hyperledger / fabric-x-committer / 34470402467

91%

Build Type

push

github

Committed by web-flow

Commit Message

[snapshot-hasher, vc] Hash snapshots in a dedicated service (#803)

#### Type of change

- New feature
- Improvement (improvement to code, performance, etc)
- Test update
- Documentation update

#### Description

- Add `service/snapshothasher`, a new single-instance service that owns
snapshot hashing end to end: it polls the latest durable `_snapshot`
record every `poll-interval` and hashes the record's clone inline, so
one path covers a fresh snapshot, a resubmitted one, and one orphaned
mid-hash by a restart. Start it with `committer start snapshot-hasher`
(gRPC 3001, monitoring 2120); it serves only health checks, since work
arrives through the state database, so `WaitForReady` is unconditionally
true -- the readiness handshake exists to hold back a gRPC server that
would otherwise answer requests before it can. It is named for hashing
rather than for snapshots because creating a snapshot and its clone
stays in the VC.
- Move the hasher (table discovery, keyset-paginated scans,
deterministic per-table and root digests) out of `service/vc` into that
service, and remove snapshot hashing from the VC entirely. The VC's only
snapshot duty is now to make the record durable atomically with its
clone.
- Because exactly one scheduler exists and hashing runs inline, no
cross-process exclusion is introduced at all: no lease, no ownership
token, no fenced state transitions, no leader election.
- Extract the durable `_snapshot` record contract into
`utils/statedb/snapshot_state.go` as a `SnapshotStateManager`
(latest-record pointer, encoding, `FOR UPDATE` read/update) and cover it
with unit tests. It lives in `statedb`, next to the schema it reads,
rather than in a package of its own; `utils/statedb` therefore joins
`REQUIRES_DB_PACKAGES` in the Makefile, since its tests now need a
database but not a particular one. Both processes share it: the VC reads
it to gate a new snapshot request and will write CHECKPOINTED through it
when checkpointing lands, while the ... (continued)

Coverage Stats

313 of 374 new or added lines in 16 files covered. (83.69%)

4 existing lines in 3 files now uncovered.

9505 of 10482 relevant lines covered (90.68%)

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