panic: interface conversion: interface {} is nil, not chan *sarama.ProducerError

封云亭

　　使用golang kafka sarama 包时，遇到如下问题：
　　高并发情况下使用同步sync producer，偶尔遇到crash:

　　panic: interface conversion: interface {} is nil, not chan *sarama.ProducerError

　　goroutine 413 [running]:
　　github.com/Shopify/sarama.(*syncProducer).handleSuccesses(0xc420384840)
　　/home/lanyang/github.com/Shopify/sarama/sync_producer.go:147 +0x139
　　github.com/Shopify/sarama.handleSuccesses)-fm()
　　/home/lanyang/src/github.com/Shopify/sarama/sync_producer.go:76 +0x2f
　　github.com/Shopify/sarama.withRecover(0xc4201d0750)
　　/home/lanyang/src/github.com/Shopify/sarama/utils.go:43 +0x45
　　created by github.com/Shopify/sarama.newSyncProducerFromAsyncProducer
　　/home/lanyang/src/github.com/Shopify/sarama/sync_producer.go:76 +0x112

　　问题不容易复现，github上已经留言：
　　https://github.com/Shopify/sarama/issues/785
　　download
　　https://github.com/Shopify/sarama
　　https://shopify.github.io/sarama/
　　doc
　　https://godoc.org/github.com/Shopify/sarama
　　依赖

　　github.com/davecgh/go-spew
　　github.com/eapache/go-resiliency
　　github.com/eapache/go-xerial-snappy
　　github.com/eapache/queue

　　github.com/pierrec/lz4
　　github.com/pierrec/xxHash

　　github.com/rcrowley/go-metrics

　　github.com/golang/snappy

　　如果kafka down掉，又恢复，client 可自动连接上。
　　异步方式，网络断开后，仍然会从queue，放入producer的channel中，重连后，这些内容丢失。
　　例子参考
　　sync
　　http://legendtkl.com/2016/06/30/kafka-in-action/
　　https://studygolang.com/articles/7102
　　async
　　https://studygolang.com/articles/11199