125 lines
3.1 KiB
Go
125 lines
3.1 KiB
Go
// 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 netconnlimit
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import (
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"io"
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"net"
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"sync"
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"testing"
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"time"
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"github.com/stretchr/testify/require"
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)
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func TestSharedLimitListenerConcurrency(t *testing.T) {
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testCases := []struct {
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name string
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semCapacity int
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connCount int
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expected int // Expected number of connections processed simultaneously.
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}{
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{
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name: "Single connection allowed",
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semCapacity: 1,
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connCount: 3,
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expected: 1,
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},
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{
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name: "Two connections allowed",
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semCapacity: 2,
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connCount: 3,
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expected: 2,
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},
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{
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name: "Three connections allowed",
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semCapacity: 3,
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connCount: 3,
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expected: 3,
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},
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}
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for _, tc := range testCases {
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t.Run(tc.name, func(t *testing.T) {
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sem := NewSharedSemaphore(tc.semCapacity)
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listener, err := net.Listen("tcp", "127.0.0.1:0")
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require.NoError(t, err, "failed to create listener")
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defer listener.Close()
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limitedListener := SharedLimitListener(listener, sem)
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var wg sync.WaitGroup
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var activeConnCount int64
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var mu sync.Mutex
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wg.Add(tc.connCount)
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// Accept connections.
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for i := 0; i < tc.connCount; i++ {
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go func() {
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defer wg.Done()
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conn, err := limitedListener.Accept()
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require.NoError(t, err, "failed to accept connection")
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defer conn.Close()
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// Simulate work and track the active connection count.
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mu.Lock()
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activeConnCount++
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require.LessOrEqual(t, activeConnCount, int64(tc.expected), "too many simultaneous connections")
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mu.Unlock()
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time.Sleep(100 * time.Millisecond)
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mu.Lock()
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activeConnCount--
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mu.Unlock()
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}()
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}
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// Create clients that attempt to connect to the listener.
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for i := 0; i < tc.connCount; i++ {
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go func() {
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conn, err := net.Dial("tcp", listener.Addr().String())
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require.NoError(t, err, "failed to connect to listener")
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defer conn.Close()
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_, _ = io.WriteString(conn, "hello")
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}()
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}
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wg.Wait()
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// Ensure all connections are released and semaphore is empty.
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require.Empty(t, sem)
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})
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}
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}
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func TestSharedLimitListenerClose(t *testing.T) {
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sem := NewSharedSemaphore(2)
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listener, err := net.Listen("tcp", "127.0.0.1:0")
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require.NoError(t, err, "failed to create listener")
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limitedListener := SharedLimitListener(listener, sem)
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// Close the listener and ensure it does not accept new connections.
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err = limitedListener.Close()
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require.NoError(t, err, "failed to close listener")
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conn, err := limitedListener.Accept()
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require.Error(t, err, "expected error on accept after listener closed")
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if conn != nil {
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conn.Close()
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}
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}
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