Add an internal access-decision boundary that all handlers go through
instead of calling zddc.AllowedWithChain directly. Two implementations
ship:
* InternalDecider — wraps the existing zddc.AllowedWithChain. The
default. No new dependencies, identical semantics to the legacy
code path. ZDDC_OPA_URL=internal (or unset).
* HTTPDecider — POSTs the canonical OPA wire format
(POST /v1/data/zddc/access/allow with {"input": {...}}, response
{"result": true|false}) over HTTP, HTTPS, or a Unix-domain socket.
For federal customers running their own audited Rego policies
alongside zddc-server. ZDDC_OPA_URL=http(s)://… or unix:///….
External-mode failure semantics: unreachable / non-2xx / malformed
response → fail closed (deny) by default with a WARN log. Operators
who prefer availability over correctness flip with ZDDC_OPA_FAIL_OPEN=1.
The decider is constructed once at startup, plumbed through ACLMiddleware
into the request context. Handlers retrieve it via DeciderFromContext;
non-request callers (fs.ListDirectory, EnumerateProjects, enumerateAccess)
take it as an explicit parameter.
zddc.ZddcFile and zddc.ACLRules gain JSON tags so external Rego authors
get idiomatic input shape (acl.allow, admins, …) instead of Go field
names (ACL.Allow, Admins, …).
Test coverage:
* InternalDecider parity tests against zddc.AllowedWithChain (every
documented cascade scenario: empty chain, leaf-allow-wins, leaf-
deny-beats-parent, leaf-allows-what-parent-denies, deepest-match-
wins, etc.)
* HTTPDecider happy-path test (canonical wire format)
* Fail-closed / fail-open / malformed-response tests
Production binary size unchanged (no new deps; HTTP transport is
stdlib net/http). 11 ACL call sites migrated. End-to-end verified
against the worked-example layout in zddc/README.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ZDDC
e911806eda