The last unanswered action, and the only one whose output is not the
input with edits -- it emits a record that never existed, which is why
it was deferred twice.
It emits the window's first record unchanged, tagged with
cairnobs.aggregated, cairnobs.count, and the observed window bounds.
That follows the convention the agent already uses for heartbeat and
host-metrics records rather than inventing a second synthetic-record
mechanism, and keeping the first record intact means a reader sees a
real example of what was collapsed instead of an invented summary.
It tags even when the count is one. Emitting a bare record there would
be tidier and would make cairnobs.count present only sometimes, so
summing it silently breaks on quiet windows. window_last is the last
record that actually contributed, never window_start + window_ms,
because a window flushed early must not claim an end that never
happened.
Specifying it surfaced a problem the other nine actions do not have.
Windows are measured on record time, so a window can only be closed by a
later record arriving. suppress_duplicates never has anything pending;
aggregate_count holds state, so a matching stream that goes quiet leaves
its aggregate unemitted indefinitely -- data loss dressed as latency.
Emission therefore has a second trigger, end of stream, which the corpus
defines as an implicit flush after the last input and which production
gets from the batch flush. The cost is stated rather than hidden:
window_ms becomes a maximum, not a guarantee, and one burst can produce
more than one aggregate.
And it has a consequence nobody should meet in production first: stats
count undercounts aggregated data silently, so every panel and alert
counting rows changes meaning the moment a rule aggregates the data
behind it. Nothing here fixes that. The correct idiom is summing
cairnobs.count; teaching the query layer to do it automatically is a
Phase 2 change to the IR, recorded as the open question this decision
leaves in its place rather than quietly inherited.
Six cases added, corpus at 45. The validator's unspecified-action guard
stays in place with an empty set, still rejecting anything added to it.
Signed-off-by: John Coffey <[email protected]>
jcoffey-dev
ec4b860ba8