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62 lines
2.0 KiB
62 lines
2.0 KiB
// 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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