我是新手，开始学习频道。我使用融合的kafka消费者来创建一个功能性消费者。我想完成的是将消息发送到缓冲通道（2000）中，然后使用管道将消息写入到redis的通道中。我只需要做一个 println 一个接一个的发送消息，直到到达偏移量的末尾，但是当我尝试添加一个通道时，它似乎击中了 default: 案例 switch 然后别动。
我好像也没把频道填好？这个 fmt.Println("count is: ", len(redisChnl)) 总是打印 0 到目前为止，我掌握的情况如下：

// Example function-based high-level Apache Kafka consumer
package main

import (
    "fmt"
    "github.com/confluentinc/confluent-kafka-go/kafka"
    "os"
    "os/signal"
    "syscall"
    "time"
    "encoding/json"
    "regexp"
    "github.com/go-redis/redis"
    "encoding/binary"
)

var client *redis.Client

func init() {
    client = redis.NewClient(&redis.Options{
        Addr:         ":6379",
        DialTimeout:  10 * time.Second,
        ReadTimeout:  30 * time.Second,
        WriteTimeout: 30 * time.Second,
        PoolSize:     10,
        PoolTimeout:  30 * time.Second,
    })
    client.FlushDB()
}

type MessageFormat struct {
    MetricValueNumber float64     `json:"metric_value_number"`
    Path              string      `json:"path"`
    Cluster           string      `json:"cluster"`
    Timestamp         time.Time   `json:"@timestamp"`
    Version           string      `json:"@version"`
    Host              string      `json:"host"`
    MetricPath        string      `json:"metric_path"`
    Type              string      `json:"string"`
    Region            string      `json:"region"`
}

//func redis_pipeline(ky string, vl string) {
//  pipe := client.Pipeline()
//
//  exec := pipe.Set(ky, vl, time.Hour)
//
//  incr := pipe.Incr("pipeline_counter")
//  pipe.Expire("pipeline_counter", time.Hour)
//
//  // Execute
//  //
//  //     INCR pipeline_counter
//  //     EXPIRE pipeline_counts 3600
//  //
//  // using one client-server roundtrip.
//  _, err := pipe.Exec()
//  fmt.Println(incr.Val(), err)
//  // Output: 1 <nil>
//}

func main() {

    sigchan := make(chan os.Signal, 1)
    signal.Notify(sigchan, syscall.SIGINT, syscall.SIGTERM)

    c, err := kafka.NewConsumer(&kafka.ConfigMap{
        "bootstrap.servers":               "kafka.com:9093",
        "group.id":                        "testehb",
        "security.protocol":               "ssl",
        "ssl.key.location":                "/Users/key.key",
        "ssl.certificate.location":        "/Users/cert.cert",
        "ssl.ca.location":                 "/Users/ca.pem",
    })

    if err != nil {
        fmt.Fprintf(os.Stderr, "Failed to create consumer: %s\n", err)
        os.Exit(1)
    }

    fmt.Printf("Created Consumer %v\n", c)

    err = c.SubscribeTopics([]string{"jmx"}, nil)

    redisMap := make(map[string]string)

    redisChnl := make(chan []byte, 2000)

    run := true

    for run == true {
        select {
        case sig := <-sigchan:
            fmt.Printf("Caught signal %v: terminating\n", sig)
            run = false
        default:
            ev := c.Poll(100)
            if ev == nil {
                continue
            }

            switch e := ev.(type) {
            case *kafka.Message:

                //fmt.Printf("%% Message on %s:\n%s\n",
                //  e.TopicPartition, string(e.Value))
                if e.Headers != nil {
                    fmt.Printf("%% Headers: %v\n", e.Headers)
                }

                str := e.Value
                res := MessageFormat{}
                json.Unmarshal([]byte(str), &res)

                fmt.Println("size", binary.Size([]byte(str)))

                host:= regexp.MustCompile(`^([^.]+)`).FindString(res.MetricPath)

                redisMap[host] = string(str)
                fmt.Println("count is: ", len(redisChnl)) //this always prints "count is:  0"

                redisChnl <- e.Value //I think this is the write way to put the messages in the channel?

            case kafka.PartitionEOF:
                fmt.Printf("%% Reached %v\n", e)
            case kafka.Error:
                fmt.Fprintf(os.Stderr, "%% Error: %v\n", e)
                run = false
            default:
                fmt.Printf("Ignored %v\n", e)
            }

            <- redisChnl // I thought I could just empty the channel like this once the buffer is full?

        }
    }

    fmt.Printf("Closing consumer\n")
    c.Close()
}

-------编辑-------
好吧，我想我是通过移动 <- redisChnl 内部 default 但现在我看到 count before read 以及 count after read 内部 default 总是打印 2,000 ……我本以为 count before read = 2,000 然后 count after read = 0 既然那频道是空的？？

select {
    case sig := <-sigchan:
        fmt.Printf("Caught signal %v: terminating\n", sig)
        run = false
    default:
        ev := c.Poll(100)
        if ev == nil {
            continue
        }

        switch e := ev.(type) {
        case *kafka.Message:

            //fmt.Printf("%% Message on %s:\n%s\n",
            //  e.TopicPartition, string(e.Value))
            if e.Headers != nil {
                fmt.Printf("%% Headers: %v\n", e.Headers)
            }

            str := e.Value
            res := MessageFormat{}
            json.Unmarshal([]byte(str), &res)

            //fmt.Println("size", binary.Size([]byte(str)))

            host:= regexp.MustCompile(`^([^.]+)`).FindString(res.MetricPath)

            redisMap[host] = string(str)

            go func() {
                redisChnl <- e.Value
            }()

        case kafka.PartitionEOF:
            fmt.Printf("%% Reached %v\n", e)
        case kafka.Error:
            fmt.Fprintf(os.Stderr, "%% Error: %v\n", e)
            run = false
        default:
            fmt.Println("count before read: ", len(redisChnl))

            fmt.Printf("Ignored %v\n", e)

            <-redisChnl

            fmt.Println("count after read: ", len(redisChnl)) //would've expected this to be 0

        }

    }