From b2ee466f799a64dcbf864c3ee4d3698cfdab375a Mon Sep 17 00:00:00 2001
From: Ivan Martinez <ivanthegreatdev@gmail.com>
Date: Wed, 6 May 2020 18:17:36 -0400
Subject: [PATCH] Add--disable-historical-detection flag to slasher (#5759)

* Add--disable-historical-detection flag
* Merge branch 'master' into slasher-add-hist-flag
* Fix for comments
* Add flag to usage help
* Merge branch 'master' into slasher-add-hist-flag
* Update slasher/usage.go
* Fix imports
* Merge branch 'master' into slasher-add-hist-flag
* Merge branch 'master' into slasher-add-hist-flag
* Merge branch 'master' into slasher-add-hist-flag
---
 shared/featureconfig/config.go | 10 +++++++++-
 shared/featureconfig/flags.go  |  8 +++++++-
 slasher/detection/BUILD.bazel  |  1 +
 slasher/detection/service.go   |  9 ++++++---
 slasher/usage.go               |  5 +++++
 5 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/shared/featureconfig/config.go b/shared/featureconfig/config.go
index 7935cc6840..2e3072e2ee 100644
--- a/shared/featureconfig/config.go
+++ b/shared/featureconfig/config.go
@@ -60,7 +60,8 @@ type Flags struct {
 	DisableForkChoice bool
 
 	// BroadcastSlashings enables p2p broadcasting of proposer or attester slashing.
-	BroadcastSlashings bool
+	BroadcastSlashings         bool
+	DisableHistoricalDetection bool
 
 	// Cache toggles.
 	EnableSSZCache          bool // EnableSSZCache see https://github.com/prysmaticlabs/prysm/pull/4558.
@@ -217,6 +218,13 @@ func ConfigureBeaconChain(ctx *cli.Context) {
 // on what flags are enabled for the slasher client.
 func ConfigureSlasher(ctx *cli.Context) {
 	complainOnDeprecatedFlags(ctx)
+	cfg := &Flags{}
+	cfg = configureConfig(ctx, cfg)
+	if ctx.Bool(disableHistoricalDetectionFlag.Name) {
+		log.Warn("Disabling historical attestation detection")
+		cfg.DisableHistoricalDetection = true
+	}
+	Init(cfg)
 }
 
 // ConfigureValidator sets the global config based
diff --git a/shared/featureconfig/flags.go b/shared/featureconfig/flags.go
index d8f88558c2..505c27d462 100644
--- a/shared/featureconfig/flags.go
+++ b/shared/featureconfig/flags.go
@@ -146,6 +146,10 @@ var (
 		Name:  "wait-for-synced",
 		Usage: "Uses WaitForSynced for validator startup, to ensure a validator is able to communicate with the beacon node as quick as possible",
 	}
+	disableHistoricalDetectionFlag = &cli.BoolFlag{
+		Name:  "disable-historical-detection",
+		Usage: "Disables historical attestation detection for the slasher",
+	}
 )
 
 // devModeFlags holds list of flags that are set when development mode is on.
@@ -362,7 +366,9 @@ var ValidatorFlags = append(deprecatedFlags, []cli.Flag{
 }...)
 
 // SlasherFlags contains a list of all the feature flags that apply to the slasher client.
-var SlasherFlags = append(deprecatedFlags, []cli.Flag{}...)
+var SlasherFlags = append(deprecatedFlags, []cli.Flag{
+	disableHistoricalDetectionFlag,
+}...)
 
 // E2EValidatorFlags contains a list of the validator feature flags to be tested in E2E.
 var E2EValidatorFlags = []string{
diff --git a/slasher/detection/BUILD.bazel b/slasher/detection/BUILD.bazel
index e1941a259d..7932f10ef1 100644
--- a/slasher/detection/BUILD.bazel
+++ b/slasher/detection/BUILD.bazel
@@ -14,6 +14,7 @@ go_library(
     deps = [
         "//beacon-chain/state/stateutil:go_default_library",
         "//shared/event:go_default_library",
+        "//shared/featureconfig:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/sliceutil:go_default_library",
         "//slasher/beaconclient:go_default_library",
diff --git a/slasher/detection/service.go b/slasher/detection/service.go
index 657a1d7193..5a6f3e71a3 100644
--- a/slasher/detection/service.go
+++ b/slasher/detection/service.go
@@ -5,6 +5,7 @@ import (
 
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/shared/event"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
 	"github.com/prysmaticlabs/prysm/slasher/beaconclient"
 	"github.com/prysmaticlabs/prysm/slasher/db"
@@ -85,9 +86,11 @@ func (ds *Service) Start() {
 	<-ch
 	sub.Unsubscribe()
 
-	// The detection service runs detection on all historical
-	// chain data since genesis.
-	go ds.detectHistoricalChainData(ds.ctx)
+	if !featureconfig.Get().DisableHistoricalDetection {
+		// The detection service runs detection on all historical
+		// chain data since genesis.
+		go ds.detectHistoricalChainData(ds.ctx)
+	}
 
 	// We subscribe to incoming blocks from the beacon node via
 	// our gRPC client to keep detecting slashable offenses.
diff --git a/slasher/usage.go b/slasher/usage.go
index 35d77e5194..a679fbfe67 100644
--- a/slasher/usage.go
+++ b/slasher/usage.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/prysmaticlabs/prysm/shared/cmd"
 	"github.com/prysmaticlabs/prysm/shared/debug"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/slasher/flags"
 	"gopkg.in/urfave/cli.v2"
 )
@@ -78,6 +79,10 @@ var appHelpFlagGroups = []flagGroup{
 			flags.BeaconRPCProviderFlag,
 		},
 	},
+	{
+		Name:  "features",
+		Flags: featureconfig.ActiveFlags(featureconfig.SlasherFlags),
+	},
 }
 
 func init() {