Phase 2 enhancements to the policy decider, plus listing-level ETags
that benefit every deployment regardless of decider mode.
Reference Rego policy
---------------------
internal/policy/rego/access.rego mirrors InternalDecider's semantics
exactly — bottom-up walk, deny-first within a level, default-deny when
HasAnyFile=true, glob matching with @-boundary semantics (special-cased
bare "*" because OPA's glob.match treats empty delimiters
inconsistently for that pattern).
Embedded into the binary via go:embed; --print-rego dumps it to stdout
so federal customers standing up an external OPA can use it as a
parity-tested baseline:
zddc-server --print-rego > /etc/opa/policies/zddc-access.rego
Parity test runner
------------------
parity_test.go imports the OPA Go module as a TEST-ONLY dependency
(github.com/open-policy-agent/opa@v0.70.0). Every fixture from the
internal Go evaluator's test set runs through both implementations;
any divergence fails CI. The test-only import means production
binaries (built by `go build ./cmd/zddc-server`) stay OPA-free —
release-flag binary size unchanged at ~13 MB.
The parity test caught a real bug on first run: bare "*" patterns
didn't match through OPA's glob.match with empty delimiters. Fixed
in access.rego with a special-case rule. This is exactly the kind of
subtle drift the parity guard exists to catch.
External-mode decision cache
----------------------------
HTTPDecider is now wrapped in a cachingDecider with a default 1s TTL.
Bursty patterns like .archive listings (one OPA round-trip per entry
before, one per (email, decision-input) tuple per TTL window after)
amortize cleanly. Verified: 20 identical /D/ requests produce 1 OPA
hit with cache, 40 hits without (each listing makes 2 ACL queries).
ZDDC_OPA_CACHE_TTL knob (default 1s) lets operators tune. 0 disables.
1s matches the fsnotify watcher debounce window — staleness is
bounded the same way other policy-edit propagation already is.
Internal mode unchanged; the in-process Go evaluator is already
cheaper than a cache lookup would be.
Listing ETags
-------------
GET / (project list) and GET /<dir>/ (directory listing JSON) now
carry content-hash ETag + Cache-Control: private, max-age=0,
must-revalidate. SHA-256 of the rendered JSON, truncated to 16 hex
chars (64 bits — collision risk on a listing of any realistic size
is vanishingly small).
Server-side caching deliberately not added: it would require
mtime-based invalidation, and Azure Files SMB mounts (a common
deployment substrate) don't support fsnotify reliably. The
content-hash ETag delivers the bandwidth savings (304 on identical
fetches) without depending on watcher correctness — the hash is the
actual response, so it can't lie about staleness regardless of
underlying watcher behavior.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add --access-log <path> (env ZDDC_ACCESS_LOG). When set, every access-
log record is written as a JSON line to the configured file in
addition to the existing slog.Default() stderr output. Empty (default)
keeps the prior behavior — stderr only.
Rotation via gopkg.in/natefinch/lumberjack.v2:
100 MB per file, 10 backups, 90-day max age, gzip rotated files.
Operator usage (e.g. behind a Caddy/quadlet stack):
zddc-server --access-log /srv/.zddc.d/logs/access.log ...
Architecture:
AccessLogMiddleware now takes an optional *slog.Logger. main.go wires
it via setupAccessAuditLog() which builds a slog.JSONHandler over a
lumberjack rotator. Stderr emission stays via slog.Default(); the
audit logger gets the same fields in line-delimited JSON, the format
every standard log shipper (Vector, Loki, fluentbit, journalbeat)
parses natively.
Tests cover the audit logger receiving the same email/path/status
fields as the stderr stream.
Add github.com/klauspost/compress/gzhttp wrapper around the request
handler. With MinSize(1024), responses ≥ 1 KB get gzip-encoded when
the client advertises Accept-Encoding: gzip; smaller bodies + 304
Not Modified pass through unchanged.
The wrapper auto-appends Vary: Accept-Encoding (compatible with the
existing Vary: Accept on directory.go's content-negotiated path).
Live-tested against zddc-server -root /tmp/empty:
GET / w/ Accept-Encoding: gzip → 20.9 KB compressed (was 80.9 KB
uncompressed). 74% reduction.
Decompresses cleanly back to the original bytes.
Helps every code path that bypasses Caddy: devshell pods, local dev
binaries, tests, anywhere zddc-server is hit directly. Production
behind Caddy already had compression at the proxy layer; this just
makes the Go server self-sufficient.
Tests in cmd/zddc-server/main_test.go cover:
- large body + Accept-Encoding → compressed + Vary header
- small body → not compressed (under MinSize)
- no Accept-Encoding header → plain bytes
ZDDC — Zero Day Document Control. A file-naming convention plus five
single-file HTML tools (archive, transmittal, classifier, mdedit,
landing) and an optional Go HTTP server (zddc-server) with ACL and a
virtual archive index. Self-contained, offline-capable, dependency-free.
See README.md for an overview, AGENTS.md and ARCHITECTURE.md for the
build/release/architecture detail, bootstrap/README.md for the
two-level deployment install pattern, and zddc/README.md for the
HTTP server.
