ipn/store: add common package for instantiating ipn.StateStores

Also move KubeStore and MemStore into their own package.

RELNOTE: tsnet now supports providing a custom ipn.StateStore.

Signed-off-by: Maisem Ali <maisem@tailscale.com>

ipn/store_test.go

@@ -1,120 +0,0 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package ipn
-
-import (
-	"path/filepath"
-	"testing"
-
-	"tailscale.com/tstest"
-)
-
-func testStoreSemantics(t *testing.T, store StateStore) {
-	t.Helper()
-
-	tests := []struct {
-		// if true, data is data to write. If false, data is expected
-		// output of read.
-		write bool
-		id    StateKey
-		data  string
-		// If write=false, true if we expect a not-exist error.
-		notExists bool
-	}{
-		{
-			id:        "foo",
-			notExists: true,
-		},
-		{
-			write: true,
-			id:    "foo",
-			data:  "bar",
-		},
-		{
-			id:   "foo",
-			data: "bar",
-		},
-		{
-			id:        "baz",
-			notExists: true,
-		},
-		{
-			write: true,
-			id:    "baz",
-			data:  "quux",
-		},
-		{
-			id:   "foo",
-			data: "bar",
-		},
-		{
-			id:   "baz",
-			data: "quux",
-		},
-	}
-
-	for _, test := range tests {
-		if test.write {
-			if err := store.WriteState(test.id, []byte(test.data)); err != nil {
-				t.Errorf("writing %q to %q: %v", test.data, test.id, err)
-			}
-		} else {
-			bs, err := store.ReadState(test.id)
-			if err != nil {
-				if test.notExists && err == ErrStateNotExist {
-					continue
-				}
-				t.Errorf("reading %q: %v", test.id, err)
-				continue
-			}
-			if string(bs) != test.data {
-				t.Errorf("reading %q: got %q, want %q", test.id, string(bs), test.data)
-			}
-		}
-	}
-}
-
-func TestMemoryStore(t *testing.T) {
-	tstest.PanicOnLog()
-
-	store := &MemoryStore{}
-	testStoreSemantics(t, store)
-}
-
-func TestFileStore(t *testing.T) {
-	tstest.PanicOnLog()
-
-	dir := t.TempDir()
-	path := filepath.Join(dir, "test-file-store.conf")
-
-	store, err := NewFileStore(path)
-	if err != nil {
-		t.Fatalf("creating file store failed: %v", err)
-	}
-
-	testStoreSemantics(t, store)
-
-	// Build a brand new file store and check that both IDs written
-	// above are still there.
-	store, err = NewFileStore(path)
-	if err != nil {
-		t.Fatalf("creating second file store failed: %v", err)
-	}
-
-	expected := map[StateKey]string{
-		"foo": "bar",
-		"baz": "quux",
-	}
-	for key, want := range expected {
-		bs, err := store.ReadState(key)
-		if err != nil {
-			t.Errorf("reading %q (2nd store): %v", key, err)
-			continue
-		}
-		if string(bs) != want {
-			t.Errorf("reading %q (2nd store): got %q, want %q", key, bs, want)
-		}
-	}
-}