Work with go gin error

[darrkz]

Description

I use confluent-kafka-go with github.com/gin-gonic/gin web server

all code logic is :
get message info from http get
convert it to json string
write the json string to kafka using confluent-kafka-go asyncProducer

code like this

func AsyncProducer(p *kafka.Producer, topic string, msg string) {
	//-- -------------------------------
	//--> @Description
	//-->
	// https://docs.confluent.io/kafka-clients/go/current/overview.html#asynchronous-writes
	deliveryChan := make(chan kafka.Event, 1000)
	err := p.Produce(&kafka.Message{
		TopicPartition: kafka.TopicPartition{Topic: &topic, Partition: kafka.PartitionAny},
		Value:          []byte(msg),
		Headers:        []kafka.Header{{Key: "myTestHeader", Value: []byte("header values are binary")}},
	}, deliveryChan)

	if err != nil {
		fmt.Println("Failed to produce message")
		fmt.Printf("some error: \n%v\n", err)
		panic(err)
	}

	go func() {
		for e := range p.Events() {
			switch ev := e.(type) {
			case *kafka.Message:
				if ev.TopicPartition.Error != nil {
					fmt.Printf("=Failed to deliver message: %v\n%s\n=", ev.TopicPartition, ev.TopicPartition.Error)
				} else {
					fmt.Printf("Successfully produced record to topic %s partition [%d] @ offset %v\n",
						*ev.TopicPartition.Topic, ev.TopicPartition.Partition, ev.TopicPartition.Offset)
				}
			case kafka.Error:
				// Generic client instance-level errors, such as
				// broker connection failures, authentication issues, etc.
				//
				// These errors should generally be considered informational
				// as the underlying client will automatically try to
				// recover from any errors encountered, the application
				// does not need to take action on them.
				fmt.Printf("kafka Error: %v\n", ev)
			default:
				fmt.Printf("Ignored kafka event: %s\n", ev)
			}
		}
	}()
}

when I access the web server , it retuen http 500 and return error

Local: Invalid argument or configuration

if I add os.Exit(0) before run go-gin, no message was writen to kafka
if I add os.Exit(0) before run go-gin and sleep for a while , about 10 second, then the messages used to test can write to kafka correctly

if I remove the os.Exit(0) , and the gin web server start ok , but when I access the server with http get method, it returns http 500

So I don't konw why, and how to fix this

How to reproduce

Checklist

Please provide the following information:

• confluent-kafka-go and librdkafka version (LibraryVersion()):
  v2.3.0
• Apache Kafka broker version:
  3.6.1
• Client configuration: ConfigMap{...}
  &map[acks:1 bootstrap.servers:192.168.11.60:9092,192.168.11.61:9092,192.168.11.62:9092 debug:msg delivery.report.only.error:false linger.ms:500 message.max.bytes:1000000 retries:2147482647 retry.backoff.ms:1000 security.protocol
  :plaintext sticky.partitioning.linger.ms:1000]
• Operating system:
  WSL: kali 2023.4
• Provide client logs (with "debug": ".." as necessary)

Failed to produce message
some error:
Local: Invalid argument or configuration


Local: Invalid argument or configuration
/mnt/e/go/go_gin_kafka/utils/bigdata/gokafka.go:154 (0x59a4c4)
        AsyncProducer: panic(err)
/mnt/e/go/go_gin_kafka/webserver.go:78 (0x86718b)
        WriteKafka: goKafka.AsyncProducer(p, ConfMap["topic"], message)
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/context.go:174 (0x86765b)
        (*Context).Next: c.handlers[c.index](c)
/mnt/e/go/go_gin_kafka/webserver.go:141 (0x867649)
        DataCheck: c.Next()
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/context.go:174 (0x86749e)
        (*Context).Next: c.handlers[c.index](c)
/mnt/e/go/go_gin_kafka/webserver.go:123 (0x86748c)
        Url2Json: c.Next() // 作用类似于goto.. 直接跳到下一个中间件执行完再返回
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/context.go:174 (0x83b599)
        (*Context).Next: c.handlers[c.index](c)
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/recovery.go:102 (0x83b587)
        CustomRecoveryWithWriter.func1: c.Next()
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/context.go:174 (0x83a6dc)
        (*Context).Next: c.handlers[c.index](c)
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/logger.go:240 (0x83a6c3)
        LoggerWithConfig.func1: c.Next()
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/context.go:174 (0x839caa)
        (*Context).Next: c.handlers[c.index](c)
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/gin.go:656 (0x839c97)
        serveError: c.Next()
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/gin.go:649 (0x839a04)
        (*Engine).handleHTTPRequest: serveError(c, http.StatusNotFound, default404Body)
/home/darkz/go/pkg/mod/github.com/gin-gonic/gin@v1.9.1/gin.go:576 (0x8394f1)
        (*Engine).ServeHTTP: engine.handleHTTPRequest(c)
/home/darkz/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.22.0.linux-amd64/src/net/http/server.go:3137 (0x6e0b6d)
        serverHandler.ServeHTTP: handler.ServeHTTP(rw, req)
/home/darkz/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.22.0.linux-amd64/src/net/http/server.go:2039 (0x6dc6e7)
        (*conn).serve: serverHandler{c.server}.ServeHTTP(w, w.req)
/home/darkz/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.22.0.linux-amd64/src/runtime/asm_amd64.s:1695 (0x47a420)
        goexit: BYTE    $0x90   // NOP

• Provide broker log excerpts

None....

• Critical issue

[milindl]

Hi @darrkz , can you log before producing the topic name? it might be because topic string is empty

[darrkz]

@milindl that's OK, I found I miss a var setting outer function main, and use := redefined it in main, so it could not user in other where.
And I think the log not show this err clearly, cost so much time....

[milindl]

Alright @darrkz thanks for the update . Would be be interested in making a PR to improve the messaging around the error? I'm not certain how the error was solved so it might be useful to others in the future.

[darrkz]

@milindl Just my mistake, and not something wrong about confluent-kafka-go...

The pr I will make it later...

[darrkz]

@milindl pr is here
#1162

Please review for it