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## Summary
Two gaps in relay telemetry: WebSocket reads (`REQ`, NIP-AR sync,
`COUNT`) have no latency or outcome metric, and
`buzz_event_processing_seconds` only measures stored EVENTs that
succeed.
**What this does**
- **`buzz_ws_read_seconds{type, outcome, reason}`** (new histogram).
It's recorded from `access::ReadLog::drop`. Every WebSocket read already
finishes through that one seam, whether it ends `served`, `denied`,
`error`, or `aborted` (future dropped mid-read), so this adds no new
exit paths and changes no handler. Duration runs from the moment the
handler takes the frame until `EOSE` is queued (`REQ`), the initial set
ends (sync), or the total is sent (`COUNT`). `reason` is the existing
fixed denial/error code (`query_timed_out`, `database_error`,
`not_channel_member`, …), or `none`. The histogram's `_count` doubles as
the outcome counter, so one metric gives both read latency and read
failure rate.
- It's recorded *before* the refusal budget check, because the budget
only exists to suppress log lines. When `refused_read` is over budget,
it records the sample without building the log line, so its cost under a
refusal flood stays the same.
- **`buzz_event_processing_seconds{outcome}`**. Before this change it
was recorded only when `ingest_event` returned `Ok`. A store that was
slow *and failing* (statement timeouts, pool exhaustion) produced no
samples, so latency looked better while the store was degrading. It's
now recorded on every persistent-ingest outcome: `accepted`,
`not_accepted` (for example a duplicate), `invalid`, `auth`, `error`.
Queries that sum across all outcomes still work.
**Cardinality.** Every label value is a `&'static str` from a
code-defined set: 3 types × 4 outcomes, with about 25 reasons that only
appear alongside `denied`/`error`. On purpose, there's no `kind` label:
`bounded_kind_label` still admits around 200 values, which is too many
to cross with histogram buckets.
**What got simpler:** `ReadOutcome::parts()` replaces the inline
outcome→label match in `Drop`, so the log line and the metric share one
mapping. There's no new instrumentation seam: the read metric reuses the
access log's lifecycle.
### Related issue
None found. This came out of a monitoring-gap review: without these
signals, alerts can't catch a slow or failing WebSocket read path, or a
failing EVENT store.
### Testing
-
`access::tests::every_read_is_measured_even_when_its_line_is_suppressed`
(unit). It drives the real `ReadLog` constructors and `Drop`: 20
admission refusals against a 16-line budget, a handler denial past the
budget, a `COUNT` error, a served sync and an aborted `REQ`. It asserts
the exact `(type, outcome, reason, samples)` rows. Two mutants each fail
it: removing the over-budget branch in `refused_read`, and moving the
measurement after the budget check in `Drop`.
-
`handlers::event::tests::postgres_tests::event_processing_is_timed_for_accepted_and_refused_ingest`
(Postgres lane). It sends one accepted text note, then a refused one
from a cached-ban sender, through `handle_event`, and asserts one sample
each under `accepted` and `auth` (a ban maps to the `auth` class).
Removing the `Err`-arm measurement fails it.
- Blox gate at `b314df43f2` (tree `4ca9ebc1`): `cargo fmt --check`
clean. The new Postgres test passes, and removing the `Err`-arm
measurement fails it. buzz-relay unit lane (`cargo nextest run -p
buzz-relay --lib --bins`): 1708/1708 passed.
- At `539796bd51` (the same code; only the second commit's test
assertion differs): workspace clippy (`--all-targets -D warnings`)
passed. The new unit test passed, and each of its two mutants failed it.
buzz-relay Postgres lane: 604/605 passed. The one failure was this
test's old `invalid` expectation, which `b314df43f2` corrects.
- CI at `b314df43f2`: both new tests appear in the CI logs as passing
(Rust / Unit Tests, PostgreSQL Domain / PostgreSQL Tests).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Signed-off-by: Luke Tornquist <tornquist@squareup.com>
Co-authored-by: Elrond <28d6302a099e5225b02c4155ac4236e4912603df2ab08dbfc2f4fef08ce598c8@buzz.block.builderlab.xyz>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>