feat: new subject cache

server/src/_luaScriptsV2/fullSubject/releaseFullSubjectReservation.lua

@@ -0,0 +1,24 @@
+--[[
+  Release a FullSubject write reservation if the token matches.
+
+  KEYS:
+    [1] reserveKey
+
+  ARGV:
+    [1] token
+
+  Returns:
+    "RELEASED" = reservation matched and was deleted
+    "SKIPPED" = key missing or token mismatch
+]]
+
+local reserveKey = KEYS[1]
+local token = ARGV[1]
+
+local existingToken = redis.call("GET", reserveKey)
+if existingToken ~= token then
+  return "SKIPPED"
+end
+
+redis.call("DEL", reserveKey)
+return "RELEASED"

server/src/_luaScriptsV2/fullSubject/reserveFullSubjectWrite.lua

@@ -0,0 +1,50 @@
+--[[
+  Reserve a FullSubject write so only one non-overwrite writer proceeds.
+
+  KEYS:
+    [1] subjectKey
+    [2] reserveKey
+    [3] guardKey
+
+  ARGV:
+    [1] token
+    [2] reserveTtl
+    [3] overwrite - "true" to bypass reservation, "false" to reserve if missing
+    [4] fetchTimeMs
+
+  Returns:
+    "RESERVED" = caller may proceed with the write
+    "CACHE_EXISTS" = subject already exists or another writer already reserved it
+    "STALE_WRITE" = guard exists with newer timestamp than this write
+]]
+
+local subjectKey = KEYS[1]
+local reserveKey = KEYS[2]
+local guardKey = KEYS[3]
+local token = ARGV[1]
+local reserveTtl = tonumber(ARGV[2])
+local overwrite = ARGV[3] == "true"
+local fetchTimeMs = tonumber(ARGV[4])
+
+if overwrite then
+  return "RESERVED"
+end
+
+local guardTime = redis.call("GET", guardKey)
+if guardTime and guardTime ~= cjson.null and fetchTimeMs then
+  local guardTimeNum = tonumber(guardTime)
+  if guardTimeNum and guardTimeNum > fetchTimeMs then
+    return "STALE_WRITE"
+  end
+end
+
+if redis.call("EXISTS", subjectKey) == 1 then
+  return "CACHE_EXISTS"
+end
+
+local reserved = redis.call("SET", reserveKey, token, "EX", reserveTtl, "NX")
+if not reserved then
+  return "CACHE_EXISTS"
+end
+
+return "RESERVED"

server/src/_luaScriptsV2/fullSubject/updateCustomerDataV2.lua

@@ -0,0 +1,50 @@
+--[[
+  Lua Script: Update Customer Data in FullSubject V2 Redis Cache
+
+  Atomically updates top-level customer fields in the cached FullSubject JSON.
+
+  KEYS[1] = FullSubject cache key
+
+  ARGV[1] = updates JSON object
+  ARGV[2] = cache TTL in seconds
+  ARGV[3] = current timestamp in ms
+
+  Returns JSON:
+    { "success": true, "updated_fields": ["name", "email"] }
+    or
+    { "success": false, "cache_miss": true }
+]]
+
+local subject_key = KEYS[1]
+local updates = cjson.decode(ARGV[1])
+local cache_ttl = tonumber(ARGV[2])
+local now_ms = tonumber(ARGV[3])
+
+local has_updates = false
+for _ in pairs(updates) do
+  has_updates = true
+  break
+end
+
+if not has_updates then
+  return cjson.encode({ success = true, updated_fields = {} })
+end
+
+local current_raw = redis.call("GET", subject_key)
+if not current_raw then
+  return cjson.encode({ success = false, cache_miss = true })
+end
+
+local cached = cjson.decode(current_raw)
+local updated_fields = {}
+
+for field_name, field_value in pairs(updates) do
+  cached.customer[field_name] = field_value
+  table.insert(updated_fields, field_name)
+end
+
+-- cached._cachedAt = now_ms
+
+redis.call("SET", subject_key, cjson.encode(cached), "EX", cache_ttl)
+
+return cjson.encode({ success = true, updated_fields = updated_fields })