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package main
import (
"context"
"time"
"hakurei.app/fhs"
"hakurei.app/internal/report"
"hakurei.app/internal/uevent"
"hakurei.app/message"
)
// newRejectColdboot returns a function to be called on every subsequent pending
// coldboot, and returns whether coldboot should proceed. Rejection is sticky.
func newRejectColdboot() func() bool {
// one coldboot per five minutes, two consecutive coldboot
const (
coldbootInterval = 5 * time.Minute
coldbootBurst = 2
)
done := make(chan struct{})
s := make(chan struct{}, coldbootBurst)
s <- struct{}{} // for early fault before reporting is ready
go func() {
t := time.NewTicker(coldbootInterval)
for {
select {
case <-done:
return
case <-t.C:
select {
case s <- struct{}{}:
default:
}
}
}
}()
return func() bool {
select {
case <-s:
return true
case <-done:
return false
default:
close(done)
return false
}
}
}
// consume continuously consumes events from conn with retries.
func consume(
ctx context.Context,
msg message.Msg,
r *report.Reporter,
conn *uevent.Conn,
uuid uevent.UUID,
events chan<- *uevent.Message,
) {
defer close(events)
nextColdboot := newRejectColdboot()
coldboot := true
retry:
if dispatchErr := conn.Consume(ctx, fhs.Sys, &uuid, events, coldboot, func(path string) {
msg.Verbose("coldboot visited", path)
}, func(err error) bool {
if _, ok := err.(uevent.NeedsColdboot); ok && !nextColdboot() {
r.Dispatch(
report.Degraded,
"rejecting coldboot loop",
err,
)
return false
}
r.Dispatch(
report.Inconsistent,
"consumed invalid message",
err,
)
return true
}, nil); dispatchErr != nil {
if _, ok := dispatchErr.(uevent.Recoverable); !ok {
r.Dispatch(
report.Fatal,
"discontinuing uevent processing due to nonrecoverable error",
dispatchErr,
)
return
}
if _, ok := dispatchErr.(uevent.NeedsColdboot); ok {
// coldboot loop rejected by handler
coldboot = false
}
goto retry
}
}
|
