heroku metrics

vendor/github.com/heroku/x/hmetrics/onload/init.go

@@ -0,0 +1,71 @@
+/* Copyright (c) 2018 Salesforce
+ * All rights reserved.
+ * Licensed under the BSD 3-Clause license.
+ * For full license text, see LICENSE.txt file in the repo root  or https://opensource.org/licenses/BSD-3-Clause
+ */
+
+/*
+Package onload automatically starts hmetrics reporting, ignoring errors and
+retrying reporting, backing off in 10 second increments.
+
+Use this package when you don't care about stopping reporting, specifying the
+endpoint, or being notified of any reporting errors.
+
+This package will log all reporting errors via the stdlib log package if the
+environment variable HMETRICS_VERBOSE is set to "1", or any other true-like
+value as defined by strconv#ParseBool (see $ godoc strconv for more
+information).
+
+usage:
+
+  import (
+	_ "github.com/heroku/x/hmetrics/onload"
+  )
+
+See the package documentation at https://godoc.org/github.com/heroku/x/hmetrics
+for more info about Heroku Go metrics and advanced usage.
+
+*/
+package onload
+
+import (
+	"context"
+	"log"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/heroku/x/hmetrics"
+)
+
+const (
+	interval = 10
+)
+
+func init() {
+	var logger hmetrics.ErrHandler = func(_ error) error { return nil }
+
+	val := os.Getenv("HMETRICS_VERBOSE")
+	should, err := strconv.ParseBool(val)
+	if err == nil && should {
+		logger = func(err error) error {
+			log.Printf("[hmetrics] error: %v", err)
+			return nil
+		}
+	}
+
+	go func() {
+		var backoff int64
+		for backoff = 1; ; backoff++ {
+			start := time.Now()
+
+			err = hmetrics.Report(context.Background(), hmetrics.DefaultEndpoint, logger)
+			if time.Since(start) > 5*time.Minute {
+				backoff = 1
+			}
+			logger(err)
+
+			time.Sleep(time.Duration(backoff*interval) * time.Second)
+		}
+	}()
+}