blob: bc48573a419756c1cbb9707b874f957f2336d8d7 [file] [log] [blame]
/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
package grpc
import (
"time"
"golang.org/x/net/context"
"google.golang.org/grpc/transport"
)
// Picker picks a Conn for RPC requests.
// This is EXPERIMENTAL and please do not implement your own Picker for now.
type Picker interface {
// Init does initial processing for the Picker, e.g., initiate some connections.
Init(cc *ClientConn) error
// Pick blocks until either a transport.ClientTransport is ready for the upcoming RPC
// or some error happens.
Pick(ctx context.Context) (transport.ClientTransport, error)
// State returns the connectivity state of the underlying connections.
State() ConnectivityState
// WaitForStateChange blocks until the state changes to something other than
// the sourceState or timeout fires on cc. It returns false if timeout fires,
// and true otherwise.
WaitForStateChange(timeout time.Duration, sourceState ConnectivityState) bool
// Close closes all the Conn's owned by this Picker.
Close() error
}
// unicastPicker is the default Picker which is used when there is no custom Picker
// specified by users. It always picks the same Conn.
type unicastPicker struct {
conn *Conn
}
func (p *unicastPicker) Init(cc *ClientConn) error {
c, err := NewConn(cc)
if err != nil {
return err
}
p.conn = c
return nil
}
func (p *unicastPicker) Pick(ctx context.Context) (transport.ClientTransport, error) {
return p.conn.Wait(ctx)
}
func (p *unicastPicker) State() ConnectivityState {
return p.conn.State()
}
func (p *unicastPicker) WaitForStateChange(timeout time.Duration, sourceState ConnectivityState) bool {
return p.conn.WaitForStateChange(timeout, sourceState)
}
func (p *unicastPicker) Close() error {
if p.conn != nil {
return p.conn.Close()
}
return nil
}