Provide file hashes in the URLs to avoid unnecessary file downloads (…

…bandwidth saver) (#1433)

Supply sha256 query parameters using boto3 to avoid hundreds of extra Gigabytes of downloads each day during pipenv and poetry resolution lock cycles.

Fixes point 1 in pytorch/pytorch#76557
Fixes #1347

s3_management/manage.py

@@ -1,20 +1,22 @@
 #!/usr/bin/env python
 
 import argparse
+import base64
+import dataclasses
+import functools
 import time
 
 from os import path, makedirs
 from datetime import datetime
 from collections import defaultdict
-from typing import Iterator, List, Type, Dict, Set, TypeVar, Optional
+from typing import Iterable, List, Type, Dict, Set, TypeVar, Optional
 from re import sub, match, search
 from packaging.version import parse
 
 import boto3
 
 
 S3 = boto3.resource('s3')
-CLIENT = boto3.client('s3')
 BUCKET = S3.Bucket('pytorch')
 
 ACCEPTED_FILE_EXTENSIONS = ("whl", "zip", "tar.gz")
@@ -107,6 +109,23 @@
 
 S3IndexType = TypeVar('S3IndexType', bound='S3Index')
 
+
+@dataclasses.dataclass(frozen=True)
+@functools.total_ordering
+class S3Object:
+    key: str
+    checksum: str | None
+
+    def __str__(self):
+        return self.key
+
+    def __eq__(self, other):
+        return self.key == other.key
+
+    def __lt__(self, other):
+        return self.key < other.key
+
+
 def extract_package_build_time(full_package_name: str) -> datetime:
     result = search(PACKAGE_DATE_REGEX, full_package_name)
     if result is not None:
@@ -124,7 +143,7 @@ def between_bad_dates(package_build_time: datetime):
 
 
 class S3Index:
-    def __init__(self: S3IndexType, objects: List[str], prefix: str) -> None:
+    def __init__(self: S3IndexType, objects: List[S3Object], prefix: str) -> None:
         self.objects = objects
         self.prefix = prefix.rstrip("/")
         self.html_name = PREFIXES_WITH_HTML[self.prefix]
@@ -134,7 +153,7 @@ def __init__(self: S3IndexType, objects: List[str], prefix: str) -> None:
             path.dirname(obj) for obj in objects if path.dirname != prefix
         }
 
-    def nightly_packages_to_show(self: S3IndexType) -> Set[str]:
+    def nightly_packages_to_show(self: S3IndexType) -> Set[S3Object]:
         """Finding packages to show based on a threshold we specify
 
         Basically takes our S3 packages, normalizes the version for easier
@@ -174,8 +193,8 @@ def nightly_packages_to_show(self: S3IndexType) -> Set[str]:
             if self.normalize_package_version(obj) in to_hide
         })
 
-    def is_obj_at_root(self, obj:str) -> bool:
-        return path.dirname(obj) == self.prefix
+    def is_obj_at_root(self, obj: S3Object) -> bool:
+        return path.dirname(str(obj)) == self.prefix
 
     def _resolve_subdir(self, subdir: Optional[str] = None) -> str:
         if not subdir:
@@ -187,7 +206,7 @@ def gen_file_list(
         self,
         subdir: Optional[str]=None,
         package_name: Optional[str] = None
-    ) -> Iterator[str]:
+    ) -> Iterable[S3Object]:
         objects = (
             self.nightly_packages_to_show() if self.prefix == 'whl/nightly'
             else self.objects
@@ -197,23 +216,23 @@ def gen_file_list(
             if package_name is not None:
                 if self.obj_to_package_name(obj) != package_name:
                     continue
-            if self.is_obj_at_root(obj) or obj.startswith(subdir):
+            if self.is_obj_at_root(obj) or str(obj).startswith(subdir):
                 yield obj
 
     def get_package_names(self, subdir: Optional[str] = None) -> List[str]:
         return sorted(set(self.obj_to_package_name(obj) for obj in self.gen_file_list(subdir)))
 
-    def normalize_package_version(self: S3IndexType, obj: str) -> str:
+    def normalize_package_version(self: S3IndexType, obj: S3Object) -> str:
         # removes the GPU specifier from the package name as well as
         # unnecessary things like the file extension, architecture name, etc.
         return sub(
             r"%2B.*",
             "",
-            "-".join(path.basename(obj).split("-")[:2])
+            "-".join(path.basename(str(obj)).split("-")[:2])
         )
 
-    def obj_to_package_name(self, obj: str) -> str:
-        return path.basename(obj).split('-', 1)[0]
+    def obj_to_package_name(self, obj: S3Object) -> str:
+        return path.basename(str(obj)).split('-', 1)[0]
 
     def to_legacy_html(
         self,
@@ -258,7 +277,8 @@ def to_simple_package_html(
         out.append('  <body>')
         out.append('    <h1>Links for {}</h1>'.format(package_name.lower().replace("_","-")))
         for obj in sorted(self.gen_file_list(subdir, package_name)):
-            out.append(f'    <a href="/{obj}">{path.basename(obj).replace("%2B","+")}</a><br/>')
+            maybe_fragment = f"#sha256={obj.checksum}" if obj.checksum else ""
+            out.append(f'    <a href="/{obj}{maybe_fragment}">{path.basename(obj).replace("%2B","+")}</a><br/>')
         # Adding html footer
         out.append('  </body>')
         out.append('</html>')
@@ -319,7 +339,6 @@ def upload_pep503_htmls(self) -> None:
                     Body=self.to_simple_package_html(subdir=subdir, package_name=pkg_name)
                 )
 
-
     def save_legacy_html(self) -> None:
         for subdir in self.subdirs:
             print(f"INFO Saving {subdir}/{self.html_name}")
@@ -351,10 +370,18 @@ def from_S3(cls: Type[S3IndexType], prefix: str) -> S3IndexType:
                 for pattern in ACCEPTED_SUBDIR_PATTERNS
             ]) and obj.key.endswith(ACCEPTED_FILE_EXTENSIONS)
             if is_acceptable:
+                # Add PEP 503-compatible hashes to URLs to allow clients to avoid spurious downloads, if possible.
+                response = obj.meta.client.head_object(Bucket=BUCKET.name, Key=obj.key, ChecksumMode="ENABLED")
+                sha256 = (_b64 := response.get("ChecksumSHA256")) and base64.b64decode(_b64).hex()
                 sanitized_key = obj.key.replace("+", "%2B")
-                objects.append(sanitized_key)
+                s3_object = S3Object(
+                    key=sanitized_key,
+                    checksum=sha256,
+                )
+                objects.append(s3_object)
         return cls(objects, prefix)
 
+
 def create_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser("Manage S3 HTML indices for PyTorch")
     parser.add_argument(
@@ -366,6 +393,7 @@ def create_parser() -> argparse.ArgumentParser:
     parser.add_argument("--generate-pep503", action="store_true")
     return parser
 
+
 def main():
     parser = create_parser()
     args = parser.parse_args()
@@ -390,5 +418,6 @@ def main():
             if args.generate_pep503:
                 idx.upload_pep503_htmls()
 
+
 if __name__ == "__main__":
     main()