peridot/vendor/cloud.google.com/go/auth/grpctransport/pool.go
2024-10-16 12:56:53 +02:00

120 lines
3.2 KiB
Go

// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package grpctransport
import (
"context"
"fmt"
"sync/atomic"
"google.golang.org/grpc"
)
// GRPCClientConnPool is an interface that satisfies
// [google.golang.org/grpc.ClientConnInterface] and has some utility functions
// that are needed for connection lifecycle when using in a client library. It
// may be a pool or a single connection. This interface is not intended to, and
// can't be, implemented by others.
type GRPCClientConnPool interface {
// Connection returns a [google.golang.org/grpc.ClientConn] from the pool.
//
// ClientConn aren't returned to the pool and should not be closed directly.
Connection() *grpc.ClientConn
// Len returns the number of connections in the pool. It will always return
// the same value.
Len() int
// Close closes every ClientConn in the pool. The error returned by Close
// may be a single error or multiple errors.
Close() error
grpc.ClientConnInterface
// private ensure others outside this package can't implement this type
private()
}
// singleConnPool is a special case for a single connection.
type singleConnPool struct {
*grpc.ClientConn
}
func (p *singleConnPool) Connection() *grpc.ClientConn { return p.ClientConn }
func (p *singleConnPool) Len() int { return 1 }
func (p *singleConnPool) private() {}
type roundRobinConnPool struct {
conns []*grpc.ClientConn
idx uint32 // access via sync/atomic
}
func (p *roundRobinConnPool) Len() int {
return len(p.conns)
}
func (p *roundRobinConnPool) Connection() *grpc.ClientConn {
i := atomic.AddUint32(&p.idx, 1)
return p.conns[i%uint32(len(p.conns))]
}
func (p *roundRobinConnPool) Close() error {
var errs multiError
for _, conn := range p.conns {
if err := conn.Close(); err != nil {
errs = append(errs, err)
}
}
if len(errs) == 0 {
return nil
}
return errs
}
func (p *roundRobinConnPool) Invoke(ctx context.Context, method string, args interface{}, reply interface{}, opts ...grpc.CallOption) error {
return p.Connection().Invoke(ctx, method, args, reply, opts...)
}
func (p *roundRobinConnPool) NewStream(ctx context.Context, desc *grpc.StreamDesc, method string, opts ...grpc.CallOption) (grpc.ClientStream, error) {
return p.Connection().NewStream(ctx, desc, method, opts...)
}
func (p *roundRobinConnPool) private() {}
// multiError represents errors from multiple conns in the group.
type multiError []error
func (m multiError) Error() string {
s, n := "", 0
for _, e := range m {
if e != nil {
if n == 0 {
s = e.Error()
}
n++
}
}
switch n {
case 0:
return "(0 errors)"
case 1:
return s
case 2:
return s + " (and 1 other error)"
}
return fmt.Sprintf("%s (and %d other errors)", s, n-1)
}