/
router.go
169 lines (136 loc) · 3.84 KB
/
router.go
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package v1
import (
"math/rand"
"sync"
"code.cloudfoundry.org/loggregator-release/src/plumbing"
"github.com/cloudfoundry/sonde-go/events"
"google.golang.org/protobuf/proto"
)
type shardID string
type filterType uint8
const (
noType filterType = iota
logType
metricType
)
type filter struct {
appID string
envelopeType filterType
}
// Router routes envelopes to particular buffers (called DataSetter here). In
// effect, the Router implements pub-sub. After a buffer has been registered
// with the Register method, calls to SendTo will ensure a particular envelope
// is sent to all registered buffers.
type Router struct {
lock sync.RWMutex
subscriptions map[filter]map[shardID][]DataSetter
}
// NewRouter is the constructor for Router.
func NewRouter() *Router {
return &Router{
subscriptions: make(map[filter]map[shardID][]DataSetter),
}
}
// Register stores a request with its corresponding DataSetter. Callers should
// invoke the cleanup function once a registered request should no longer
// receive envelopes.
func (r *Router) Register(req *plumbing.SubscriptionRequest, dataSetter DataSetter) (cleanup func()) {
r.lock.Lock()
defer r.lock.Unlock()
r.registerSetter(req, dataSetter)
return r.buildCleanup(req, dataSetter)
}
// SendTo sends an envelope for an application to all registered DataSetters.
func (r *Router) SendTo(appID string, envelope *events.Envelope) {
data := r.marshal(envelope)
if data == nil {
return
}
typedFilters := r.createTypedFilters(appID, envelope)
r.lock.RLock()
defer r.lock.RUnlock()
for _, typedFilter := range typedFilters {
for id, setters := range r.subscriptions[typedFilter] {
r.writeToShard(id, setters, data)
}
}
}
func (r *Router) writeToShard(id shardID, setters []DataSetter, data []byte) {
if id == "" {
for _, setter := range setters {
setter.Set(data)
}
return
}
setters[rand.Intn(len(setters))].Set(data) //nolint:gosec
}
func (r *Router) createTypedFilters(appID string, envelope *events.Envelope) []filter {
filters := make([]filter, 2, 4)
filters[0] = filter{appID: "", envelopeType: r.filterTypeFromEnvelope(envelope)}
filters[1] = filter{}
if appID != "" {
filters = append(filters, filter{appID: appID, envelopeType: noType})
filters = append(filters, filter{appID: appID, envelopeType: r.filterTypeFromEnvelope(envelope)})
}
return filters
}
func (r *Router) registerSetter(req *plumbing.SubscriptionRequest, dataSetter DataSetter) {
f := r.convertFilter(req)
m, ok := r.subscriptions[f]
if !ok {
m = make(map[shardID][]DataSetter)
r.subscriptions[f] = m
}
m[shardID(req.ShardID)] = append(m[shardID(req.ShardID)], dataSetter)
}
func (r *Router) buildCleanup(req *plumbing.SubscriptionRequest, dataSetter DataSetter) func() {
return func() {
r.lock.Lock()
defer r.lock.Unlock()
f := r.convertFilter(req)
var setters []DataSetter
for _, s := range r.subscriptions[f][shardID(req.ShardID)] {
if s != dataSetter {
setters = append(setters, s)
}
}
if len(setters) > 0 {
r.subscriptions[f][shardID(req.ShardID)] = setters
return
}
delete(r.subscriptions[f], shardID(req.ShardID))
if len(r.subscriptions[f]) == 0 {
delete(r.subscriptions, f)
}
}
}
func (r *Router) marshal(envelope *events.Envelope) []byte {
data, err := proto.Marshal(envelope)
if err != nil {
return nil
}
return data
}
func (r *Router) convertFilter(req *plumbing.SubscriptionRequest) filter {
if req.GetFilter() == nil {
return filter{}
}
f := filter{
appID: req.Filter.AppID,
}
if req.GetFilter().GetLog() != nil {
f.envelopeType = logType
}
if req.GetFilter().GetMetric() != nil {
f.envelopeType = metricType
}
return f
}
func (r *Router) filterTypeFromEnvelope(envelope *events.Envelope) filterType {
switch envelope.GetEventType() {
case events.Envelope_LogMessage:
return logType
default:
return metricType
}
}