federation production layer: actor model + follower graph + delivery timer + signatures (LIVE)

The full fed-sx production layer, live-verified across A (blog.rose-ash.com) and B (sx_host_b). ACTOR MODEL + FOLLOWER GRAPH: activities carry a real :actor (SX_ACTOR); delivery targets FOLLOWERS, not a static peer list. A peer subscribes by POSTing {verb:follow, actor, base} to /inbox (host/blog--add-follower!); B follows A at boot (SX_FOLLOW) so A delivers to B. host/blog--{actor, self-base, followers, follow!, delivery-bases} + durable followers store. BACKGROUND DELIVERY TIMER: serve.sh's detached _fed_delivery_loop hits GET /fed-tick every 15s (over /dev/tcp) → re-follow (idempotent, recovers a target that was down at boot) + flush the durable outbox. Federation is eventually-consistent, not best-effort-at-emit. SIGNATURE VERIFICATION: every federated POST is signed (host/blog--fed-sign = dr/sess-sig shared-secret MAC over the body, SX_FED_SECRET); /inbox rejects a bad/missing signature with 403 (empty secret = open). Applies to both follows and activity delivery. PUBLIC DOMAIN: B joins externalnet so Caddy CAN reverse_proxy a subdomain to it — the DNS + Caddy route itself is external ops config (no local Caddyfile). LIVE PROOF: B follows A (followers:1); publish on A → SIGNED delivery to follower B → B verifies + fires validate+notify; a forged POST (bad x-fed-sig) → 403; B down → publish queues → the background timer auto-delivers the backlog when B returns (no manual flush). blog 218/218, full conformance green. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 20:03:35 +00:00
parent afb9ce5e90
commit 43c085e8e8
4 changed files with 128 additions and 22 deletions
--- a/lib/host/blog.sx
+++ b/lib/host/blog.sx
@@ -132,7 +132,7 @@
    (let ((r (host/blog-get slug)))
      (if (nil? r) nil
        (let ((cid (host/blog-cid slug)))
-          {:verb verb :actor "site"
+          {:verb verb :actor host/blog--actor
           :object cid :object-type (host/blog--post-type slug)
           :slug slug :category (host/blog--post-category slug)
           :delta verb :id (str verb ":" cid)})))))
@@ -143,7 +143,7 @@
 ;; id would false-dedup across different edges on the same object.
 (define host/blog--relation-activity
  (fn (verb src kind dst)
-    {:verb verb :actor "site"
+    {:verb verb :actor host/blog--actor
     :object src :object-type (host/blog--post-type src)
     :relation kind :target dst
     :delta (str verb " " kind " " dst)
@@ -188,9 +188,47 @@
 (define host/blog--runner-fleet (list host/flow--exec-runner))
 (define host/blog--add-runner! (fn (r) (set! host/blog--runner-fleet (concat host/blog--runner-fleet (list r)))))
 (define host/blog--kernel-base "")
-;; TA-live: peer base URLs — emitted activities federate to each peer's /inbox (serve-set from SX_PEERS).
-(define host/blog--peers (list))
-(define host/blog--set-peers! (fn (ps) (set! host/blog--peers ps)))
+;; ── the ACTOR MODEL — who WE are + who FOLLOWS us (fed-sx delivery is FOLLOWER-based, not a static
+;; peer list). An emitted activity carries our :actor and delivers to our followers' inboxes. A peer
+;; FOLLOWS us by POSTing a {verb:follow, actor, base} to our /inbox; we add it to our followers.
+(define host/blog--actor "site")           ;; our actor id (serve-set from SX_ACTOR)
+(define host/blog--self-base "")           ;; our base URL — followers POST to <base>/inbox (serve-set)
+(define host/blog--set-actor! (fn (a base) (begin (set! host/blog--actor a) (set! host/blog--self-base base))))
+(define host/blog--followers (list))       ;; [{actor, base}] — who follows us (we deliver here)
+(define host/blog--followers-key "followers")
+(define host/blog-load-followers!
+  (fn () (let ((v (persist/backend-kv-get host/blog-store host/blog--followers-key)))
+           (when (and v (= (type-of v) "list")) (set! host/blog--followers v)))))
+(define host/blog--follows? (fn (base) (some (fn (f) (= (get f "base") base)) host/blog--followers)))
+(define host/blog--add-follower!
+  (fn (actor base)
+    (when (and base (not (= base "")) (not (host/blog--follows? base)))
+      (begin (set! host/blog--followers (concat host/blog--followers (list {"actor" actor "base" base})))
+             (persist/backend-kv-put host/blog-store host/blog--followers-key host/blog--followers)))))
+(define host/blog--delivery-bases (fn () (map (fn (f) (get f "base")) host/blog--followers)))
+;; the actor we follow at boot / on each tick (serve-set from SX_FOLLOW; idempotent re-follow).
+(define host/blog--follow-target "")
+(define host/blog--set-follow-target! (fn (t) (set! host/blog--follow-target t)))
+;; ── federation SIGNATURE: every POST we send is signed (shared-secret MAC over the body); /inbox
+;; verifies before accepting. An empty secret disables verification (back-compat / open demo). ──
+(define host/blog--fed-secret "")
+(define host/blog--set-fed-secret! (fn (s) (set! host/blog--fed-secret s)))
+(define host/blog--fed-sign (fn (body) (if (= host/blog--fed-secret "") "" (dr/sess-sig host/blog--fed-secret body))))
+;; POST a wire to a peer's /inbox WITH a signature header (may raise; callers guard).
+(define host/blog--fed-post
+  (fn (base wire)
+    (http-request "POST" (str base "/inbox")
+      {"content-type" "text/plain" "x-fed-sig" (host/blog--fed-sign wire)} wire)))
+;; verify an inbound POST's signature (accept if no secret configured, else require a matching MAC).
+(define host/blog--fed-verify?
+  (fn (req body)
+    (or (= host/blog--fed-secret "")
+        (= (str (or (dream-header req "x-fed-sig") "")) (dr/sess-sig host/blog--fed-secret body)))))
+;; FOLLOW another actor: POST a follow to its /inbox announcing OUR actor + base, so it delivers to us.
+(define host/blog--follow!
+  (fn (target-base)
+    (guard (e (true false))
+      (begin (host/blog--fed-post target-base (serialize {"verb" "follow" "actor" host/blog--actor "base" host/blog--self-base})) true))))
 ;; per-type behavior declaration, stored on the type-post (string-keyed → persist-safe).
 (define host/blog--type-behavior (fn (type) (or (get (host/blog-get type) :behavior) (list))))
 (define host/blog--set-type-behavior!
@@ -309,13 +347,13 @@
 (define host/blog--enqueue-outbox!
  (fn (a)
    (begin
-      (for-each (fn (peer) (set! host/blog--outbox
-                             (concat host/blog--outbox (list {"peer" peer "wire" (host/ta--serialize a)}))))
-                host/blog--peers)
+      (for-each (fn (base) (set! host/blog--outbox
+                             (concat host/blog--outbox (list {"peer" base "wire" (host/ta--serialize a)}))))
+                (host/blog--delivery-bases))
      (host/blog--outbox-persist!))))
-;; guarded delivery: POST the wire; a connection failure returns false (item kept), never raises.
+;; guarded, SIGNED delivery: POST the wire; a connection failure returns false (item kept), never raises.
 (define host/blog--try-deliver
-  (fn (peer wire) (guard (e (true false)) (begin (host/ta--post peer wire) true))))
+  (fn (peer wire) (guard (e (true false)) (begin (host/blog--fed-post peer wire) true))))
 ;; deliver every pending item; KEEP the ones that failed (peer down) for the next retry.
 (define host/blog--flush-outbox!
  (fn ()
@@ -2866,6 +2904,16 @@
            (persist/backend-kv-put host/blog-store host/blog--flowlog-key host/blog--flow-log)
            (host/blog--drop-pending! id)))
        r))))
+;; ── /fed-tick — the background federation worker (hit periodically by serve.sh's detached loop) ──
+;; Re-follows our target (idempotent — recovers if it was down at boot) and flushes the durable
+;; outbox (delivers any backlog to followers who are now up). This is the delivery TIMER.
+(define host/blog-fed-tick
+  (fn (req)
+    (begin
+      (when (not (= host/blog--follow-target "")) (host/blog--follow! host/blog--follow-target))
+      (host/blog--flush-outbox!)
+      (host/ok {:outbox (len host/blog--outbox) :followers (len host/blog--followers)}))))
+
 ;; ── /flows — the behavior surface: what fired + what's SUSPENDED (RA-live). ?resume=<id> resumes. ─
 (define host/blog-flows
  (fn (req)
@@ -2930,8 +2978,16 @@
 ;; (host/blog--receive! is defined with emit! above — process-local only, no re-federation.)
 (define host/blog-inbox
  (fn (req)
-    (let ((a (host/ta--deserialize (dream-body req))))
-      (begin (host/blog--receive! a) (host/ok {:received (or (get a :id) "")})))))
+    (let ((body (dream-body req)))
+      (if (not (host/blog--fed-verify? req body))
+        (host/error 403 "bad federation signature")     ;; reject unsigned/forged POSTs
+        (let ((w (parse-safe body)))
+          (if (= (get w "verb") "follow")
+            ;; a FOLLOW: register the sender as a follower (deliver our activities to its inbox).
+            (begin (host/blog--add-follower! (get w "actor") (get w "base")) (host/ok {:followed (get w "actor")}))
+            ;; a regular activity: process it (fires our behaviors on the peer's event).
+            (let ((a (host/ta--wire->activity w)))
+              (begin (host/blog--receive! a) (host/ok {:received (or (get a :id) "")})))))))))

 ;; ── routes ──────────────────────────────────────────────────────────
 ;; Public reads + the create form. /, /posts, /new BEFORE /:slug (catch-all).
@@ -2946,6 +3002,7 @@
    (dream-get "/meta" host/blog-meta-index)
    (dream-get "/workflow-demo" host/blog-workflow-demo)
    (dream-get "/flows" host/blog-flows)
+    (dream-get "/fed-tick" host/blog-fed-tick)
    (dream-get "/activities" host/blog-activities)
    (dream-get "/:slug/source" host/blog-source)
    (dream-get "/:slug/relate-options" host/blog-relate-options)
--- a/lib/host/serve.sh
+++ b/lib/host/serve.sh
@@ -49,6 +49,24 @@ _warm_serving_jit() {
 }
 _warm_serving_jit &

+# TA-live: the background FEDERATION DELIVERY loop. Every 15s, hit /fed-tick (the container has no
+# curl, so speak HTTP over /dev/tcp), which re-follows our target (idempotent — recovers if it was
+# down at boot) and flushes the durable outbox (delivers backlog to followers who are now up). This
+# is the delivery TIMER — federation is eventually-consistent, not best-effort-at-emit-only.
+_fed_delivery_loop() {
+  for _ in $(seq 1 240); do
+    case "$( { exec 3<>/dev/tcp/127.0.0.1/"$PORT" && printf 'GET /health HTTP/1.0\r\nHost: x\r\n\r\n' >&3 && head -1 <&3; exec 3>&- 3<&-; } 2>/dev/null )" in
+      *200*) break ;;
+    esac
+    sleep 0.5
+  done
+  while true; do
+    { exec 3<>/dev/tcp/127.0.0.1/"$PORT" && printf 'GET /fed-tick HTTP/1.0\r\nHost: x\r\n\r\n' >&3 && cat <&3 >/dev/null; exec 3>&- 3<&-; } 2>/dev/null
+    sleep 15
+  done
+}
+_fed_delivery_loop &
+
 # Modules: every load line from conformance.sh's MODULES list, minus the ledger
 # (not needed to serve). server.sx supplies host/serve.
 MODULES=(
@@ -220,15 +238,22 @@ EPOCH=1
  echo "(epoch $EPOCH)"
  echo "(eval \"(host/blog-load-pendinglog!)\")"
  EPOCH=$((EPOCH+1))
-  # TA-live: federate emitted activities to peer /inbox endpoints (comma-separated SX_PEERS, e.g.
-  # "http://sx_host_b:8000"). Empty by default (no federation). A peer that receives does NOT
-  # re-federate, so an acyclic peer graph doesn't loop.
-  PEERS_SX="(list"
-  IFS=',' read -ra _PEER_ARR <<< "${SX_PEERS:-}"
-  for _p in "${_PEER_ARR[@]:-}"; do [ -n "$_p" ] && PEERS_SX="$PEERS_SX \\\"$_p\\\""; done
-  PEERS_SX="$PEERS_SX)"
+  # TA-live ACTOR MODEL: our actor id (SX_ACTOR) + base URL (SX_SELF_URL — followers POST to
+  # <base>/inbox). Load our persisted followers. If SX_FOLLOW is set, follow that actor's base at
+  # boot (POST a follow to its /inbox), so it delivers ITS activities to us. Follower-based delivery
+  # replaces the static peer list; the background loop re-follows (idempotent) if the target was down.
  echo "(epoch $EPOCH)"
-  echo "(eval \"(host/blog--set-peers! $PEERS_SX)\")"
+  echo "(eval \"(host/blog--set-actor! \\\"${SX_ACTOR:-site}\\\" \\\"${SX_SELF_URL:-}\\\")\")"
+  EPOCH=$((EPOCH+1))
+  echo "(epoch $EPOCH)"
+  echo "(eval \"(host/blog-load-followers!)\")"
+  EPOCH=$((EPOCH+1))
+  echo "(epoch $EPOCH)"
+  echo "(eval \"(host/blog--set-follow-target! \\\"${SX_FOLLOW:-}\\\")\")"
+  EPOCH=$((EPOCH+1))
+  # TA-live: the shared federation secret (peers sign every POST; /inbox verifies). Empty = open.
+  echo "(epoch $EPOCH)"
+  echo "(eval \"(host/blog--set-fed-secret! \\\"${SX_FED_SECRET:-}\\\")\")"
  EPOCH=$((EPOCH+1))
  # TA-live: rebuild the durable outbox + RETRY any deliveries that were pending from before a
  # restart (a peer that was down gets its backlog once it + we are back up).