u

src/store/healthcheck/check.js

@@ -0,0 +1,57 @@
+import * as mssqlQueries from '../../providers/mssql/queries/healthcheck.js';
+import * as sqliteQueries from '../../providers/sqlite3/queries/healthcheck.js';
+import makeRunner from '../runner.js';
+
+export default function check(provider) {
+  const isSqlite = provider?.dialect === 'sqlite3';
+  const queries = isSqlite ? sqliteQueries : mssqlQueries;
+
+  /**
+   * Executes a database health check:
+   * 1. Ensures the healthcheck table has one row (creates with sequence 0 if not).
+   * 2. Selects that row for update with minimal, reasonable locking within a transaction.
+   * 3. Updates the sequence by 1 in a separate statement within the transaction.
+   *
+   * @param {object} [tx] - Optional transaction to run within.
+   * @returns {Promise<{ok: boolean, sequence: number}>} The health check result.
+   *
+   * @example
+   * const result = await store.healthcheck.check();
+   * // => { ok: true, sequence: 1 }
+   */
+  return async (tx) => {
+    const runTx = async (runner) => {
+      // 1. Ensure table has one row, if not create that row with number 0
+      await runner.query(queries.ENSURE_ROW);
+
+      // 2. Select for update on that row with minimal, reasonable locking
+      const selected = await runner.query(queries.SELECT_FOR_UPDATE);
+      const row = selected.rows[0];
+      if (!row) {
+        throw new Error('Healthcheck row not found');
+      }
+
+      // 3. Updating the number by 1 and do an update (not in one statement, but in a tx)
+      const currentSeq = Number(row.sequence ?? 0);
+      const nextSeq = currentSeq + 1;
+
+      await runner.query(queries.UPDATE_SEQUENCE, {
+        id: row.id,
+        sequence: nextSeq,
+      });
+
+      return {
+        ok: true,
+        sequence: nextSeq,
+      };
+    };
+
+    if (tx) {
+      return runTx(makeRunner(provider, tx));
+    }
+    if (typeof provider?.transaction === 'function') {
+      return provider.transaction((runner) => runTx(makeRunner(provider, runner)));
+    }
+    return runTx(makeRunner(provider));
+  };
+}