Changed tm-bench output to json (#83)

* Changed output to json

* Added -output-format parameter (issue #40)

* remove leftover debug message

tm-bench/main.go

@@ -1,16 +1,18 @@
 package main
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
 	"os"
 	"strings"
-	"text/tabwriter"
 	"time"
 
 	"github.com/go-kit/kit/log/term"
 	metrics "github.com/rcrowley/go-metrics"
 
+	"text/tabwriter"
+
 	tmtypes "github.com/tendermint/tendermint/types"
 	"github.com/tendermint/tmlibs/log"
 	"github.com/tendermint/tools/tm-monitor/monitor"
@@ -29,17 +31,19 @@ type statistics struct {
 func main() {
 	var duration, txsRate, connections int
 	var verbose bool
+	var outputFormat string
 
 	flag.IntVar(&connections, "c", 1, "Connections to keep open per endpoint")
 	flag.IntVar(&duration, "T", 10, "Exit after the specified amount of time in seconds")
 	flag.IntVar(&txsRate, "r", 1000, "Txs per second to send in a connection")
+	flag.StringVar(&outputFormat, "output-format", "plain", "Output format: plain or json")
 	flag.BoolVar(&verbose, "v", false, "Verbose output")
 
 	flag.Usage = func() {
 		fmt.Println(`Tendermint blockchain benchmarking tool.
 
 Usage:
-	tm-bench [-c 1] [-T 10] [-r 1000] [endpoints]
+	tm-bench [-c 1] [-T 10] [-r 1000] [endpoints] [-output-format <plain|json>]
 
 Examples:
 	tm-bench localhost:46657`)
@@ -55,6 +59,10 @@ Examples:
 	}
 
 	if verbose {
+		if outputFormat == "json" {
+			fmt.Println("Verbose mode not supported with json output.")
+			os.Exit(1)
+		}
 		// Color errors red
 		colorFn := func(keyvals ...interface{}) term.FgBgColor {
 			for i := 1; i < len(keyvals); i += 2 {
@@ -65,9 +73,9 @@ Examples:
 			return term.FgBgColor{}
 		}
 		logger = log.NewTMLoggerWithColorFn(log.NewSyncWriter(os.Stdout), colorFn)
-	}
 
-	fmt.Printf("Running %ds test @ %s\n", duration, flag.Arg(0))
+		fmt.Printf("Running %ds test @ %s\n", duration, flag.Arg(0))
+	}
 
 	endpoints := strings.Split(flag.Arg(0), ",")
 
@@ -110,7 +118,7 @@ Examples:
 				t.Stop()
 			}
 
-			printStatistics(stats)
+			printStatistics(stats, outputFormat)
 
 			for _, n := range nodes {
 				n.Stop()
@@ -154,20 +162,47 @@ func startTransacters(endpoints []string, connections int, txsRate int) []*trans
 	return transacters
 }
 
-func printStatistics(stats *statistics) {
-	w := tabwriter.NewWriter(os.Stdout, 0, 0, 5, ' ', 0)
-	fmt.Fprintln(w, "Stats\tAvg\tStdev\tMax\t")
-	fmt.Fprintln(w, fmt.Sprintf("Block latency\t%.2fms\t%.2fms\t%dms\t",
-		stats.BlockLatency.Mean()/1000000.0,
-		stats.BlockLatency.StdDev()/1000000.0,
-		stats.BlockLatency.Max()/1000000))
-	fmt.Fprintln(w, fmt.Sprintf("Blocks/sec\t%.3f\t%.3f\t%d\t",
-		stats.BlockTimeSample.Mean(),
-		stats.BlockTimeSample.StdDev(),
-		stats.BlockTimeSample.Max()))
-	fmt.Fprintln(w, fmt.Sprintf("Txs/sec\t%.0f\t%.0f\t%d\t",
-		stats.TxThroughputSample.Mean(),
-		stats.TxThroughputSample.StdDev(),
-		stats.TxThroughputSample.Max()))
-	w.Flush()
+type Results struct {
+	BlockLatencyMean   float64
+	BlockLatencyMax    int64
+	BlockLatencyStdDev float64
+	BlockTimeMean      float64
+	BlockTimeMax       int64
+	BlockTimeStdDev    float64
+	TxThroughputMean   float64
+	TxThroughputMax    int64
+	TxThroughputStdDev float64
+}
+
+func printStatistics(stats *statistics, outputFormat string) {
+	if outputFormat == "json" {
+		result, _ := json.Marshal(Results{
+			stats.BlockLatency.Mean() / 1000000.0,
+			stats.BlockLatency.Max() / 1000000.0,
+			stats.BlockLatency.StdDev() / 1000000.0,
+			stats.BlockTimeSample.Mean(),
+			stats.BlockTimeSample.Max(),
+			stats.BlockTimeSample.StdDev(),
+			stats.TxThroughputSample.Mean(),
+			stats.TxThroughputSample.Max(),
+			stats.TxThroughputSample.StdDev(),
+		})
+		fmt.Println(string(result))
+	} else {
+		w := tabwriter.NewWriter(os.Stdout, 0, 0, 5, ' ', 0)
+		fmt.Fprintln(w, "Stats\tAvg\tStdev\tMax\t")
+		fmt.Fprintln(w, fmt.Sprintf("Block latency\t%.2fms\t%.2fms\t%dms\t",
+			stats.BlockLatency.Mean()/1000000.0,
+			stats.BlockLatency.StdDev()/1000000.0,
+			stats.BlockLatency.Max()/1000000))
+		fmt.Fprintln(w, fmt.Sprintf("Blocks/sec\t%.3f\t%.3f\t%d\t",
+			stats.BlockTimeSample.Mean(),
+			stats.BlockTimeSample.StdDev(),
+			stats.BlockTimeSample.Max()))
+		fmt.Fprintln(w, fmt.Sprintf("Txs/sec\t%.0f\t%.0f\t%d\t",
+			stats.TxThroughputSample.Mean(),
+			stats.TxThroughputSample.StdDev(),
+			stats.TxThroughputSample.Max()))
+		w.Flush()
+	}
 }