[build] use bazel to update python requirements

Author: titusfortner

Rakefile

@@ -563,6 +563,14 @@ namespace :py do
     @git.add(conf)
   end
 
+  desc 'Update Python dependencies'
+  task :update do
+    Bazel.execute('run', [], '//scripts:update_py_deps')
+    Bazel.execute('run', [], '//py:requirements.update')
+    @git.add('py/requirements.txt')
+    @git.add('py/requirements_lock.txt')
+  end
+
   namespace :test do
     desc 'Python unit tests'
     task :unit do

scripts/BUILD.bazel

@@ -47,6 +47,11 @@ py_binary(
     ],
 )
 
+py_binary(
+    name = "update_py_deps",
+    srcs = ["update_py_deps.py"],
+)
+
 java_binary(
     name = "google-java-format",
     jvm_flags = [

scripts/update_py_dependencies.sh

@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+
+import json
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+# Updates py/requirements.txt with latest compatible versions using pip
+# Run with: bazel run //scripts:update_py_deps
+
+
+def main():
+    script_dir = Path(__file__).resolve().parent
+    requirements_file = script_dir.parent / "py" / "requirements.txt"
+
+    if not requirements_file.exists():
+        print(f"Error: {requirements_file} not found")
+        return
+
+    print(f"Checking {requirements_file}")
+
+    # Parse current requirements preserving original format
+    current_lines = requirements_file.read_text().strip().split("\n")
+    packages = []  # (original_line, package_name_with_extras, package_name_normalized)
+    for line in current_lines:
+        line = line.strip()
+        if line and not line.startswith("#") and "==" in line:
+            name_with_extras, version = line.split("==", 1)
+            # Normalize: remove extras for pip queries
+            name_normalized = name_with_extras.split("[")[0].lower()
+            packages.append((line, name_with_extras, name_normalized))
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        venv_dir = Path(tmpdir) / "venv"
+
+        # Create virtual environment
+        print("Creating temporary virtual environment...")
+        subprocess.run(
+            [sys.executable, "-m", "venv", str(venv_dir)],
+            check=True,
+            capture_output=True,
+        )
+
+        pip = venv_dir / "bin" / "pip"
+
+        # Upgrade pip first
+        subprocess.run(
+            [str(pip), "install", "-q", "--upgrade", "pip"],
+            check=True,
+            capture_output=True,
+        )
+
+        # Install packages (with extras) to let pip resolve versions
+        install_names = [p[1] for p in packages]  # name_with_extras
+        print(f"Installing {len(install_names)} packages...")
+        result = subprocess.run(
+            [str(pip), "install", "-q"] + install_names,
+            capture_output=True,
+            text=True,
+        )
+        if result.returncode != 0:
+            print(f"Error installing packages:\n{result.stderr}")
+            return
+
+        # Get installed versions
+        result = subprocess.run(
+            [str(pip), "list", "--format=json"],
+            capture_output=True,
+            text=True,
+            check=True,
+        )
+        installed = {pkg["name"].lower(): pkg["version"] for pkg in json.loads(result.stdout)}
+
+        # Update versions in original lines
+        updated_lines = []
+        updates = []
+        for orig_line, name_with_extras, name_normalized in packages:
+            old_version = orig_line.split("==")[1]
+            new_version = installed.get(name_normalized)
+
+            if new_version and new_version != old_version:
+                updates.append((name_with_extras, old_version, new_version))
+                updated_lines.append(f"{name_with_extras}=={new_version}")
+                print(f"  {name_with_extras}: {old_version} -> {new_version}")
+            else:
+                updated_lines.append(orig_line)
+
+        if not updates:
+            print("\nAll packages are up to date!")
+            return
+
+        # Rebuild file preserving non-package lines
+        new_content = []
+        pkg_idx = 0
+        for line in current_lines:
+            stripped = line.strip()
+            if stripped and not stripped.startswith("#") and "==" in stripped:
+                new_content.append(updated_lines[pkg_idx])
+                pkg_idx += 1
+            else:
+                new_content.append(line)
+
+        requirements_file.write_text("\n".join(new_content) + "\n")
+        print(f"\nUpdated {len(updates)} package(s)")
+        print("\nNow run: bazel run //py:requirements.update")
+
+
+if __name__ == "__main__":
+    main()