Allow configured loopback Loki endpoints for native-data - #919

Scope

NativeStack2604 uses Loki on port 21300, but native-data's config validation required the authoring host's port 13100. Accept the configured loki_url for HTTP IPv4 loopback literals (127/8) or IPv6 ::1, an explicit valid port and the exact /loki/api/v1/push path. The existing publisher already sends to config["loki_url"]; removing the fixed endpoint restriction makes that configuration usable.

• Base commit: 52ed48881115adb072385456060a80e70e57e3d8.
• Lane: lane:shared, because the required evidence hash registrations touch the shared manifest. Other-lane acknowledgement remains required before merge.
• Owned paths: observability/native-data/snapshot.py, observability/native-data/README.md, tests/test_native_dashboard_data.py, and only those three entries in manifests/evidence.json.

SOTA sources

• python/cpython v3.13.16, Lib/ipaddress.py: maintained loopback classification and strict IP literal parsing. IPv6 classification delegates mapped addresses to IPv4, so the collector explicitly restricts IPv6 to ::1.
• python/cpython v3.13.16, Lib/urllib/parse.py: URL parsing strips controls. Validate the untouched string first to reject control characters, DNS names, userinfo, scope identifiers, query/fragment delimiters and path variants. Retain existing proxy suppression and redirect rejection.
• grafana/loki v3.7.8, push API reference and POST route registration, matching the official Loki API. The intended service's buildinfo reports 3.7.8, revision 09e6ce2f. The collector keeps the supported JSON push envelope and content type.
• Existing native adapter/config/service/timer at repository base 52ed48881115adb072385456060a80e70e57e3d8; this change uses the installed standard library and the existing adapter without adding a dependency or replacing a native runtime.

Evidence-class table

Local commands run

timeout 600 nice -n 10 ionice -c2 -n7 python3 -B -m unittest tests.test_native_dashboard_data -v
46 tests; OK; rc 0

timeout 600 nice -n 10 ionice -c2 -n7 python3 -B scripts/validate.py
status passed; rc 0

git diff --check
rc 0

Decision record

The NativeStack2604 section in observability/native-data/README.md records the configurable endpoint, private-config and published timer requirements, report-source dependency and post-application acceptance. The dated 2026-10-09 source/proposal record accompanies the CC packet. A strict regex on the original string plus the maintained IP parser was selected over parser-only URL validation because the parser normalizes controls. A change in upstream IP/URL semantics would require rerunning the boundary tests and reviewing the guard.

Placeholder-only private-config and user-timer diffs, each with an inverse, are retained in the CC coordination packet with SHA-256 custody. The CC must render and apply them privately with config mode 0600 and state mode 0700. Context Mode for both clients, Headroom and jCodeMunch come from an existing current token_report and matching scope labels; this collector does not refresh that producer. No private configuration or systemd unit is installed by this PR or this lane.

Host acceptance remains pending CC application: a positive Loki count_over_time({service_name="agent-stack-native-data"}[30m]), then native-foundation-data screenshot, zero console errors/failed network requests and the current generation across savings, memory and coverage panels. Buildinfo and local fixture HTTP tests do not establish host ingestion.

Host evidence

No files under evidence/hosts/ or platform status fields change. No native-proven ingestion claim is made.

Checklist

• No new or changed GitHub Actions; workflow pin/permission requirements remain intact.
• No secrets printed, logged or committed; private proposal roots and identifiers are placeholders.
• No new paid hosting, subscription or billing surface.
• Peer-owned files and worktrees preserved.
• Designated independent reads, green CI, co-op pre-cue result, other-lane acknowledgement and explicit CC cue before 5f landing.