* feat(odm): merge the source listing into ListObjectsV2
Adds policy.list_through: ListObjectsV2 merges the local and source
listings into one ordered page so clients see the whole namespace during
an on-demand migration. Local entries win a key both sides hold,
CommonPrefixes are unioned under a delimiter, and the continuation token
is an opaque versioned envelope carrying both cursors.
A source listing failure or an open breaker follows policy.source_error:
propagate answers 424, not_found answers from local state and marks the
response x-rustfs-on-demand-migration-list: local_only. Source listings
are capped at 10 per second per bucket.
* test(odm): refresh the e2e-full darwin selection digest
The list-through e2e module adds seven cases to the merge lane.
* fix(odm): declare the remote client retry policy per consumer
The SDK retry policy was an inherited default: one logical call could cost
three wire requests, so the migration breaker counted logical calls on top
of a threefold amplification against a source that was already failing.
Make it an explicit RemoteS3EndpointSpec field. Replication targets declare
today's standard three attempts and keep their behaviour; the on-demand
migration source and its admin probe declare a disabled policy, so one
counted failure is exactly one source request and pull.rs owns the only
retry budget.
* fix(odm): count a stalled inline source as a source timeout
The inline tee wraps its source body in the idle guard, but the tee turns a
stalled source into an ordinary body read error, so the write-back reported
it as a local write failure. Hand commit_inline the guard so the pull is
counted under source_timeout instead.
The background pump now enforces the idle budget through the same guard
rather than a second copy of the timeout loop.
* test(odm): cover a stalled source body end to end
The fake target can now deliver a GetObject body in slices with a pause
between them, so the inline abort can be driven by a stalled source instead
of a truncated one. Two fault cases drop the workarounds they carried for
the SDK's retries: the scripted fault count and the observed source request
count now have to agree.
The operations guide records the retry and idle-timeout guarantees.
* feat(odm): enable on-demand migration by default
The module switch RUSTFS_ON_DEMAND_MIGRATION_ENABLED now defaults to true,
so the feature is reachable without an opt-in; setting it to false still
keeps the module out of the read path entirely. A bucket without an
on-demand-migration.json is never resolved by the runtime and makes no
source call, so the flip changes nothing for unconfigured buckets.
The admin plane now reads the switch through the predicate published by
module_switches.rs instead of its own duplicated env constant; the
behaviour (an environment read per call) is unchanged.
* test(e2e): wire three on-demand migration cases into e2e-smoke
The PR smoke lane gains one case per user-visible contract: a GET miss
that pulls and persists, a HEAD miss that answers from the source and
stores nothing, and the admin config/status pair that must redact the
source secret. The HEAD case did not exist outside the nightly
real-source lane, so it is added to get_basic_test.
Measured on darwin: the lane goes from 168 tests in 101.98 s to 171
tests in 101.92 s, since the three cases overlap the lane's existing
work. The darwin selection digests for e2e-smoke and e2e-full are
regenerated; the e2e-full linux digest still needs a Linux runner.
* docs(changelog): record the on-demand migration feature
* docs(odm): add the on-demand migration operations guide
Positioning against replication, site replication, tiering and the
replication read-proxy; the admin API walkthrough; the full config field
table with defaults and bounds; the semantics table with the test that
pins each row; provider presets and least-privilege source permissions;
integrity, ETag and metadata mapping; protections, error codes,
observability with PromQL, troubleshooting, known limitations and
security notes.
Adds docs/architecture/background-services-inventory.md with the
write-back pipeline, backfill job and backfill recovery loop rows, and
registers it in the architecture index.
Refs rustfs/backlog#2160, rustfs/backlog#2147.
* docs(odm): note migration sources on the replication egress guard
Refs rustfs/backlog#2160.
Zhengchao An