added new cache libraries
This commit is contained in:
527
vendor/github.com/garyburd/redigo/redis/pool.go
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vendored
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527
vendor/github.com/garyburd/redigo/redis/pool.go
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vendored
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@ -0,0 +1,527 @@
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// Copyright 2012 Gary Burd
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package redis
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import (
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"bytes"
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"crypto/rand"
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"crypto/sha1"
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"errors"
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"io"
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"strconv"
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"sync"
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"sync/atomic"
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"time"
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"github.com/garyburd/redigo/internal"
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)
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var (
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_ ConnWithTimeout = (*pooledConnection)(nil)
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_ ConnWithTimeout = (*errorConnection)(nil)
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)
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var nowFunc = time.Now // for testing
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// ErrPoolExhausted is returned from a pool connection method (Do, Send,
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// Receive, Flush, Err) when the maximum number of database connections in the
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// pool has been reached.
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var ErrPoolExhausted = errors.New("redigo: connection pool exhausted")
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var (
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errPoolClosed = errors.New("redigo: connection pool closed")
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errConnClosed = errors.New("redigo: connection closed")
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)
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// Pool maintains a pool of connections. The application calls the Get method
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// to get a connection from the pool and the connection's Close method to
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// return the connection's resources to the pool.
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//
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// The following example shows how to use a pool in a web application. The
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// application creates a pool at application startup and makes it available to
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// request handlers using a package level variable. The pool configuration used
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// here is an example, not a recommendation.
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//
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// func newPool(addr string) *redis.Pool {
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// return &redis.Pool{
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// MaxIdle: 3,
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// IdleTimeout: 240 * time.Second,
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// Dial: func () (redis.Conn, error) { return redis.Dial("tcp", addr) },
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// }
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// }
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//
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// var (
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// pool *redis.Pool
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// redisServer = flag.String("redisServer", ":6379", "")
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// )
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//
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// func main() {
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// flag.Parse()
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// pool = newPool(*redisServer)
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// ...
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// }
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//
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// A request handler gets a connection from the pool and closes the connection
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// when the handler is done:
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//
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// func serveHome(w http.ResponseWriter, r *http.Request) {
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// conn := pool.Get()
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// defer conn.Close()
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// ...
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// }
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//
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// Use the Dial function to authenticate connections with the AUTH command or
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// select a database with the SELECT command:
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//
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// pool := &redis.Pool{
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// // Other pool configuration not shown in this example.
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// Dial: func () (redis.Conn, error) {
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// c, err := redis.Dial("tcp", server)
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// if err != nil {
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// return nil, err
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// }
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// if _, err := c.Do("AUTH", password); err != nil {
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// c.Close()
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// return nil, err
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// }
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// if _, err := c.Do("SELECT", db); err != nil {
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// c.Close()
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// return nil, err
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// }
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// return c, nil
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// },
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// }
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//
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// Use the TestOnBorrow function to check the health of an idle connection
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// before the connection is returned to the application. This example PINGs
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// connections that have been idle more than a minute:
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//
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// pool := &redis.Pool{
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// // Other pool configuration not shown in this example.
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// TestOnBorrow: func(c redis.Conn, t time.Time) error {
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// if time.Since(t) < time.Minute {
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// return nil
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// }
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// _, err := c.Do("PING")
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// return err
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// },
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// }
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//
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type Pool struct {
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// Dial is an application supplied function for creating and configuring a
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// connection.
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//
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// The connection returned from Dial must not be in a special state
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// (subscribed to pubsub channel, transaction started, ...).
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Dial func() (Conn, error)
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// TestOnBorrow is an optional application supplied function for checking
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// the health of an idle connection before the connection is used again by
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// the application. Argument t is the time that the connection was returned
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// to the pool. If the function returns an error, then the connection is
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// closed.
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TestOnBorrow func(c Conn, t time.Time) error
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// Maximum number of idle connections in the pool.
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MaxIdle int
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// Maximum number of connections allocated by the pool at a given time.
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// When zero, there is no limit on the number of connections in the pool.
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MaxActive int
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// Close connections after remaining idle for this duration. If the value
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// is zero, then idle connections are not closed. Applications should set
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// the timeout to a value less than the server's timeout.
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IdleTimeout time.Duration
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// If Wait is true and the pool is at the MaxActive limit, then Get() waits
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// for a connection to be returned to the pool before returning.
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Wait bool
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chInitialized uint32 // set to 1 when field ch is initialized
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mu sync.Mutex // mu protects the following fields
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closed bool // set to true when the pool is closed.
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active int // the number of open connections in the pool
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ch chan struct{} // limits open connections when p.Wait is true
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idle idleList // idle connections
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}
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// NewPool creates a new pool.
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//
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// Deprecated: Initialize the Pool directory as shown in the example.
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func NewPool(newFn func() (Conn, error), maxIdle int) *Pool {
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return &Pool{Dial: newFn, MaxIdle: maxIdle}
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}
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// Get gets a connection. The application must close the returned connection.
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// This method always returns a valid connection so that applications can defer
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// error handling to the first use of the connection. If there is an error
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// getting an underlying connection, then the connection Err, Do, Send, Flush
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// and Receive methods return that error.
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func (p *Pool) Get() Conn {
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c, err := p.get(nil)
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if err != nil {
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return errorConnection{err}
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}
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return &pooledConnection{p: p, c: c}
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}
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// PoolStats contains pool statistics.
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type PoolStats struct {
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// ActiveCount is the number of connections in the pool. The count includes
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// idle connections and connections in use.
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ActiveCount int
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// IdleCount is the number of idle connections in the pool.
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IdleCount int
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}
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// Stats returns pool's statistics.
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func (p *Pool) Stats() PoolStats {
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p.mu.Lock()
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stats := PoolStats{
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ActiveCount: p.active,
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IdleCount: p.idle.count,
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}
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p.mu.Unlock()
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return stats
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}
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// ActiveCount returns the number of connections in the pool. The count
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// includes idle connections and connections in use.
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func (p *Pool) ActiveCount() int {
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p.mu.Lock()
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active := p.active
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p.mu.Unlock()
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return active
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}
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// IdleCount returns the number of idle connections in the pool.
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func (p *Pool) IdleCount() int {
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p.mu.Lock()
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idle := p.idle.count
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p.mu.Unlock()
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return idle
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}
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// Close releases the resources used by the pool.
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func (p *Pool) Close() error {
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p.mu.Lock()
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if p.closed {
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p.mu.Unlock()
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return nil
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}
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p.closed = true
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p.active -= p.idle.count
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ic := p.idle.front
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p.idle.count = 0
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p.idle.front, p.idle.back = nil, nil
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if p.ch != nil {
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close(p.ch)
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}
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p.mu.Unlock()
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for ; ic != nil; ic = ic.next {
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ic.c.Close()
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}
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return nil
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}
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func (p *Pool) lazyInit() {
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// Fast path.
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if atomic.LoadUint32(&p.chInitialized) == 1 {
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return
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}
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// Slow path.
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p.mu.Lock()
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if p.chInitialized == 0 {
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p.ch = make(chan struct{}, p.MaxActive)
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if p.closed {
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close(p.ch)
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} else {
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for i := 0; i < p.MaxActive; i++ {
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p.ch <- struct{}{}
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}
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}
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atomic.StoreUint32(&p.chInitialized, 1)
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}
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p.mu.Unlock()
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}
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// get prunes stale connections and returns a connection from the idle list or
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// creates a new connection.
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func (p *Pool) get(ctx interface {
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Done() <-chan struct{}
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Err() error
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}) (Conn, error) {
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// Handle limit for p.Wait == true.
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if p.Wait && p.MaxActive > 0 {
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p.lazyInit()
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if ctx == nil {
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<-p.ch
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} else {
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select {
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case <-p.ch:
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case <-ctx.Done():
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return nil, ctx.Err()
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}
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}
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}
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p.mu.Lock()
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// Prune stale connections at the back of the idle list.
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if p.IdleTimeout > 0 {
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n := p.idle.count
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for i := 0; i < n && p.idle.back != nil && p.idle.back.t.Add(p.IdleTimeout).Before(nowFunc()); i++ {
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c := p.idle.back.c
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p.idle.popBack()
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p.mu.Unlock()
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c.Close()
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p.mu.Lock()
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p.active--
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}
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}
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// Get idle connection from the front of idle list.
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for p.idle.front != nil {
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ic := p.idle.front
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p.idle.popFront()
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p.mu.Unlock()
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if p.TestOnBorrow == nil || p.TestOnBorrow(ic.c, ic.t) == nil {
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return ic.c, nil
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}
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ic.c.Close()
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p.mu.Lock()
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p.active--
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}
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// Check for pool closed before dialing a new connection.
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if p.closed {
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p.mu.Unlock()
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return nil, errors.New("redigo: get on closed pool")
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}
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// Handle limit for p.Wait == false.
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if !p.Wait && p.MaxActive > 0 && p.active >= p.MaxActive {
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p.mu.Unlock()
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return nil, ErrPoolExhausted
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}
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p.active++
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p.mu.Unlock()
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c, err := p.Dial()
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if err != nil {
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c = nil
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p.mu.Lock()
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p.active--
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if p.ch != nil && !p.closed {
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p.ch <- struct{}{}
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}
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p.mu.Unlock()
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}
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return c, err
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}
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func (p *Pool) put(c Conn, forceClose bool) error {
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p.mu.Lock()
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if !p.closed && !forceClose {
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p.idle.pushFront(&idleConn{t: nowFunc(), c: c})
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if p.idle.count > p.MaxIdle {
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c = p.idle.back.c
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p.idle.popBack()
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} else {
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c = nil
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}
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}
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if c != nil {
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p.mu.Unlock()
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c.Close()
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p.mu.Lock()
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p.active--
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}
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if p.ch != nil && !p.closed {
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p.ch <- struct{}{}
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}
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p.mu.Unlock()
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return nil
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}
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type pooledConnection struct {
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p *Pool
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c Conn
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state int
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}
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var (
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sentinel []byte
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sentinelOnce sync.Once
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)
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func initSentinel() {
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p := make([]byte, 64)
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if _, err := rand.Read(p); err == nil {
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sentinel = p
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} else {
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h := sha1.New()
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io.WriteString(h, "Oops, rand failed. Use time instead.")
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io.WriteString(h, strconv.FormatInt(time.Now().UnixNano(), 10))
|
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sentinel = h.Sum(nil)
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}
|
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}
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func (pc *pooledConnection) Close() error {
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c := pc.c
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if _, ok := c.(errorConnection); ok {
|
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return nil
|
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}
|
||||
pc.c = errorConnection{errConnClosed}
|
||||
|
||||
if pc.state&internal.MultiState != 0 {
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c.Send("DISCARD")
|
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pc.state &^= (internal.MultiState | internal.WatchState)
|
||||
} else if pc.state&internal.WatchState != 0 {
|
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c.Send("UNWATCH")
|
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pc.state &^= internal.WatchState
|
||||
}
|
||||
if pc.state&internal.SubscribeState != 0 {
|
||||
c.Send("UNSUBSCRIBE")
|
||||
c.Send("PUNSUBSCRIBE")
|
||||
// To detect the end of the message stream, ask the server to echo
|
||||
// a sentinel value and read until we see that value.
|
||||
sentinelOnce.Do(initSentinel)
|
||||
c.Send("ECHO", sentinel)
|
||||
c.Flush()
|
||||
for {
|
||||
p, err := c.Receive()
|
||||
if err != nil {
|
||||
break
|
||||
}
|
||||
if p, ok := p.([]byte); ok && bytes.Equal(p, sentinel) {
|
||||
pc.state &^= internal.SubscribeState
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
c.Do("")
|
||||
pc.p.put(c, pc.state != 0 || c.Err() != nil)
|
||||
return nil
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) Err() error {
|
||||
return pc.c.Err()
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) Do(commandName string, args ...interface{}) (reply interface{}, err error) {
|
||||
ci := internal.LookupCommandInfo(commandName)
|
||||
pc.state = (pc.state | ci.Set) &^ ci.Clear
|
||||
return pc.c.Do(commandName, args...)
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) DoWithTimeout(timeout time.Duration, commandName string, args ...interface{}) (reply interface{}, err error) {
|
||||
cwt, ok := pc.c.(ConnWithTimeout)
|
||||
if !ok {
|
||||
return nil, errTimeoutNotSupported
|
||||
}
|
||||
ci := internal.LookupCommandInfo(commandName)
|
||||
pc.state = (pc.state | ci.Set) &^ ci.Clear
|
||||
return cwt.DoWithTimeout(timeout, commandName, args...)
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) Send(commandName string, args ...interface{}) error {
|
||||
ci := internal.LookupCommandInfo(commandName)
|
||||
pc.state = (pc.state | ci.Set) &^ ci.Clear
|
||||
return pc.c.Send(commandName, args...)
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) Flush() error {
|
||||
return pc.c.Flush()
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) Receive() (reply interface{}, err error) {
|
||||
return pc.c.Receive()
|
||||
}
|
||||
|
||||
func (pc *pooledConnection) ReceiveWithTimeout(timeout time.Duration) (reply interface{}, err error) {
|
||||
cwt, ok := pc.c.(ConnWithTimeout)
|
||||
if !ok {
|
||||
return nil, errTimeoutNotSupported
|
||||
}
|
||||
return cwt.ReceiveWithTimeout(timeout)
|
||||
}
|
||||
|
||||
type errorConnection struct{ err error }
|
||||
|
||||
func (ec errorConnection) Do(string, ...interface{}) (interface{}, error) { return nil, ec.err }
|
||||
func (ec errorConnection) DoWithTimeout(time.Duration, string, ...interface{}) (interface{}, error) {
|
||||
return nil, ec.err
|
||||
}
|
||||
func (ec errorConnection) Send(string, ...interface{}) error { return ec.err }
|
||||
func (ec errorConnection) Err() error { return ec.err }
|
||||
func (ec errorConnection) Close() error { return nil }
|
||||
func (ec errorConnection) Flush() error { return ec.err }
|
||||
func (ec errorConnection) Receive() (interface{}, error) { return nil, ec.err }
|
||||
func (ec errorConnection) ReceiveWithTimeout(time.Duration) (interface{}, error) { return nil, ec.err }
|
||||
|
||||
type idleList struct {
|
||||
count int
|
||||
front, back *idleConn
|
||||
}
|
||||
|
||||
type idleConn struct {
|
||||
c Conn
|
||||
t time.Time
|
||||
next, prev *idleConn
|
||||
}
|
||||
|
||||
func (l *idleList) pushFront(ic *idleConn) {
|
||||
ic.next = l.front
|
||||
ic.prev = nil
|
||||
if l.count == 0 {
|
||||
l.back = ic
|
||||
} else {
|
||||
l.front.prev = ic
|
||||
}
|
||||
l.front = ic
|
||||
l.count++
|
||||
return
|
||||
}
|
||||
|
||||
func (l *idleList) popFront() {
|
||||
ic := l.front
|
||||
l.count--
|
||||
if l.count == 0 {
|
||||
l.front, l.back = nil, nil
|
||||
} else {
|
||||
ic.next.prev = nil
|
||||
l.front = ic.next
|
||||
}
|
||||
ic.next, ic.prev = nil, nil
|
||||
}
|
||||
|
||||
func (l *idleList) popBack() {
|
||||
ic := l.back
|
||||
l.count--
|
||||
if l.count == 0 {
|
||||
l.front, l.back = nil, nil
|
||||
} else {
|
||||
ic.prev.next = nil
|
||||
l.back = ic.prev
|
||||
}
|
||||
ic.next, ic.prev = nil, nil
|
||||
}
|
Reference in New Issue
Block a user