Add postgres backup script for alert-api DB

.gitignore

@@ -17,4 +17,5 @@ id_rsa
 .ansible/
 .env
 .vault_passwrd*
-*.iml
+*.iml
+backups/

bin/backup_postgres.sh

@@ -0,0 +1,90 @@
+#!/bin/bash
+set -euo pipefail
+
+# ====== CONFIG (overridable via env) ======
+INVENTORY="${INVENTORY:-inventory/hosts_prod}"
+GROUP="${GROUP:-alert_server}"
+SSH_USER="${SSH_USER:-ubuntu}"
+CONTAINER="${CONTAINER:-alert-api-db-1}"
+ENV_FILE="${ENV_FILE:-/home/alert_api/.env}"
+OUTPUT_DIR="${OUTPUT_DIR:-backups}"
+DATE=$(date +%Y%m%d_%H%M)
+
+# Run from repo root regardless of CWD
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$REPO_ROOT"
+
+if [ ! -f "${INVENTORY}" ]; then
+  echo "ERROR: inventory '${INVENTORY}' not found — run 'make prepare' first" >&2
+  exit 1
+fi
+
+# ====== RESOLVE SERVER IP FROM INVENTORY ======
+# Allow manual override; otherwise try local ansible-inventory; fall back to docker container.
+if [ -z "${SERVER_HOST:-}" ]; then
+  echo "Resolving IP for group ${GROUP} via Ansible inventory..."
+
+  if command -v ansible-inventory >/dev/null 2>&1; then
+    INV_JSON=$(ansible-inventory -i "${INVENTORY}" --list)
+  else
+    echo "  ansible-inventory not in PATH — using pyro-ansible docker container"
+    INV_JSON=$(docker compose run --rm -T pyro-ansible \
+      ansible-inventory -i "${INVENTORY}" --list 2>/dev/null)
+  fi
+
+  SERVER_HOST=$(echo "${INV_JSON}" | python3 -c "
+import json, sys
+data = sys.stdin.read()
+data = data[data.find('{'):]   # strip any entrypoint pre-output
+d = json.loads(data)
+host = d['${GROUP}']['hosts'][0]
+print(d['_meta']['hostvars'][host]['ansible_host'])
+")
+fi
+
+echo "Target: ${SSH_USER}@${SERVER_HOST}"
+
+# Quote remote-side values to survive spaces / shell metacharacters.
+Q_ENV_FILE=$(printf '%q' "${ENV_FILE}")
+Q_CONTAINER=$(printf '%q' "${CONTAINER}")
+
+# ====== READ DB CREDS FROM SERVER ======
+echo "Reading DB config from ${ENV_FILE}..."
+read_env_var() {
+  local key="$1"
+  ssh "${SSH_USER}@${SERVER_HOST}" \
+    "set -o pipefail; grep -E ^${key}= ${Q_ENV_FILE} | head -n1 | cut -d= -f2-"
+}
+
+PGUSER=$(read_env_var POSTGRES_USER)
+DB=$(read_env_var POSTGRES_DB)
+
+if [ -z "${PGUSER}" ] || [ -z "${DB}" ]; then
+  echo "ERROR: POSTGRES_USER or POSTGRES_DB missing in ${ENV_FILE}" >&2
+  exit 1
+fi
+
+Q_PGUSER=$(printf '%q' "${PGUSER}")
+Q_DB=$(printf '%q' "${DB}")
+
+mkdir -p "${OUTPUT_DIR}"
+OUTPUT_FILE="${OUTPUT_DIR}/${DB}_${DATE}.dump"
+TMP_FILE="${OUTPUT_FILE}.tmp.$$"
+trap 'rm -f "${TMP_FILE}"' EXIT INT TERM
+
+# ====== BACKUP ======
+echo "Starting backup of ${DB} (user=${PGUSER}) → ${OUTPUT_FILE}..."
+ssh "${SSH_USER}@${SERVER_HOST}" \
+  "sudo docker exec ${Q_CONTAINER} pg_dump -U ${Q_PGUSER} -d ${Q_DB} -Fc" \
+  > "${TMP_FILE}"
+
+# ====== VERIFY ======
+SIZE=$(stat -f%z "${TMP_FILE}" 2>/dev/null || stat -c%s "${TMP_FILE}")
+if [ "${SIZE}" -lt 1024 ]; then
+  echo "ERROR: backup file too small (${SIZE} bytes)" >&2
+  exit 1
+fi
+
+mv "${TMP_FILE}" "${OUTPUT_FILE}"
+trap - EXIT INT TERM
+echo "Backup OK: ${OUTPUT_FILE} (${SIZE} bytes)"