pool

README

Pool

Pool is a thread safe connection pool for net.Conn interface. It can be used to manage and reuse connections.

Install and Usage

Install the package with:

go get gopkg.in/fatih/pool.v2

Import it with:

import "gopkg.in/fatih/pool.v2"

and use pool as the package name inside the code.

Example

// create a factory() to be used with channel based pool
factory    := func() (net.Conn, error) { return net.Dial("tcp", "127.0.0.1:4000") }

// create a new channel based pool with an initial capacity of 5 and maximum
// capacity of 30. The factory will create 5 initial connections and put it
// into the pool.
p, err := pool.NewChannelPool(5, 30, factory)

// now you can get a connection from the pool, if there is no connection
// available it will create a new one via the factory function.
conn, err := p.Get()

// do something with conn and put it back to the pool by closing the connection
// (this doesn't close the underlying connection instead it's putting it back
// to the pool).
conn.Close()

// close pool any time you want, this closes all the connections inside a pool
p.Close()

// currently available connections in the pool
current := p.Len()

Credits

• Fatih Arslan
• sougou

License

The MIT License (MIT) - see LICENSE for more details

Documentation

Overview

Package pool implements a pool of net.Conn interfaces to manage and reuse them.

Index

• Variables
• type Factory
• type Pool
  • func NewChannelPool(initialCap, maxCap int, factory Factory) (Pool, error)
• type PoolConn
  • func (p PoolConn) Close() error
  • func (p *PoolConn) MarkUnusable()

Variables

var (
	// ErrClosed is the error resulting if the pool is closed via pool.Close().
	ErrClosed = errors.New("pool is closed")
)

Types

type Factory

type Factory func() (net.Conn, error)

Factory is a function to create new connections.

type Pool

type Pool interface {
	// Get returns a new connection from the pool. Closing the connections puts
	// it back to the Pool. Closing it when the pool is destroyed or full will
	// be counted as an error.
	Get() (net.Conn, error)

	// Close closes the pool and all its connections. After Close() the pool is
	// no longer usable.
	Close()

	// Len returns the current number of connections of the pool.
	Len() int
}

Pool interface describes a pool implementation. A pool should have maximum capacity. An ideal pool is threadsafe and easy to use.

func NewChannelPool

func NewChannelPool(initialCap, maxCap int, factory Factory) (Pool, error)

NewChannelPool returns a new pool based on buffered channels with an initial capacity and maximum capacity. Factory is used when initial capacity is greater than zero to fill the pool. A zero initialCap doesn't fill the Pool until a new Get() is called. During a Get(), If there is no new connection available in the pool, a new connection will be created via the Factory() method.

type PoolConn

type PoolConn struct {
	net.Conn
	// contains filtered or unexported fields
}

PoolConn is a wrapper around net.Conn to modify the the behavior of net.Conn's Close() method.

func (PoolConn) Close

func (p PoolConn) Close() error

Close() puts the given connects back to the pool instead of closing it.

func (*PoolConn) MarkUnusable

func (p *PoolConn) MarkUnusable()

MarkUnusable() marks the connection not usable any more, to let the pool close it instead of returning it to pool.