From 882cd1af8b9d38792f21eeecd1cf88e0abaf3181 Mon Sep 17 00:00:00 2001
From: Gerard Vanloo <gvanloo@redhat.com>
Date: Mon, 28 Aug 2023 09:44:27 -0400
Subject: [PATCH] fix: allow generated logs to have unique hostnames

---
 internal/config.go              | 29 +++++++++++++++--------------
 internal/generator/generator.go | 10 ++++++++--
 main.go                         |  2 ++
 3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/internal/config.go b/internal/config.go
index a065e50..80dc53e 100644
--- a/internal/config.go
+++ b/internal/config.go
@@ -1,18 +1,19 @@
 package internal
 
 type Options struct {
-	Command              string
-	Destination          string
-	OutputFile           string
-	ClientURL            string
-	DisableSecurityCheck bool
-	LogsPerSecond        int
-	LogType              string
-	LogFormat            string
-	LabelType            string
-	SyntheticPayloadSize int
-	Tenant               string
-	QueriesPerMinute     int
-	Query                string
-	QueryRange           string
+	Command               string
+	Destination           string
+	OutputFile            string
+	ClientURL             string
+	DisableSecurityCheck  bool
+	LogsPerSecond         int
+	LogType               string
+	LogFormat             string
+	LabelType             string
+	SyntheticPayloadSize  int
+	RequireUniqueHostname bool
+	Tenant                string
+	QueriesPerMinute      int
+	Query                 string
+	QueryRange            string
 }
diff --git a/internal/generator/generator.go b/internal/generator/generator.go
index 403c8b7..75c1da3 100644
--- a/internal/generator/generator.go
+++ b/internal/generator/generator.go
@@ -3,6 +3,7 @@ package generator
 import (
 	"context"
 	"fmt"
+	"math/rand"
 	"os"
 	"time"
 
@@ -112,7 +113,7 @@ func NewLogGenerator(opts Options) (*LogGenerator, error) {
 	return &generator, nil
 }
 
-func (g *LogGenerator) GenerateLogs(logType LogType, logFormat Format, logSize int, labelOpts LabelSetOptions) {
+func (g *LogGenerator) GenerateLogs(logType LogType, logFormat Format, logSize int, labelOpts LabelSetOptions, isHostnameUnique bool) {
 	host, err := os.Hostname()
 	if err != nil {
 		log.Fatalf("error getting hostname: %s", err)
@@ -122,6 +123,11 @@ func (g *LogGenerator) GenerateLogs(logType LogType, logFormat Format, logSize i
 
 	var lineCount int64 = 0
 
+	logHostname = host
+	if isHostnameUnique {
+		logHostname = fmt.Sprintf("%s.%032X", host, rand.Uint64())
+	}
+
 	for {
 		next := time.Now().UTC().Add(1 * time.Second)
 
@@ -131,7 +137,7 @@ func (g *LogGenerator) GenerateLogs(logType LogType, logFormat Format, logSize i
 				log.Fatalf("error creating log: %s", err)
 			}
 
-			formattedLogLine, err := FormatLog(logFormat, host, lineCount, logLine)
+			formattedLogLine, err := FormatLog(logFormat, logHostname, lineCount, logLine)
 			if err != nil {
 				log.Fatalf("error formating log: %s", err)
 			}
diff --git a/main.go b/main.go
index 644092e..33bc155 100644
--- a/main.go
+++ b/main.go
@@ -29,6 +29,7 @@ func init() {
 	flag.StringVar(&opts.LogType, "log-type", "simple", "Overwrite to control the type of logs generated. Allowed values: simple, application, synthetic.")
 	flag.StringVar(&opts.LogFormat, "log-format", "default", "Overwrite to control the format of logs generated. Allowed values: default, crio (mimic CRIO output), csv, json")
 	flag.StringVar(&opts.LabelType, "label-type", "none", "Overwrite to control what labels are included in Loki logs. Allowed values: none, client, client-host")
+	flag.BoolVar(&opts.RequireUniqueHostname, "require-unique-hostname", false, "Ensures that the hostname field is unique by adding a random integer to the end.")
 	flag.IntVar(&opts.SyntheticPayloadSize, "synthetic-payload-size", 100, "Overwrite to control size of synthetic log line.")
 	flag.StringVar(&opts.Tenant, "tenant", "test", "Loki tenant ID for writing logs.")
 	flag.IntVar(&opts.QueriesPerMinute, "queries-per-minute", 1, "The rate to generate queries. This rate may not always be achievable.")
@@ -74,6 +75,7 @@ func main() {
 			generator.Format(opts.LogFormat),
 			opts.SyntheticPayloadSize,
 			generator.LabelSetOptions(opts.LabelType),
+			opts.RequireUniqueHostname,
 		)
 	case "query":
 		querierOpts := querier.Options{