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archvillainette 3f78197f0a Purge the edge after a repair, or verify answers per PoP (#89) (#90)
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#89 asked for a decision. This is it, and it is the laziest of the three options listed there: **purge the whole pull zone by hand after a repair, one call, documented in the repair procedure.**

Why not the other two:

- Purging from `emit --verify` needs a CDN credential `emit` deliberately does not hold, and `emit` reports how many blobs it wrote, never which ones — so it could not target the keys anyway.
- Waiting out the TTL means 30 days.

Whole-zone rather than per-key costs a cold cache on a zone whose objects are mostly cold, and a repair scatters thousands of keys across the tree regardless.

Also answers the question #89 left open: **the zone does not negative-cache.** A missing key answers 404 with `cache-control: no-cache` and `cdn-cache: MISS`, still MISS on an immediate retry (checked credential-free, 2026-08-01).

Docs only — `docs/command-surface.md` and `nwsync`'s usage text. The procedure itself lives in sow-platform's NWSync runbook, next to the zone it acts on.

Closes #89.

🤖 Generated with [Claude Code](https://claude.com/claude-code)Reviewed-on: #90
Reviewed-by: xtul <mpiasecki720@protonmail.com>
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
2026-07-31 23:13:55 +00:00
archvillainette 7cc53aeb68 fix(nwsync): declare Frame_Content_Size on every blob, and verify what is published (#87)
build-binaries / build-binaries (push) Successful in 2m40s
Closes #86. Closes #85.

These land together on purpose. Fixing the encoder alone changes nothing for the blobs already in the zone, because `emit` skips whatever is already present.

## #86 — the framing fix

`klauspost/compress` omits the zstd `Frame_Content_Size` field for inputs under 256 bytes, which the format permits. Reference libzstd never does, so the NWN client — which sizes its output buffer from `ZSTD_getFrameContentSize` and has therefore never met a frame without one — rejected roughly 6% of our blobs outright. Any single one stops a sync dead, so no client could complete a sync of the live manifest.

No encoder option changes this, so `compressBlob` re-headers the affected frames into the shape libzstd itself emits: `Single_Segment_flag` set, `Window_Descriptor` dropped, and the freed byte spent on a one-byte `Frame_Content_Size`. Same length in, same length out, and the same descriptor byte (`0x24`) the issue recorded from libzstd.

`compressBlob` then asserts its own output. An encoder upgrade that finds another way to omit the field would otherwise reproduce #86 in silence, and a blob is skipped by every later emit once written.

`emitter_version` goes to `2`, so `assemble` refuses to merge an index written by the encoder that omitted the field.

**Proved against the reference decoder, not just a round trip.** A real emitted 175-byte blob:

```
Frames  Skips  Compressed  Uncompressed  Ratio  Check  Filename
     1      0      48   B       175   B  3.646  XXH64  frame.zst
c59d6620d4ffd4bf3fe73df43b19b7afcfe8fea4  -            <- zstd -dc | sha1sum
c59d6620d4ffd4bf3fe73df43b19b7afcfe8fea4               <- the blob's own name
```

Before the fix that `Uncompressed` column was blank.

## #85 — `nwsync verify`

`crucible nwsync verify <manifest-sha1>` reads a manifest and its blobs back through the **public pull zone**, with no credential, because what matters is the bytes a client is served, edge behaviour included. Every distinct blob is decompressed and hashed; failures are reported per blob as missing / malformed framing / size mismatch / hash mismatch, and the exit code is 1.

- `--sample N` makes a routine check cheap against a manifest that is ~69,000 blobs and 15 GB; the default is a full sweep.
- `--base URL` / `NWSYNC_PULL_BASE` overrides the public host.
- The manifest is checked against its own sha1 before a single blob is fetched.
- `emit --verify` applies the same check where `emit` would otherwise trust presence, and replaces a stored blob that is not what its name claims. This is what makes the #86 blobs repairable.

## Why the existing checks missed this

Both new checks assert the **frame property**, not just a round trip. The conformance suite (#59) compares decompressed bytes, so a frame that decodes correctly passes regardless of its header; and the earlier zone audit decompressed 68 blobs with the `zstd` CLI, a *more* capable decoder than the client's, which certified exactly the blobs the client rejects.

## Checks

`make check` and `make smoke` green. Second commit is the fixes from a two-axis review of the first.

## Not in this PR

Three follow-ups, filed separately: the backfill has not been run, replacing a blob does not purge the pull-zone edge cache, and #85's runbook line belongs to `sow-platform`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)Reviewed-on: #87

Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
2026-07-31 22:33:12 +00:00
2 changed files with 14 additions and 0 deletions
+12
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@@ -97,6 +97,18 @@ broken — is skipped by every later run forever and no backfill repairs it. Wit
and replaced when it does not match. It costs a full GET per existing blob, so and replaced when it does not match. It costs a full GET per existing blob, so
it is a repair pass, not the default. it is a repair pass, not the default.
**After a repair, purge the pull zone before believing `verify`.** A repair is
the one thing that makes a key serve different bytes than it did before, and the
edge caches these objects for 30 days precisely because that normally cannot
happen. The two commands therefore look at different copies on purpose: `emit
--verify` repairs the **origin**, `verify` reads the **edge**, and in between a
warm PoP still answers with the old bytes while a cold one answers with the new.
Until the zone is purged `verify`'s verdict is per-PoP and settles nothing — a
pass is not proof, and a failure is not the repair having failed. The purge is
one call against the pull zone; it belongs in the repair procedure rather than
in `emit`, which holds a storage credential and no CDN one (sow-tools#89, and
the procedure itself is in sow-platform's NWSync runbook).
`emit` uploads blobs first and the index last, so the presence of an index is `emit` uploads blobs first and the index last, so the presence of an index is
the publication marker: an artifact whose emit died halfway leaves real blobs in the publication marker: an artifact whose emit died halfway leaves real blobs in
the zone and no index. Blob names are content hashes, so re-running skips the zone and no index. Blob names are content hashes, so re-running skips
+2
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@@ -67,6 +67,8 @@ check on a published blob upstream of a player's client.
--verify makes emit hash what it would otherwise skip. emit normally treats a --verify makes emit hash what it would otherwise skip. emit normally treats a
blob's presence as proof of its contents, so without this an object written blob's presence as proof of its contents, so without this an object written
truncated, or written by an emitter since found broken, is skipped forever. truncated, or written by an emitter since found broken, is skipped forever.
--verify repairs the storage zone, while verify reads the edge in front of it,
so purge the pull zone after a repair or verify answers differently per PoP.
--out DIR writes to a local repository tree instead of uploading, which is the --out DIR writes to a local repository tree instead of uploading, which is the
conformance path against upstream nwn_nwsync_write. Without it, the zone comes conformance path against upstream nwn_nwsync_write. Without it, the zone comes