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640b2fa3ae
This adds a new helper to the netmon package that allows us to rate-limit log messages, so that they only print once per (major) LinkChange event. We then use this when constructing the portmapper, so that we don't keep spamming logs forever on the same network. Updates #13145 Signed-off-by: Andrew Dunham <andrew@du.nham.ca> Change-Id: I6e7162509148abea674f96efd76be9dffb373ae4
79 lines
1.9 KiB
Go
79 lines
1.9 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package netmon
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import (
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"bytes"
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"fmt"
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"testing"
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)
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func TestLinkChangeLogLimiter(t *testing.T) {
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mon, err := New(t.Logf)
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if err != nil {
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t.Fatal(err)
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}
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defer mon.Close()
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var logBuffer bytes.Buffer
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logf := func(format string, args ...any) {
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t.Logf("captured log: "+format, args...)
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if format[len(format)-1] != '\n' {
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format += "\n"
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}
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fmt.Fprintf(&logBuffer, format, args...)
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}
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logf, unregister := LinkChangeLogLimiter(logf, mon)
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defer unregister()
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// Log once, which should write to our log buffer.
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logf("hello %s", "world")
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if got := logBuffer.String(); got != "hello world\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Log again, which should not write to our log buffer.
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logf("hello %s", "andrew")
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if got := logBuffer.String(); got != "hello world\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Log a different message, which should write to our log buffer.
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logf("other message")
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if got := logBuffer.String(); got != "hello world\nother message\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Synthesize a fake major change event, which should clear the format
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// string cache and allow the next log to write to our log buffer.
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//
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// InjectEvent doesn't work because it's not a major event, so we
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// instead reach into the netmon and grab the callback, and then call
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// it ourselves.
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mon.mu.Lock()
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var cb func(*ChangeDelta)
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for _, c := range mon.cbs {
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cb = c
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break
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}
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mon.mu.Unlock()
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cb(&ChangeDelta{Major: true})
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logf("hello %s", "world")
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if got := logBuffer.String(); got != "hello world\nother message\nhello world\n" {
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t.Errorf("unexpected log buffer contents: %q", got)
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}
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// Unregistering the callback should clear our 'cbs' set.
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unregister()
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mon.mu.Lock()
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if len(mon.cbs) != 0 {
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t.Errorf("expected no callbacks, got %v", mon.cbs)
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}
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mon.mu.Unlock()
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}
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