89 lines
3.2 KiB
Python
89 lines
3.2 KiB
Python
#!/usr/bin/env python3
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r"""chunk_dl.py — 分片并行下载器（断点续传），2026-11-03 CI 迁移批收编。
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背景：GitHub 直连在本项目两台机器均不可用，加速镜像站速度慢且会掐连接/回错误页。
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本件把大文件切成 N 片经镜像并行拉取（单片断了自动续传重试），全部齐后拼合。
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已实证：74MB Godot Linux 包约 15 分钟拉完（2026-11-03 mac_setup 依赖此件拉 Godot macOS 包）。
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用法: python3 tools/ci/chunk_dl.py <URL> <输出路径> [分片数=16]
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镜像回落顺序：直连 → gh-proxy.net → gh-proxy.com（HEAD 探测 Content-Length 决定实际用的源）。
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校验：分片按字节范围落盘、按序拼合；zip 结构校验由调用方（mac_setup.sh 的 unzip -tq）承担。
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退出码：0=成功 1=失败。
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"""
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import concurrent.futures as cf
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import os
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import subprocess
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import sys
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MIRRORS = ["", "https://gh-proxy.net/", "https://gh-proxy.com/"]
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def pick_mirror(url: str):
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"""HEAD 探测取 Content-Length；返回（实际可用 URL, 字节数）或 (None, 0)。"""
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for m in MIRRORS:
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u = m + url
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r = subprocess.run(["curl", "-sIL", "-m", "30", u], capture_output=True, text=True)
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size = 0
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for line in r.stdout.splitlines():
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if line.lower().startswith("content-length:"):
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try:
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size = int(line.split(":", 1)[1].strip())
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except ValueError:
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size = 0
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if size > 0:
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return u, size
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return None, 0
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def fetch(job) -> bool:
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i, s, e, url, out = job
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p = "%s.part%02d" % (out, i)
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want = e - s + 1
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for _attempt in range(200):
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have = os.path.getsize(p) if os.path.exists(p) else 0
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if have >= want:
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return True
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r0 = s + have
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subprocess.run(
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["curl", "-sL", "--speed-limit", "1024", "--speed-time", "30",
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"-m", "600", "-r", "%d-%d" % (r0, e), "-o", p + ".new", url],
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capture_output=True)
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if os.path.exists(p + ".new"):
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with open(p, "ab") as f, open(p + ".new", "rb") as g:
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f.write(g.read())
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os.remove(p + ".new")
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return False
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def main() -> int:
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if len(sys.argv) < 3:
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print("用法: python3 chunk_dl.py <URL> <输出路径> [分片数=16]")
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return 1
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url, out = sys.argv[1], sys.argv[2]
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n = int(sys.argv[3]) if len(sys.argv) > 3 else 16
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real, size = pick_mirror(url)
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if not real:
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print("全部下载源失败")
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return 1
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print("size=%d url=%s" % (size, real), flush=True)
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chunk = (size + n - 1) // n
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jobs = [(i, i * chunk, min((i + 1) * chunk, size) - 1, real, out)
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for i in range(n) if i * chunk < size]
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with cf.ThreadPoolExecutor(n) as ex:
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for ok in ex.map(fetch, jobs):
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if not ok:
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print("分片重试耗尽")
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return 1
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with open(out, "wb") as f:
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for i, _, _, _, _ in jobs:
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with open("%s.part%02d" % (out, i), "rb") as g:
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f.write(g.read())
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for i, _, _, _, _ in jobs:
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os.remove("%s.part%02d" % (out, i))
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print("done %d" % os.path.getsize(out))
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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