package order

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promauto"
)

// Define the counter object to be monitored
var (
    opsProcessed = promauto.NewCounterVec(prometheus.CounterOpts{
        Name: "order_service_processed_orders_total",
        Help: "The total number of processed orders",
    }, []string{"status"}) // Processing status
)

// Process the order
func makeOrder() {
    opsProcessed.WithLabelValues("success").Inc() // Success
    // opsProcessed.WithLabelValues("fail").Inc() // Failure

    // Order placement business logic
}

rate(order_service_processed_orders_total[5m])

package order

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promauto"
)

// Define the gauge object to be monitored
var (
    queueSize = promauto.NewGaugeVec(prometheus.GaugeOpts{
        Name: "order_service_order_queue_size",
        Help: "The size of order queue",
    }, []string{"type"})
)

type OrderQueue struct {
    queue chan string
}

func newOrderQueue() *OrderQueue  {
    return &OrderQueue{
        queue: make(chan string,100),
    }
}

// Produce an order message 
func (q *OrderQueue)produceOrder() {
    // Produce an order message

    // Increase the queue size by 1
    queueSize.WithLabelValues("make_order").Inc() // Order placement queue
    // queueSize.WithLabelValues("cancel_order").Inc() // Order cancellation queue
}

// Consume an order message 
func (q *OrderQueue)consumeOrder() {
    // Consume an order message

    // Reduce the queue size by 1
    queueSize.WithLabelValues("make_order").Dec()
}

order_service_order_queue_size

package order

import (
    "net/http"
    "time"

    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promauto"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

// Define the summary object to be monitored
var (
    opsProcessCost = promauto.NewSummaryVec(prometheus.SummaryOpts{
        Name: "order_service_process_order_duration",
        Help: "The order process duration",
    }, []string{"status"})
)

func makeOrder() {
    start := time.Now().UnixNano()
    // The order placement logic processing is completed, and the processing duration is recorded
    defer opsProcessCost.WithLabelValues("success").Observe((float64)(time.Now().UnixNano() - start))

    // Order placement business logic
    time.Sleep(time.Second) // Simulate the processing duration
}

order_service_processed_order_duration_sum / order_service_processed_order_duration_count

package main

import (
    "net/http"

    "github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
        // Business code

        // Expose Prometheus metrics in the HTTP service
        http.Handle("/metrics", promhttp.Handler())

        // Business code
}