shashank created CAMEL-25275:
--------------------------------
Summary: camel-consul - the key/value and event consumers stop
watching for good after one failed query, while the route stays started
Key: CAMEL-25275
URL: https://issues.apache.org/jira/browse/CAMEL-25275
Project: Camel
Issue Type: Bug
Components: camel-consul
Reporter: shashank
The {{consul:kv}} and {{consul:event}} consumers watch with a chain of blocking
queries: the callback of each query ({{ConsulResponseCallback.onComplete}} /
{{EventResponseCallback.onComplete}}) processes the answer and starts the next
query. The failure callback only reports the exception:
{code:java}
@Override
public void onFailure(Throwable throwable) {
onError(throwable); // exception handler, nothing else
}
{code}
So when a single query fails (the Consul agent restarts, a network error, a 500
while the Consul cluster has no leader, a read timeout), no further query is
started: the consumer receives no change anymore, for good, while the route
stays started. Only one WARN line from the exception handler shows it.
h3. Reproduction
Unit tests with a mocked {{Consul}} client ({{consulClient=#consul}}):
* {{ConsulKeyValueWatchTest}}: the first {{getValue}} fails with
{{ConsulException}}: main never calls {{getValue}} again ({{Wanted 2 times ...
But was 1 time}}); with the fix the second query answers and the value reaches
the route.
* {{ConsulEventWatchTest}}: the same for {{listEvents}}.
h3. Proposed fix
* {{ConsulKeyValueConsumer}}: after a failure, query the key again after
{{blockSeconds}} (at least one second, so that an agent that is down is not
queried in a loop), on a single-thread scheduler of the consumer (started and
shut down with it, as {{ConsulEventConsumer}} already does).
* {{ConsulEventConsumer}}: after a failure, schedule the next query as after an
answer (its {{watch()}} already waits {{blockSeconds}}, see CAMEL-12418).
Both only while the consumer runs. With the fix the two tests pass and the
camel-consul unit tests pass (6; the 27 ITs need Docker). {{mockito-core}} is
added as a test dependency.
Affected: 4.14.x, 4.18.x and main (same code since 2017).
Duplicate check (2026-10-02): JIRA component camel-consul and text "consul" (90
issues): watch related are CAMEL-12418 (CPU load, the scheduling delay),
CAMEL-12511 (NPE on start), CAMEL-10073; none about failures. GitHub pull
requests "consul consumer": none.
_Filed with Claude Code on behalf of allthingssecurity._
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