Fix #12, wait for DB migrations to finish before attempting to use the database

src/lib/server/db.ts

@@ -5,11 +5,12 @@ import { isTruthy } from '$lib/truthyString';
 import sqlite3 from 'sqlite3';
 const { DEV } = import.meta.env;
 
-const db: sqlite3.Database = new sqlite3.Database('moshingmammut.db');
+const db: sqlite3.Database = new sqlite3.Database('moshingmammut3.db');
 const ignoredUsers: string[] =
   IGNORE_USERS === undefined
     ? []
     : IGNORE_USERS.split(',').map((u) => (u.startsWith('@') ? u.substring(1) : u));
+let databaseReady = false;
 
 if (DEV && isTruthy(env.VERBOSE)) {
   sqlite3.verbose();
@@ -39,13 +40,25 @@ db.on('open', () => {
   db.all('SELECT id FROM migrations', (err, rows) => {
     if (err !== null) {
       console.error('Could not fetch existing migrations', err);
+      databaseReady = true;
       return;
     }
     console.debug('Already applied migrations', rows);
     const appliedMigrations: Set<number> = new Set(rows.map((row: any) => row['id']));
     const toApply = getMigrations().filter((m) => !appliedMigrations.has(m.id));
+    let remaining = toApply.length;
+    if (remaining === 0) {
+      databaseReady = true;
+      return;
+    }
     for (const migration of toApply) {
       db.exec(migration.statement, (err) => {
+        remaining--;
+        // This will set databaseReady to true before the migration has been inserted as applies,
+        // but that doesn't matter. It's only important that is has been applied
+        if (remaining === 0) {
+          databaseReady = true;
+        }
         if (err !== null) {
           console.error(`Failed to apply migration ${migration.name}`, err);
           return;
@@ -104,7 +117,28 @@ function getMigrations(): Migration[] {
   ];
 }
 
+async function waitReady(): Promise<undefined> {
+  // Simpler than a semaphore and is really only needed on startup
+  return new Promise((resolve) => {
+    const interval = setInterval(() => {
+      if (DEV) {
+        console.debug('Waiting for database to be ready');
+      }
+      if (databaseReady) {
+        if (DEV) {
+          console.debug('DB is ready');
+        }
+        clearInterval(interval);
+        resolve(undefined);
+      }
+    }, 100);
+  });
+}
+
 export async function savePost(post: Post): Promise<undefined> {
+  if (!databaseReady) {
+    await waitReady();
+  }
   return new Promise((resolve, reject) => {
     console.debug(`Saving post ${post.url}`);
     const account = post.account;
@@ -198,6 +232,9 @@ export async function savePost(post: Post): Promise<undefined> {
 }
 
 export async function getPosts(since: string | null, before: string | null, limit: number) {
+  if (!databaseReady) {
+    await waitReady();
+  }
   const promise = await new Promise<Post[]>((resolve, reject) => {
     let filter_query = '';
     const params: any = { $limit: limit };

src/routes/+page.svelte

@@ -155,7 +155,7 @@
   <div />
   <div class="posts">
     {#if data.posts.length === 0}
-      Sorry, no posts recommending music aave been found yet
+      Sorry, no posts recommending music have been found yet
     {/if}
     {#each data.posts as post (post.url)}
       <div