63 lines
2.0 KiB
Go
63 lines
2.0 KiB
Go
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// Copyright 2024 The Prometheus Authors
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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 remote
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import (
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"context"
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"math/rand"
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"net"
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"net/http"
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"time"
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"github.com/prometheus/common/config"
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)
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type hostResolver interface {
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LookupHost(context.Context, string) ([]string, error)
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}
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type dialContextWithRoundRobinDNS struct {
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dialContext config.DialContextFunc
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resolver hostResolver
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rand *rand.Rand
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}
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// newDialContextWithRoundRobinDNS creates a new dialContextWithRoundRobinDNS.
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// We discourage creating new instances of struct dialContextWithRoundRobinDNS by explicitly setting its members,
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// except for testing purposes, and recommend using newDialContextWithRoundRobinDNS.
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func newDialContextWithRoundRobinDNS() *dialContextWithRoundRobinDNS {
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return &dialContextWithRoundRobinDNS{
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dialContext: http.DefaultTransport.(*http.Transport).DialContext,
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resolver: net.DefaultResolver,
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rand: rand.New(rand.NewSource(time.Now().Unix())),
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}
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}
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func (dc *dialContextWithRoundRobinDNS) dialContextFn() config.DialContextFunc {
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return func(ctx context.Context, network, addr string) (net.Conn, error) {
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host, port, err := net.SplitHostPort(addr)
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if err != nil {
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return dc.dialContext(ctx, network, addr)
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}
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addrs, err := dc.resolver.LookupHost(ctx, host)
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if err != nil || len(addrs) == 0 {
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return dc.dialContext(ctx, network, addr)
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}
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randomAddr := net.JoinHostPort(addrs[dc.rand.Intn(len(addrs))], port)
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return dc.dialContext(ctx, network, randomAddr)
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}
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}
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