be provided via the
"ssl" parameter as a named array.
The following example (which does not necessarily represent an example of good
practices!) illustrates how to set the "ssl" parameter using a named array and
the equivalent URI string:
// Parameters as named array
$parameters = [
'scheme' => 'tls',
'host' => '127.0.0.1',
'ssl' => [
'cafile' => '/home/adaniele/redis.pem',
'verify_peer_name' => false,
],
];
// Parameters as URI string
$parameters = 'tls://127.0.0.1?ssl[cafile]=redis.pem&ssl[verify_peer_name]=1';
Support for SSL is currently limited to the Predis\Connection\StreamConnection
backend but we intend to investigate if it is possible to extend this feature
to Predis\Connection\PhpiredisStreamConnection in the future.
Be aware that using encrypted connections may lead to a performance degradation
especially in the connect() operation due to the overhead of the TLS handshake.
Unfortunately there is no real way to reuse SSL sessions from userland, aside
from enabling persistent connections, but this will work only on PHP >= 7.0.0
because previous versions of PHP do not provide enough info about a stream from
get_stream_meta_data().
NOTE: Redis does not have built-in support for SSL-encrypted connections, but if
you want to expose it to public networks you may want to rely on "stunnel".
Falling back to a default timeout values should be done by the connection class
as it is an implementation detail that may vary depending on the backend.
These parameters augment the set of user-supplied parameters when creating a new
connection, but they do not override specific parameters when already defined.
An example of self-contained configuration using client options:
$client = new Predis\Client('tcp://127.0.0.1', [
'parameters' => [
'timeout' => 10,
],
'connections' => function ($options) {
$factory = $options->getDefault('connections');
$factory->setDefaultParameters($options->parameters);
return $factory;
},
]);
This change will be useful for both redis-cluster and redis-sentinel as it makes
it easy to apply shared parameters such as a common password for authentication
when the server returns one ore more new nodes from response (think of -MOVED).
stream_socket_client() has the undocumented ability to open different persistent
streams by providing a path in the $address string. Previously we supported this
behaviour with a combination of "persistent" and "path" (see #139) but this can
be confusing, especially now that we support the redis:// scheme which uses the
path part of an URI string to specify a database number.
After this change, instead of using an URI string such as:
$parameters = 'tcp://127.0.0.1/first?persistent=1&database=5';
You should use the following ones:
$parameters = 'tcp://127.0.0.1?persistent=first&database=5';
$parameters = 'redis://127.0.0.1/5?persistent=first';
Avoiding "path" makes even more sense when using array connection parameters:
$parameters = [
'host' => '127.0.0.1',
'database' => 5,
'persistent' => 'first',
]
This feature is not supported when using UNIX domain sockets because the path
trick of stream_socket_client() does not play well with the actual path of the
socket file. The client will throw an InvalidArgumentException exception to
notify the user.
NOTE: unfortunately we have to disable the tests for persistent connections when
running under HHVM due to a bug in their implementation of get_resource_type()
preventing us to recognize a persistent stream from userland code.
Serializing an instance of a redis-cluster connection with its nodes
can take more than 1 seconds on extremely slow hardware.
See issue #220 for reference.
Daniele Alessandri
Pascal Hofmann