shashank created CAMEL-25279:
--------------------------------
Summary: camel-knative - a consumer with reply=false answers 204
No Content when the route fails, so Knative takes the event as delivered
Key: CAMEL-25279
URL: https://issues.apache.org/jira/browse/CAMEL-25279
Project: Camel
Issue Type: Bug
Components: camel-knative-http
Reporter: shashank
{{KnativeHttpConsumer}} computes the status of the response from the exchange
({{500}} when it failed, or {{CamelHttpResponseCode}}), then:
{code:java}
if (request.response().getStatusCode() != 204 && configuration.isReply()) {
body = computeResponseBody(exchange.getMessage());
...
}
if (body != null) {
request.response().end(body);
} else {
request.response().setStatusCode(204);
request.response().end();
}
{code}
With {{reply=false}} (endpoint option, or the {{Knative.KNATIVE_REPLY}}
metadata of the resource set to false) there is never a body, so the error
status is always overwritten with {{204 No Content}}. Knative (broker, channel,
source) takes a 2xx answer as a delivered event, so an event whose route failed
is not retried and not sent to the dead letter sink: it is lost. CAMEL-24428
fixed the same overwrite for {{muteException}} with {{reply=true}} ("a null
body makes the caller send 204 No Content, which would discard the error
status").
h3. Reproduction
{{KnativeHttpTest.testNoReplyFailure}} (like {{testNoReply}}, the route
throws): main answers {{Expected status code <500> but was <204>}} for the
three CloudEvents versions.
h3. Proposed fix
Without a body, set 204 only when the exchange did not fail; a failed exchange
keeps its error status, with an empty body. With the fix the camel-knative-http
tests pass (176). The upgrade guide for 4.23 gets a short note.
Affected: 4.14.x, 4.18.x and main (same code).
Duplicate check (2026-10-02): JIRA text "knative" with "reply"/"204"/"failed"
(15 issues): only CAMEL-24428 (the muteException case). GitHub pull requests
"knative reply": none.
_Filed with Claude Code on behalf of allthingssecurity._
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