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This means that, when not saturated, objects in the pool will be reused more often. This behavior allows you to create a pool of objects which in turn have some kind of time outs themselves. For instance, objects which keep an underlying TCP connection open until they're idle for some time. An example of this is `Net::HTTP::Persistent`. See also issue #20. |
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| Gemfile | ||
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| README.md | ||
connection_pool
Generic connection pooling for Ruby.
MongoDB has its own connection pool. ActiveRecord has its own connection pool. This is a generic connection pool that can be used with anything, e.g. Redis, Dalli and other Ruby network clients.
Install
gem install connection_pool
Notes
- Connections are eager created when the pool is created.
- There is no provision for repairing or checking the health of a connection; connections should be self-repairing. This is true of the dalli and redis clients.
Usage
Create a pool of objects to share amongst the fibers or threads in your Ruby application:
@memcached = ConnectionPool.new(:size => 5, :timeout => 5) { Dalli::Client.new }
Then use the pool in your application:
@memcached.with_connection do |dalli|
dalli.get('some-count')
end
If all the objects in the connection pool are in use, with_connection will block
until one becomes available. If no object is available within :timeout seconds,
with_connection will raise a Timeout::Error.
You can use ConnectionPool::Wrapper to wrap a single global connection, making
it easier to port your connection code over time:
$redis = ConnectionPool::Wrapper.new(:size => 5, :timeout => 3) { Redis.connect }
$redis.sadd('foo', 1)
$redis.smembers('foo')
The Wrapper uses method_missing to checkout a connection, run the
requested method and then immediately check the connection back into the
pool. It's not high-performance so you'll want to port your
performance sensitive code to use with_connection as soon as possible.
$redis.with_connection do |conn|
conn.sadd('foo', 1)
conn.smembers('foo')
end
Once you've ported your entire system to use with, you can simply
remove ::Wrapper and use a simple, fast ConnectionPool.
Author
Mike Perham, @mperham, http://mikeperham.com