This is a first implementation that is based on the work of @vmattila but some
more changes and missing bits are required in order to be considered complete.
To leverage redis-sentinel the client must be configured using the "aggregate"
option instead of the usual "replication" option, thought this may change for
the release of Predis v1.1.0 (it __will__ change for Predis v2.0.0 but this is
a whole different matter). This is a configuration example:
use Predis\Connection\Aggregate\SentinelReplication;
$sentinels = [
'tcp://127.0.0.1:5381',
'tcp://127.0.0.1:5382',
'tcp://127.0.0.1:5383',
];
$client = new Predis\Client($sentinels, [
'service' => 'nrk-master',
'aggregate' => function() {
return function ($sentinels, $options) {
$service = $option->service;
$connections = $options->connections;
return new SentinelReplication($sentinels, $service, $connections);
};
},
]);
The missing bits right now are:
- A more solid handling of failures when querying sentinels.
- When the connection fails while executing a command on one of the servers,
we should query again a sentinel and then re-issue the command accordingly.
Apparently HHVM is more strict than PHP in stream_socket_client() and does not
like at all IPv4 addresses and hostnames eclosed in square brackets. Note that
it is not that weird as square brackets are mandatory only when IPv6 addresses
are embedded in URI strings, so it is more like a weird incompatiblity of HHVM
with the behaviour of the standard PHP interpreter. The connect() attempt fails
but not due to the server being unavailable or some connectivity issue.
The important lesson is: never rely on undocumented behaviours especially when
targeting different runtimes, and do not forget to run the test suite on every
platform right before release like I unfortunately did.
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.
This trivial change makes it possible to use overridden static methods
when extending Predis\Command\Processor\KeyPrefixProcessor. PHP always
invokes the static methods of a parent class when using self:: even if
the extended classes override them.
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".
The redis-cluster connection relies on a client-initialized connection factory,
so use Connection\Factory::setDefaultParameters() to set the default parameters
that must be applied to new nodes discovered through -MOVED or -ASK responses.
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.
Each connection class should implement its own checks for connection parameters,
even at the cost of some code duplication (inheritance is not just about code
reuse after all).
Daniele Alessandri