java.lang.NullPointerException：Riemann中的null

Question

我已将riemann-0.2.13-1.noarch安装为RPM服务。我从logstash 5.2.1发送事件，我安装的插件是logstash-output-riemann-3.0.0我写了下面的riemann代码来触发电子邮件。我越来越异常了。请指出我哪里出错了。

Riemann Config：

(let [email (mailer {:host "XXXXX"
                            :port 25
                            :subject (fn [events] "Consecutive login failed")
                            :body (fn [events] "Hello Team, \n \n There are more consecutive logins failure occured @" (riemann.common/time-at (:timestamp event))"")
                            :from "XXXX"})]
  (streams
 ;Check for every 120sec events
      (fixed-time-window
        120
        (smap
          (fn [events]
            (let [count-of-failures (count (filter #(re-find #"com.thed.server.access.Exception. Please reset credentials for user. Last error occurred was:Authentication failed, please check user credentials*" (:message %)) events))] ;Calculate the count for matched value
              (event
                {:status "Class failures"
                 :metric  count-of-failures 
                 :total-fail (> count-of-failures 1)})))  

          (where (and (= (:status event) "Class failures")
                      (:total-fail event))
            (rollup 1 120
            (email "xxx","xxx","xxx")
            ))prn))))

错误：

WARN [2017-07-06 17:45:49,204] defaultEventExecutorGroup-2-1 - riemann.streams - riemann.streams$smap$stream__6639@55d73fdc threw
java.lang.NullPointerException: null
    at java.util.regex.Matcher.getTextLength(Matcher.java:1283)
    at java.util.regex.Matcher.reset(Matcher.java:309)
    at java.util.regex.Matcher.<init>(Matcher.java:229)
    at java.util.regex.Pattern.matcher(Pattern.java:1093)
    at clojure.core$re_matcher.invokeStatic(core.clj:4674)
    at clojure.core$re_find.invokeStatic(core.clj:4716)
    at clojure.core$re_find.invoke(core.clj:4716)
    at riemann.config$eval88$fn__93$fn__94.invoke(riemann.config:48)
    at clojure.core$filter$fn__4812.invoke(core.clj:2708)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:521)
    at clojure.lang.RT.countFrom(RT.java:625)
    at clojure.lang.RT.count(RT.java:618)
    at riemann.config$eval88$fn__93.invoke(riemann.config:48)
    at riemann.streams$smap$stream__6639.invoke(streams.clj:161)
    at riemann.streams$fixed_time_window_fn$stream__6889$fn__6922.invoke(streams.clj:374)
    at riemann.streams$fixed_time_window_fn$stream__6889.invoke(streams.clj:374)
    at riemann.core$stream_BANG_$fn__8578.invoke(core.clj:19)
    at riemann.core$stream_BANG_.invokeStatic(core.clj:18)
    at riemann.core$stream_BANG_.invoke(core.clj:14)
    at riemann.transport$handle.invokeStatic(transport.clj:171)
    at riemann.transport$handle.invoke(transport.clj:165)
    at riemann.transport.tcp$tcp_handler.invokeStatic(tcp.clj:95)
    at riemann.transport.tcp$tcp_handler.invoke(tcp.clj:88)
    at riemann.transport.tcp$gen_tcp_handler$fn__11550.invoke(tcp.clj:66)
    at riemann.transport.tcp.proxy$io.netty.channel.ChannelInboundHandlerAdapter$ff19274a.channelRead(Unknown Source)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:372)
    at io.netty.channel.AbstractChannelHandlerContext.access$600(AbstractChannelHandlerContext.java:38)
    at io.netty.channel.AbstractChannelHandlerContext$7.run(AbstractChannelHandlerContext.java:363)
    at io.netty.util.concurrent.DefaultEventExecutor.run(DefaultEventExecutor.java:66)
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:877)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
    at java.lang.Thread.run(Thread.java:745)

每当我使用时 (let [count-of-failures (count (filter #(re-find #"com.thed.server.access.Exception. Please reset credentials for user. Last error occurred was:Authentication failed, please check user credentials*" (:message %)) events))]。 它把我抛到异常之上，但是当我使用它时  (let [count-of-failures (count (filter #(= "com.thed.server.access.Exception. Please reset credentials for user. Last error occurred was:Authentication failed, please check user credentials" (:message %)) events))]。 它发送电子邮件