mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-20 23:46:23 +01:00
120 lines
3.2 KiB
Go
120 lines
3.2 KiB
Go
// Copyright 2023 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain 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,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package grpctransport
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import (
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"context"
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"fmt"
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"sync/atomic"
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"google.golang.org/grpc"
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)
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// GRPCClientConnPool is an interface that satisfies
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// [google.golang.org/grpc.ClientConnInterface] and has some utility functions
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// that are needed for connection lifecycle when using in a client library. It
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// may be a pool or a single connection. This interface is not intended to, and
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// can't be, implemented by others.
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type GRPCClientConnPool interface {
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// Connection returns a [google.golang.org/grpc.ClientConn] from the pool.
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//
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// ClientConn aren't returned to the pool and should not be closed directly.
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Connection() *grpc.ClientConn
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// Len returns the number of connections in the pool. It will always return
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// the same value.
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Len() int
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// Close closes every ClientConn in the pool. The error returned by Close
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// may be a single error or multiple errors.
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Close() error
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grpc.ClientConnInterface
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// private ensure others outside this package can't implement this type
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private()
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}
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// singleConnPool is a special case for a single connection.
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type singleConnPool struct {
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*grpc.ClientConn
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}
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func (p *singleConnPool) Connection() *grpc.ClientConn { return p.ClientConn }
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func (p *singleConnPool) Len() int { return 1 }
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func (p *singleConnPool) private() {}
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type roundRobinConnPool struct {
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conns []*grpc.ClientConn
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idx uint32 // access via sync/atomic
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}
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func (p *roundRobinConnPool) Len() int {
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return len(p.conns)
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}
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func (p *roundRobinConnPool) Connection() *grpc.ClientConn {
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i := atomic.AddUint32(&p.idx, 1)
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return p.conns[i%uint32(len(p.conns))]
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}
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func (p *roundRobinConnPool) Close() error {
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var errs multiError
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for _, conn := range p.conns {
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if err := conn.Close(); err != nil {
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errs = append(errs, err)
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}
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}
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if len(errs) == 0 {
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return nil
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}
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return errs
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}
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func (p *roundRobinConnPool) Invoke(ctx context.Context, method string, args interface{}, reply interface{}, opts ...grpc.CallOption) error {
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return p.Connection().Invoke(ctx, method, args, reply, opts...)
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}
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func (p *roundRobinConnPool) NewStream(ctx context.Context, desc *grpc.StreamDesc, method string, opts ...grpc.CallOption) (grpc.ClientStream, error) {
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return p.Connection().NewStream(ctx, desc, method, opts...)
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}
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func (p *roundRobinConnPool) private() {}
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// multiError represents errors from multiple conns in the group.
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type multiError []error
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func (m multiError) Error() string {
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s, n := "", 0
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for _, e := range m {
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if e != nil {
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if n == 0 {
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s = e.Error()
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}
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n++
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}
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}
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switch n {
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case 0:
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return "(0 errors)"
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case 1:
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return s
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case 2:
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return s + " (and 1 other error)"
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}
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return fmt.Sprintf("%s (and %d other errors)", s, n-1)
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}
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