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package fastcgi
import (
"errors"
"sync"
"sync/atomic"
"time"
)
type dialer interface {
Dial() (Client, error)
Close(Client) error
}
// basicDialer is a basic dialer that wraps default fcgi functions.
type basicDialer struct {
network string
address string
timeout time.Duration
}
func (b basicDialer) Dial() (Client, error) {
return DialTimeout(b.network, b.address, b.timeout)
}
func (b basicDialer) Close(c Client) error { return c.Close() }
// persistentDialer keeps a pool of fcgi connections.
// connections are not closed after use, rather added back to the pool for reuse.
type persistentDialer struct {
size int
network string
address string
timeout time.Duration
pool []Client
sync.Mutex
}
func (p *persistentDialer) Dial() (Client, error) {
p.Lock()
// connection is available, return first one.
if len(p.pool) > 0 {
client := p.pool[0]
p.pool = p.pool[1:]
p.Unlock()
return client, nil
}
p.Unlock()
// no connection available, create new one
return DialTimeout(p.network, p.address, p.timeout)
}
func (p *persistentDialer) Close(client Client) error {
p.Lock()
if len(p.pool) < p.size {
// pool is not full yet, add connection for reuse
p.pool = append(p.pool, client)
p.Unlock()
return nil
}
p.Unlock()
// otherwise, close the connection.
return client.Close()
}
type loadBalancingDialer struct {
dialers []dialer
current int64
}
func (m *loadBalancingDialer) Dial() (Client, error) {
nextDialerIndex := atomic.AddInt64(&m.current, 1) % int64(len(m.dialers))
currentDialer := m.dialers[nextDialerIndex]
client, err := currentDialer.Dial()
if err != nil {
return nil, err
}
return &dialerAwareClient{Client: client, dialer: currentDialer}, nil
}
func (m *loadBalancingDialer) Close(c Client) error {
// Close the client according to dialer behaviour
if da, ok := c.(*dialerAwareClient); ok {
return da.dialer.Close(c)
}
return errors.New("Cannot close client")
}
type dialerAwareClient struct {
Client
dialer dialer
}
|
