cpp-hiredis-cluster

c++ cluster wrapper for hiredis with async and unix sockets features

Features:

• redis cluster support
• async hiredis functions are supported
• support of clustering through unix sockets (see examples)
• threaded safe connection pool support
• maximum hiredis compliance in functions invocations (easy to migrate from existing hiredis source code)
• follow moved redirections
• follow ask redirections
• understandable sources
• best performance (see performance test result here)

Dependencies:

• library "hiredis" versioned >= 0.12.0
• installed redis server versioned >= 3.0.0
• configured cluster, see cluster tutorial on how to setup cluster
• its better for you to know about "moved" and "asking" redirections clusterspec (not necessary for quick start)
• libevent-2.0 (only if you choose asynchronous client, see "Asynchronous client example"), the latest stable version is libevent-2.0.22

Examples

Synchronous client example

    // Declare cluster pointer
    Cluster<redisContext>::ptr_t cluster_p;
    // Declare pointer to simple hiredis reply structure
    redisReply * reply;
    // Create cluster passing acceptable address and port of one node of the cluster nodes 
    cluster_p = HiredisCommand<>::createCluster( "127.0.0.1", 7000 );
    // send command to redis passing created cluster pointer, key which you wish to access in the command
    // and command itself with parameters with printf like syntax
    reply = static_cast<redisReply*>( HiredisCommand<>::Command( cluster_p, "FOO", "SET %s %s", "FOO", "BAR1" ) );
    // Check reply state and type
    if( reply->type == REDIS_REPLY_STATUS  || reply->type == REDIS_REPLY_ERROR )
    {
       // Process reply
        cout << " Reply to SET FOO BAR " << endl;
        cout << reply->str << endl;
    }
    // free hiredis reply structure
    freeReplyObject( reply );
    // delete cluster by its pointer
    delete cluster_p;

source code is available in src/examples/example.cpp

Asynchronous client example

// declare a callback to process reply to redis command
static void setCallback( typename Cluster<redisAsyncContext>::ptr_t cluster_p, void *r, void *data )
{
    // declare local pointer to work with reply
    redisReply * reply = static_cast<redisReply*>( r );
    // cast data that you pass as callback parameter below (not necessary)
    string *demoData = static_cast<string*>( data );
    // check redis reply usual
    if( reply->type == REDIS_REPLY_STATUS  || reply->type == REDIS_REPLY_ERROR )
    {
        // process reply
        cout << " Reply to SET FOO BAR " << endl;
        cout << reply->str << endl;
    }
    // process callback parameter if you want (not necessary)
    cout << *demoData << endl;
    delete demoData;
    // disconnecting cluster will brake the event loop
    cluster_p->disconnect();
}
// declare a functions that invokes redis commanf
void processAsyncCommand()
{
    // Declare cluster pointer with redisAsyncContext as template parameter
    Cluster<redisAsyncContext>::ptr_t cluster_p;
    // ignore sigpipe as we use libevent
    signal(SIGPIPE, SIG_IGN);
    // create libevent base
    struct event_base *base = event_base_new();
    // create custom data that will be passed to callback (not necessary)
    string *demoData = new string("Demo data is ok");
    // Create cluster passing acceptable address and port of one node of the cluster nodes
    cluster_p = AsyncHiredisCommand<>::createCluster( "127.0.0.1", 7000, static_cast<void*>( base ) );
    // send command to redis passing created cluster pointer, key which you wish to access in the command
    // callback function, that just already declared above, pointer to any user defined data
    // and command itself with parameters with printf like syntax
    AsyncHiredisCommand<>::Command( cluster_p,                      // cluster pointer
                                     "FOO",                             // key accessed in current command
                                 setCallback,                       // callback to process reply
                                 static_cast<void*>( demoData ),    // custom user data pointer
                                 "SET %s %s",                       // command
                                 "FOO",                             // paramener - key
                                 "BAR1" );                          // parameter - value
    // process event loop
    event_base_dispatch(base);
    // delete cluster object
    delete cluster_p;
    // free event base
    event_base_free(base);
}

source code is available in src/examples/asyncexample.cpp

it's easy to modify asynchronous client for use with another event loop libraries

Other examples

• example showing how to create a threaded connection pool (src/examples/threadpool.cpp)
• example showing how to user unix sockets (src/examples/unixsocketexample.cpp)
• example showing how to process errors in case of asynchronous operation (src/examples/asyncerrorshandling.cpp)

Installing:

• This is a header only library! No need to install, just include headers in your project
• Run cmake if you want to build examples

Issuses:

• If you have link errors for hiredis sds functions just wrap all hiredis headers in extern C in your project

• If you used this library before note that usage of AsyncHiredisCommand and HiredisCommand little. AsyncHiredisCommand and HiredisCommand change to AsyncHiredisCommand<> HiredisCommand<>

AsyncHiredisCommand -> AsyncHiredisCommand<>
HiredisCommand -> HiredisCommand<>

#Mail shinmail at gmail dot com