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/awsstore/store_aws_test.go

@@ -0,0 +1,166 @@
+// Copyright (c) 2021 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.
+
+//go:build linux
+// +build linux
+
+package awsstore
+
+import (
+	"context"
+	"testing"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/aws/arn"
+	"github.com/aws/aws-sdk-go-v2/service/ssm"
+	ssmTypes "github.com/aws/aws-sdk-go-v2/service/ssm/types"
+	"tailscale.com/ipn"
+	"tailscale.com/tstest"
+)
+
+type mockedAWSSSMClient struct {
+	value string
+}
+
+func (sp *mockedAWSSSMClient) GetParameter(_ context.Context, input *ssm.GetParameterInput, _ ...func(*ssm.Options)) (*ssm.GetParameterOutput, error) {
+	output := new(ssm.GetParameterOutput)
+	if sp.value == "" {
+		return output, &ssmTypes.ParameterNotFound{}
+	}
+
+	output.Parameter = &ssmTypes.Parameter{
+		Value: aws.String(sp.value),
+	}
+
+	return output, nil
+}
+
+func (sp *mockedAWSSSMClient) PutParameter(_ context.Context, input *ssm.PutParameterInput, _ ...func(*ssm.Options)) (*ssm.PutParameterOutput, error) {
+	sp.value = *input.Value
+	return new(ssm.PutParameterOutput), nil
+}
+
+func TestAWSStoreString(t *testing.T) {
+	store := &awsStore{
+		ssmARN: arn.ARN{
+			Service:   "ssm",
+			Region:    "eu-west-1",
+			AccountID: "123456789",
+			Resource:  "parameter/foo",
+		},
+	}
+	want := "awsStore(\"arn::ssm:eu-west-1:123456789:parameter/foo\")"
+	if got := store.String(); got != want {
+		t.Errorf("AWSStore.String = %q; want %q", got, want)
+	}
+}
+
+func TestNewAWSStore(t *testing.T) {
+	tstest.PanicOnLog()
+
+	mc := &mockedAWSSSMClient{}
+	storeParameterARN := arn.ARN{
+		Service:   "ssm",
+		Region:    "eu-west-1",
+		AccountID: "123456789",
+		Resource:  "parameter/foo",
+	}
+
+	s, err := newStore(storeParameterARN.String(), mc)
+	if err != nil {
+		t.Fatalf("creating aws store failed: %v", err)
+	}
+	testStoreSemantics(t, s)
+
+	// Build a brand new file store and check that both IDs written
+	// above are still there.
+	s2, err := newStore(storeParameterARN.String(), mc)
+	if err != nil {
+		t.Fatalf("creating second aws store failed: %v", err)
+	}
+	store2 := s.(*awsStore)
+
+	// This is specific to the test, with the non-mocked API, LoadState() should
+	// have been already called and successful as no err is returned from NewAWSStore()
+	s2.(*awsStore).LoadState()
+
+	expected := map[ipn.StateKey]string{
+		"foo": "bar",
+		"baz": "quux",
+	}
+	for id, want := range expected {
+		bs, err := store2.ReadState(id)
+		if err != nil {
+			t.Errorf("reading %q (2nd store): %v", id, err)
+		}
+		if string(bs) != want {
+			t.Errorf("reading %q (2nd store): got %q, want %q", id, string(bs), want)
+		}
+	}
+}
+
+func testStoreSemantics(t *testing.T, store ipn.StateStore) {
+	t.Helper()
+
+	tests := []struct {
+		// if true, data is data to write. If false, data is expected
+		// output of read.
+		write bool
+		id    ipn.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 == ipn.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)
+			}
+		}
+	}
+}