Motivation:
Some Redis commands are very connection specific that have impacts on future access that makes it difficult in the current
checkout-use-return cycle that `RedisConnectionPool` uses.
Developers need a way to borrow a specific connection, chain several commands together, and then return the connection to the pool.
Modifications:
- Add: `leaseConnection` method to `RedisConnectionPool` which provides a connection from the pool and returns it after a provided closure's ELF resolves
- Add: `allowSubscriptions` property to `RedisConnection` for controlling the ability to make PubSub subscriptions
- Add: `RedisClientError.pubsubNotAllowed` case for when `RedisConnection.allowSubscriptions` is set to `false` and a subscription was still attempted
Result:
Developers should now have an "escape hatch" with `RedisConnectionPool` to do limited exclusive chains of operations on a specific connection.
Motivation:
One of the great features of Redis is being able to subscribe and receive messages published to specific channels
as a way of acting as a message queue for processing jobs.
PubSub requires a specific understanding of the connection model that can only be implemented directly in this library.
Modifications:
- Add: `RedisPubSubHandler` to sit in front of `RedisCommandHandler` to manage subscription callbacks and Redis registration
- Add: `publish` and the `pubsub` commands
- Add: `addPubSubHandler` extension to `NIO.Channel`
- Add: Type-safe String wrapper of `RedisChannelName` for PubSub methods
- Add: `pubsubSubscriptionNotFound` error case
- Add: `isSubscribed` property to `RedisConnection`
- Add: `availableConnectionCount` and `leasedConnectionCount` properties to `RedisConnectionPool`
- Add: Metrics for PubSub
- Add: `makeNewPool` factory method to `RedisConnectionPoolIntegrationTestCase`
- Change: `RedisClient` to require methods for PubSub management, as they are intrinsicly tied to the client's connection model
- Change: Parsing of `PING` response for handling special case in PubSub mode
- Rename: `ActiveConnectionGauge` to `RedisMetrics.IncrementalGauge`
Result:
Developers will now be able to use Redis in PubSub mode with both connections and pools.
This resolves#6
Nathan Harris