Merge pull request #56 from dramforever/add-nix-channels

Update nix channels

nix-channels.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import hashlib
+import json
 import logging
 import lzma
 import os
@@ -11,6 +12,7 @@ import subprocess
 from pyquery import PyQuery as pq
 from datetime import datetime, timedelta
 from pathlib import Path
+from concurrent.futures import ThreadPoolExecutor
 
 from urllib3.util.retry import Retry
 
@@ -26,6 +28,11 @@ else:
     MIRROR_BASE_URL = os.getenv("MIRROR_BASE_URL", 'https://mirrors.tuna.tsinghua.edu.cn/nix-channels')
     WORKING_DIR = os.getenv("TUNASYNC_WORKING_DIR", 'working-channels')
 
+PATH_BATCH = int(os.getenv('NIX_MIRROR_PATH_BATCH', 8192))
+THREADS = int(os.getenv('NIX_MIRROR_THREADS', 10))
+DELETE_OLD = os.getenv('NIX_MIRROR_DELETE_OLD', '1') == '1'
+RETAIN_DAYS = float(os.getenv('NIX_MIRROR_RETAIN_DAYS', 30))
+
 STORE_DIR = 'store'
 RELEASES_DIR = 'releases'
 CLONE_SINCE = datetime(2018, 12, 1)
@@ -258,6 +265,9 @@ def clone_channels():
 
     return channels_to_update
 
+def hash_part(path):
+    return path.split('/')[-1].split('-', 1)[0]
+
 def update_channels(channels):
     logging.info(f'- Updating binary cache')
 
@@ -266,9 +276,11 @@ def update_channels(channels):
     for channel in channels:
         logging.info(f'  - {channel}')
 
+        chan_path = working_dir / channel
         chan_path_update = working_dir / f'.{channel}.update'
 
         upstream_binary_cache = (chan_path_update / '.original-binary-cache-url').read_text()
+        upstream_binary_cache = upstream_binary_cache.rstrip('/')
 
         # All the channels should have https://cache.nixos.org as binary cache
         # URL. We download nix-cache-info here (once per sync) to avoid
@@ -287,34 +299,144 @@ def update_channels(channels):
 
         logging.info(f'    - {len(paths)} paths listed')
 
-        # xargs can splits up the argument lists and invokes nix copy multiple
-        # times to avoid E2BIG (Argument list too long)
-        nix_process = subprocess.Popen(
-            [ 'xargs', 'nix', 'copy',
-                '--from', upstream_binary_cache,
-                '--to', nix_store_dest,
-                '--verbose'
-            ],
-            universal_newlines=True,
-            stdin=subprocess.PIPE
-        )
+        todo = {}
+        channel_failure = False
 
-        for path in paths:
-            nix_process.stdin.write(path.decode() + '\n')
+        # Batch paths to avoid E2BIG
 
-        retcode = nix_process.wait()
-
-        if retcode == 0:
-            chan_path_update.rename(working_dir / channel)
-            logging.info(f'    - Done')
+        for i in range(0, len(paths), PATH_BATCH):
+            batch = paths[i : i + PATH_BATCH]
+            process = subprocess.run(
+                [
+                    'nix', 'path-info',
+                    '--store', upstream_binary_cache,
+                    '--recursive', '--json'
+                ] + batch,
+                stdout=subprocess.PIPE
+            )
+            if process.returncode != 0:
+                channel_failure = True
+                logging.info(f'    - Error status: {process.returncode}')
+                break
         else:
-            global failure
-            failure = True
+            infos = json.loads(process.stdout)
+            for info in infos:
+                ha = hash_part(info['path'])
+                todo[ha] = (info['url'], f'{ha}.narinfo')
 
-            logging.info(f'    - nix copy failed')
+            logging.info(f'    - {len(todo)} paths to download')
+
+            digits = len(str(len(todo)))
+
+            def try_mirror(index, paths):
+                index += 1
+                prefix = f'[{str(index).rjust(digits)}/{len(todo)}]'
+                try:
+                    for path in paths:
+                        url = f'{upstream_binary_cache}/{path}'
+                        dest = working_dir / STORE_DIR / path
+                        if dest.exists(): continue
+                        download(url, dest)
+                        logging.info(f'    - {prefix} {path}')
+                    return True
+                except (requests.exceptions.ConnectionError, WrongSize):
+                    return False
+
+            with ThreadPoolExecutor(max_workers=THREADS) as executor:
+                results = executor.map(
+                    lambda job: try_mirror(*job),
+                    enumerate(todo.values())
+                )
+                if not all(results):
+                    channel_failure = True
+
+        if channel_failure:
+            logging.info(f'    - Finished with errors, not updating symlink')
+        else:
+            chan_path_update.rename(chan_path)
+            logging.info(f'    - Finished with success, symlink updated')
+
+def parse_narinfo(narinfo):
+    res = {}
+    for line in narinfo.splitlines():
+        key, value = line.split(': ', 1)
+        res[key] = value
+    return res
+
+def garbage_collect():
+    logging.info(f'- Collecting garbage')
+
+    time_threshold = datetime.now() - timedelta(days=RETAIN_DAYS)
+
+    last_updated = {}
+    latest = {}
+    alive = set()
+
+    for release in (working_dir / RELEASES_DIR).iterdir():
+        channel = release.name.split('@')[0]
+        date_str = (release / '.released-time').read_text()
+        released_date = datetime.strptime(date_str, '%Y-%m-%d %H:%M:%S')
+
+        if released_date >= time_threshold:
+            alive.add(release)
+
+        if channel not in last_updated \
+            or last_updated[channel] < released_date:
+            last_updated[channel] = released_date
+            latest[channel] = release
+
+    alive.update(latest.values())
+
+    logging.info(f'  - {len(alive)} releases alive')
+
+    closure = set()
+
+    for release in alive:
+        with lzma.open(str(release / 'store-paths.xz')) as f:
+            paths = [ path.rstrip() for path in f ]
+
+        for i in range(0, len(paths), PATH_BATCH):
+            batch = paths[i : i + PATH_BATCH]
+
+            process = subprocess.run(
+                [
+                    'nix', 'path-info',
+                    '--store', nix_store_dest,
+                    '--recursive'
+                ] + batch,
+                stdout=subprocess.PIPE
+            )
+
+            for path in process.stdout.decode().splitlines():
+                closure.add(hash_part(path))
+
+    logging.info(f'  - {len(closure)} paths in closure')
+
+    deleted = 0
+
+    for path in (working_dir / STORE_DIR).iterdir():
+        if not path.name.endswith('.narinfo'):
+            continue
+
+        hash = path.name.split('.narinfo', 1)[0]
+        if hash in closure:
+            continue
+
+        deleted += 1
+
+        if DELETE_OLD:
+            narinfo = parse_narinfo(path.read_text())
+            path.unlink(missing_ok=True)
+            (working_dir / STORE_DIR / narinfo['URL']).unlink(missing_ok=True)
+
+    if DELETE_OLD:
+        logging.info(f'  - {deleted} paths deleted')
+    else:
+        logging.info(f'  - {deleted} paths now unreachable')
 
 if __name__ == '__main__':
     channels = clone_channels()
     update_channels(channels)
+    garbage_collect()
     if failure:
         sys.exit(1)