provider/mesh: extract silence deletion into state

provider/mesh/peer.go

@@ -2,7 +2,6 @@ package mesh
 
 import (
 	"fmt"
-	"time"
 
 	"github.com/prometheus/alertmanager/provider"
 	"github.com/prometheus/alertmanager/types"
@@ -161,31 +160,16 @@ func (s *Silences) Set(sil *types.Silence) (uuid.UUID, error) {
 }
 
 func (s *Silences) Del(id uuid.UUID) error {
-	s.st.mtx.RLock()
+	sil, err := s.st.del(id)
-	sil, ok := s.st.m[id]
+	if err != nil {
-	s.st.mtx.RUnlock()
+		return err
-	if !ok {
-		return provider.ErrNotFound
 	}
-	now := time.Now()
-	if sil.EndsAt.Before(now) {
-		return fmt.Errorf("silence already ended")
-	}
-	// Silences are immutable by contract so we create a completely
-	// new object instead.
-	newSil := *sil
-	newSil.UpdatedAt = now
-	newSil.EndsAt = now
 
-	if err := newSil.Init(); err != nil {
-		return fmt.Errorf("silence init: %s", err)
-	}
 	update := &silenceState{
 		m: map[uuid.UUID]*types.Silence{
-			newSil.ID: &newSil,
+			sil.ID: sil,
 		},
 	}
-	s.st.Merge(update)
 	s.send.GossipBroadcast(update)
 
 	return nil

provider/mesh/state.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/prometheus/alertmanager/provider"
 	"github.com/prometheus/alertmanager/types"
 	"github.com/satori/go.uuid"
 	"github.com/weaveworks/mesh"
@@ -133,11 +134,10 @@ func (st *silenceState) Encode() [][]byte {
 
 // silenceModAllowed checks whether silence a may be changed to silence b.
 // Returns an error stating the reason if not.
-func (st *silenceState) silenceModAllowed(a, b *types.Silence) error {
+func silenceModAllowed(a, b *types.Silence, now time.Time) error {
 	if !b.StartsAt.Equal(a.StartsAt) {
 		return fmt.Errorf("silence start time must not be modified")
 	}
-	now := st.now()
 	if a.EndsAt.Before(now) {
 		return fmt.Errorf("end time must not be modified for elapsed silence")
 	}
@@ -154,7 +154,8 @@ func (st *silenceState) set(s *types.Silence) error {
 	st.mtx.Lock()
 	defer st.mtx.Unlock()
 
-	s.UpdatedAt = st.now()
+	now := st.now()
+	s.UpdatedAt = now
 
 	if err := s.Validate(); err != nil {
 		return err
@@ -165,13 +166,39 @@ func (st *silenceState) set(s *types.Silence) error {
 		st.m[s.ID] = s
 		return nil
 	}
-	if err := st.silenceModAllowed(prev, s); err != nil {
+	if err := silenceModAllowed(prev, s, now); err != nil {
 		return err
 	}
 	st.m[s.ID] = s
 	return nil
 }
 
+func (st *silenceState) del(id uuid.UUID) (*types.Silence, error) {
+	st.mtx.Lock()
+	defer st.mtx.Unlock()
+
+	prev, ok := st.m[id]
+	if !ok {
+		return nil, provider.ErrNotFound
+	}
+	// Silences are immutable by contract so we create a
+	// shallow copy.
+	sil := *prev
+	now := st.now()
+	sil.UpdatedAt = now
+	sil.EndsAt = now
+
+	if err := sil.Validate(); err != nil {
+		return nil, err
+	}
+
+	if err := silenceModAllowed(prev, &sil, now); err != nil {
+		return nil, err
+	}
+	st.m[sil.ID] = &sil
+	return &sil, nil
+}
+
 func (st *silenceState) Merge(other mesh.GossipData) mesh.GossipData {
 	o := other.(*silenceState)
 	o.mtx.RLock()

types/types.go

@@ -16,6 +16,7 @@ package types
 import (
 	"fmt"
 	"hash/fnv"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -276,6 +277,7 @@ func (s *Silence) Init() error {
 			return err
 		}
 	}
+	sort.Sort(s.Matchers)
 	return nil
 }