// eachRecordableValue visits each metric in the registry, calling the supplied
// function once for each recordable value represented by that metric. This is
// useful to expand certain metric types (such as histograms) into multiple
// recordable values.
func eachRecordableValue(reg *metric.Registry, fn func(string, float64)) {
reg.Each(func(name string, mtr interface{}) {
if histogram, ok := mtr.(*metric.Histogram); ok {
// TODO(mrtracy): Where should this comment go for better
// visibility?
//
// Proper support of Histograms for time series is difficult and
// likely not worth the trouble. Instead, we aggregate a windowed
// histogram at fixed quantiles. If the scraping window and the
// histogram's eviction duration are similar, this should give
// good results; if the two durations are very different, we either
// report stale results or report only the more recent data.
//
// Additionally, we can only aggregate max/min of the quantiles;
// roll-ups don't know that and so they will return mathematically
// nonsensical values, but that seems acceptable for the time
// being.
curr, _ := histogram.Windowed()
for _, pt := range recordHistogramQuantiles {
fn(name+pt.suffix, float64(curr.ValueAtQuantile(pt.quantile)))
}
} else {
val, err := extractValue(mtr)
if err != nil {
log.Warning(context.TODO(), err)
return
}
fn(name, val)
}
})
}
// newServer creates and returns a server struct.
func newServer(
ambient log.AmbientContext,
nodeID *base.NodeIDContainer,
stopper *stop.Stopper,
registry *metric.Registry,
) *server {
s := &server{
AmbientContext: ambient,
NodeID: nodeID,
stopper: stopper,
tighten: make(chan struct{}, 1),
nodeMetrics: makeMetrics(),
serverMetrics: makeMetrics(),
}
s.mu.is = newInfoStore(s.AmbientContext, nodeID, util.UnresolvedAddr{}, stopper)
s.mu.incoming = makeNodeSet(minPeers, metric.NewGauge(MetaConnectionsIncomingGauge))
s.mu.nodeMap = make(map[util.UnresolvedAddr]serverInfo)
s.mu.ready = make(chan struct{})
registry.AddMetric(s.mu.incoming.gauge)
registry.AddMetricStruct(s.nodeMetrics)
return s
}
func makeNodeMetrics(reg *metric.Registry, sampleInterval time.Duration) nodeMetrics {
nm := nodeMetrics{
Latency: metric.NewLatency(metaExecLatency, sampleInterval),
Success: metric.NewCounter(metaExecSuccess),
Err: metric.NewCounter(metaExecError),
}
reg.AddMetricStruct(nm)
return nm
}
// New creates an instance of a gossip node.
// The higher level manages the NodeIDContainer instance (which can be shared by
// various server components). The ambient context is expected to already
// contain the node ID.
func New(
ambient log.AmbientContext,
nodeID *base.NodeIDContainer,
rpcContext *rpc.Context,
grpcServer *grpc.Server,
resolvers []resolver.Resolver,
stopper *stop.Stopper,
registry *metric.Registry,
) *Gossip {
ambient.SetEventLog("gossip", "gossip")
g := &Gossip{
server: newServer(ambient, nodeID, stopper, registry),
Connected: make(chan struct{}),
rpcContext: rpcContext,
outgoing: makeNodeSet(minPeers, metric.NewGauge(MetaConnectionsOutgoingGauge)),
bootstrapping: map[string]struct{}{},
disconnected: make(chan *client, 10),
stalledCh: make(chan struct{}, 1),
stallInterval: defaultStallInterval,
bootstrapInterval: defaultBootstrapInterval,
cullInterval: defaultCullInterval,
nodeDescs: map[roachpb.NodeID]*roachpb.NodeDescriptor{},
resolverAddrs: map[util.UnresolvedAddr]resolver.Resolver{},
bootstrapAddrs: map[util.UnresolvedAddr]roachpb.NodeID{},
}
stopper.AddCloser(stop.CloserFn(g.server.AmbientContext.FinishEventLog))
registry.AddMetric(g.outgoing.gauge)
g.clientsMu.breakers = map[string]*circuit.Breaker{}
resolverAddrs := make([]string, len(resolvers))
for i, resolver := range resolvers {
resolverAddrs[i] = resolver.Addr()
}
ctx := g.AnnotateCtx(context.Background())
if log.V(1) {
log.Infof(ctx, "initial resolvers: %v", resolverAddrs)
}
g.SetResolvers(resolvers)
g.mu.Lock()
// Add ourselves as a SystemConfig watcher.
g.mu.is.registerCallback(KeySystemConfig, g.updateSystemConfig)
// Add ourselves as a node descriptor watcher.
g.mu.is.registerCallback(MakePrefixPattern(KeyNodeIDPrefix), g.updateNodeAddress)
g.mu.Unlock()
RegisterGossipServer(grpcServer, g.server)
return g
}