A key that cannot be described was handled two incompatible ways. Vault KV2 swallowed every describe failure and dropped the key from the page, so a damaged or newer-format record silently disappeared from the operator's inventory and from the deletion sweep's census. Local failed the whole listing instead, so one bad record stopped every scheduled deletion on the node for as long as the damage lasted. Both force a per-key problem into a whole-page answer.
ListKeysResponse now carries unreadable_key_ids, and the backends that read local key records classify per-key failures in one place: KeyNotFound is a concurrent deletion and is skipped, a material-level error names the key on the page, and anything else fails the listing, because it says nothing about a particular key and reporting it as key damage would turn a backend outage into a false data-loss alarm. A listing that covered the entire key set and found nothing readable still fails, since an empty page there is indistinguishable from a deployment with no keys; the guard is scoped to a page with no successor so a damaged key can never strand the keys behind it. The deletion sweep destroys the expired keys it can read, counts the unreadable ones, and withholds its lifecycle gauges rather than publishing a census over a key set it did not fully see.
Vault Transit needs the same treatment and is easy to miss: its per-key metadata records live in KV2 too, so folding every non-404 failure into a backend error left its per-key classification unreachable and one metadata record written by a newer build still failed every listing on the node.
Vault KV2 record reads gain the typed errors this needs: an unparseable body is MaterialCorrupt and an absent data envelope is MaterialMissing, where both were previously indistinguishable from Vault being unreachable. Only the parse failure's category and position are reported, because serde's own message embeds the offending scalar and that message reaches a log line and an admin HTTP body.
The admin list handlers refuse a malformed limit with 400 instead of silently substituting the default page size, and every page is capped at 1000 where it is cut, so a single request can no longer fan out one metadata lookup per key without bound. The four operation-level KMS metrics gain a backend label, since operation names are shared across backends and a Transit latency regression was previously indistinguishable from an AWS one. The Static backend captures its reported creation date once instead of reading the clock on every describe and list. POST /kms/clear-cache gains a named response type with an unchanged wire shape.
* feat(kms): record operation metrics in the retry policy engine
Instrument policy::execute — the single choke point every outbound Vault
call and credential exchange already flows through — so no call site
needs its own instrumentation:
- rustfs_kms_backend_operations_total (counter): operation, op_class,
outcome (success / fatal / budget_exhausted / deadline_exceeded /
cancelled)
- rustfs_kms_backend_attempt_failures_total (counter): operation,
error_class (retryable_conn / retryable_status / fatal /
attempt_timeout)
- rustfs_kms_backend_operation_duration_seconds (histogram): wall-clock
duration including retries and backoff
- rustfs_kms_backend_operation_attempts (histogram): attempts used
Metric labels carry only static enum values (operation names, classes,
outcomes) — never key identifiers, key material, ciphertext, or tokens.
Emission goes through the process-global metrics facade recorder, the
same pattern the rest of the workspace uses, so no new wiring is needed
in rustfs/src.
Tests drive a paused-clock runtime under a thread-local debugging
recorder, so counts, attempts, and even the recorded (virtual-clock)
durations are asserted deterministically with zero real sleeps.
Refs rustfs/backlog#1569 (part of rustfs/backlog#1562)
* test(kms): add Vault fault-injection matrix
Offline cases inject transport faults locally and are fully
deterministic: a refused connection is retried up to the configured
budget, and a stalled connection is cut off by the per-attempt timeout
instead of hanging. Ignored cases run against a real dev Vault
(RUSTFS_KMS_VAULT_ADDR) and pin the fail-closed auth behavior: an
invalid token and a missing key each resolve in exactly one attempt.
Every case asserts through the policy metrics recorded by a
thread-local debugging recorder, which doubles as the request-count
assertion even against a real server. Throttling and recoverable 5xx
responses cannot be forced on a stock dev Vault; those paths stay
pinned by the scripted-Vault wiring tests and the engine tests.
Refs rustfs/backlog#1569 (part of rustfs/backlog#1562)
* test(kms): add a scripted loopback Vault for policy wiring tests
A minimal HTTP/1.1 responder that serves canned Vault responses in order
and records the method/path sequence, so wiring tests can assert exactly
how many requests a code path performed (retries, read-confirm) without
a live Vault server.
* feat(kms): route Vault operations through the retry policy engine
Wire every outbound vaultrs call in the KV2 and Transit backends through
policy::execute, completing the wiring half of the operation policy work
(the engine landed separately):
- Reads (KV2 read/read_metadata/read_version/list, transit read/list/
encrypt/decrypt, health checks) run as ReadIdempotent: bounded retries
with exponential backoff and jitter on 429, recoverable 5xx, and
connection-level failures; 400/401/403/404 stay fatal.
- Writes (KV2 set/CAS set/delete_metadata, transit create/update/rotate/
delete, metadata writes) run as MutatingNonIdempotent: exactly one
attempt under the per-attempt timeout, never replayed. CAS conflicts
in the rotation protocol pass through unchanged as the concurrency
signal they are.
- Each attempt takes a fresh credential snapshot, so a retry after a
credential rotation uses the new token.
- Read-confirm recovery for lost create responses: when a create finds
an existing key that is exactly what it would have produced (same
algorithm, enabled, usable material, and for request-level creates the
same usage/description/tags), it reports the stored key as the create
result instead of KeyAlreadyExists. Any divergence keeps failing.
- Deletes treat already-deleted records as completed deletes (KV2
version records; transit metadata already did), so re-running an
interrupted deletion converges.
- A failed existence pre-check inside create now fails the create
instead of falling through to a blind overwrite (fail closed).
- The policy module sheds its allow(dead_code) now that it is wired.
Wiring tests run against a scripted loopback Vault and assert request
counts and endpoints for the retry, single-attempt, CAS-conflict, and
read-confirm paths.
Refs rustfs/backlog#1569 (part of rustfs/backlog#1562)
Zhengchao An