Limit daemon-wide Git process pressure (#2797)

* perf(server): bound Git process starts Git refresh bursts could keep creating short-lived processes at the concurrency ceiling, causing sustained process churn on constrained hosts. Apply one daemon-global start-rate and concurrency policy to every Git command while preserving the legacy concurrency environment variable. * build(nix): update npm dependency hash * fix(server): hold Git slots until process exit * fix(server): enforce Git limits across process lifetime * fix(server): align Git metrics with process exit * Fix Git limiter test deadlocks * Tune default Git process rate
2026-08-02 19:59:43 +02:00
parent f682156302
commit 2e188787ff
23 changed files with 822 additions and 225 deletions
@@ -0,0 +1,90 @@
+import { afterEach, describe, expect, test, vi } from "vitest";
+
+import { GitProcessScheduler, resolveGitProcessPolicy } from "./git-process-scheduler.js";
+
+function createConcurrencyTask(
+  index: number,
+  started: number[],
+  releases: Array<() => void>,
+): () => { result: Promise<void>; exited: Promise<void> } {
+  return () => {
+    started.push(index);
+    if (index >= 2) {
+      const completed = Promise.resolve();
+      return { result: completed, exited: completed };
+    }
+    const completed = new Promise<void>((resolve) => {
+      releases.push(resolve);
+    });
+    return { result: completed, exited: completed };
+  };
+}
+
+describe("GitProcessScheduler", () => {
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  test("limits unresolved processes independently of their start rate", async () => {
+    const scheduler = new GitProcessScheduler({
+      maxProcessesPerSecond: 100,
+      maxProcessConcurrency: 2,
+    });
+    const releases: Array<() => void> = [];
+    const started: number[] = [];
+    const tasks = Array.from({ length: 4 }, (_, index) =>
+      scheduler.run(createConcurrencyTask(index, started, releases)),
+    );
+
+    await vi.waitFor(() => expect(started).toEqual([0, 1]));
+    releases.shift()?.();
+    await vi.waitFor(() => expect(started).toContain(2));
+    releases.shift()?.();
+    await Promise.all(tasks);
+
+    expect(scheduler.activeCount).toBe(0);
+    expect(scheduler.pendingCount).toBe(0);
+  });
+
+  test("limits process starts in each strict one-second interval", async () => {
+    vi.useFakeTimers();
+    const scheduler = new GitProcessScheduler({
+      maxProcessesPerSecond: 2,
+      maxProcessConcurrency: 4,
+    });
+    const startedAt: number[] = [];
+    const recordStart = () => {
+      startedAt.push(Date.now());
+      const completed = Promise.resolve();
+      return { result: completed, exited: completed };
+    };
+    const tasks = Array.from({ length: 4 }, () => scheduler.run(recordStart));
+
+    await vi.advanceTimersByTimeAsync(0);
+    expect(startedAt).toHaveLength(2);
+    await vi.advanceTimersByTimeAsync(999);
+    expect(startedAt).toHaveLength(2);
+    await vi.advanceTimersByTimeAsync(1);
+    expect(startedAt).toHaveLength(3);
+    await vi.advanceTimersByTimeAsync(500);
+    await Promise.all(tasks);
+
+    expect(startedAt).toHaveLength(4);
+    expect(startedAt[2]! - startedAt[0]!).toBeGreaterThanOrEqual(1_000);
+  });
+});
+
+describe("resolveGitProcessPolicy", () => {
+  test("prefers renamed environment variables over legacy and persisted values", () => {
+    expect(
+      resolveGitProcessPolicy({
+        env: {
+          PASEO_GIT_MAX_PROCESSES_PER_SECOND: "12",
+          PASEO_GIT_MAX_PROCESS_CONCURRENCY: "7",
+          PASEO_GIT_CONCURRENCY: "3",
+        },
+        persisted: { maxProcessesPerSecond: 5, maxProcessConcurrency: 4 },
+      }),
+    ).toEqual({ maxProcessesPerSecond: 12, maxProcessConcurrency: 7 });
+  });
+});