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https://github.com/tailscale/tailscale.git
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c56e94af2d
Rather than make each ipn.StateStore implementation guard against useless writes (a write of the same value that's already in the store), do writes via a new wrapper that has a fast path for the unchanged case. This then fixes profileManager's flood of useless writes to AWS SSM, etc. Updates #8785 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
49 lines
954 B
Go
49 lines
954 B
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package ipn
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import (
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"bytes"
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"sync"
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"testing"
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"tailscale.com/util/mak"
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)
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type memStore struct {
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mu sync.Mutex
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writes int
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m map[StateKey][]byte
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}
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func (s *memStore) ReadState(k StateKey) ([]byte, error) {
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s.mu.Lock()
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defer s.mu.Unlock()
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return bytes.Clone(s.m[k]), nil
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}
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func (s *memStore) WriteState(k StateKey, v []byte) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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mak.Set(&s.m, k, bytes.Clone(v))
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s.writes++
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return nil
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}
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func TestWriteState(t *testing.T) {
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var ss StateStore = new(memStore)
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WriteState(ss, "foo", []byte("bar"))
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WriteState(ss, "foo", []byte("bar"))
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got, err := ss.ReadState("foo")
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if err != nil {
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t.Fatal(err)
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}
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if want := []byte("bar"); !bytes.Equal(got, want) {
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t.Errorf("got %q; want %q", got, want)
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}
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if got, want := ss.(*memStore).writes, 1; got != want {
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t.Errorf("got %d writes; want %d", got, want)
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}
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}
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