Add automated schema management

schema/init/meta.sql

@@ -1,2 +1 @@
 create table "meta" ("schemaver" integer not null);
-insert into "meta" values (6);

src/checkdb.ts

@@ -0,0 +1,135 @@
+import { readdirSync, readFileSync } from "fs";
+import logger from "debug";
+import { resolve } from "path";
+import sql from "sql-bricks-postgres";
+
+import { DataSource, Transaction } from "./sql";
+
+const scripts = [
+  // Order matters! Later scripts reference schema instantiated earlier.
+  "meta.sql",
+  "aime.sql",
+  "idz.sql",
+];
+
+const debug = logger("app:checkdb");
+const initPath = "./schema/init";
+const migratePath = "./schema/migrate";
+const migrateRx = new RegExp("^M([0-9]{4})-.+\\.sql$");
+
+async function initdb(txn: Transaction): Promise<void> {
+  // Get latest schemaver from migration script filenames
+
+  const migrations = readdirSync(migratePath);
+  let schemaver = 0;
+
+  for (const filename of migrations) {
+    const captures = filename.match(migrateRx);
+
+    if (captures === null) {
+      continue;
+    }
+
+    const migrationNo = parseInt(captures[1]);
+
+    if (schemaver < migrationNo) {
+      schemaver = migrationNo;
+    }
+  }
+
+  // Run init scripts
+
+  debug("Initializing database");
+
+  for (const script of scripts) {
+    debug(`Executing ${script}`);
+
+    const scriptPath = resolve(initPath, script);
+    const scriptSql = readFileSync(scriptPath, "utf-8");
+
+    await txn.raw(scriptSql);
+  }
+
+  // Set up metadata table
+
+  const metaInsert = sql.insert("meta", { schemaver });
+
+  await txn.modify(metaInsert);
+
+  debug(`Initialized new database to schema version ${schemaver}`);
+}
+
+async function migratedb(
+  txn: Transaction,
+  schemaver: number
+): Promise<number | undefined> {
+  const filenames = readdirSync(migratePath);
+  let lastMigrationNo: number | undefined;
+
+  filenames.sort();
+
+  for (const filename of filenames) {
+    const captures = filename.match(migrateRx);
+
+    if (captures === null) {
+      debug(`Warning: Unexpected file ${filename} in SQL migrations dir`);
+
+      continue;
+    }
+
+    const migrationNo = parseInt(captures[1]);
+
+    if (migrationNo <= schemaver) {
+      continue;
+    }
+
+    debug(`Executing database upgrade: ${filename}`);
+
+    const scriptPath = resolve(migratePath, filename);
+    const scriptSql = readFileSync(scriptPath, "utf-8");
+
+    await txn.raw(scriptSql);
+
+    lastMigrationNo = migrationNo;
+  }
+
+  if (lastMigrationNo !== undefined) {
+    const metaUpdate = sql.update("meta", { schemaver: lastMigrationNo });
+
+    await txn.modify(metaUpdate);
+  }
+
+  return lastMigrationNo;
+}
+
+export default async function checkdb(db: DataSource): Promise<void> {
+  const stmt = sql.select("schemaver").from("meta");
+  let maybe: number | undefined;
+
+  try {
+    const row = await db.transaction(txn => txn.fetchRow(stmt));
+
+    if (row !== undefined) {
+      maybe = parseInt(row.schemaver);
+    }
+  } catch (e) {
+    return db.transaction(initdb);
+  }
+
+  if (maybe === undefined) {
+    throw new Error(
+      "Database corrupted: `meta` table singleton row is missing"
+    );
+  }
+
+  const schemaver = maybe;
+  const newver = await db.transaction(txn => migratedb(txn, schemaver));
+
+  if (newver !== undefined) {
+    debug(`Upgraded database to version ${newver}`);
+
+    await db.vacuum();
+
+    debug("Post-upgrade housekeeping complete");
+  }
+}