/
routine.go
161 lines (140 loc) · 4.07 KB
/
routine.go
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package v2
import (
"fmt"
"strings"
"sync/atomic"
"github.com/Workiva/go-datastructures/queue"
"github.com/tendermint/tendermint/libs/log"
)
type handleFunc = func(event Event) (Event, error)
const historySize = 25
// Routine is a structure that models a finite state machine as serialized
// stream of events processed by a handle function. This Routine structure
// handles the concurrency and messaging guarantees. Events are sent via
// `send` are handled by the `handle` function to produce an iterator
// `next()`. Calling `stop()` on a routine will conclude processing of all
// sent events and produce `final()` event representing the terminal state.
type Routine struct {
name string
handle handleFunc
queue *queue.PriorityQueue
history []Event
out chan Event
fin chan error
rdy chan struct{}
running *uint32
logger log.Logger
metrics *Metrics
}
func newRoutine(name string, handleFunc handleFunc, bufferSize int) *Routine {
return &Routine{
name: name,
handle: handleFunc,
queue: queue.NewPriorityQueue(bufferSize, true),
history: make([]Event, 0, historySize),
out: make(chan Event, bufferSize),
rdy: make(chan struct{}, 1),
fin: make(chan error, 1),
running: new(uint32),
logger: log.NewNopLogger(),
metrics: NopMetrics(),
}
}
func (rt *Routine) setLogger(logger log.Logger) {
rt.logger = logger
}
func (rt *Routine) start() {
rt.logger.Info("routine start", "msg", log.NewLazySprintf("%s: run", rt.name))
running := atomic.CompareAndSwapUint32(rt.running, uint32(0), uint32(1))
if !running {
panic(fmt.Sprintf("%s is already running", rt.name))
}
close(rt.rdy)
defer func() {
if r := recover(); r != nil {
var (
b strings.Builder
j int
)
for i := len(rt.history) - 1; i >= 0; i-- {
fmt.Fprintf(&b, "%d: %+v\n", j, rt.history[i])
j++
}
panic(fmt.Sprintf("%v\nlast events:\n%v", r, b.String()))
}
stopped := atomic.CompareAndSwapUint32(rt.running, uint32(1), uint32(0))
if !stopped {
panic(fmt.Sprintf("%s is failed to stop", rt.name))
}
}()
for {
events, err := rt.queue.Get(1)
if err == queue.ErrDisposed {
rt.terminate(nil)
return
} else if err != nil {
rt.terminate(err)
return
}
oEvent, err := rt.handle(events[0].(Event))
rt.metrics.EventsHandled.With("routine", rt.name).Add(1)
if err != nil {
rt.terminate(err)
return
}
rt.metrics.EventsOut.With("routine", rt.name).Add(1)
rt.logger.Debug("routine start", "msg", log.NewLazySprintf("%s: produced %T %+v", rt.name, oEvent, oEvent))
// Skip rTrySchedule and rProcessBlock events as they clutter the history
// due to their frequency.
switch events[0].(type) {
case rTrySchedule:
case rProcessBlock:
default:
rt.history = append(rt.history, events[0].(Event))
if len(rt.history) > historySize {
rt.history = rt.history[1:]
}
}
rt.out <- oEvent
}
}
// XXX: look into returning OpError in the net package
func (rt *Routine) send(event Event) bool {
rt.logger.Debug("routine send", "msg", log.NewLazySprintf("%s: received %T %+v", rt.name, event, event))
if !rt.isRunning() {
return false
}
err := rt.queue.Put(event)
if err != nil {
rt.metrics.EventsShed.With("routine", rt.name).Add(1)
rt.logger.Error(fmt.Sprintf("%s: send failed, queue was full/stopped", rt.name))
return false
}
rt.metrics.EventsSent.With("routine", rt.name).Add(1)
return true
}
func (rt *Routine) isRunning() bool {
return atomic.LoadUint32(rt.running) == 1
}
func (rt *Routine) next() chan Event {
return rt.out
}
func (rt *Routine) ready() chan struct{} {
return rt.rdy
}
func (rt *Routine) stop() {
if !rt.isRunning() { // XXX: this should check rt.queue.Disposed()
return
}
rt.logger.Info("routine stop", "msg", log.NewLazySprintf("%s: stop", rt.name))
rt.queue.Dispose() // this should block until all queue items are free?
}
func (rt *Routine) final() chan error {
return rt.fin
}
// XXX: Maybe get rid of this
func (rt *Routine) terminate(reason error) {
// We don't close the rt.out channel here, to avoid spinning on the closed channel
// in the event loop.
rt.fin <- reason
}