Merge pull request #77 from facundobatista/unpacking-metadata

Save metadata related to the unpacking in the project's dir.

pyempaq/unpacker.py

@@ -14,6 +14,7 @@
 import shutil
 import subprocess
 import sys
+import time
 import venv
 import zipfile
 from types import ModuleType
@@ -91,6 +92,18 @@ def run_command(venv_bin_dir: pathlib.Path, cmd: List[str]) -> subprocess.Comple
     return subprocess.run(cmd, env=newenv)
 
 
+def get_file_hexdigest(filepath: pathlib.Path) -> str:
+    """Hash a file and return its hexdigest."""
+    hasher = hashlib.sha256()
+    with open(filepath, "rb") as fh:
+        while True:
+            data = fh.read(65536)
+            hasher.update(data)
+            if not data:
+                break
+    return hasher.hexdigest()
+
+
 def setup_project_directory(
     zf: zipfile.ZipFile,
     project_dir: pathlib.Path,
@@ -141,6 +154,17 @@ def setup_project_directory(
         log("Virtualenv setup finished")
     else:
         log("Skipping virtualenv (no requirements)")
+
+    # store unpacking metadata
+    zf_hash = get_file_hexdigest(zf.filename)
+    metadata = {
+        "pyz_path": str(zf.filename),
+        "pyz_hash": zf_hash,
+        "timestamp": time.time(),
+    }
+    (project_dir / "unpacking.json").write_text(json.dumps(metadata))
+
+    # save the flag for completeness
     (project_dir / COMPLETE_FLAG_FILE).touch()
 
 
@@ -170,14 +194,8 @@ def build_project_install_dir(zip_path: pathlib.Path, metadata: Dict[str, str]):
     project_name = metadata["project_name"]
 
     # get the first part of the hash of the file
-    hasher = hashlib.sha256()
-    with open(zip_path, "rb") as fh:
-        while True:
-            data = fh.read(65536)
-            hasher.update(data)
-            if not data:
-                break
-    file_hash_partial = hasher.hexdigest()[:20]
+    hexdigest = get_file_hexdigest(zip_path)
+    file_hash_partial = hexdigest[:20]
 
     # Python details
     py_impl = platform.python_implementation().lower()

tests/test_unpacker.py

@@ -5,8 +5,10 @@
 """Unpacker tests."""
 
 import hashlib
+import json
 import os
 import platform
+import time
 import zipfile
 from pathlib import Path
 from subprocess import CompletedProcess
@@ -237,6 +239,31 @@ def test_projectdir_requirements(tmp_path, logs):
     assert "Virtualenv setup finished" in logs.info
 
 
+def test_projectdir_metadata(tmp_path, logs):
+    """Project directory without special requirements."""
+    # fake a compressed project
+    compressed_project = tmp_path / "project.zip"
+    with zipfile.ZipFile(compressed_project, "w") as zf:
+        zf.writestr("fake_file", b"fake content")
+
+    # get its hash
+    zipfile_hash = hashlib.sha256(compressed_project.read_bytes()).hexdigest()
+
+    # unpack
+    zf = zipfile.ZipFile(compressed_project)
+    new_dir = tmp_path / "new_dir"
+    before_timestamp = time.time()
+    setup_project_directory(zf, new_dir, [])
+    after_timestamp = time.time()
+
+    # check metadata file
+    unpack_metadata = json.loads((new_dir / "unpacking.json").read_text())
+    assert unpack_metadata["pyz_path"] == str(compressed_project)
+    assert unpack_metadata["pyz_hash"] == zipfile_hash
+    stored_timestamp = unpack_metadata["timestamp"]
+    assert before_timestamp <= stored_timestamp <= after_timestamp
+
+
 # --- tests for enforcing the unpacking restrictions