A simple Redis pool for node using generic-pool.

npm install sol-redis-pool

Pull requests welcome...

Create a new Redis connection pool.

    // Configure the Redis client connection settings.
    var redisSettings = {
        host: "127.0.0.1",
        port: 6379,
        password: "dingbats",
        db: 3 // Set the default DB number.
    };
    
    // Configure the generic-pool settings.
    var poolSettings = {
        max: 10,
        min: 2
    };
    
    var myPool = RedisPool(redisSettings, poolSettings);

The auth_pass option is deprecated. Please use the password option instead.

When you acquire a new client these options can be passed to the Redis client. See https://github.com/NodeRedis/node_redis/blob/master/README.md for more details.

Note: The error value is set to null on the first failure.

// The first connection attempt.
{ attempt: 1,
  error: null,
  total_retry_time: 0,
  times_connected: 1 }
// The second attempt.
{ attempt: 2,
  error: 
   { [Error: Redis connection to 127.0.0.1:6379 failed - connect ECONNREFUSED 127.0.0.1:6379]
     code: 'ECONNREFUSED',
     errno: 'ECONNREFUSED',
     syscall: 'connect',
     address: '127.0.0.1',
     port: 6379 },
  total_retry_time: 1000,
  times_connected: 1 }

    retry_strategy: function (options) {
        if (options.attempt > 10) {
            // Stop retrying afer 10 attempts.
            return undefined;
        }
        // Increase reconnect delay by 150ms.
        return options.attempt * 150;
    }

Use this strategy when you want to pool to not attempt reconnections.

    retry_strategy: function (options) {
        return undefined;
    }

Supported generic-pool settings. See https://github.com/coopernurse/node-pool/blob/master/README.md for more information.

Acquires a redis client from the pool. The callback is passed an err and client. The client object is a normal redis client. Make sure you release the client using the .release(client) method when you are done.

The pool now supports optional priority queueing. This becomes relevant when no resources are available and the caller has to wait. acquire() accepts an optional priority int which specifies the caller's relative position in the queue. This requires setting the pool option priorityRange. See https://github.com/coopernurse/node-pool/blob/master/README.md for more information.

Same as the aquire method but allows you to select a DB.

This method will release your client object back into the pool. Use this method when you no longer need the client.

This method will drain the connection pool completely and execute the callback when finished. You should call this when you want to close your application. If you do not your application will continue to run forever.

Returns the factory.name for this pool.

Returns number of resources in the pool regardless of whether they are free or in use.

Returns number of unused resources in the pool.

Returns number of callers waiting to acquire a resource.

Additional events will be added.

This event is emitted when a Redis client emits an "error", connection error event. You still need to pay attention to the err passed to your callback when you issue an acquire. The error object contains an attribute named cid for tracking which client connection had an error.

The pool will emit reconnecting when trying to reconnect to the Redis server after losing the connection. Listeners are passed an object containing delay (in ms), attempt (the attempt #), and cid attributes.

This event is emitted when a Redis client is closed by the connection pool. The event will pass an error and cid value.

Examples are located in the examples/ folder in the repository. These examples will automatically close when done. If you change the min option for the pool the application will stay running forever.

• authentication.js - shows an example using a redis password.
• oversubscribe.js - shows what happens when you request more clients than you have in your pool.
• ping-example.js - a simple example that issues a Redis PING command.
• offline.js - shows how the enable_offline_queue option and recovery works.
• retry.js - shows a retry_strategy option in action.
• unix.js - shows a unix socket connection.

0.3.3 - April 28 2017

• Added prefix option. #25

0.3.2 - October 23 2016

• Added bluebird promise support for underlying redis connections in the pool. #21
• Added the tls redis option. #22

0.3.1 - August 31 2016

• Prevent the pool.release(client) method from releasing a disconnected client back into the pool. Fixes issue #19. Some users may need to watch their pool min value.
• Added connection tracking to all clients int the pool. You may access the value using the client._sol_cid property. This value is passed to the destroy, reconnecting, and error events as well. This should help users with their application logging.
• Improved the retry_strategy examples in the README.md and fixed the retry.js example.
• Fixed some examples.
• Fixed a bug in the reconnecting event.
• Updated redis-pool-spec.js file.
• Moved older changes to CHANGES.md

0.3.0 - August 28 2016

• Client Connection Changes:
  • Replaced the auth_pass option with password.
  • Replaced the unix_socket option with path.
  • Added the url option for connections.
  • Fixed an issue with an extra select statement being sent on client connect when the db option is set.
• Added support for the redis client retry_strategy option.
• Removed deprecated options: 'parser', 'socket_nodelay', 'retry_max_delay', 'connect_timeout', 'max_attempts'
• Added options: 'string_numbers', 'retry_unfulfilled_commands', 'disable_resubscribing', 'rename_commands'
• Changed minimum redis client version to 2.6.2.
• Added a reconnecting event.