log errors to error channel, not debug

* refactor exporter code for better readability and structure
* modified startup log output a little

README.md

@@ -1,3 +1,7 @@
+[![Actions](https://github.com/tlinden/io-exporter/actions/workflows/ci.yaml/badge.svg)](https://github.com/tlinden/io-exporter/actions)
+[![License](https://img.shields.io/badge/license-GPL-blue.svg)](https://github.com/tlinden/io-exporter/blob/master/LICENSE)
+[![Go Report Card](https://goreportcard.com/badge/github.com/tlinden/io-exporter)](https://goreportcard.com/report/github.com/tlinden/io-exporter)
+
 # io-exporter
 
 Report if a given filesystem is operating properly

blah

@@ -1 +0,0 @@
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cmd/config.go

@@ -15,7 +15,7 @@ import (
 )
 
 const (
-	Version = `v0.0.6`
+	Version = `v0.0.7`
 	SLEEP   = 5
 	Usage   = `io-exporter [options] <file>
 Options:

cmd/exporter.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"log/slog"
 	"os"
+	"sync"
 	"time"
 
 	"github.com/ncw/directio"
@@ -32,7 +33,10 @@ func NewExporter(conf *Config, alloc *Alloc, metrics *Metrics) *Exporter {
 }
 
 // starts the primary go-routine, which will run the io checks for ever
-func (exp *Exporter) RunIOchecks() {
+func (exp *Exporter) RunIOchecks() *sync.WaitGroup {
+	var wg sync.WaitGroup
+	wg.Add(1)
+
 	go func() {
 		for {
 			var res_r, res_w Result
@@ -49,7 +53,7 @@ func (exp *Exporter) RunIOchecks() {
 				slog.Debug("elapsed read time", "elapsed", res_r.elapsed, "result", res_r.result)
 			}
 
-			if exp.conf.WriteMode && exp.conf.ReadMode {
+			if (exp.conf.WriteMode && exp.conf.ReadMode) && (res_r.result && res_w.result) {
 				if !exp.alloc.Compare() {
 					res_r.result = false
 				}
@@ -60,6 +64,8 @@ func (exp *Exporter) RunIOchecks() {
 			time.Sleep(time.Duration(exp.conf.Sleeptime) * time.Second)
 		}
 	}()
+
+	return &wg
 }
 
 // call an io measurement and collect time needed
@@ -72,6 +78,11 @@ func (exp *Exporter) measure(mode int) Result {
 	now := time.Now()
 	elapsed := float64(now.Sub(start).Nanoseconds()) / 10000000000
 
+	// makes no sense to measure latency if operation failed
+	if !result {
+		elapsed = 0
+	}
+
 	return Result{elapsed: elapsed, result: result}
 }
 

cmd/root.go

@@ -31,7 +31,7 @@ func Run() {
 	alloc := NewAlloc()
 	exporter := NewExporter(conf, alloc, metrics)
 
-	exporter.RunIOchecks()
+	wg := exporter.RunIOchecks()
 
 	http.Handle("/metrics", promhttp.HandlerFor(
 		metrics.registry,
@@ -49,14 +49,22 @@ func Run() {
 	if err := http.ListenAndServe(fmt.Sprintf(":%d", conf.Port), nil); err != nil {
 		log.Fatal(err)
 	}
+
+	wg.Wait()
 }
 
 func report(err error, fd *os.File) bool {
-	slog.Debug("failed to check io", "error", err)
+	failure := err.Error()
+	if err.Error() == "context deadline exceeded" {
+		failure = "operation timed out"
+	}
+
+	slog.Error("io error", "error", failure)
 
 	if fd != nil {
 		if err := fd.Close(); err != nil {
-			slog.Debug("failed to close filehandle", "error", err)
+
+			slog.Debug("failed to close filehandle", "error", failure)
 		}
 	}