From fb24d158aee671d3effad17a423669220d9fbe1b Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Wed, 25 Dec 2019 21:29:20 -0800
Subject: [PATCH] fix: CurrentState without processed/failed data

---
 internal/rdb/inspect.go      | 66 ++++++++++++++++++++++++------------
 internal/rdb/inspect_test.go | 24 +++++++++++++
 tools/asynqmon/cmd/stats.go  |  8 ++++-
 3 files changed, 75 insertions(+), 23 deletions(-)

diff --git a/internal/rdb/inspect.go b/internal/rdb/inspect.go
index 5bfee07..afd2ceb 100644
--- a/internal/rdb/inspect.go
+++ b/internal/rdb/inspect.go
@@ -3,13 +3,13 @@ package rdb
 import (
 	"encoding/json"
 	"fmt"
-	"strconv"
 	"strings"
 	"time"
 
 	"github.com/go-redis/redis/v7"
 	"github.com/hibiken/asynq/internal/base"
 	"github.com/rs/xid"
+	"github.com/spf13/cast"
 )
 
 // Stats represents a state of queues at a certain time.
@@ -77,35 +77,57 @@ type DeadTask struct {
 
 // CurrentStats returns a current state of the queues.
 func (r *RDB) CurrentStats() (*Stats, error) {
+	// KEYS[1] -> asynq:queues:default
+	// KEYS[2] -> asynq:in_progress
+	// KEYS[3] -> asynq:scheduled
+	// KEYS[4] -> asynq:retry
+	// KEYS[5] -> asynq:dead
+	// KEYS[6] -> asynq:processed:<yyyy-mm-dd>
+	// KEYS[7] -> asynq:failure:<yyyy-mm-dd>
+	script := redis.NewScript(`
+	local qlen = redis.call("LLEN", KEYS[1])
+	local plen = redis.call("LLEN", KEYS[2])
+	local slen = redis.call("ZCARD", KEYS[3])
+	local rlen = redis.call("ZCARD", KEYS[4])
+	local dlen = redis.call("ZCARD", KEYS[5])
+	local pcount = 0
+	local p = redis.call("GET", KEYS[6])
+	if p then
+		pcount = tonumber(p) 
+	end
+	local fcount = 0
+	local f = redis.call("GET", KEYS[7])
+	if f then
+		fcount = tonumber(f)
+	end
+	return {qlen, plen, slen, rlen, dlen, pcount, fcount}
+	`)
+
 	now := time.Now()
-	pipe := r.client.Pipeline()
-	qlen := pipe.LLen(base.DefaultQueue)
-	plen := pipe.LLen(base.InProgressQueue)
-	slen := pipe.ZCard(base.ScheduledQueue)
-	rlen := pipe.ZCard(base.RetryQueue)
-	dlen := pipe.ZCard(base.DeadQueue)
-	pcount := pipe.Get(base.ProcessedKey(now))
-	fcount := pipe.Get(base.FailureKey(now))
-	_, err := pipe.Exec()
+	res, err := script.Run(r.client, []string{
+		base.DefaultQueue,
+		base.InProgressQueue,
+		base.ScheduledQueue,
+		base.RetryQueue,
+		base.DeadQueue,
+		base.ProcessedKey(now),
+		base.FailureKey(now),
+	}).Result()
 	if err != nil {
 		return nil, err
 	}
-	p, err := strconv.Atoi(pcount.Val())
-	if err != nil {
-		return nil, err
-	}
-	f, err := strconv.Atoi(fcount.Val())
+	nums, err := cast.ToIntSliceE(res)
 	if err != nil {
 		return nil, err
 	}
 	return &Stats{
-		Enqueued:   int(qlen.Val()),
-		InProgress: int(plen.Val()),
-		Scheduled:  int(slen.Val()),
-		Retry:      int(rlen.Val()),
-		Dead:       int(dlen.Val()),
-		Processed:  p,
-		Failed:     f,
+		Enqueued:   nums[0],
+		InProgress: nums[1],
+		Scheduled:  nums[2],
+		Retry:      nums[3],
+		Dead:       nums[4],
+		Processed:  nums[5],
+		Failed:     nums[6],
 		Timestamp:  now,
 	}, nil
 }
diff --git a/internal/rdb/inspect_test.go b/internal/rdb/inspect_test.go
index 8584c25..9b8b888 100644
--- a/internal/rdb/inspect_test.go
+++ b/internal/rdb/inspect_test.go
@@ -138,6 +138,30 @@ func TestCurrentStats(t *testing.T) {
 	}
 }
 
+func TestCurrentStatsWithoutData(t *testing.T) {
+	r := setup(t)
+
+	want := &Stats{
+		Enqueued:   0,
+		InProgress: 0,
+		Scheduled:  0,
+		Retry:      0,
+		Dead:       0,
+		Processed:  0,
+		Failed:     0,
+		Timestamp:  time.Now(),
+	}
+
+	got, err := r.CurrentStats()
+	if err != nil {
+		t.Fatalf("r.CurrentStats() = %v, %v, want %+v, nil", got, err, want)
+	}
+
+	if diff := cmp.Diff(want, got, timeCmpOpt); diff != "" {
+		t.Errorf("r.CurrentStats() = %v, %v, want %+v, nil; (-want, +got)\n%s", got, err, want, diff)
+	}
+}
+
 func TestRedisInfo(t *testing.T) {
 	r := setup(t)
 
diff --git a/tools/asynqmon/cmd/stats.go b/tools/asynqmon/cmd/stats.go
index fd3424f..f3e4a1f 100644
--- a/tools/asynqmon/cmd/stats.go
+++ b/tools/asynqmon/cmd/stats.go
@@ -84,7 +84,13 @@ func printStats(s *rdb.Stats) {
 	tw := new(tabwriter.Writer).Init(os.Stdout, 0, 8, 2, ' ', 0)
 	fmt.Fprintf(tw, format, "Processed", "Failed", "Error Rate")
 	fmt.Fprintf(tw, format, "---------", "------", "----------")
-	fmt.Fprintf(tw, format, s.Processed, s.Failed, fmt.Sprintf("%.2f%%", float64(s.Failed)/float64(s.Processed)*100))
+	var errrate string
+	if s.Processed == 0 {
+		errrate = "N/A"
+	} else {
+		errrate = fmt.Sprintf("%.2f%%", float64(s.Failed)/float64(s.Processed)*100)
+	}
+	fmt.Fprintf(tw, format, s.Processed, s.Failed, errrate)
 	tw.Flush()
 }