Add a control option to disable sliding window limiter (#4676)

<!-- PR description-->

Add a killswitch for sliding window limiter.  This is only relevant for exchange backups  Setting this flag switches exchange backups to use the default token bucket rate limiter.

---

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [x] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/cli/backup/exchange.go

@@ -84,6 +84,7 @@ func addExchangeCommands(cmd *cobra.Command) *cobra.Command {
 		flags.AddEnableImmutableIDFlag(c)
 		flags.AddDeltaPageSizeFlag(c)
 		flags.AddGenericBackupFlags(c)
+		flags.AddDisableSlidingWindowLimiterFlag(c)
 
 	case listCommand:
 		c, fs = utils.AddCommand(cmd, exchangeListCmd())

src/cli/backup/exchange_test.go

@@ -108,6 +108,7 @@ func (suite *ExchangeUnitSuite) TestBackupCreateFlags() {
 				// bool flags
 				"--" + flags.DisableDeltaFN,
 				"--" + flags.EnableImmutableIDFN,
+				"--" + flags.DisableSlidingWindowLimiterFN,
 			},
 			flagsTD.PreparedGenericBackupFlags(),
 			flagsTD.PreparedProviderFlags(),
@@ -124,6 +125,7 @@ func (suite *ExchangeUnitSuite) TestBackupCreateFlags() {
 	assert.True(t, co.ToggleFeatures.ForceItemDataDownload)
 	assert.True(t, co.ToggleFeatures.DisableDelta)
 	assert.True(t, co.ToggleFeatures.ExchangeImmutableIDs)
+	assert.True(t, co.ToggleFeatures.DisableSlidingWindowLimiter)
 	flagsTD.AssertGenericBackupFlags(t, cmd)
 	flagsTD.AssertProviderFlags(t, cmd)
 	flagsTD.AssertStorageFlags(t, cmd)

src/cli/flags/options.go

@@ -9,6 +9,7 @@ const (
 	DeltaPageSizeFN               = "delta-page-size"
 	DisableDeltaFN                = "disable-delta"
 	DisableIncrementalsFN         = "disable-incrementals"
+	DisableSlidingWindowLimiterFN = "disable-sliding-window-limiter"
 	ForceItemDataDownloadFN       = "force-item-data-download"
 	EnableImmutableIDFN           = "enable-immutable-id"
 	FailFastFN                    = "fail-fast"
@@ -26,6 +27,7 @@ var (
 	DeltaPageSizeFV               int
 	DisableDeltaFV                bool
 	DisableIncrementalsFV         bool
+	DisableSlidingWindowLimiterFV bool
 	ForceItemDataDownloadFV       bool
 	EnableImmutableIDFV           bool
 	FailFastFV                    bool
@@ -159,3 +161,18 @@ func AddRunModeFlag(cmd *cobra.Command, persistent bool) {
 	fs.StringVar(&RunModeFV, RunModeFN, "run", "What mode to run: dry, test, run.  Defaults to run.")
 	cobra.CheckErr(fs.MarkHidden(RunModeFN))
 }
+
+// AddDisableSlidingWindowLimiterFN disables the experimental sliding window rate
+// limiter for graph API requests. This is only relevant for exchange backups.
+// Exchange restores continue to use the default token bucket rate limiter.
+// Setting this flag switches exchange backups to use the default token bucket
+// rate limiter.
+func AddDisableSlidingWindowLimiterFlag(cmd *cobra.Command) {
+	fs := cmd.Flags()
+	fs.BoolVar(
+		&DisableSlidingWindowLimiterFV,
+		DisableSlidingWindowLimiterFN,
+		false,
+		"Disable sliding window rate limiter.")
+	cobra.CheckErr(fs.MarkHidden(DisableSlidingWindowLimiterFN))
+}

src/cli/utils/options.go

@@ -25,6 +25,7 @@ func Control() control.Options {
 	opt.ToggleFeatures.DisableIncrementals = flags.DisableIncrementalsFV
 	opt.ToggleFeatures.ForceItemDataDownload = flags.ForceItemDataDownloadFV
 	opt.ToggleFeatures.DisableDelta = flags.DisableDeltaFV
+	opt.ToggleFeatures.DisableSlidingWindowLimiter = flags.DisableSlidingWindowLimiterFV
 	opt.ToggleFeatures.ExchangeImmutableIDs = flags.EnableImmutableIDFV
 	opt.Parallelism.ItemFetch = flags.FetchParallelismFV
 

src/cli/utils/options_test.go

@@ -36,6 +36,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 			assert.True(t, flags.SkipReduceFV, flags.SkipReduceFN)
 			assert.Equal(t, 2, flags.FetchParallelismFV, flags.FetchParallelismFN)
 			assert.Equal(t, 499, flags.DeltaPageSizeFV, flags.DeltaPageSizeFN)
+			assert.True(t, flags.DisableSlidingWindowLimiterFV, flags.DisableSlidingWindowLimiterFN)
 		},
 	}
 
@@ -50,6 +51,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 	flags.AddSkipReduceFlag(cmd)
 	flags.AddFetchParallelismFlag(cmd)
 	flags.AddDeltaPageSizeFlag(cmd)
+	flags.AddDisableSlidingWindowLimiterFlag(cmd)
 
 	// Test arg parsing for few args
 	cmd.SetArgs([]string{
@@ -63,6 +65,7 @@ func (suite *OptionsUnitSuite) TestAddExchangeCommands() {
 		"--" + flags.SkipReduceFN,
 		"--" + flags.FetchParallelismFN, "2",
 		"--" + flags.DeltaPageSizeFN, "499",
+		"--" + flags.DisableSlidingWindowLimiterFN,
 	})
 
 	err := cmd.Execute()

src/pkg/control/options.go

@@ -87,4 +87,10 @@ type Toggles struct {
 	// the protected resource. PreviewBackups are used to demonstrate value by
 	// being quick to create.
 	PreviewBackup bool `json:"previewBackup"`
+
+	// DisableSlidingWindowLimiter disables the experimental sliding window rate
+	// limiter for graph API requests. This is only relevant for exchange backups.
+	// Setting this flag switches exchange backups to fallback to the default token
+	// bucket rate limiter.
+	DisableSlidingWindowLimiter bool `json:"disableSlidingWindowLimiter"`
 }