mirror of https://github.com/tailscale/tailscale/
Introduce a state store to LocalBackend.
The store is passed-in by callers of NewLocalBackend and ipnserver.Run, but currently all callers are hardcoded to an in-memory store. The store is unused. Signed-Off-By: David Anderson <dave@natulte.net>pull/10/head
David Anderson
5 years ago
committed by
Dave Anderson
parent
21280ca2d1
commit
5bc632271b
@ -0,0 +1,117 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ipn
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import (
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"encoding/json"
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"errors"
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"io/ioutil"
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"os"
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"sync"
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"tailscale.com/atomicfile"
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)
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// ErrStateNotExist is returned by StateStore.ReadState when the
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// requested state id doesn't exist.
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var ErrStateNotExist = errors.New("no state with given id")
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// StateStore persists state, and produces it back on request.
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type StateStore interface {
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// ReadState returns the bytes associated with id. Returns (nil,
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// ErrStateNotExist) if the id doesn't have associated state.
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ReadState(id StateKey) ([]byte, error)
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// WriteState saves bs as the state associated with id.
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WriteState(id StateKey, bs []byte) error
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}
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// MemoryStore is a store that keeps state in memory only.
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type MemoryStore struct {
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mu sync.Mutex
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cache map[StateKey][]byte
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}
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func (s *MemoryStore) ReadState(id StateKey) ([]byte, error) {
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s.mu.Lock()
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defer s.mu.Unlock()
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if s.cache == nil {
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s.cache = map[StateKey][]byte{}
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}
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bs, ok := s.cache[id]
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if !ok {
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return nil, ErrStateNotExist
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}
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return bs, nil
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}
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func (s *MemoryStore) WriteState(id StateKey, bs []byte) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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if s.cache == nil {
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s.cache = map[StateKey][]byte{}
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}
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s.cache[id] = append([]byte(nil), bs...)
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return nil
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}
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// FileStore is a StateStore that uses a JSON file for persistence.
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type FileStore struct {
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path string
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mu sync.RWMutex
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cache map[StateKey][]byte
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}
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// NewFileStore returns a new file store that persists to path.
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func NewFileStore(path string) (*FileStore, error) {
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bs, err := ioutil.ReadFile(path)
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if err != nil {
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if os.IsNotExist(err) {
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// Write out an initial file, to verify that we can write
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// to the path.
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if err = atomicfile.WriteFile(path, []byte("{}"), 0600); err != nil {
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return nil, err
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}
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return &FileStore{
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path: path,
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cache: map[StateKey][]byte{},
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}, nil
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}
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return nil, err
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}
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ret := &FileStore{
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path: path,
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cache: map[StateKey][]byte{},
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}
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if err := json.Unmarshal(bs, &ret.cache); err != nil {
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return nil, err
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}
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return ret, nil
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}
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// ReadState returns the bytes persisted for id, if any.
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func (s *FileStore) ReadState(id StateKey) ([]byte, error) {
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s.mu.RLock()
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defer s.mu.RUnlock()
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bs, ok := s.cache[id]
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if !ok {
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return nil, ErrStateNotExist
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}
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return bs, nil
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}
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// WriteState persists bs under the key id.
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func (s *FileStore) WriteState(id StateKey, bs []byte) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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s.cache[id] = append([]byte(nil), bs...)
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bs, err := json.MarshalIndent(s.cache, "", " ")
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if err != nil {
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return err
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}
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return atomicfile.WriteFile(s.path, bs, 0600)
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}
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@ -0,0 +1,121 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ipn
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import (
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"io/ioutil"
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"os"
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"testing"
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)
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func testStoreSemantics(t *testing.T, store StateStore) {
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t.Helper()
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tests := []struct {
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// if true, data is data to write. If false, data is expected
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// output of read.
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write bool
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id StateKey
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data string
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// If write=false, true if we expect a not-exist error.
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notExists bool
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}{
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{
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id: "foo",
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notExists: true,
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},
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{
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write: true,
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id: "foo",
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data: "bar",
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},
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{
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id: "foo",
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data: "bar",
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},
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{
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id: "baz",
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notExists: true,
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},
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{
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write: true,
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id: "baz",
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data: "quux",
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},
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{
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id: "foo",
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data: "bar",
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},
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{
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id: "baz",
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data: "quux",
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},
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}
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for _, test := range tests {
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if test.write {
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if err := store.WriteState(test.id, []byte(test.data)); err != nil {
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t.Errorf("writing %q to %q: %v", test.data, test.id, err)
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}
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} else {
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bs, err := store.ReadState(test.id)
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if err != nil {
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if test.notExists && err == ErrStateNotExist {
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continue
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}
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t.Errorf("reading %q: %v", test.id, err)
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continue
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}
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if string(bs) != test.data {
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t.Errorf("reading %q: got %q, want %q", test.id, string(bs), test.data)
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}
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}
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}
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}
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func TestMemoryStore(t *testing.T) {
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store := &MemoryStore{}
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testStoreSemantics(t, store)
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}
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func TestFileStore(t *testing.T) {
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f, err := ioutil.TempFile("", "test_ipn_store")
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if err != nil {
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t.Fatal(err)
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}
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path := f.Name()
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f.Close()
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if err := os.Remove(path); err != nil {
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t.Fatal(err)
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}
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store, err := NewFileStore(path)
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if err != nil {
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t.Fatalf("creating file store failed: %v", err)
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}
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testStoreSemantics(t, store)
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// Build a brand new file store and check that both IDs written
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// above are still there.
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store, err = NewFileStore(path)
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if err != nil {
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t.Fatalf("creating second file store failed: %v", err)
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}
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expected := map[StateKey]string{
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"foo": "bar",
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"baz": "quux",
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}
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for id, want := range expected {
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bs, err := store.ReadState(id)
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if err != nil {
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t.Errorf("reading %q (2nd store): %v", id, err)
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}
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if string(bs) != want {
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t.Errorf("reading %q (2nd store): got %q, want %q", id, string(bs), want)
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}
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}
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}
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