Add ps command to asynqmon

tools/asynqmon/cmd/ls.go

@@ -10,7 +10,6 @@ import (
 	"os"
 	"strconv"
 	"strings"
-	"text/tabwriter"
 	"time"
 
 	"github.com/go-redis/redis/v7"
@@ -215,18 +214,3 @@ func listDead(r *rdb.RDB) {
 	printTable(cols, printRows)
 	fmt.Printf("\nShowing %d tasks from page %d\n", len(tasks), pageNum)
 }
-
-func printTable(cols []string, printRows func(w io.Writer, tmpl string)) {
-	format := strings.Repeat("%v\t", len(cols)) + "\n"
-	tw := new(tabwriter.Writer).Init(os.Stdout, 0, 8, 2, ' ', 0)
-	var headers []interface{}
-	var seps []interface{}
-	for _, name := range cols {
-		headers = append(headers, name)
-		seps = append(seps, strings.Repeat("-", len(name)))
-	}
-	fmt.Fprintf(tw, format, headers...)
-	fmt.Fprintf(tw, format, seps...)
-	printRows(tw, format)
-	tw.Flush()
-}

tools/asynqmon/cmd/ps.go

@@ -0,0 +1,89 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/go-redis/redis/v7"
+	"github.com/hibiken/asynq/internal/rdb"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+// psCmd represents the ps command
+var psCmd = &cobra.Command{
+	Use:   "ps",
+	Short: "Shows all background worker processes",
+	Long: `Ps (asynqmon ps) will show all background worker processes
+backed by the specified redis instance.
+
+The command shows the following for each process:
+* Host and PID of the process
+* Number of active workers out of worker pool
+* Queues configuration
+* State of the process ("running" | "stopped")
+
+A "running" process is processing tasks in queues.
+A "stopped" process are no longer processing new tasks.`,
+	Args: cobra.NoArgs,
+	Run:  ps,
+}
+
+func init() {
+	rootCmd.AddCommand(psCmd)
+}
+
+func ps(cmd *cobra.Command, args []string) {
+	c := redis.NewClient(&redis.Options{
+		Addr:     viper.GetString("uri"),
+		DB:       viper.GetInt("db"),
+		Password: viper.GetString("password"),
+	})
+	r := rdb.NewRDB(c)
+
+	processes, err := r.ListProcesses()
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	if len(processes) == 0 {
+		fmt.Println("No processes")
+		return
+	}
+	cols := []string{"Host", "PID", "State", "Active Workers", "Queues", "Started"}
+	printRows := func(w io.Writer, tmpl string) {
+		for _, ps := range processes {
+			fmt.Fprintf(w, tmpl,
+				ps.Host, ps.PID, ps.State,
+				fmt.Sprintf("%d/%d", ps.ActiveWorkerCount, ps.Concurrency),
+				formatQueues(ps.Queues), timeAgo(ps.Started))
+		}
+	}
+	printTable(cols, printRows)
+}
+
+// timeAgo takes a time and returns a string of the format "<duration> ago".
+func timeAgo(since time.Time) string {
+	d := time.Since(since).Round(time.Second)
+	return fmt.Sprintf("%v ago", d)
+}
+
+func formatQueues(queues map[string]uint) string {
+	var b strings.Builder
+	l := len(queues)
+	for qname, p := range queues {
+		fmt.Fprintf(&b, "%s:%d", qname, p)
+		l--
+		if l > 0 {
+			b.WriteString(" ")
+		}
+	}
+	return b.String()
+}

tools/asynqmon/cmd/root.go

@@ -6,7 +6,10 @@ package cmd
 
 import (
 	"fmt"
+	"io"
 	"os"
+	"strings"
+	"text/tabwriter"
 
 	"github.com/spf13/cobra"
 
@@ -81,3 +84,36 @@ func initConfig() {
 		fmt.Println("Using config file:", viper.ConfigFileUsed())
 	}
 }
+
+// printTable is a helper function to print data in table format.
+//
+// cols is a list of headers and printRow specifies how to print rows.
+//
+// Example:
+// type User struct {
+//     Name string
+//     Addr string
+//     Age  int
+// }
+// data := []*User{{"user1", "addr1", 24}, {"user2", "addr2", 42}, ...}
+// cols := []string{"Name", "Addr", "Age"}
+// printRows := func(w io.Writer, tmpl string) {
+//     for _, u := range data {
+//         fmt.Fprintf(w, tmpl, u.Name, u.Addr, u.Age)
+//     }
+// }
+// printTable(cols, printRows)
+func printTable(cols []string, printRows func(w io.Writer, tmpl string)) {
+	format := strings.Repeat("%v\t", len(cols)) + "\n"
+	tw := new(tabwriter.Writer).Init(os.Stdout, 0, 8, 2, ' ', 0)
+	var headers []interface{}
+	var seps []interface{}
+	for _, name := range cols {
+		headers = append(headers, name)
+		seps = append(seps, strings.Repeat("-", len(name)))
+	}
+	fmt.Fprintf(tw, format, headers...)
+	fmt.Fprintf(tw, format, seps...)
+	printRows(tw, format)
+	tw.Flush()
+}