Files
tessera/services/data_service/internal/manager/session.go

130 lines
3.1 KiB
Go

package manager
import (
"time"
"github.com/google/uuid"
"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/domain"
)
// Session holds per-session state. Owned by the manager loop.
type session struct {
id uuid.UUID
clientIn chan domain.Message // caller writes
clientOut chan domain.Message // caller reads
bound map[domain.Identifier]struct{}
closed bool
attached bool
idleAfter time.Duration
idleTimer *time.Timer
}
// attachSession wires channels, stops idle timer, and registers ready routes.
// Precondition: session exists and is not attached/closed. Runs in loop.
func (m *Manager) attachSession(s *session, inBuf, outBuf int) (chan<- domain.Message, <-chan domain.Message, error) {
if inBuf <= 0 {
inBuf = defaultClientBuf
}
if outBuf <= 0 {
outBuf = defaultClientBuf
}
cin := make(chan domain.Message, inBuf)
cout := make(chan domain.Message, outBuf)
s.clientIn, s.clientOut = cin, cout
if s.idleTimer != nil {
s.idleTimer.Stop()
s.idleTimer = nil
}
// Forward clientIn to router.Incoming with drop on backpressure.
go func(src <-chan domain.Message, dst chan<- domain.Message) {
for msg := range src {
select {
case dst <- msg:
default:
lg().Warn("drop message on clientIn backpressure", "identifier", msg.Identifier.Key())
}
}
}(cin, m.router.IncomingChannel())
// Register all currently bound that are ready.
for ident := range s.bound {
if !ident.IsRaw() {
m.router.RegisterRoute(ident, cout)
continue
}
// Raw: register only if provider stream is active.
if p, subj, err := m.resolveProvider(ident); err == nil && p.IsStreamActive(subj) {
m.router.RegisterRoute(ident, cout)
}
}
s.attached = true
return cin, cout, nil
}
// detachSession deregisters all routes, closes channels, and arms idle timer.
// Precondition: session exists and is attached. Runs in loop.
func (m *Manager) detachSession(sid uuid.UUID, s *session) error {
if s.clientOut != nil {
for ident := range s.bound {
m.router.DeregisterRoute(ident, s.clientOut)
}
close(s.clientOut)
}
if s.clientIn != nil {
close(s.clientIn)
}
s.clientIn, s.clientOut = nil, nil
s.attached = false
// Arm idle timer to auto-close the session.
s.idleTimer = time.AfterFunc(s.idleAfter, func() {
m.cmdCh <- closeSessionCmd{sid: sid, resp: make(chan error, 1)}
})
return nil
}
// closeSession performs full teardown and refcount drops. Runs in loop.
func (m *Manager) closeSession(sid uuid.UUID, s *session) {
if s.closed {
return
}
s.closed = true
// Detach if attached.
if s.attached {
if s.clientOut != nil {
for ident := range s.bound {
m.router.DeregisterRoute(ident, s.clientOut)
}
close(s.clientOut)
}
if s.clientIn != nil {
close(s.clientIn)
}
} else if s.idleTimer != nil {
s.idleTimer.Stop()
s.idleTimer = nil
}
// Drop refs for raw identifiers and stop streams if last ref. Fire-and-forget.
for ident := range s.bound {
if !ident.IsRaw() {
continue
}
if last := m.decrementStreamRefCount(ident); last {
if p, subj, err := m.resolveProvider(ident); err == nil {
_ = p.StopStreams([]string{subj}) // do not wait
}
}
}
delete(m.sessions, sid)
}