296 lines
6.9 KiB
Go
296 lines
6.9 KiB
Go
// Package pubsubmon implements a PeerMonitor component for IPFS Cluster that
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// uses PubSub to send and receive metrics.
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package pubsubmon
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import (
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"bytes"
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"context"
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"time"
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"sync"
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"github.com/ipfs-cluster/ipfs-cluster/api"
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"github.com/ipfs-cluster/ipfs-cluster/monitor/metrics"
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logging "github.com/ipfs/go-log/v2"
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peer "github.com/libp2p/go-libp2p/core/peer"
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rpc "github.com/libp2p/go-libp2p-gorpc"
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pubsub "github.com/libp2p/go-libp2p-pubsub"
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gocodec "github.com/ugorji/go/codec"
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"go.opencensus.io/trace"
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)
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var logger = logging.Logger("monitor")
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// PubsubTopic specifies the topic used to publish Cluster metrics.
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var PubsubTopic = "monitor.metrics"
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var msgpackHandle = &gocodec.MsgpackHandle{}
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// Monitor is a component in charge of monitoring peers, logging
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// metrics and detecting failures
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type Monitor struct {
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ctx context.Context
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cancel func()
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rpcClient *rpc.Client
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rpcReady chan struct{}
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pubsub *pubsub.PubSub
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topic *pubsub.Topic
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subscription *pubsub.Subscription
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peers PeersFunc
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metrics *metrics.Store
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checker *metrics.Checker
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config *Config
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shutdownLock sync.Mutex
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shutdown bool
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wg sync.WaitGroup
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}
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// PeersFunc allows the Monitor to filter and discard metrics
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// that do not belong to a given peerset.
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type PeersFunc func(context.Context) ([]peer.ID, error)
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// New creates a new PubSub monitor, using the given host, config and
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// PeersFunc. The PeersFunc can be nil. In this case, no metric filtering is
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// done based on peers (any peer is considered part of the peerset).
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func New(
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ctx context.Context,
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cfg *Config,
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psub *pubsub.PubSub,
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peers PeersFunc,
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) (*Monitor, error) {
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err := cfg.Validate()
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if err != nil {
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return nil, err
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}
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ctx, cancel := context.WithCancel(ctx)
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mtrs := metrics.NewStore()
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checker := metrics.NewChecker(ctx, mtrs)
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topic, err := psub.Join(PubsubTopic)
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if err != nil {
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cancel()
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return nil, err
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}
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subscription, err := topic.Subscribe()
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if err != nil {
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cancel()
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return nil, err
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}
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mon := &Monitor{
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ctx: ctx,
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cancel: cancel,
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rpcReady: make(chan struct{}, 1),
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pubsub: psub,
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topic: topic,
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subscription: subscription,
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peers: peers,
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metrics: mtrs,
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checker: checker,
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config: cfg,
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}
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go mon.run()
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return mon, nil
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}
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func (mon *Monitor) run() {
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select {
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case <-mon.rpcReady:
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go mon.logFromPubsub()
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go mon.checker.Watch(mon.ctx, mon.peers, mon.config.CheckInterval)
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case <-mon.ctx.Done():
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}
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}
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// logFromPubsub logs metrics received in the subscribed topic.
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func (mon *Monitor) logFromPubsub() {
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ctx, span := trace.StartSpan(mon.ctx, "monitor/pubsub/logFromPubsub")
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defer span.End()
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decodeWarningPrinted := false
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// Previous versions use multicodec with the following header, which
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// we need to remove.
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multicodecPrefix := append([]byte{byte(9)}, []byte("/msgpack\n")...)
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for {
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select {
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case <-ctx.Done():
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return
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default:
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msg, err := mon.subscription.Next(ctx)
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if err != nil { // context canceled enters here
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continue
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}
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data := msg.GetData()
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buf := bytes.NewBuffer(data)
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dec := gocodec.NewDecoder(buf, msgpackHandle)
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metric := api.Metric{}
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err = dec.Decode(&metric)
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if err != nil {
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if bytes.HasPrefix(data, multicodecPrefix) {
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buf := bytes.NewBuffer(data[len(multicodecPrefix):])
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dec := gocodec.NewDecoder(buf, msgpackHandle)
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err = dec.Decode(&metric)
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if err != nil {
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logger.Error(err)
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continue
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}
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// managed to decode an older version metric. Warn about it once.
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if !decodeWarningPrinted {
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logger.Warning("Peers in versions <= v0.13.3 detected. These peers will not receive metrics from this or other newer peers. Please upgrade them.")
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decodeWarningPrinted = true
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}
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} else {
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logger.Error(err)
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continue
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}
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}
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debug("received", metric)
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err = mon.LogMetric(ctx, metric)
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if err != nil {
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logger.Error(err)
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continue
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}
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}
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}
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}
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// SetClient saves the given rpc.Client for later use
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func (mon *Monitor) SetClient(c *rpc.Client) {
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mon.rpcClient = c
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mon.rpcReady <- struct{}{}
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}
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// Shutdown stops the peer monitor. It particular, it will
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// not deliver any alerts.
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func (mon *Monitor) Shutdown(ctx context.Context) error {
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_, span := trace.StartSpan(ctx, "monitor/pubsub/Shutdown")
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defer span.End()
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mon.shutdownLock.Lock()
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defer mon.shutdownLock.Unlock()
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if mon.shutdown {
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logger.Warn("Monitor already shut down")
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return nil
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}
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logger.Info("stopping Monitor")
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close(mon.rpcReady)
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mon.cancel()
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mon.wg.Wait()
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mon.shutdown = true
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return nil
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}
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// LogMetric stores a metric so it can later be retrieved.
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func (mon *Monitor) LogMetric(ctx context.Context, m api.Metric) error {
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_, span := trace.StartSpan(ctx, "monitor/pubsub/LogMetric")
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defer span.End()
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mon.metrics.Add(m)
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debug("logged", m)
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if !m.Discard() { // We received a valid metric so avoid alerting.
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mon.checker.ResetAlerts(m.Peer, m.Name)
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}
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return nil
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}
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// PublishMetric broadcasts a metric to all current cluster peers.
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func (mon *Monitor) PublishMetric(ctx context.Context, m api.Metric) error {
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ctx, span := trace.StartSpan(ctx, "monitor/pubsub/PublishMetric")
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defer span.End()
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if m.Discard() {
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logger.Warnf("discarding invalid metric: %+v", m)
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return nil
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}
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var b bytes.Buffer
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enc := gocodec.NewEncoder(&b, msgpackHandle)
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err := enc.Encode(m)
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if err != nil {
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logger.Error(err)
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return err
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}
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debug("publish", m)
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err = mon.topic.Publish(ctx, b.Bytes())
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if err != nil {
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logger.Error(err)
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return err
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}
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return nil
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}
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// LatestMetrics returns last known VALID metrics of a given type. A metric
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// is only valid if it has not expired and belongs to a current cluster peer.
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func (mon *Monitor) LatestMetrics(ctx context.Context, name string) []api.Metric {
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ctx, span := trace.StartSpan(ctx, "monitor/pubsub/LatestMetrics")
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defer span.End()
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latest := mon.metrics.LatestValid(name)
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if mon.peers == nil {
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return latest
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}
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// Make sure we only return metrics in the current peerset if we have
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// a peerset provider.
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peers, err := mon.peers(ctx)
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if err != nil {
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return []api.Metric{}
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}
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return metrics.PeersetFilter(latest, peers)
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}
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// LatestForPeer returns the latest metric received for a peer (it may have
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// expired). It returns nil if no metric exists.
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func (mon *Monitor) LatestForPeer(ctx context.Context, name string, pid peer.ID) api.Metric {
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return mon.metrics.PeerLatest(name, pid)
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}
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// Alerts returns a channel on which alerts are sent when the
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// monitor detects a failure.
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func (mon *Monitor) Alerts() <-chan api.Alert {
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return mon.checker.Alerts()
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}
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// MetricNames lists all metric names.
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func (mon *Monitor) MetricNames(ctx context.Context) []string {
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_, span := trace.StartSpan(ctx, "monitor/pubsub/MetricNames")
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defer span.End()
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return mon.metrics.MetricNames()
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}
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func debug(event string, m api.Metric) {
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logger.Debugf(
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"%s metric: '%s' - '%s' - '%s' - '%s'",
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event,
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m.Peer,
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m.Name,
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m.Value,
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time.Unix(0, m.Expire),
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)
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}
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