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https://issues.apache.org/jira/browse/CAMEL-26779?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Work on CAMEL-26779 started by Salvatore Mongiardo.
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> camel-snmp - the consumer can run its first poll before it is started, and
> fails with a NullPointerException
> ------------------------------------------------------------------------------------------------------------
>
> Key: CAMEL-26779
> URL: https://issues.apache.org/jira/browse/CAMEL-26779
> Project: Camel
> Issue Type: Bug
> Components: camel-snmp
> Affects Versions: 4.22.1
> Reporter: Salvatore Mongiardo
> Assignee: Salvatore Mongiardo
> Priority: Minor
> Fix For: 4.22.3, 4.24.0
>
>
> SnmpOIDPoller.doStart() calls super.doStart() first.
> ScheduledPollConsumer.doStart() schedules the poll task, and only afterwards
> doStart() creates the Snmp instance, the USM, the target and (in 4.22.x) the
> request PDU, and starts the transport listener.
> If this initialization is slow, the first scheduled poll runs in between and
> finds the fields not yet set. In 4.22.x the poll fails with:
> {noformat}
> WARN SnmpOIDPoller : Failed polling endpoint: snmp://udp:<host>/<port>. Will
> try again at next poll.
> Caused by: [java.lang.NullPointerException - Cannot invoke
> "org.snmp4j.PDU.clear()" because "this.pdu" is null]
> at
> org.apache.camel.component.snmp.SnmpOIDPoller.poll(SnmpOIDPoller.java:103)
> {noformat}
> Observed with Camel 4.22.1 on Windows x86_64 and JDK 21, where the gap
> between the route start and "Started OID poller" was about 17 seconds. It
> happened in 3 of 3 runs.
> On main, poll() creates a new PDU for each poll (CAMEL-25924), so the PDU is
> no longer null. The race remains for snmp and target, which are still created
> after super.doStart() has scheduled the poll.
> The consumer recovers on the next poll cycle, but the first poll fails with a
> WARN and the first expected message is delayed or lost.
> Proposed change: in SnmpOIDPoller.doStart(), initialize snmp, the USM, the
> target and the transport first, call transport.listen(), and call
> super.doStart() last. The scheduler then starts only when the consumer is
> ready to poll.
> Fix for main and for camel-4.22.x.
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