1886782530
License: MIT Signed-off-by: Hector Sanjuan <code@hector.link>
285 lines
6.3 KiB
Go
285 lines
6.3 KiB
Go
// Package basic implements a basic PeerMonitor component for IPFS Cluster. This
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// component is in charge of logging metrics and triggering alerts when a peer
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// goes down.
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package basic
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import (
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"context"
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"sync"
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"time"
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rpc "github.com/hsanjuan/go-libp2p-gorpc"
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logging "github.com/ipfs/go-log"
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peer "github.com/libp2p/go-libp2p-peer"
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"github.com/ipfs/ipfs-cluster/api"
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"github.com/ipfs/ipfs-cluster/monitor/util"
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)
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var logger = logging.Logger("monitor")
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// AlertChannelCap specifies how much buffer the alerts channel has.
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var AlertChannelCap = 256
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// DefaultWindowCap sets the amount of metrics to store per peer.
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var DefaultWindowCap = 25
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type metricsByPeer map[peer.ID]*util.MetricsWindow
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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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metrics map[string]metricsByPeer
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metricsMux sync.RWMutex
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windowCap int
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alerts chan api.Alert
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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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// NewMonitor creates a new monitor. It receives the window capacity
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// (how many metrics to keep for each peer and type of metric) and the
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// monitoringInterval (interval between the checks that produce alerts)
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// as parameters
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func NewMonitor(cfg *Config) (*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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if DefaultWindowCap <= 0 {
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panic("windowCap too small")
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}
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ctx, cancel := context.WithCancel(context.Background())
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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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metrics: make(map[string]metricsByPeer),
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windowCap: DefaultWindowCap,
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alerts: make(chan api.Alert, AlertChannelCap),
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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.monitor()
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case <-mon.ctx.Done():
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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() error {
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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.Warning("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(m api.Metric) {
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mon.metricsMux.Lock()
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defer mon.metricsMux.Unlock()
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name := m.Name
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peer := m.Peer
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mbyp, ok := mon.metrics[name]
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if !ok {
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mbyp = make(metricsByPeer)
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mon.metrics[name] = mbyp
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}
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window, ok := mbyp[peer]
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if !ok {
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// We always lock the outer map, so we can use unsafe
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// MetricsWindow.
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window = util.NewMetricsWindow(mon.windowCap, false)
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mbyp[peer] = window
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}
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logger.Debugf("logged '%s' metric from '%s'. Expires on %d", name, peer, m.Expire)
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window.Add(m)
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}
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// func (mon *Monitor) getLastMetric(name string, p peer.ID) api.Metric {
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// mon.metricsMux.RLock()
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// defer mon.metricsMux.RUnlock()
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// emptyMetric := api.Metric{
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// Name: name,
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// Peer: p,
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// Valid: false,
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// }
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// mbyp, ok := mon.metrics[name]
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// if !ok {
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// return emptyMetric
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// }
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// window, ok := mbyp[p]
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// if !ok {
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// return emptyMetric
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// }
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// metric, err := window.Latest()
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// if err != nil {
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// return emptyMetric
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// }
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// return metric
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// }
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// LastMetrics 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) LastMetrics(name string) []api.Metric {
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// Ger current list of peers
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var peers []peer.ID
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err := mon.rpcClient.Call("",
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"Cluster",
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"ConsensusPeers",
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struct{}{},
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&peers)
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if err != nil {
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logger.Errorf("LastMetrics could not list peers: %s", err)
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return []api.Metric{}
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}
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mon.metricsMux.RLock()
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defer mon.metricsMux.RUnlock()
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mbyp, ok := mon.metrics[name]
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if !ok {
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logger.Warningf("LastMetrics: No %s metrics", name)
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return []api.Metric{}
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}
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metrics := make([]api.Metric, 0, len(mbyp))
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// only show metrics for current set of peers
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for _, peer := range peers {
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window, ok := mbyp[peer]
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if !ok {
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continue
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}
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last, err := window.Latest()
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if err != nil || last.Discard() {
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logger.Warningf("no valid last metric for peer: %+v", last)
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continue
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}
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metrics = append(metrics, last)
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}
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return metrics
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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.alerts
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}
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// monitor creates a ticker which fetches current
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// cluster peers and checks that the last metric for a peer
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// has not expired.
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func (mon *Monitor) monitor() {
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ticker := time.NewTicker(mon.config.CheckInterval)
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for {
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select {
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case <-ticker.C:
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logger.Debug("monitoring tick")
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// Get current peers
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var peers []peer.ID
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err := mon.rpcClient.Call("",
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"Cluster",
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"ConsensusPeers",
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struct{}{},
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&peers)
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if err != nil {
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logger.Error(err)
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break
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}
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for k := range mon.metrics {
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logger.Debug("check metrics ", k)
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mon.checkMetrics(peers, k)
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}
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case <-mon.ctx.Done():
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ticker.Stop()
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return
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}
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}
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}
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// This is probably the place to implement some advanced ways of detecting down
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// peers.
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// Currently easy logic, just check that all peers have a valid metric.
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func (mon *Monitor) checkMetrics(peers []peer.ID, metricName string) {
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mon.metricsMux.RLock()
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defer mon.metricsMux.RUnlock()
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// get metric windows for peers
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metricsByPeer := mon.metrics[metricName]
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// for each of the given current peers
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for _, p := range peers {
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// get metrics for that peer
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window, ok := metricsByPeer[p]
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if !ok { // no metrics from this peer
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continue
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}
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last, err := window.Latest()
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if err != nil { // no metrics for this peer
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continue
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}
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// send alert if metric is expired (but was valid at some point)
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if last.Valid && last.Expired() {
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logger.Debugf("Metric %s from peer %s expired at %s", metricName, p, last.Expire)
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mon.sendAlert(p, metricName)
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}
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}
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}
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func (mon *Monitor) sendAlert(p peer.ID, metricName string) {
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alrt := api.Alert{
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Peer: p,
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MetricName: metricName,
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}
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select {
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case mon.alerts <- alrt:
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default:
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logger.Error("alert channel is full")
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}
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}
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