Clean up logging messages and add flusher startup delay

Fixes #294

agent.go

@@ -1,7 +1,6 @@
 package telegraf
 
 import (
-	"errors"
 	"fmt"
 	"log"
 	"os"
@@ -212,7 +211,7 @@ func (a *Agent) gatherParallel(pointChan chan *client.Point) error {
 	wg.Wait()
 
 	elapsed := time.Since(start)
-	log.Printf("Default (%s) interval, gathered metrics from %d plugins in %s\n",
+	log.Printf("Gathered metrics, (%s interval), from %d plugins in %s\n",
 		a.Interval, counter, elapsed)
 	return nil
 }
@@ -240,7 +239,7 @@ func (a *Agent) gatherSeparate(
 		}
 
 		elapsed := time.Since(start)
-		log.Printf("Separate (%s) interval, gathered metrics from %s in %s\n",
+		log.Printf("Gathered metrics, (separate %s interval), from %s in %s\n",
 			plugin.config.Interval, plugin.name, elapsed)
 
 		if outerr != nil {
@@ -294,29 +293,35 @@ func (a *Agent) Test() error {
 	return nil
 }
 
-func (a *Agent) flush(points []*client.Point) error {
+func (a *Agent) flush(points []*client.Point) {
 	var wg sync.WaitGroup
-	var outerr error
 
+	start := time.Now()
+	counter := 0
 	for _, o := range a.outputs {
 		wg.Add(1)
+		counter++
 
 		go func(ro *runningOutput) {
 			defer wg.Done()
 			// Log all output errors:
 			if err := ro.output.Write(points); err != nil {
-				log.Printf("Error in output [%s]: %s", ro.name, err)
-				outerr = errors.New("Error encountered flushing outputs")
+				log.Printf("Error in output [%s]: %s", ro.name, err.Error())
 			}
 		}(o)
 	}
 
 	wg.Wait()
-	return outerr
+	elapsed := time.Since(start)
+	log.Printf("Flushed %d metrics to %d output sinks in %s\n",
+		len(points), counter, elapsed)
 }
 
 // flusher monitors the points input channel and flushes on the minimum interval
 func (a *Agent) flusher(shutdown chan struct{}, pointChan chan *client.Point) error {
+	// Inelegant, but this sleep is to allow the Gather threads to run, so that
+	// the flusher will flush after metrics are collected.
+	time.Sleep(time.Millisecond * 100)
 	ticker := time.NewTicker(a.FlushInterval.Duration)
 	points := make([]*client.Point, 0)
 	for {
@@ -324,12 +329,7 @@ func (a *Agent) flusher(shutdown chan struct{}, pointChan chan *client.Point) er
 		case <-shutdown:
 			return nil
 		case <-ticker.C:
-			start := time.Now()
-			if err := a.flush(points); err != nil {
-				log.Printf(err.Error())
-			}
-			elapsed := time.Since(start)
-			log.Printf("Flushed %d metrics in %s\n", len(points), elapsed)
+			a.flush(points)
 			points = make([]*client.Point, 0)
 		case pt := <-pointChan:
 			points = append(points, pt)

cmd/telegraf/telegraf.go

@@ -133,8 +133,8 @@ func main() {
 	log.Printf("Loaded outputs: %s", strings.Join(outputs, " "))
 	log.Printf("Loaded plugins: %s", strings.Join(plugins, " "))
 	log.Printf("Agent Config: Interval:%s, Debug:%#v, Hostname:%#v, "+
-		"Precision:%#v, UTC: %#v\n",
-		ag.Interval, ag.Debug, ag.Hostname, ag.Precision, ag.UTC)
+		"Flush Interval:%s\n",
+		ag.Interval, ag.Debug, ag.Hostname, ag.FlushInterval)
 	log.Printf("Tags enabled: %s", config.ListTags())
 
 	if *fPidfile != "" {