use a random set of "adjective-verb" style hostnames and apps instead of host-%d/app-%d in syslog msg templates

Signed-off-by: Mate Ory <[email protected]>

Author: orymate

conf/config.ini.sample

@@ -14,6 +14,13 @@
 # The amount of bytes to emit/s (default: 200)
 #byte-per-sec =
 
+# Number of different random host names to generate
+#max-random-hosts = 1000
+# Number of different app names to generate
+#max-random-apps = 100
+# Random seed for host/app list generation so that the same set of host/app names are used (if >0)
+#seed = 0
+
 [api]
 # Server listen address (default: "":11000")
 #addr =

formats/logfactory.go

@@ -20,6 +20,7 @@ import (
 	"github.com/kube-logging/log-generator/formats/syslog"
 	"github.com/kube-logging/log-generator/formats/web"
 	"github.com/kube-logging/log-generator/log"
+	"github.com/spf13/viper"
 )
 
 func FormatsByType() map[string][]string {
@@ -51,12 +52,22 @@ func LogFactory(logType string, format string, randomise bool) (log.Log, error)
 	}
 }
 
+var syslogRandomService *syslog.RandomService
+
+func syslogRandom() *syslog.RandomService {
+	if syslogRandomService == nil {
+		syslogRandomService = syslog.NewRandomService(
+			viper.GetInt("message.max-random-hosts"), viper.GetInt("message.max-random-apps"), viper.GetInt64("message.seed"))
+	}
+	return syslogRandomService
+}
+
 func NewSyslog(format string) (*log.LogTemplate, error) {
-	return log.NewLogTemplate(format, syslog.TemplateFS, syslog.SampleData())
+	return log.NewLogTemplate(format, syslog.TemplateFS, syslogRandom().SampleData())
 }
 
 func NewRandomSyslog(format string) (*log.LogTemplate, error) {
-	return log.NewLogTemplate(format, syslog.TemplateFS, syslog.RandomData())
+	return log.NewLogTemplate(format, syslog.TemplateFS, syslogRandom().RandomData())
 }
 
 func SyslogFormatNames() []string {

formats/syslog/syslog.go

@@ -17,11 +17,12 @@ package syslog
 import (
 	"embed"
 	"fmt"
+	"math/rand"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/Pallinder/go-randomdata"
-	"github.com/spf13/viper"
 )
 
 //go:embed *.tmpl
@@ -59,7 +60,47 @@ func (t TemplateData) Severity() string {
 	return strconv.FormatInt(int64(t.severity), 10)
 }
 
-func SampleData() TemplateData {
+type RandomService struct {
+	Hosts []string
+	Apps  []string
+}
+
+func NewRandomService(maxHosts int, maxApps int, seed int64) *RandomService {
+	svc := new(RandomService)
+
+	// we might experience a race condition here, but we are dealing with pseudorandom data anyway
+	if seed != 0 {
+		randomdata.CustomRand(rand.New(rand.NewSource(seed)))
+		defer randomdata.CustomRand(rand.New(rand.NewSource(time.Now().UnixNano())))
+	}
+
+	svc.Hosts = make([]string, maxHosts)
+	for i := 0; i < maxHosts; i++ {
+		svc.Hosts[i] = strings.ToLower(randomdata.SillyName())
+	}
+
+	svc.Apps = make([]string, maxApps)
+	for i := 0; i < maxApps; i++ {
+		svc.Apps[i] = strings.ToLower(randomdata.SillyName())
+	}
+	return svc
+}
+
+func (r *RandomService) RandomHost() string {
+	if len(r.Hosts) == 0 {
+		return "host"
+	}
+	return r.Hosts[randomdata.Number(0, len(r.Hosts))]
+}
+
+func (r *RandomService) RandomApp() string {
+	if len(r.Apps) == 0 {
+		return "app"
+	}
+	return r.Apps[randomdata.Number(0, len(r.Apps))]
+}
+
+func (r *RandomService) SampleData() TemplateData {
 	return TemplateData{
 		Facility: 20,
 		severity: 5,
@@ -72,13 +113,13 @@ func SampleData() TemplateData {
 	}
 }
 
-func RandomData() TemplateData {
+func (r *RandomService) RandomData() TemplateData {
 	return TemplateData{
 		Facility: randomdata.Number(0, 24),
 		severity: randomdata.Number(0, 8),
 		dateTime: time.Now().UTC(),
-		Host:     fmt.Sprintf("host-%d", randomdata.Number(viper.GetInt("message.max-random-hosts"))+1),
-		AppName:  fmt.Sprintf("app%d", randomdata.Number(viper.GetInt("message.max-random-apps"))+1),
+		Host:     r.RandomHost(),
+		AppName:  r.RandomApp(),
 		PID:      randomdata.Number(1, 10000),
 		Seq:      randomdata.Number(1, 10000),
 		Msg:      fmt.Sprintf("An application event log entry %s %s", randomdata.Noun(), randomdata.Noun()),

main.go

@@ -1,4 +1,5 @@
 // Copyright © 2021 Cisco Systems, Inc. and/or its affiliates
+// Copyright © 2023 Kube logging authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.