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|
package sub_coordinator
import (
"sort"
"sync"
)
type InflightMessageTracker struct {
messages map[string]int64
mu sync.Mutex
timestamps *RingBuffer
}
func NewInflightMessageTracker(capacity int) *InflightMessageTracker {
return &InflightMessageTracker{
messages: make(map[string]int64),
timestamps: NewRingBuffer(capacity),
}
}
// EnflightMessage tracks the message with the key and timestamp.
// These messages are sent to the consumer group instances and waiting for ack.
func (imt *InflightMessageTracker) EnflightMessage(key []byte, tsNs int64) {
// fmt.Printf("EnflightMessage(%s,%d)\n", string(key), tsNs)
imt.mu.Lock()
defer imt.mu.Unlock()
imt.messages[string(key)] = tsNs
imt.timestamps.EnflightTimestamp(tsNs)
}
// IsMessageAcknowledged returns true if the message has been acknowledged.
// If the message is older than the oldest inflight messages, returns false.
// returns false if the message is inflight.
// Otherwise, returns false if the message is old and can be ignored.
func (imt *InflightMessageTracker) IsMessageAcknowledged(key []byte, tsNs int64) bool {
imt.mu.Lock()
defer imt.mu.Unlock()
if tsNs <= imt.timestamps.OldestAckedTimestamp() {
return true
}
if tsNs > imt.timestamps.Latest() {
return false
}
if _, found := imt.messages[string(key)]; found {
return false
}
return true
}
// AcknowledgeMessage acknowledges the message with the key and timestamp.
func (imt *InflightMessageTracker) AcknowledgeMessage(key []byte, tsNs int64) bool {
// fmt.Printf("AcknowledgeMessage(%s,%d)\n", string(key), tsNs)
imt.mu.Lock()
defer imt.mu.Unlock()
timestamp, exists := imt.messages[string(key)]
if !exists || timestamp != tsNs {
return false
}
delete(imt.messages, string(key))
// Remove the specific timestamp from the ring buffer.
imt.timestamps.AckTimestamp(tsNs)
return true
}
func (imt *InflightMessageTracker) GetOldestAckedTimestamp() int64 {
return imt.timestamps.OldestAckedTimestamp()
}
// IsInflight returns true if the message with the key is inflight.
func (imt *InflightMessageTracker) IsInflight(key []byte) bool {
imt.mu.Lock()
defer imt.mu.Unlock()
_, found := imt.messages[string(key)]
return found
}
// Cleanup clears all in-flight messages. This should be called when a subscriber disconnects
// to prevent messages from being stuck in the in-flight state indefinitely.
func (imt *InflightMessageTracker) Cleanup() int {
imt.mu.Lock()
defer imt.mu.Unlock()
count := len(imt.messages)
// Clear all in-flight messages
imt.messages = make(map[string]int64)
return count
}
type TimestampStatus struct {
Timestamp int64
Acked bool
}
// RingBuffer represents a circular buffer to hold timestamps.
type RingBuffer struct {
buffer []*TimestampStatus
head int
size int
maxTimestamp int64
maxAllAckedTs int64
}
// NewRingBuffer creates a new RingBuffer of the given capacity.
func NewRingBuffer(capacity int) *RingBuffer {
return &RingBuffer{
buffer: newBuffer(capacity),
}
}
func newBuffer(capacity int) []*TimestampStatus {
buffer := make([]*TimestampStatus, capacity)
for i := range buffer {
buffer[i] = &TimestampStatus{}
}
return buffer
}
// EnflightTimestamp adds a new timestamp to the ring buffer.
func (rb *RingBuffer) EnflightTimestamp(timestamp int64) {
if rb.size < len(rb.buffer) {
rb.size++
} else {
newBuf := newBuffer(2 * len(rb.buffer))
for i := 0; i < rb.size; i++ {
newBuf[i] = rb.buffer[(rb.head+len(rb.buffer)-rb.size+i)%len(rb.buffer)]
}
rb.buffer = newBuf
rb.head = rb.size
rb.size++
}
head := rb.buffer[rb.head]
head.Timestamp = timestamp
head.Acked = false
rb.head = (rb.head + 1) % len(rb.buffer)
if timestamp > rb.maxTimestamp {
rb.maxTimestamp = timestamp
}
}
// AckTimestamp removes the specified timestamp from the ring buffer.
func (rb *RingBuffer) AckTimestamp(timestamp int64) {
// Perform binary search
index := sort.Search(rb.size, func(i int) bool {
return rb.buffer[(rb.head+len(rb.buffer)-rb.size+i)%len(rb.buffer)].Timestamp >= timestamp
})
actualIndex := (rb.head + len(rb.buffer) - rb.size + index) % len(rb.buffer)
rb.buffer[actualIndex].Acked = true
// Remove all the continuously acknowledged timestamps from the buffer
startPos := (rb.head + len(rb.buffer) - rb.size) % len(rb.buffer)
for i := 0; i < len(rb.buffer) && rb.buffer[(startPos+i)%len(rb.buffer)].Acked; i++ {
t := rb.buffer[(startPos+i)%len(rb.buffer)]
if rb.maxAllAckedTs < t.Timestamp {
rb.size--
rb.maxAllAckedTs = t.Timestamp
}
}
}
// OldestAckedTimestamp returns the oldest that is already acked timestamp in the ring buffer.
func (rb *RingBuffer) OldestAckedTimestamp() int64 {
return rb.maxAllAckedTs
}
// Latest returns the most recently known timestamp in the ring buffer.
func (rb *RingBuffer) Latest() int64 {
return rb.maxTimestamp
}
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