This is a complete overhaul of how aggregate connections are created and
initialized, now everything is self-contained in our usual 3 supported
client options: "aggregate", "cluster" and "replication".
The usage of callables acting as connection initializerss is now more
consistent through the various options. When the callable is invoked it
receives 3 arguments (the original set of connection parameters passed
by reference, the options container, the current option) and must return
an instance of Predis\Connection\AggregateConnectionInterface otherwise
an InvalidArgumentException is thrown.
When using "cluster" and "replication" the returned aggregate connection
is automatically populated by adding the list of nodes in $parameters,
on the other hand "aggregate" skips this automatism so it is up to the
user. In any case the user-supplied callable receives $parameters as a
reference, setting $parameters to NULL inside the body of the callable
makes the client skip automatic aggregation regardless of the option in
use.
In addition to this the actual procedure of adding nodes to an aggregate
connection has been moved directly into the respective options instead
of being spread between the client (which instead should just pass a set
of parameters and get back a fully-configured aggregate connection) and
the connection factory (and the scope of a connection factory is only to
create new connetion instances to single Redis servers).
We have renamed most methods to drop the "command" suffix as it is quite
redundant. Due to this change and thanks to variadic methods introduced
with PHP 5.6 we took the opportunity to replace both "supportsCommand()"
and "supportsCommands()" with a single new method "supports()".
Added more stringent typehints for method arguments and typehints for
return values now that we do not need to support anything below PHP 7.2.
Also moved from using array() to [] in source code of class involved.
There was no real meaning to have a callback here, for the most part it
was just a leftover of a previous approach implemented with ee7104d and
quickly superseded by the current approach that simply returns the new
client instance instead of using callbacks.
From feedback to #644.
When using replication backends, now the role of a connection is not
defined by its alias but by the new connection parameter "role" that
can be set to "master", "slave" and (for redis-sentinel) "sentinel".
This also led to a redesign of how connections can be retrieved from
replication backends: the method getConnectionById() now retrieves a
connection only by its ID (ip:port pair), to get a connection by its
alias there is the new method getConnectionByAlias(). This method is
not supported by the redis-sentinel backend due to its dynamic nature
(connections are retrieved and initialized at runtime from sentinels)
but it is still possible to get a single connection from the pool by
using its ID. It is also possible to retrive a connection by its role
using the method getConnectionByRole().
NOTE: the "role" parameter is an hint for the internals of aggregate
connection backends so it is still possible that the actual role of
a connection changes during the execution of a script (e.g. a slave
gets promoted to the role of master): in this case the parameters of
that connection will not be changed as they are immutable, but the
method getConnectionByRole() will return the appropriate connection.
Predis\Client::getClientBy() has been updated with the addition of
"role" and "alias" as supported selectors.
This method improves the previous one, which worked only by picking a
connection by ID, allowing users to specify a selector type among the
following ones: "id", "key", "slot", "command". These selectors are
expanded internally to methods, invoked against the connection object
in use by the client, that follow the getConnectionByXXX() convention
already in use through the library:
id => getConnectionById()
key => getConnectionByKey()
slot => getConnectionBySlot()
command => getConnectionByCommand()
The underlying connection does not necessarily need to implement the
aggregate connection interface as the client relies on a duck-typing
approach by using method_exists().
This new method acts exactly like "getClientFor()" by returning a new
client instance for the specified node unless a callback is passed as
the second argument, in this case the callback is invoked and the new
client instance is passed to it. The value returned by the callback
is used as the return value of the "on()" method.
All option classes have been moved in the Predis\Configuration\Option
namespace and some have been optimized to have less impact on client
initialization timings.
Furthermore the accepted values for some options have been changed,
this is the complete list of accepted values:
- _aggregate_: callable returning an aggregate connection.
- cluster: string value ("predis", "redis"), callable returning an
aggregate connection.
- replication: string value ("predis", "sentinel"), callable returning
an aggregate connection.
- commands: command factory, named array mapping command IDs to PHP
classes, callable returning a command factory or a named array.
- connections: connection factory, callable returning a connection
factory, named array mapping connection schemes to PHP classes.
- _prefix_: string value, command processor, callable.
- _exceptions_: boolean value.
Note that the cluster and replication options now return a closure
acting as initializer instead of an aggregate connection.
This change reduces some unnecessary complexity in the library, Redis
commands do not change much after all. Developers can still implement
their own commands factory, inject new commands or override existing
ones. The "profile" client options has been renamed to "commands" and
it accepts instances of Predis\Command\FactoryInterface.
The test suite checks at runtime the version of the running instance
of Redis for integration tests to adapt itself automatically.
Predis\Client now requires a list of connection parameters pointing to
sentinel instances and mandatory options "replication" and "service" set
respectively to "sentinel" and the chosen name for the master instance.
$sentinels = ['tcp://127.0.0.1:5381', 'tcp://127.0.0.1:5382'];
$options = ['replication' => 'sentinel', 'service' => 'mymaster'];
$client = new Predis\Client($sentinels, $options);
Despite being nice and clean on the outside I am not really fond of the
code being used internally to make this kind of configuration possible.
Improvements in this respect would require a few breaking changes (not
even an option for a minor release) so things will change for the good
with Predis 2.0.
Daniele Alessandri
Peter Gribanov
Till Krüss
orvice
Thibaud BARDIN