UBUNTU: [Packaging] provide a wrapper module for python-perf

BugLink: https://bugs.launchpad.net/bugs/2051560

Provide a virtual python module wrapper to load the actual versioned
python perf module, based on the running kernel version.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

debian/tools/python-perf.py

@@ -0,0 +1,32 @@
+import os
+import importlib.util
+from glob import glob
+
+class KernelNotFoundError(Exception):
+    def __init__(self):
+        kernel_version = os.uname().release
+        super().__init__(f"WARNING: python perf module not found for kernel {kernel_version}\n\n"
+                         f"You may need to install the following packages for this specific kernel:\n"
+                         f"  linux-tools-{kernel_version}-generic\n"
+                         f"You may also want to install of the following package to keep up to date:\n"
+                         f"  linux-tools-generic")
+
+# Extract ABI number from kernel version
+def _get_abi_version():
+    _kernel_version = os.uname().release
+    _parts = _kernel_version.split("-")
+    return "-".join(_parts[:-1])
+
+# Load the actual python-perf module for the running kernel
+_abi_version = _get_abi_version()
+_perf_dir = f"/usr/lib/python3/dist-packages/linux-tools-{_abi_version}"
+if not os.path.exists(_perf_dir):
+    raise KernelNotFoundError()
+_perf_lib = glob(os.path.join(_perf_dir, "*.so"))[-1]
+
+_spec = importlib.util.spec_from_file_location("perf", _perf_lib)
+_perf = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(_perf)
+
+# Expose the 'perf' module.
+__all__ = ['perf']