From 415b1ddfb57a030205e4616dd4b42779ecbc8f3e Mon Sep 17 00:00:00 2001
From: Roman Khavronenko <hagen1778@gmail.com>
Date: Wed, 13 May 2020 19:32:58 +0100
Subject: [PATCH] vmalert: check if remoteRead object was initied before
 calling Restore (#473)

The check for non-nil remoteRead was mistakenly dropped
during refactoring which caused panics when `vmalert`
wasn't configured with `remoteRead` flag.
---
 app/vmalert/manager.go | 2 +-
 app/vmalert/rule.go    | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/app/vmalert/manager.go b/app/vmalert/manager.go
index 92e093a2c..38504fd52 100644
--- a/app/vmalert/manager.go
+++ b/app/vmalert/manager.go
@@ -57,7 +57,7 @@ func (m *manager) close() {
 }
 
 func (m *manager) startGroup(ctx context.Context, group Group, restore bool) {
-	if restore {
+	if restore && m.rr != nil {
 		err := group.Restore(ctx, m.rr, *remoteReadLookBack)
 		if err != nil {
 			logger.Errorf("error while restoring state for group %q: %s", group.Name, err)
diff --git a/app/vmalert/rule.go b/app/vmalert/rule.go
index 5f4b42cf0..08d1d64d1 100644
--- a/app/vmalert/rule.go
+++ b/app/vmalert/rule.go
@@ -295,6 +295,10 @@ func newTimeSeries(value float64, labels map[string]string, timestamp time.Time)
 // Restore restores only Start field. Field State will be always Pending and supposed
 // to be updated on next Eval, as well as Value field.
 func (r *Rule) Restore(ctx context.Context, q datasource.Querier, lookback time.Duration) error {
+	if q == nil {
+		return fmt.Errorf("querier is nil")
+	}
+
 	// Get the last datapoint in range via MetricsQL `last_over_time`.
 	// We don't use plain PromQL since Prometheus doesn't support
 	// remote write protocol which is used for state persistence in vmalert.