Canonicalize v2 changes consumer flow and tests

README.md

@@ -38,10 +38,10 @@ unhealthy, it automatically falls back to `fs` (configurable via
 ./scripts/ingest_example.sh
 ```
 
-5. Run sample changes sync loop:
+5. Run sample changes consumer (recommended):
 
 ```sh
-./scripts/sync_loop.sh
+./scripts/v2_app.sh consume-changes
 ```
 
 ## v2 Vertical Slice CLI
@@ -52,6 +52,7 @@ Use the integrated v2 app flow wrapper:
 ./scripts/v2_app.sh startup-check
 ./scripts/v2_app.sh ingest '{"idempotency_key":"k1","mode":"continue_on_error","nodes":[{"name":"doc-1"}]}'
 ./scripts/v2_app.sh sync-once
+./scripts/v2_app.sh consume-changes --once
 ./scripts/v2_app.sh retrieve 'doc-1' 'ms.within_domain'
 ./scripts/v2_app.sh tombstone '<edge_ref>'
 ```
@@ -62,6 +63,13 @@ Run integration coverage (requires running `amduatd` + `jq`):
 ./tests/integration_v2.sh
 ```
 
+Run local cursor/handler semantics checks (no daemon required):
+
+```sh
+./tests/changes_consumer_410.sh
+./tests/changes_consumer_handler.sh
+```
+
 Run a fast end-to-end smoke (startup + ingest + sync + retrieve + tombstone):
 
 ```sh
@@ -72,4 +80,5 @@ Run a fast end-to-end smoke (startup + ingest + sync + retrieve + tombstone):
 
 - This scaffold assumes local Unix-socket access to `amduatd`.
 - Graph cursors are opaque and must be persisted exactly as returned.
+- `./scripts/sync_loop.sh` and `sync-loop` CLI are deprecated compatibility aliases.
 - Keep `contracts/amduatd-api-contract.v2.json` in sync with upstream when you pull updates.

docs/v2-app-developer-guide.md

@@ -150,6 +150,13 @@ For integration tests/examples:
 
 - `scripts/test_graph_queries.sh`
 - `scripts/test_graph_contract.sh`
+- `scripts/changes_consumer.sh` (durable changes loop with event handler hook)
+- `tests/changes_consumer_410.sh` (forced cursor-expiry path)
+- `tests/changes_consumer_handler.sh` (cursor advances only on handler success)
+
+Canonical CLI entrypoint for ongoing sync:
+
+- `./scripts/v2_app.sh consume-changes`
 
 ## 10) Copy/Paste Integration Skeleton
 
@@ -196,14 +203,42 @@ while true; do
     path="/v2/graph/changes?limit=200&wait_ms=15000"
   fi
 
-  resp="$(curl --unix-socket "${SOCK}" -sS "${BASE}${path}" -H "X-Amduat-Space: ${SPACE}")" || break
+  # Capture response body and status for explicit 410 handling.
+  raw="$(curl --unix-socket "${SOCK}" -sS -w '\n%{http_code}' "${BASE}${path}" -H "X-Amduat-Space: ${SPACE}")" || break
+  code="$(printf '%s\n' "${raw}" | tail -n1)"
+  resp="$(printf '%s\n' "${raw}" | sed '$d')"
 
-  # TODO: parse and process resp.events[] in your app.
-  next="$(printf '%s\n' "${resp}" | sed -n 's/.*"next_cursor":"\([^"]*\)".*/\1/p')"
-  [ -n "${next}" ] && cursor="${next}"
+  if [ "${code}" = "410" ]; then
+    echo "changes cursor expired; rebootstrap required" >&2
+    cursor=""   # Option: switch to a since_as_of bootstrap strategy here.
+    sleep 1
+    continue
+  fi
+  [ "${code}" = "200" ] || { echo "changes failed: HTTP ${code}" >&2; sleep 1; continue; }
+
+  # Process each event. Replace this with app-specific handler logic.
+  ok=1
+  while IFS= read -r ev; do
+    kind="$(printf '%s' "${ev}" | jq -r '.kind // "unknown"')"
+    ref="$(printf '%s' "${ev}" | jq -r '.edge_ref // .node_ref // "n/a"')"
+    echo "apply event kind=${kind} ref=${ref}"
+    # handle_event "${ev}" || { ok=0; break; }
+  done < <(printf '%s' "${resp}" | jq -c '.events[]?')
+
+  # Advance cursor only after all events in this batch are handled successfully.
+  if [ "${ok}" = "1" ]; then
+    next="$(printf '%s' "${resp}" | jq -r '.next_cursor // empty')"
+    [ -n "${next}" ] && cursor="${next}"
+  fi
 done
 ```
 
+Failure semantics for the loop above:
+
+- Keep `cursor` in durable storage (file/db) and load it at process startup.
+- Update stored cursor only after successful event processing for that response.
+- On `410 Gone`, your stored cursor is outside replay retention; reset and rebootstrap with `since_as_of` or a full sync.
+
 Agent retrieval call:
 
 ```sh

scripts/changes_consumer.sh

@@ -0,0 +1,145 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck source=/dev/null
+source "${ROOT_DIR}/src/app_v2.sh"
+
+usage() {
+  cat <<USAGE
+usage: $0 [--once]
+
+options:
+  --once    Process a single /v2/graph/changes poll and exit.
+
+env:
+  CHANGES_EVENT_HANDLER   Optional command string; executed per event with EVENT_JSON set.
+  CHANGES_LOOP_SLEEP_SEC  Sleep between polls (default: 1).
+USAGE
+}
+
+require_jq() {
+  if ! command -v jq >/dev/null 2>&1; then
+    echo "changes_consumer.sh: jq is required" >&2
+    exit 2
+  fi
+}
+
+read_cursor() {
+  if [[ -f "${CURSOR_FILE}" ]]; then
+    cat "${CURSOR_FILE}"
+  fi
+}
+
+write_cursor() {
+  local next="$1"
+  printf '%s' "${next}" > "${CURSOR_FILE}"
+}
+
+clear_cursor() {
+  rm -f "${CURSOR_FILE}"
+}
+
+handle_event() {
+  local event_json="$1"
+  if [[ -n "${CHANGES_EVENT_HANDLER:-}" ]]; then
+    EVENT_JSON="${event_json}" bash -lc "${CHANGES_EVENT_HANDLER}"
+    return $?
+  fi
+
+  local kind ref
+  kind="$(printf '%s' "${event_json}" | jq -r '.kind // "unknown"')"
+  ref="$(printf '%s' "${event_json}" | jq -r '.edge_ref // .node_ref // "n/a"')"
+  echo "apply event kind=${kind} ref=${ref}"
+}
+
+poll_once() {
+  local cursor="$1"
+  local path="/v2/graph/changes?limit=${SYNC_LIMIT}&wait_ms=${SYNC_WAIT_MS}"
+  if [[ -n "${cursor}" ]]; then
+    path+="&since_cursor=${cursor}"
+  fi
+
+  if ! amduat_api_call GET "${path}"; then
+    if [[ "${AMDUAT_LAST_STATUS}" == "410" ]]; then
+      echo "changes cursor expired; rebootstrap required" >&2
+      clear_cursor
+      printf '\n'
+      return 10
+    fi
+    echo "changes request failed: HTTP ${AMDUAT_LAST_STATUS}" >&2
+    return 1
+  fi
+
+  local ok=1
+  local event_json
+  while IFS= read -r event_json; do
+    if ! handle_event "${event_json}"; then
+      ok=0
+      break
+    fi
+  done < <(printf '%s' "${AMDUAT_LAST_BODY}" | jq -c '.events[]?')
+
+  if [[ "${ok}" != "1" ]]; then
+    echo "event handler failed; cursor not advanced" >&2
+    return 2
+  fi
+
+  local next_cursor
+  next_cursor="$(printf '%s' "${AMDUAT_LAST_BODY}" | jq -r '.next_cursor // empty')"
+  if [[ -n "${next_cursor}" ]]; then
+    write_cursor "${next_cursor}"
+  fi
+
+  printf '%s\n' "${AMDUAT_LAST_BODY}"
+  return 0
+}
+
+main() {
+  local once=0
+  if [[ $# -gt 1 ]]; then
+    usage >&2
+    return 2
+  fi
+  if [[ $# -eq 1 ]]; then
+    case "$1" in
+      --once) once=1 ;;
+      -h|--help)
+        usage
+        return 0
+        ;;
+      *)
+        usage >&2
+        return 2
+        ;;
+    esac
+  fi
+
+  require_jq
+  app_init
+
+  local loop_sleep="${CHANGES_LOOP_SLEEP_SEC:-1}"
+  while true; do
+    local cursor
+    cursor="$(read_cursor)"
+
+    poll_once "${cursor}" || {
+      status=$?
+      if [[ "${status}" != "10" && "${once}" == "1" ]]; then
+        return "${status}"
+      fi
+      if [[ "${once}" == "1" ]]; then
+        return 0
+      fi
+      sleep "${loop_sleep}"
+      continue
+    }
+
+    if [[ "${once}" == "1" ]]; then
+      return 0
+    fi
+    sleep "${loop_sleep}"
+  done
+}
+
+main "$@"

scripts/sync_loop.sh

@@ -2,39 +2,5 @@
 set -euo pipefail
 
 ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
-ENV_FILE="${ROOT_DIR}/config/env.local"
-if [[ ! -f "${ENV_FILE}" ]]; then
-  ENV_FILE="${ROOT_DIR}/config/env.example"
-fi
-# shellcheck source=/dev/null
-source "${ENV_FILE}"
-# shellcheck source=/dev/null
-source "${ROOT_DIR}/src/client.sh"
-
-limit="${SYNC_LIMIT:-200}"
-wait_ms="${SYNC_WAIT_MS:-15000}"
-cursor_file="${ROOT_DIR}/.cursor"
-cursor=""
-
-if [[ -f "${cursor_file}" ]]; then
-  cursor="$(cat "${cursor_file}")"
-fi
-
-while true; do
-  if [[ -n "${cursor}" ]]; then
-    path="/v2/graph/changes?since_cursor=${cursor}&limit=${limit}&wait_ms=${wait_ms}"
-  else
-    path="/v2/graph/changes?limit=${limit}&wait_ms=${wait_ms}"
-  fi
-
-  resp="$(api_get "${path}")"
-  echo "${resp}"
-
-  next="$(printf '%s\n' "${resp}" | sed -n 's/.*"next_cursor":"\([^"]*\)".*/\1/p')"
-  if [[ -n "${next}" ]]; then
-    cursor="${next}"
-    printf '%s' "${cursor}" > "${cursor_file}"
-  fi
-
-  sleep 1
- done
+echo "sync_loop.sh is deprecated; forwarding to scripts/changes_consumer.sh" >&2
+exec "${ROOT_DIR}/scripts/changes_consumer.sh" "$@"

scripts/v2_app.sh

@@ -13,7 +13,8 @@ commands:
   startup-check
   ingest PAYLOAD_JSON
   sync-once
-  sync-loop
+  consume-changes [--once]
+  sync-loop                  (deprecated alias for consume-changes)
   retrieve ROOTS_CSV [GOAL_PREDICATES_CSV]
   tombstone EDGE_REF
 USAGE
@@ -43,8 +44,12 @@ case "${cmd}" in
   sync-once)
     app_sync_once
     ;;
+  consume-changes)
+    "${ROOT_DIR}/scripts/changes_consumer.sh" "$@"
+    ;;
   sync-loop)
-    app_sync_loop
+    echo "sync-loop is deprecated; use consume-changes" >&2
+    "${ROOT_DIR}/scripts/changes_consumer.sh" "$@"
     ;;
   retrieve)
     if [[ $# -lt 1 || $# -gt 2 ]]; then

src/app_v2.sh

@@ -53,10 +53,10 @@ app_sync_once() {
 }
 
 app_sync_loop() {
-  while true; do
-    app_sync_once
-    sleep 1
-  done
+  local root_dir
+  root_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+  echo "app_sync_loop is deprecated; use scripts/changes_consumer.sh" >&2
+  "${root_dir}/scripts/changes_consumer.sh"
 }
 
 app_retrieve_with_fallback() {

tests/changes_consumer_410.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+fail() {
+  echo "changes_consumer_410.sh: FAIL: $1" >&2
+  exit 1
+}
+
+tmp_dir="$(mktemp -d /tmp/changes-consumer-410.XXXXXX)"
+cleanup() {
+  rm -rf "${tmp_dir}"
+}
+trap cleanup EXIT
+
+cursor_file="${tmp_dir}/cursor"
+printf '%s' "g1_expired_cursor" > "${cursor_file}"
+
+mkdir -p "${tmp_dir}/bin"
+cat > "${tmp_dir}/bin/curl" <<'MOCK'
+#!/usr/bin/env bash
+set -euo pipefail
+printf '%s\n%s' '{"error":"cursor expired"}' '410'
+MOCK
+chmod +x "${tmp_dir}/bin/curl"
+
+out_file="${tmp_dir}/out.log"
+err_file="${tmp_dir}/err.log"
+
+PATH="${tmp_dir}/bin:${PATH}" \
+CURSOR_FILE="${cursor_file}" \
+SYNC_LIMIT=10 \
+SYNC_WAIT_MS=1 \
+SOCK="${tmp_dir}/fake.sock" \
+BASE="http://localhost" \
+SPACE="app1" \
+"${ROOT_DIR}/scripts/changes_consumer.sh" --once >"${out_file}" 2>"${err_file}" || fail "consumer returned non-zero for forced 410 path"
+
+[[ ! -f "${cursor_file}" ]] || fail "cursor file should be cleared on 410"
+grep -q "cursor expired" "${err_file}" || fail "expected expired cursor message in stderr"
+
+echo "changes_consumer_410.sh: PASS"

tests/changes_consumer_handler.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+fail() {
+  echo "changes_consumer_handler.sh: FAIL: $1" >&2
+  exit 1
+}
+
+tmp_dir="$(mktemp -d /tmp/changes-consumer-handler.XXXXXX)"
+cleanup() {
+  rm -rf "${tmp_dir}"
+}
+trap cleanup EXIT
+
+mkdir -p "${tmp_dir}/bin"
+cat > "${tmp_dir}/bin/curl" <<'MOCK'
+#!/usr/bin/env bash
+set -euo pipefail
+printf '%s\n%s' '{"events":[{"kind":"edge_upsert","edge_ref":"e1"}],"next_cursor":"g1_next"}' '200'
+MOCK
+chmod +x "${tmp_dir}/bin/curl"
+
+out_file="${tmp_dir}/out.log"
+err_file="${tmp_dir}/err.log"
+
+# Case 1: handler succeeds -> cursor advances.
+cursor_success="${tmp_dir}/cursor.success"
+printf '%s' "g1_start" > "${cursor_success}"
+
+PATH="${tmp_dir}/bin:${PATH}" \
+CURSOR_FILE="${cursor_success}" \
+SYNC_LIMIT=10 \
+SYNC_WAIT_MS=1 \
+SOCK="${tmp_dir}/fake.sock" \
+BASE="http://localhost" \
+SPACE="app1" \
+CHANGES_EVENT_HANDLER='printf "%s\n" "${EVENT_JSON}" >/dev/null' \
+"${ROOT_DIR}/scripts/changes_consumer.sh" --once >"${out_file}" 2>"${err_file}" || fail "consumer failed on handler success case"
+
+[[ -f "${cursor_success}" ]] || fail "cursor file missing after handler success case"
+[[ "$(cat "${cursor_success}")" == "g1_next" ]] || fail "cursor did not advance after handler success"
+
+# Case 2: handler fails -> cursor does not advance.
+cursor_fail="${tmp_dir}/cursor.fail"
+printf '%s' "g1_start" > "${cursor_fail}"
+
+set +e
+PATH="${tmp_dir}/bin:${PATH}" \
+CURSOR_FILE="${cursor_fail}" \
+SYNC_LIMIT=10 \
+SYNC_WAIT_MS=1 \
+SOCK="${tmp_dir}/fake.sock" \
+BASE="http://localhost" \
+SPACE="app1" \
+CHANGES_EVENT_HANDLER='exit 1' \
+"${ROOT_DIR}/scripts/changes_consumer.sh" --once >"${out_file}" 2>"${err_file}"
+rc=$?
+set -e
+
+[[ "${rc}" -ne 0 ]] || fail "expected non-zero exit when handler fails"
+[[ -f "${cursor_fail}" ]] || fail "cursor file missing after handler failure case"
+[[ "$(cat "${cursor_fail}")" == "g1_start" ]] || fail "cursor advanced despite handler failure"
+grep -q "cursor not advanced" "${err_file}" || fail "missing handler-failure cursor warning"
+
+echo "changes_consumer_handler.sh: PASS"

tests/integration_v2.sh

@@ -21,6 +21,10 @@ assert_contains() {
   fi
 }
 
+# Include deterministic changes-consumer cursor semantics checks
+# in the regular integration entrypoint.
+"${ROOT_DIR}/tests/changes_consumer_handler.sh"
+
 app_init
 require_jq
 if [[ ! -S "${SOCK}" ]]; then