homeio

1import { mkdtemp, writeFile } from "node:fs/promises";
2import os from "node:os";
3import path from "node:path";
4import { beforeEach, describe, expect, it } from "vitest";
5import { readTailLines } from "@/lib/server/modules/logs/service";
6
7let dir: string;
8
9async function logFile(content: string) {
10  const filePath = path.join(dir, "home-server.log");
11  await writeFile(filePath, content, "utf8");
12  return filePath;
13}
14
15function numberedLines(count: number, width = 0) {
16  return Array.from({ length: count }, (_, i) => `{"n":${i + 1},"pad":"${"x".repeat(width)}"}`);
17}
18
19describe("readTailLines", () => {
20  beforeEach(async () => {
21    dir = await mkdtemp(path.join(os.tmpdir(), "homeio-logs-"));
22  });
23
24  it("returns the last lines of a small file", async () => {
25    const file = await logFile(`${numberedLines(10).join("\n")}\n`);
26
27    expect(await readTailLines(file, 3)).toEqual(numberedLines(10).slice(-3));
28  });
29
30  it("returns every line when the file has fewer than asked", async () => {
31    const file = await logFile("one\ntwo\n");
32
33    expect(await readTailLines(file, 500)).toEqual(["one", "two"]);
34  });
35
36  it("reads only the end of a file much larger than one chunk", async () => {
37    // ~9 MB: 60k lines of ~150 bytes, crossing many 64 KB chunk boundaries.
38    const lines = numberedLines(60_000, 130);
39    const file = await logFile(`${lines.join("\n")}\n`);
40
41    expect(await readTailLines(file, 500)).toEqual(lines.slice(-500));
42  });
43
44  it("keeps the last line when the file does not end with a newline", async () => {
45    const file = await logFile("one\ntwo\nthree");
46
47    expect(await readTailLines(file, 2)).toEqual(["two", "three"]);
48  });
49
50  it("skips empty lines", async () => {
51    const file = await logFile("one\n\n  \ntwo\n\n");
52
53    expect(await readTailLines(file, 5)).toEqual(["one", "two"]);
54  });
55
56  it("keeps multi-byte characters whole across chunk boundaries", async () => {
57    // 3-byte characters, so some of them straddle a 64 KB boundary.
58    const lines = Array.from({ length: 3_000 }, (_, i) => `${i} ${"€".repeat(40)}`);
59    const file = await logFile(`${lines.join("\n")}\n`);
60
61    expect(await readTailLines(file, 2_000)).toEqual(lines.slice(-2_000));
62  });
63
64  it("returns nothing for a missing file", async () => {
65    expect(await readTailLines(path.join(dir, "missing.log"), 500)).toEqual([]);
66  });
67});
68