forked from prometheus/alertmanager
/
silence.go
899 lines (790 loc) · 20.8 KB
/
silence.go
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// Copyright 2016 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package silence provides a storage for silences, which can share its
// state over a mesh network and snapshot it.
package silence
import (
"bytes"
"errors"
"fmt"
"io"
"math/rand"
"os"
"regexp"
"sync"
"time"
"github.com/golang/protobuf/ptypes"
"github.com/golang/protobuf/ptypes/timestamp"
"github.com/matttproud/golang_protobuf_extensions/pbutil"
pb "github.com/prometheus/alertmanager/silence/silencepb"
"github.com/prometheus/alertmanager/types"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
"github.com/prometheus/common/model"
"github.com/satori/go.uuid"
"github.com/weaveworks/mesh"
)
// ErrNotFound is returned if a silence was not found.
var ErrNotFound = fmt.Errorf("not found")
func utcNow() time.Time {
return time.Now().UTC()
}
type matcherCache map[*pb.Silence]types.Matchers
// Get retrieves the matchers for a given silence. If it is a missed cache
// access, it compiles and adds the matchers of the requested silence to the
// cache.
func (c matcherCache) Get(s *pb.Silence) (types.Matchers, error) {
if m, ok := c[s]; ok {
return m, nil
}
return c.add(s)
}
// add compiles a silences' matchers and adds them to the cache.
// It returns the compiled matchers.
func (c matcherCache) add(s *pb.Silence) (types.Matchers, error) {
var (
ms types.Matchers
mt *types.Matcher
)
for _, m := range s.Matchers {
mt = &types.Matcher{
Name: m.Name,
Value: m.Pattern,
}
switch m.Type {
case pb.Matcher_EQUAL:
mt.IsRegex = false
case pb.Matcher_REGEXP:
mt.IsRegex = true
}
err := mt.Init()
if err != nil {
return nil, err
}
ms = append(ms, mt)
}
c[s] = ms
return ms, nil
}
// Silences holds a silence state that can be modified, queried, and snapshot.
type Silences struct {
logger log.Logger
metrics *metrics
now func() time.Time
retention time.Duration
gossip mesh.Gossip // gossip channel for sharing silences
// We store silences in a map of IDs for now. Currently, the memory
// state is equivalent to the mesh.GossipData representation.
// In the future we'll want support for efficient queries by time
// range and affected labels.
// Mutex also guards the matcherCache, which always need write lock access.
mtx sync.Mutex
st gossipData
mc matcherCache
}
type metrics struct {
gcDuration prometheus.Summary
snapshotDuration prometheus.Summary
queriesTotal prometheus.Counter
queryErrorsTotal prometheus.Counter
queryDuration prometheus.Histogram
}
func newMetrics(r prometheus.Registerer) *metrics {
m := &metrics{}
m.gcDuration = prometheus.NewSummary(prometheus.SummaryOpts{
Name: "alertmanager_silences_gc_duration_seconds",
Help: "Duration of the last silence garbage collection cycle.",
})
m.snapshotDuration = prometheus.NewSummary(prometheus.SummaryOpts{
Name: "alertmanager_silences_snapshot_duration_seconds",
Help: "Duration of the last silence snapshot.",
})
m.queriesTotal = prometheus.NewCounter(prometheus.CounterOpts{
Name: "alertmanager_silences_queries_total",
Help: "How many silence queries were received.",
})
m.queryErrorsTotal = prometheus.NewCounter(prometheus.CounterOpts{
Name: "alertmanager_silences_query_errors_total",
Help: "How many silence received queries did not succeed.",
})
m.queryDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "alertmanager_silences_query_duration_seconds",
Help: "Duration of silence query evaluation.",
})
if r != nil {
r.MustRegister(
m.gcDuration,
m.snapshotDuration,
m.queriesTotal,
m.queryErrorsTotal,
m.queryDuration,
)
}
return m
}
// Options exposes configuration options for creating a new Silences object.
// Its zero value is a safe default.
type Options struct {
// A snapshot file or reader from which the initial state is loaded.
// None or only one of them must be set.
SnapshotFile string
SnapshotReader io.Reader
// Retention time for newly created Silences. Silences may be
// garbage collected after the given duration after they ended.
Retention time.Duration
// A function creating a mesh.Gossip on being called with a mesh.Gossiper.
Gossip func(g mesh.Gossiper) mesh.Gossip
// A logger used by background processing.
Logger log.Logger
Metrics prometheus.Registerer
}
func (o *Options) validate() error {
if o.SnapshotFile != "" && o.SnapshotReader != nil {
return fmt.Errorf("only one of SnapshotFile and SnapshotReader must be set")
}
return nil
}
// New returns a new Silences object with the given configuration.
func New(o Options) (*Silences, error) {
if err := o.validate(); err != nil {
return nil, err
}
if o.SnapshotFile != "" {
if r, err := os.Open(o.SnapshotFile); err != nil {
if !os.IsNotExist(err) {
return nil, err
}
} else {
o.SnapshotReader = r
}
}
s := &Silences{
mc: matcherCache{},
logger: log.NewNopLogger(),
metrics: newMetrics(o.Metrics),
retention: o.Retention,
now: utcNow,
gossip: nopGossip{},
st: gossipData{},
}
if o.Logger != nil {
s.logger = o.Logger
}
if o.Gossip != nil {
s.gossip = o.Gossip(gossiper{s})
}
if o.SnapshotReader != nil {
if err := s.loadSnapshot(o.SnapshotReader); err != nil {
return s, err
}
}
return s, nil
}
type nopGossip struct{}
func (nopGossip) GossipBroadcast(d mesh.GossipData) {}
func (nopGossip) GossipUnicast(mesh.PeerName, []byte) error { return nil }
// Maintenance garbage collects the silence state at the given interval. If the snapshot
// file is set, a snapshot is written to it afterwards.
// Terminates on receiving from stopc.
func (s *Silences) Maintenance(interval time.Duration, snapf string, stopc <-chan struct{}) {
t := time.NewTicker(interval)
defer t.Stop()
f := func() error {
start := s.now()
s.logger.Info("running maintenance")
defer s.logger.With("duration", s.now().Sub(start)).Info("maintenance done")
if _, err := s.GC(); err != nil {
return err
}
if snapf == "" {
return nil
}
f, err := openReplace(snapf)
if err != nil {
return err
}
// TODO(fabxc): potentially expose snapshot size in log message.
if _, err := s.Snapshot(f); err != nil {
return err
}
return f.Close()
}
Loop:
for {
select {
case <-stopc:
break Loop
case <-t.C:
if err := f(); err != nil {
s.logger.With("err", err).Error("running maintenance failed")
}
}
}
// No need for final maintenance if we don't want to snapshot.
if snapf == "" {
return
}
if err := f(); err != nil {
s.logger.With("err", err).Info("msg", "creating shutdown snapshot failed")
}
}
// GC runs a garbage collection that removes silences that have ended longer
// than the configured retention time ago.
func (s *Silences) GC() (int, error) {
start := time.Now()
defer func() { s.metrics.gcDuration.Observe(time.Since(start).Seconds()) }()
now, err := s.nowProto()
if err != nil {
return 0, err
}
var n int
s.mtx.Lock()
defer s.mtx.Unlock()
for id, sil := range s.st {
if !protoBefore(now, sil.ExpiresAt) {
delete(s.st, id)
delete(s.mc, sil.Silence)
n++
}
}
return n, nil
}
func protoBefore(a, b *timestamp.Timestamp) bool {
if a.Seconds > b.Seconds {
return false
}
if a.Seconds == b.Seconds {
return a.Nanos < b.Nanos
}
return true
}
func validateMatcher(m *pb.Matcher) error {
if !model.LabelName(m.Name).IsValid() {
return fmt.Errorf("invalid label name %q", m.Name)
}
switch m.Type {
case pb.Matcher_EQUAL:
if !model.LabelValue(m.Pattern).IsValid() {
return fmt.Errorf("invalid label value %q", m.Pattern)
}
case pb.Matcher_REGEXP:
if _, err := regexp.Compile(m.Pattern); err != nil {
return fmt.Errorf("invalid regular expression %q: %s", m.Pattern, err)
}
default:
return fmt.Errorf("unknown matcher type %q", m.Type)
}
return nil
}
func validateSilence(s *pb.Silence) error {
if s.Id == "" {
return errors.New("ID missing")
}
if len(s.Matchers) == 0 {
return errors.New("at least one matcher required")
}
for i, m := range s.Matchers {
if err := validateMatcher(m); err != nil {
return fmt.Errorf("invalid label matcher %d: %s", i, err)
}
}
startsAt, err := ptypes.Timestamp(s.StartsAt)
if err != nil {
return fmt.Errorf("invalid start time: %s", err)
}
endsAt, err := ptypes.Timestamp(s.EndsAt)
if err != nil {
return fmt.Errorf("invalid end time: %s", err)
}
if endsAt.Before(startsAt) {
return errors.New("end time must not be before start time")
}
if _, err := ptypes.Timestamp(s.UpdatedAt); err != nil {
return fmt.Errorf("invalid update timestamp: %s", err)
}
return nil
}
// cloneSilence returns a shallow copy of a silence.
func cloneSilence(sil *pb.Silence) *pb.Silence {
s := *sil
return &s
}
func (s *Silences) getSilence(id string) (*pb.Silence, bool) {
msil, ok := s.st[id]
if !ok {
return nil, false
}
return msil.Silence, true
}
func (s *Silences) setSilence(sil *pb.Silence) error {
endsAt, err := ptypes.Timestamp(sil.EndsAt)
if err != nil {
return err
}
expiresAt, err := ptypes.TimestampProto(endsAt.Add(s.retention))
if err != nil {
return err
}
msil := &pb.MeshSilence{
Silence: sil,
ExpiresAt: expiresAt,
}
st := gossipData{sil.Id: msil}
s.st.Merge(st)
s.gossip.GossipBroadcast(st)
return nil
}
func (s *Silences) nowProto() (*timestamp.Timestamp, error) {
now := s.now()
return ptypes.TimestampProto(now)
}
// Create adds a new silence and returns its ID.
func (s *Silences) Create(sil *pb.Silence) (id string, err error) {
if sil.Id != "" {
return "", fmt.Errorf("unexpected ID in new silence")
}
sil.Id = uuid.NewV4().String()
now, err := s.nowProto()
if err != nil {
return "", err
}
if sil.StartsAt == nil {
sil.StartsAt = now
} else if protoBefore(sil.StartsAt, now) {
return "", fmt.Errorf("new silence must not start in the past")
}
sil.UpdatedAt = now
if err := validateSilence(sil); err != nil {
return "", fmt.Errorf("invalid silence: %s", err)
}
s.mtx.Lock()
defer s.mtx.Unlock()
if err := s.setSilence(sil); err != nil {
return "", err
}
return sil.Id, nil
}
// Expire the silence with the given ID immediately.
func (s *Silences) Expire(id string) error {
s.mtx.Lock()
defer s.mtx.Unlock()
sil, ok := s.getSilence(id)
if !ok {
return ErrNotFound
}
now, err := s.nowProto()
if err != nil {
return err
}
if sil, err = silenceSetTimeRange(sil, now, sil.StartsAt, now); err != nil {
return err
}
return s.setSilence(sil)
}
// SetTimeRange adjust the time range of a silence if allowed. If start or end
// are zero times, the current value remains unmodified.
func (s *Silences) SetTimeRange(id string, start, end time.Time) error {
now, err := s.nowProto()
if err != nil {
return err
}
s.mtx.Lock()
defer s.mtx.Unlock()
sil, ok := s.getSilence(id)
if !ok {
return ErrNotFound
}
// Retrieve protobuf start and end time, default to current value
// of the silence.
var startp, endp *timestamp.Timestamp
if start.IsZero() {
startp = sil.StartsAt
} else if startp, err = ptypes.TimestampProto(start); err != nil {
return err
}
if end.IsZero() {
endp = sil.EndsAt
} else if endp, err = ptypes.TimestampProto(end); err != nil {
return err
}
if sil, err = silenceSetTimeRange(sil, now, startp, endp); err != nil {
return err
}
return s.setSilence(sil)
}
func silenceSetTimeRange(sil *pb.Silence, now, start, end *timestamp.Timestamp) (*pb.Silence, error) {
if protoBefore(end, start) {
return nil, fmt.Errorf("end time must not be before start time")
}
// Validate modification based on current silence state.
switch getState(sil, now) {
case StateActive:
if *start != *sil.StartsAt {
return nil, fmt.Errorf("start time of active silence cannot be modified")
}
if protoBefore(end, now) {
return nil, fmt.Errorf("end time cannot be set into the past")
}
case StatePending:
if protoBefore(start, now) {
return nil, fmt.Errorf("start time cannot be set into the past")
}
case StateExpired:
return nil, fmt.Errorf("expired silence must not be modified")
default:
panic("unknown silence state")
}
sil = cloneSilence(sil)
sil.StartsAt = start
sil.EndsAt = end
sil.UpdatedAt = now
return sil, nil
}
// AddComment adds a new comment to the silence with the given ID.
func (s *Silences) AddComment(id string, author, comment string) error {
panic("not implemented")
}
// QueryParam expresses parameters along which silences are queried.
type QueryParam func(*query) error
type query struct {
ids []string
filters []silenceFilter
}
// silenceFilter is a function that returns true if a silence
// should be dropped from a result set for a given time.
type silenceFilter func(*pb.Silence, *Silences, *timestamp.Timestamp) (bool, error)
var errNotSupported = errors.New("query parameter not supported")
// QIDs configures a query to select the given silence IDs.
func QIDs(ids ...string) QueryParam {
return func(q *query) error {
q.ids = append(q.ids, ids...)
return nil
}
}
// QTimeRange configures a query to search for silences that are active
// in the given time range.
// TODO(fabxc): not supported yet.
func QTimeRange(start, end time.Time) QueryParam {
return func(q *query) error {
return errNotSupported
}
}
// QMatches returns silences that match the given label set.
func QMatches(set model.LabelSet) QueryParam {
return func(q *query) error {
f := func(sil *pb.Silence, s *Silences, _ *timestamp.Timestamp) (bool, error) {
m, err := s.mc.Get(sil)
if err != nil {
return true, err
}
return m.Match(set), nil
}
q.filters = append(q.filters, f)
return nil
}
}
// SilenceState describes the state of a silence based on its time range.
type SilenceState string
// The only possible states of a silence w.r.t a timestamp.
const (
StateActive SilenceState = "active"
StatePending = "pending"
StateExpired = "expired"
)
// getState returns a silence's SilenceState at the given timestamp.
func getState(sil *pb.Silence, ts *timestamp.Timestamp) SilenceState {
if protoBefore(ts, sil.StartsAt) {
return StatePending
}
if protoBefore(sil.EndsAt, ts) {
return StateExpired
}
return StateActive
}
// QState filters queried silences by the given states.
func QState(states ...SilenceState) QueryParam {
return func(q *query) error {
f := func(sil *pb.Silence, _ *Silences, now *timestamp.Timestamp) (bool, error) {
s := getState(sil, now)
for _, ps := range states {
if s == ps {
return true, nil
}
}
return false, nil
}
q.filters = append(q.filters, f)
return nil
}
}
// Query for silences based on the given query parameters.
func (s *Silences) Query(params ...QueryParam) ([]*pb.Silence, error) {
start := time.Now()
s.metrics.queriesTotal.Inc()
sils, err := func() ([]*pb.Silence, error) {
q := &query{}
for _, p := range params {
if err := p(q); err != nil {
return nil, err
}
}
nowpb, err := s.nowProto()
if err != nil {
return nil, err
}
return s.query(q, nowpb)
}()
if err != nil {
s.metrics.queryErrorsTotal.Inc()
}
s.metrics.queryDuration.Observe(time.Since(start).Seconds())
return sils, err
}
func (s *Silences) query(q *query, now *timestamp.Timestamp) ([]*pb.Silence, error) {
// If we have an ID constraint, all silences are our base set.
// This and the use of post-filter functions is the
// the trivial solution for now.
var res []*pb.Silence
s.mtx.Lock()
defer s.mtx.Unlock()
if q.ids != nil {
for _, id := range q.ids {
if s, ok := s.st[string(id)]; ok {
res = append(res, s.Silence)
}
}
} else {
for _, sil := range s.st {
res = append(res, sil.Silence)
}
}
var resf []*pb.Silence
for _, sil := range res {
remove := false
for _, f := range q.filters {
ok, err := f(sil, s, now)
if err != nil {
return nil, err
}
if !ok {
remove = true
break
}
}
if !remove {
resf = append(resf, sil)
}
}
return resf, nil
}
// loadSnapshot loads a snapshot generated by Snapshot() into the state.
// Any previous state is wiped.
func (s *Silences) loadSnapshot(r io.Reader) error {
st := gossipData{}
s.mtx.Lock()
defer s.mtx.Unlock()
for {
var sil pb.MeshSilence
if _, err := pbutil.ReadDelimited(r, &sil); err != nil {
if err == io.EOF {
break
}
return err
}
st[sil.Silence.Id] = &sil
_, err := s.mc.Get(sil.Silence)
if err != nil {
return err
}
}
s.st = st
return nil
}
// Snapshot writes the full internal state into the writer and returns the number of bytes
// written.
func (s *Silences) Snapshot(w io.Writer) (int, error) {
start := time.Now()
defer func() { s.metrics.snapshotDuration.Observe(time.Since(start).Seconds()) }()
s.mtx.Lock()
defer s.mtx.Unlock()
var n int
for _, s := range s.st {
m, err := pbutil.WriteDelimited(w, s)
if err != nil {
return n + m, err
}
n += m
}
return n, nil
}
type gossiper struct {
*Silences
}
// Gossip implements the mesh.Gossiper interface.
func (g gossiper) Gossip() mesh.GossipData {
g.mtx.Lock()
defer g.mtx.Unlock()
return g.st.clone()
}
// OnGossip implements the mesh.Gossiper interface.
func (g gossiper) OnGossip(msg []byte) (mesh.GossipData, error) {
gd, err := decodeGossipData(msg)
if err != nil {
return nil, err
}
g.mtx.Lock()
defer g.mtx.Unlock()
if delta := g.st.mergeDelta(gd); len(delta) > 0 {
return delta, nil
}
return nil, nil
}
// OnGossipBroadcast implements the mesh.Gossiper interface.
func (g gossiper) OnGossipBroadcast(src mesh.PeerName, msg []byte) (mesh.GossipData, error) {
gd, err := decodeGossipData(msg)
if err != nil {
return nil, err
}
g.mtx.Lock()
defer g.mtx.Unlock()
return g.st.mergeDelta(gd), nil
}
// OnGossipUnicast implements the mesh.Gossiper interface.
// It always panics.
func (g gossiper) OnGossipUnicast(src mesh.PeerName, msg []byte) error {
panic("not implemented")
}
type gossipData map[string]*pb.MeshSilence
func decodeGossipData(msg []byte) (gossipData, error) {
gd := gossipData{}
rd := bytes.NewReader(msg)
for {
var s pb.MeshSilence
if _, err := pbutil.ReadDelimited(rd, &s); err != nil {
if err == io.EOF {
break
}
return gd, err
}
gd[s.Silence.Id] = &s
}
return gd, nil
}
// Encode implements the mesh.GossipData interface.
func (gd gossipData) Encode() [][]byte {
// Split into sub-messages of ~1MB.
const maxSize = 1024 * 1024
var (
buf bytes.Buffer
res [][]byte
n int
)
for _, s := range gd {
m, err := pbutil.WriteDelimited(&buf, s)
n += m
if err != nil {
// TODO(fabxc): log error and skip entry. Or can this really not happen with a bytes.Buffer?
panic(err)
}
if n > maxSize {
res = append(res, buf.Bytes())
buf = bytes.Buffer{}
}
}
if buf.Len() > 0 {
res = append(res, buf.Bytes())
}
return res
}
func (gd gossipData) clone() gossipData {
res := make(gossipData, len(gd))
for id, s := range gd {
res[id] = s
}
return res
}
// Merge the silence set with gossip data and return a new silence state.
func (gd gossipData) Merge(other mesh.GossipData) mesh.GossipData {
for id, s := range other.(gossipData) {
prev, ok := gd[id]
if !ok {
gd[id] = s
continue
}
pts, err := ptypes.Timestamp(prev.Silence.UpdatedAt)
if err != nil {
panic(err)
}
sts, err := ptypes.Timestamp(s.Silence.UpdatedAt)
if err != nil {
panic(err)
}
if pts.Before(sts) {
gd[id] = s
}
}
return gd
}
// mergeDelta behaves like Merge but returns a gossipData only
// containing things that have changed.
func (gd gossipData) mergeDelta(od gossipData) gossipData {
delta := gossipData{}
for id, s := range od {
prev, ok := gd[id]
if !ok {
gd[id] = s
delta[id] = s
continue
}
pts, err := ptypes.Timestamp(prev.Silence.UpdatedAt)
if err != nil {
panic(err)
}
sts, err := ptypes.Timestamp(s.Silence.UpdatedAt)
if err != nil {
panic(err)
}
if pts.Before(sts) {
gd[id] = s
delta[id] = s
}
}
return delta
}
// replaceFile wraps a file that is moved to another filename on closing.
type replaceFile struct {
*os.File
filename string
}
func (f *replaceFile) Close() error {
if err := f.File.Sync(); err != nil {
return err
}
if err := f.File.Close(); err != nil {
return err
}
return os.Rename(f.File.Name(), f.filename)
}
// openReplace opens a new temporary file that is moved to filename on closing.
func openReplace(filename string) (*replaceFile, error) {
tmpFilename := fmt.Sprintf("%s.%x", filename, uint64(rand.Int63()))
f, err := os.Create(tmpFilename)
if err != nil {
return nil, err
}
rf := &replaceFile{
File: f,
filename: filename,
}
return rf, nil
}