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| package main
import ( "context" "encoding/json" "fmt" "log" "sync" "time"
"github.com/Shopify/sarama" "github.com/prometheus/client_golang/prometheus" "github.com/prometheus/client_golang/prometheus/promauto" "github.com/prometheus/client_golang/prometheus/promhttp" "net/http" )
type MonitorConfig struct { BrokerList []string Topics []string ConsumerGroup string Interval time.Duration }
type KafkaMonitor struct { config *MonitorConfig client sarama.Client admin sarama.ClusterAdmin metrics *KafkaMetrics prometheus *PrometheusMetrics mu sync.RWMutex }
type PrometheusMetrics struct { consumerLag *prometheus.GaugeVec consumerThroughput *prometheus.GaugeVec topicSize *prometheus.GaugeVec errorCount *prometheus.CounterVec }
func initPrometheusMetrics() *PrometheusMetrics { return &PrometheusMetrics{ consumerLag: promauto.NewGaugeVec( prometheus.GaugeOpts{ Name: "kafka_consumer_lag", Help: "Kafka consumer lag in messages", }, []string{"topic", "partition", "consumer_group"}, ), consumerThroughput: promauto.NewGaugeVec( prometheus.GaugeOpts{ Name: "kafka_consumer_throughput", Help: "Kafka consumer throughput in messages/sec", }, []string{"topic", "consumer_group"}, ), topicSize: promauto.NewGaugeVec( prometheus.GaugeOpts{ Name: "kafka_topic_size", Help: "Kafka topic size in bytes", }, []string{"topic"}, ), errorCount: promauto.NewCounterVec( prometheus.CounterOpts{ Name: "kafka_monitor_errors_total", Help: "Total number of monitoring errors", }, []string{"type"}, ), } }
func NewKafkaMonitor(config *MonitorConfig) (*KafkaMonitor, error) { conf := sarama.NewConfig() conf.Version = sarama.V2_4_0_0
client, err := sarama.NewClient(config.BrokerList, conf) if err != nil { return nil, fmt.Errorf("failed to create client: %v", err) return nil, fmt.Errorf("failed to create admin client: %v", err) }
admin, err := sarama.NewClusterAdmin(config.BrokerList, conf) if err != nil { return nil, fmt.Errorf("failed to create admin client: %v", err) }
return &KafkaMonitor{ config: config, client: client, admin: admin, metrics: &KafkaMetrics{}, prometheus: initPrometheusMetrics(), }, nil }
func (km *KafkaMonitor) monitorConsumerLag(ctx context.Context) { for { select { case <-ctx.Done(): return default: for _, topic := range km.config.Topics { partitions, err := km.client.Partitions(topic) if err != nil { km.prometheus.errorCount.WithLabelValues("consumer_lag").Inc() continue }
for _, partition := range partitions { latestOffset, err := km.client.GetOffset(topic, partition, sarama.OffsetNewest) if err != nil { continue }
offset, err := km.admin.ListConsumerGroupOffsets(km.config.ConsumerGroup, map[string][]int32{ topic: {partition}, }) if err != nil { continue }
block := offset.Blocks[topic][partition] lag := latestOffset - block.Offset
km.prometheus.consumerLag.WithLabelValues( topic, fmt.Sprintf("%d", partition), km.config.ConsumerGroup, ).Set(float64(lag))
km.mu.Lock() km.metrics.ConsumerLag = lag km.mu.Unlock() } } time.Sleep(km.config.Interval) } } }
func (km *KafkaMonitor) monitorTopicMetrics(ctx context.Context) { for { select { case <-ctx.Done(): return default: for _, topic := range km.config.Topics { topicDetails, err := km.admin.DescribeTopics([]string{topic}) if err != nil { km.prometheus.errorCount.WithLabelValues("topic_metrics").Inc() continue }
var totalSize int64 var messageCount int64
for _, detail := range topicDetails { for _, partition := range detail.Partitions { newest, err := km.client.GetOffset(topic, partition.ID, sarama.OffsetNewest) if err != nil { continue } oldest, err := km.client.GetOffset(topic, partition.ID, sarama.OffsetOldest) if err != nil { continue } messageCount += newest - oldest } }
km.prometheus.topicSize.WithLabelValues(topic).Set(float64(totalSize))
km.mu.Lock() km.metrics.TopicSize = totalSize km.metrics.MessageCount = messageCount km.metrics.LastUpdateTime = time.Now() km.mu.Unlock() } time.Sleep(km.config.Interval) } } }
func (km *KafkaMonitor) metricsHandler(w http.ResponseWriter, r *http.Request) { km.mu.RLock() defer km.mu.RUnlock()
response, err := json.Marshal(km.metrics) if err != nil { http.Error(w, err.Error(), http.StatusInternalServerError) type MonitorWorkerPool struct { workers int tasks chan MonitorTask }
func NewMonitorWorkerPool(workers int) *MonitorWorkerPool { return &MonitorWorkerPool{ workers: workers, tasks: make(chan MonitorTask, workers*2), } }
func (p *MonitorWorkerPool) Start() { for i := 0; i < p.workers; i++ { go p.worker() } }
func (p *MonitorWorkerPool) worker() { for task := range p.tasks { task.Execute() } }
type AutoScaler struct { metrics *KafkaMetrics scaleThreshold float64 cooldownPeriod time.Duration lastScaleTime time.Time }
func (as *AutoScaler) CheckAndScale() { if time.Since(as.lastScaleTime) < as.cooldownPeriod { return } w.Header().Set("Content-Type", "application/json") w.Write(response) if as.metrics.ConsumerLag > int64(as.scaleThreshold) { as.scaleOut() } else if as.metrics.ConsumerLag < int64(as.scaleThreshold/2) { as.scaleIn() } }
type SmartAlert struct { history []Alert threshold map[string]float64 correlation map[string][]string func NewMonitorWorkerPool(workers int) *MonitorWorkerPool { return &MonitorWorkerPool{ workers: workers, tasks: make(chan MonitorTask, workers*2), } sa.adjustThresholds() func (as *AutoScaler) CheckAndScale() { if time.Since(as.lastScaleTime) < as.cooldownPeriod { return } Topics: []string{"important-topic"}, ConsumerGroup: "monitor-group", Interval: time.Second * 30, }
monitor, err := NewKafkaMonitor(config) if err != nil { log.Fatalf("Failed to create Kafka monitor: %v", err) }
ctx, cancel := context.WithCancel(context.Background()) defer cancel()
go monitor.monitorConsumerLag(ctx) go monitor.monitorTopicMetrics(ctx)
http.HandleFunc("/metrics/kafka", monitor.metricsHandler) http.Handle("/metrics", promhttp.Handler()) http.Handle("/metrics", promhttp.Handler())
log.Fatal(http.ListenAndServe(":8080", nil)) }
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