Refactor the project's install directory name.

pyempaq/unpacker.py

@@ -4,6 +4,8 @@
 
 """Unpacking functionality.."""
 
+import hashlib
+import importlib
 import json
 import logging
 import os
@@ -12,7 +14,6 @@
 import shutil
 import subprocess
 import sys
-import time
 import venv
 import zipfile
 from types import ModuleType
@@ -33,6 +34,10 @@
     "restrictions_not_met": 64
 }
 
+# the real magic number is a byte sequence with "\r\n" at the end; it's built here
+# so it's easily patchable by tests
+MAGIC_NUMBER = importlib.util.MAGIC_NUMBER[:-2].hex()
+
 # setup logging
 logger = logging.getLogger()
 handler = logging.StreamHandler()
@@ -160,6 +165,28 @@ def restrictions_ok(version: ModuleType, restrictions: Dict[str, Any]) -> bool:
     return True
 
 
+def build_project_install_dir(zip_path: pathlib.Path, metadata: Dict[str, str]):
+    """Build the name of the directory where everything will be extracted."""
+    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]
+
+    # Python details
+    py_impl = platform.python_implementation().lower()
+    py_version = ".".join(platform.python_version_tuple()[:2])
+
+    name = f"{project_name}-{file_hash_partial}-{py_impl}.{py_version}.{MAGIC_NUMBER}"
+    return name
+
+
 def run():
     """Run the unpacker."""
     log("PyEmpaq start")
@@ -184,8 +211,7 @@ def run():
     log("Temp base dir: %r", str(pyempaq_dir))
 
     # create a temp dir and extract the project there
-    timestamp = time.strftime("%Y%m%d%H%M%S", time.gmtime(pyempaq_filepath.stat().st_ctime))
-    project_dir = pyempaq_dir / "{}-{}".format(metadata["project_name"], timestamp)
+    project_dir = pyempaq_dir / build_project_install_dir(pyempaq_filepath, metadata)
     original_project_dir = project_dir / "orig"
     venv_requirements = [original_project_dir / fname for fname in metadata["requirement_files"]]
     setup_project_directory(zf, project_dir, venv_requirements)

requirements-dev.txt

@@ -6,4 +6,5 @@ logassert
 packaging
 pydocstyle
 pytest
+pytest-mock
 pytest-subprocess

tests/test_unpacker.py

@@ -4,6 +4,7 @@
 
 """Unpacker tests."""
 
+import hashlib
 import os
 import platform
 import zipfile
@@ -19,6 +20,7 @@
 from pyempaq.unpacker import (
     PROJECT_VENV_DIR,
     build_command,
+    build_project_install_dir,
     restrictions_ok,
     run_command,
     setup_project_directory,
@@ -291,3 +293,24 @@ def test_enforcerestrictions_pythonversion_good_comparison(logs):
     """Enforce minimum python version using a proper comparison, not strings."""
     ok = restrictions_ok(version, {"minimum_python_version": "3.0009"})
     assert ok is True
+
+
+# --- tests for the project install dir name
+
+
+def test_installdirname_complete(mocker, tmp_path):
+    """Check the name is properly built."""
+    mocker.patch("platform.python_implementation", return_value="PyPy")
+    mocker.patch("platform.python_version_tuple", return_value=("3", "18", "7alpha"))
+    mocker.patch("pyempaq.unpacker.MAGIC_NUMBER", "xyz")
+
+    zip_path = tmp_path / "somestuff.zip"
+    content = b"some content to be hashed"
+    zip_path.write_bytes(content)
+    content_hash = hashlib.sha256(content).hexdigest()
+
+    fake_metadata = {"foo": "bar", "project_name": "testproj"}
+
+    dirname = build_project_install_dir(zip_path, fake_metadata)
+
+    assert dirname == f"testproj-{content_hash[:20]}-pypy.3.18.xyz"