package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "go.opencensus.io/exporter/stackdriver"
    "go.opencensus.io/stats"
    "go.opencensus.io/stats/view"
    "go.opencensus.io/tag"
)

var MerrorCount = stats.Int64("razvan.test/measures/error_count", "number of errors encounterd", "1")

var (
    ErrorCountView = &view.View{
        Name:        "demo/razvan/rep_period_test",
        Measure:     MerrorCount,
        Description: "Testing various reporting periods",
        Aggregation: view.Count(),
    }
)

func main() {

    KeyMethod, _ := tag.NewKey("test")
    ctx := context.Background()
    ctx, _ = tag.New(ctx, tag.Insert(KeyMethod, "30 sec reporting"))
    // Register the views
    if err := view.Register(ErrorCountView); err != nil {
        log.Fatalf("Failed to register views: %v", err)
    }
    // SD Exporter
    sd, err := stackdriver.NewExporter(stackdriver.Options{
        ProjectID: "opencensus-test",
        // MetricPrefix helps uniquely identify your metrics.
        MetricPrefix: "opencensus-test",
    })
    if err != nil {
        log.Fatalf("Failed to create the Stackdriver exporter: %v", err)
    }
    // It is imperative to invoke flush before your main function exits
    defer sd.Flush()

    view.RegisterExporter(sd)

    // Set reporting period to report data at every second.
    view.SetReportingPeriod(60000 * time.Millisecond)

    ticker := time.NewTicker(1000 * time.Millisecond)
    i := 0
    go func() {
        for {
            select {
            case <-ticker.C:
                stats.Record(ctx, MerrorCount.M(1))
                i++
            }
        }
    }()
    runtime := 65000
    time.Sleep(time.Duration(runtime) * time.Millisecond)
    fmt.Printf("Incremented  %d times\n", i)
}