Sync engine (#298)

Fixes #261
2023-01-13 15:41:29 +01:00
parent de6f531e91
commit a56e14bff1
51 changed files with 1033 additions and 1418 deletions
@@ -0,0 +1,143 @@
+import { SpaceSync, SyncStatusItem } from "./sync.ts";
+import { DiskSpacePrimitives } from "./disk_space_primitives.ts";
+import { assertEquals } from "../../test_deps.ts";
+
+Deno.test("Test store", async () => {
+  const primaryPath = await Deno.makeTempDir();
+  const secondaryPath = await Deno.makeTempDir();
+  console.log("Primary", primaryPath);
+  console.log("Secondary", secondaryPath);
+  const primary = new DiskSpacePrimitives(primaryPath);
+  const secondary = new DiskSpacePrimitives(secondaryPath);
+  const statusMap = new Map<string, SyncStatusItem>();
+  const sync = new SpaceSync(primary, secondary, statusMap);
+
+  // Write one page to primary
+  await primary.writeFile("index", "utf8", "Hello");
+  assertEquals((await secondary.fetchFileList()).length, 0);
+  console.log("Initial sync ops", await doSync());
+
+  assertEquals((await secondary.fetchFileList()).length, 1);
+  assertEquals((await secondary.readFile("index", "utf8")).data, "Hello");
+
+  // Should be a no-op
+  assertEquals(await doSync(), 0);
+
+  // Now let's make a change on the secondary
+  await secondary.writeFile("index", "utf8", "Hello!!");
+  await secondary.writeFile("test", "utf8", "Test page");
+
+  // And sync it
+  await doSync();
+
+  assertEquals((await primary.fetchFileList()).length, 2);
+  assertEquals((await secondary.fetchFileList()).length, 2);
+
+  assertEquals((await primary.readFile("index", "utf8")).data, "Hello!!");
+
+  // Let's make some random edits on both ends
+  await primary.writeFile("index", "utf8", "1");
+  await primary.writeFile("index2", "utf8", "2");
+  await secondary.writeFile("index3", "utf8", "3");
+  await secondary.writeFile("index4", "utf8", "4");
+  await doSync();
+
+  assertEquals((await primary.fetchFileList()).length, 5);
+  assertEquals((await secondary.fetchFileList()).length, 5);
+
+  assertEquals(await doSync(), 0);
+
+  console.log("Deleting pages");
+  // Delete some pages
+  await primary.deleteFile("index");
+  await primary.deleteFile("index3");
+
+  await doSync();
+
+  assertEquals((await primary.fetchFileList()).length, 3);
+  assertEquals((await secondary.fetchFileList()).length, 3);
+
+  // No-op
+  assertEquals(await doSync(), 0);
+
+  await secondary.deleteFile("index4");
+  await primary.deleteFile("index2");
+
+  await doSync();
+
+  // Just "test" left
+  assertEquals((await primary.fetchFileList()).length, 1);
+  assertEquals((await secondary.fetchFileList()).length, 1);
+
+  // No-op
+  assertEquals(await doSync(), 0);
+
+  await secondary.writeFile("index", "utf8", "I'm back");
+
+  await doSync();
+
+  assertEquals((await primary.readFile("index", "utf8")).data, "I'm back");
+
+  // Cause a conflict
+  console.log("Introducing a conflict now");
+  await primary.writeFile("index", "utf8", "Hello 1");
+  await secondary.writeFile("index", "utf8", "Hello 2");
+
+  await doSync();
+
+  // Sync conflicting copy back
+  await doSync();
+
+  // Verify that primary won
+  assertEquals((await primary.readFile("index", "utf8")).data, "Hello 1");
+  assertEquals((await secondary.readFile("index", "utf8")).data, "Hello 1");
+
+  // test + index + index.conflicting copy
+  assertEquals((await primary.fetchFileList()).length, 3);
+  assertEquals((await secondary.fetchFileList()).length, 3);
+
+  // Introducing a fake conflict (same content, so not really conflicting)
+  await primary.writeFile("index", "utf8", "Hello 1");
+  await secondary.writeFile("index", "utf8", "Hello 1");
+
+  await doSync();
+  await doSync();
+
+  // test + index + previous index.conflicting copy but nothing more
+  assertEquals((await primary.fetchFileList()).length, 3);
+
+  console.log("Bringing a third device in the mix");
+
+  const ternaryPath = await Deno.makeTempDir();
+
+  console.log("Ternary", ternaryPath);
+
+  const ternary = new DiskSpacePrimitives(ternaryPath);
+  const sync2 = new SpaceSync(
+    secondary,
+    ternary,
+    new Map<string, SyncStatusItem>(),
+  );
+  console.log("N ops", await sync2.syncFiles());
+  await sleep(2);
+  assertEquals(await sync2.syncFiles(), 0);
+
+  await Deno.remove(primaryPath, { recursive: true });
+  await Deno.remove(secondaryPath, { recursive: true });
+  await Deno.remove(ternaryPath, { recursive: true });
+
+  async function doSync() {
+    await sleep();
+    const r = await sync.syncFiles(
+      SpaceSync.primaryConflictResolver,
+    );
+    await sleep();
+    return r;
+  }
+});
+
+function sleep(ms = 10): Promise<void> {
+  return new Promise((resolve) => {
+    setTimeout(resolve, ms);
+  });
+}