Add the new Xen-Bugtool Test Environment

Signed-off-by: Bernhard Kaindl <[email protected]>

.github/workflows/main.yml

@@ -14,7 +14,7 @@ env:
   PYTHONDEVMODE: yes
 jobs:
   python-checks:
-    name: Python checks
+    name: Run the Xen-Bugtool Test Environment
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout code
@@ -32,5 +32,5 @@ jobs:
 
       - name: Run pylint-1.9.4 for pylint --py3k linting (configured in .pylintrc)
         run: python2 -m pylint xen-bugtool
-      - name: Run python2 -m pytest to execute unit tests
-        run: python2 -m pytest
+      - name: Run python2 -m pytest to execute all unit and integration tests
+        run: python2 -m pytest -v -rA

.pylintrc

@@ -25,6 +25,7 @@ analyse-fallback-blocks=yes
 # be loaded. Extensions are loading into the active Python interpreter and may
 # run arbitrary code.
 extension-pkg-allow-list=xen.lowlevel
+extension-pkg-whitelist=lxml.etree
 
 # Return non-zero exit code if any of these messages/categories are detected,
 # even if score is above --fail-under value. Syntax same as enable. Messages

README-pytest.md

@@ -0,0 +1,84 @@
+# Guide to Setting Up and Running the Xen-Bugtool Test Environment
+
+This document provides detailed information about the test environment for `xen-bugtool`,
+a tool designed to assist with debugging XenServer issues.
+The test environment runs `xen-bugtool` in a container with simulated `root` capabilities,
+allowing it to be run by any regular user without requiring special system configuration.
+
+This document guides you through the setup of the container and the execution of each test case.
+
+## Lessons Learned from the Initial Prototype
+
+The initial shell-based tests were quick to create, but were only meant as an early prototype.
+These tests required an external environment with root privileges (preferably a container) to run.
+Additionally, failed checks because of mismatched file paths could go unnoticed,
+leading to tests passing even when the `bugtool` output was not properly verified.
+
+## Installing Packages to Run the Xen-Bugtool Test Environment
+
+Ensure that `pip` is installed in your `python2.7` environment. Same for Python3, but it's optional.
+
+Install the libraries required by `xen-bugtool` with the following command:
+
+```sh
+# Install the libraries required to run `xen-bugtool` itself into your environment:
+python2 -m pip install --user -r requirements.txt
+```
+
+The test framework itself can use Python2 or Python3.
+Depending on the installed builds, you can install one or both:
+
+```sh
+# Install pytest and its depdendencies into your environment:
+python2 -m pip install --user -r requirements-dev.txt # and/or:
+python3 -m pip install --user -r requirements-dev.txt
+```
+
+## Running the Xen-Bugtool Test Environment
+
+```py
+# Run the Xen-Bugtool Test Environment
+python3 -m pytest tests/integration
+```
+Hint: `python2 -m pytest` could be used too, but it may run into problems on CentOS 8.0.
+
+## Implementation of the Xen-Bugtool Test Environment in Pytest
+
+This section provides detailed information about the test environment for `xen-bugtool`.
+It explains how the container is set up and how each test case is executed.
+
+The test environment is implemented by automatic `pytest` fixtures creating a container for the `pytest` process session and its sub-processes.
+A fresh instance of a clean `bugtool` output directory (located at `/var/opt/xen/bug-report`)
+is provided for invocation of the test functions.
+
+## Container Setup
+
+The container is implemented in [tests/integration/namespace_container.py](tests/integration/namespace_container.py).
+
+`xen-bugtool` requires to be run as root and checks it and writes its output to `/var/opt/xen/bug-report`.
+The container setup provides these root privileges and a new mount namespace to bind-mount the test files.
+It allows to bind-mount the directory trees with test files at the places where `xen-bugtool` collects them.
+The mount namespace also allows to create a `tmpfs` mount for the output data.
+It avoids the need to create a temporary directory and to bind-mount it into the container
+Additionally, it ensures that no temporary data can accumulate on the host.
+
+It implements the equivalent of `/usr/bin/unshare --map-root-user --mount --net` and mounts test directories:
+
+- `--map-root-user`: Creates a Linux user namespace where the effective user and group IDs of the current user are mapped to the superuser UID and GID.
+- `--mount`: Creates a Linux mount namespace for mounting temporary file systems and bind-mounting test data.
+- `--net`: Creates a Linux network namespace to ensure that `bugtool` works without outside connectivity.
+
+The container then bind-mounts the directory trees from [tests/integration/dom0-template](tests/integration/dom0-template) into the container.
+This means the object under test (`xen-bugtool`) runs in an isolated test environment.
+
+## Test Case Execution
+
+For each test case and each output format, the test fixture and the test case code perform the following steps:
+
+1. The fixture mounts a `tmpfs` directory for `bugtool` to use for its output at the static path it uses.
+2. The fixture yields to the test case implementation for running the individual test.
+3. The test case code implementation runs `xen-bugtool` with the arguments required by the test.
+4. The function to run it checks that the `inventory.xml` in the output archive conforms to the XML schema.
+5. The test case checks all output files and removes all files that it successfully verified.
+6. The fixture then asserts that the test case has not left any remaining unexpected files in the output tree.
+7. The fixture then unmounts the temporary output directory, preparing for the next test case to start afresh.

pytest.ini

@@ -0,0 +1,10 @@
+[pytest]
+# By default, show reports for failed tests:
+addopts=-rF
+# imp is only used in a unit test, will be updated to python3 later:
+filterwarnings=ignore:the imp module is deprecated
+# Enable live logging of the python log output, starting with log level INFO by default:
+log_cli=True
+log_cli_level=INFO
+# By default, run the tests in the tests directory:
+testpaths=tests/

requirements-dev.txt

@@ -1 +1,2 @@
+lxml
 pytest

requirements.txt

@@ -1 +1,5 @@
-defusedxml==0.5.0
+# Initially, xen-bugtool was deployed in xs8 using defusedxml==0.5.0.
+# The common python-defusedxml.srpm has since been updated to the current
+# defusedxml-0.7.1.
+# Tests are now free to use the current version of defusedxml:
+defusedxml

tests/integration/conftest.py

@@ -0,0 +1,48 @@
+"""conftest.py: Test fixtures to test xen-bugtool using namespaces, supported on any Linux and GitHub CI"""
+from __future__ import print_function
+
+import os
+
+import pytest
+
+from namespace_container import activate_private_test_namespace, mount, umount
+from utils import BUGTOOL_DOM0_TEMPL, run
+
+
+@pytest.fixture(autouse=True, scope="session")
+def create_and_enter_test_environment():
+    """At the start of the pytest session, activate a namespace with bindmounts for testing xen-bugtool"""
+    activate_private_test_namespace(BUGTOOL_DOM0_TEMPL, ["/etc", "/opt", "/usr/sbin", "/usr/lib/systemd"])
+    os.environ["PYTHONPATH"] = "tests/mocks"
+
+
+# zip, tar, tar.bz2 are the three output formats suppored by xen_bugtool:
+@pytest.fixture(scope="function", params=("zip", "tar", "tar.bz2"))
+def output_archive_type(request):
+    """Parameterized fixture which causes the tests to run for each of the three output_archive_types"""
+    return request.param
+
+
+@pytest.fixture(autouse=True, scope="function")
+def run_test_functions_with_private_tmpfs_output_directory():
+    """Run each test function with a private bugtool output directory using tmpfs"""
+    # Works in conjunction of having entered a private test namespace for the entire pytest session before:
+    mount(target="/var", fs="tmpfs", options="size=128M")
+    # To provide test files below /var, subdirectores can be bind-mounted/created here
+    # (or the tmpfs mount above could be done on BUGTOOL_OUTPUT_DIR)
+    # run_bugtool_entry() will chdir to the output directory, so change back afterwards:
+    srcdir = os.getcwd()
+    yield
+    # Assert that the test case did not leave any unchecked output fileas in the output directory:
+    remaining_files = []
+    for currentpath, _, files in os.walk("."):
+        for file in files:
+            remaining_files.append(os.path.join(currentpath, file))
+    if remaining_files:
+        print("Remaining (possibly unchecked) files found:")
+        print(remaining_files)
+        run(["find", "-type", "f"])
+        print("Ensure that these files are checked, remove them when checked.")
+        raise RuntimeError("Remaining (possibly unchecked) files found. Run 'pytest -rF' for logs")
+    os.chdir(srcdir)
+    umount("/var")

tests/integration/dom0-template/opt/xensource/bin/static-vdis

@@ -0,0 +1,2 @@
+#!/bin/sh
+echo -n "$@"

tests/integration/dom0-template/usr/sbin/mdadm

@@ -0,0 +1,2 @@
+#!/bin/sh
+echo -n "$@"

tests/integration/namespace_container.py

@@ -0,0 +1,77 @@
+"""namespace_container.py: Functions for creating a test environment container on any Linux and GitHub CI"""
+import ctypes
+import os
+
+from utils import run
+
+CLONE_NEWUSER = 0x10000000
+CLONE_NEWNET = 0x40000000
+CLONE_NEWNS = 0x00020000
+MS_BIND = 4096
+MS_REC = 16384
+MS_PRIVATE = 1 << 18
+
+
+def unshare(flags):
+    """Wrapper for the Linux libc/system call to unshare Linux kernel namespaces"""
+    libc = ctypes.CDLL(None, use_errno=True)
+    libc.unshare.argtypes = [ctypes.c_int]
+    rc = libc.unshare(flags)
+    if rc != 0:
+        errno = ctypes.get_errno()
+        raise OSError(errno, os.strerror(errno), flags)
+
+
+def mount(source="none", target="", fs="", flags=0, options=""):
+    """Wrapper for the Linux libc/system call to mount an fs, supports Python2.7 and Python3.x"""
+    libc = ctypes.CDLL(None, use_errno=True)
+    libc.mount.argtypes = (
+        ctypes.c_char_p,
+        ctypes.c_char_p,
+        ctypes.c_char_p,
+        ctypes.c_ulong,
+        ctypes.c_char_p,
+    )
+    print("mount -t " + fs + " -o '" + options + "' " + source + "\t" + target)
+    result = libc.mount(source.encode(), target.encode(), fs.encode(), flags, options.encode())
+    if result < 0:
+        errno = ctypes.get_errno()
+        raise OSError(errno, "mount " + target + " (options=" + options + "): " + os.strerror(errno))
+
+
+def umount(target):
+    """Wrapper for the Linux umount system call, supports Python2.7 and Python3.x"""
+    libc = ctypes.CDLL(None, use_errno=True)
+    result = libc.umount(ctypes.c_char_p(target.encode()))
+    if result < 0:
+        errno = ctypes.get_errno()
+        raise OSError(errno, "umount " + target + ": " + os.strerror(errno))
+
+
+# Create a temporary namespace for the pytest session. The xen-bugtool processes will run in it as well.
+# The tests run inside a Linux user- and mount namespace. This is needed because xen-bugtool requires to
+# be run as root and checks it. The mount namespace with a tmpfs mount for the output data also enables
+# `xen-bugtool` to have it's own private "/var/opt/xen/bug-report output directory. It allows us to
+# bind-mount the directory trees with test files at the places where `xen-bugtool` collects them from:
+def activate_private_test_namespace(bindmount_root, bindmount_mountpoints):
+    """Activate a new private mount, network and user namespace with the user behaving like uid 0 (root)"""
+    # Implements the sequence that `unshare -rmn <command>` uses. Namespace is active even without fork():
+    real_uid = os.getuid()
+    real_gid = os.getgid()
+    unshare(CLONE_NEWUSER | CLONE_NEWNET | CLONE_NEWNS)
+    # Setup uidmap for the user's uid to behave like uid 0 would (eg for bugtool's root user check)
+    with open("/proc/self/uid_map", "wb") as proc_self_uidmap:
+        proc_self_uidmap.write(b"0 %d 1" % real_uid)
+    # Setup setgroups behave like gid 0 would (needed for new tmpfs mounts for test output files):
+    with open("/proc/self/setgroups", "wb") as proc_self_setgroups:
+        proc_self_setgroups.write(b"deny")
+    # Setup gidmap for the user's gid to behave like gid 0 would (needed for tmpfs mounts):
+    with open("/proc/self/gid_map", "wb") as proc_self_gidmap:
+        proc_self_gidmap.write(b"0 %d 1" % real_gid)
+    # Prepare a private root mount in the new mount namespace, needed for mounting a private tmpfs on /var:
+    mount(target="/", flags=MS_REC | MS_PRIVATE)
+    # Bind-mount the Dom0 template directories in the private mount namespace to provide the test files:
+    for mountpoint in bindmount_mountpoints:
+        if not os.path.exists(mountpoint):
+            raise RuntimeError("Mountpoint missing on host! Please run: sudo mkdir " + mountpoint)
+        mount(source=bindmount_root + mountpoint, target=mountpoint, flags=MS_BIND)

tests/integration/test_xenserver_config.py

@@ -0,0 +1,18 @@
+"""tests/integration/test_xenserver_config.py: Test xen-bugtool --entries=xenserver-config"""
+import os
+
+from utils import check_cmd, check_file, run_bugtool_entry, verify_content_from_dom0_template
+
+
+def test_xenserver_config(output_archive_type):
+    """Test xen-bugtool --entries=xenserver-config in test jail created by auto-fixtures in conftest.py"""
+    entry = "xenserver-config"
+    run_bugtool_entry(output_archive_type, entry)
+    assert check_file("ls-lR-%opt%xensource.out").splitlines()[0] == "/opt/xensource:"
+    assert check_file("ls-lR-%etc%xensource%static-vdis.out") == ""
+    assert check_file("static-vdis-list.out") == "list"
+    os.chdir("..")
+    check_cmd(["tar", "xvf", entry + "/etc/systemd.tar"], entry + "/etc/systemd.tar")
+    os.chdir(entry)
+    verify_content_from_dom0_template("etc/xensource-inventory")
+    verify_content_from_dom0_template("etc/systemd")

tests/integration/utils.py

@@ -0,0 +1,90 @@
+"""tests/integration/utils.py: utility functions to test xen-bugtool by invoking it"""
+from __future__ import print_function
+
+import filecmp
+import os
+import shutil
+import sys
+import tarfile
+import zipfile
+from subprocess import PIPE, Popen
+
+from lxml import etree
+
+if sys.version_info.major == 2:
+    from commands import getoutput  # pyright: ignore[reportMissingImports]
+else:
+    from subprocess import getoutput
+
+BUGTOOL_OUTPUT_DIR = "/var/opt/xen/bug-report/"
+BUGTOOL_DOM0_TEMPL = "tests/integration/dom0-template"
+
+
+def run(command):
+    """Run the given shell command, print it's stdout and stderr and return them"""
+    process = Popen(command, stdout=PIPE, stderr=PIPE, universal_newlines=True)
+    stdout, stderr = process.communicate()
+    returncode = process.wait()
+    print("# " + " ".join(command) + ":")
+    if returncode:
+        raise Exception(returncode, stderr)
+    print(stdout, stderr)
+    return stdout, stderr
+
+
+def check_cmd(cmd, remove_file):
+    """Run the given command, print its stdout and stderr and return them. Remove the given remove_file"""
+    stdout, stderr = run(cmd)
+    # After successfuly verficiation of the files, remove the checked output file(missed files remain):
+    os.unlink(remove_file)
+    return stdout, stderr
+
+
+def check_file(path):
+    """Return the contents of the passed bugtool output file for verification"""
+    with open(path) as handle:
+        contents = handle.read()
+    # After successfuly verficiation of the files, remove the checked output file (missed files remain):
+    os.unlink(path)
+    return contents
+
+
+def verify_content_from_dom0_template(path):
+    """Compare the contents of output directories or files with the test's Dom0 template directories"""
+    assert path[0] != "/"
+    assert filecmp.dircmp(path, BUGTOOL_DOM0_TEMPL + path)
+    # After successfuly verficiation of the files, remove the checked output files (missed files remain):
+    try:
+        os.unlink(path)
+    except OSError:
+        shutil.rmtree(path)
+
+
+def run_bugtool_entry(archive_type, test_entries):
+    """Run bugtool for the given entry or entries, extract the output, and chdir to it"""
+    os.environ["XENRT_BUGTOOL_BASENAME"] = test_entries
+    # For case the default python interpreter of the user is python3, we must use python2(for now):
+    command = "python2 ./xen-bugtool -y --output=%s --entries=%s" % (archive_type, test_entries)
+    print("# " + command)
+    print(getoutput(command))
+    srcdir = os.getcwd()
+    os.chdir(BUGTOOL_OUTPUT_DIR)
+    output_file = test_entries + "." + archive_type
+    print("# Unpacking " + BUGTOOL_OUTPUT_DIR + output_file + " and verifying inventory.xml")
+    # Python2.7 does not have shutil.unpack_archive():
+    # shutil.unpack_archive(output_file):
+    if archive_type == "zip":
+        archive = zipfile.ZipFile(output_file)
+    elif archive_type == "tar":
+        archive = tarfile.open(output_file)
+    elif archive_type == "tar.bz2":
+        archive = tarfile.open(output_file, "r:bz2")
+    else:
+        raise RuntimeError("Unsupported output archive type: %s" % archive_type)
+    archive.extractall()
+    os.chdir(test_entries)
+    # Validate the extracted inventory.xml using the XML schema from the test framework:
+    with open(srcdir + "/tests/integration/inventory.xsd") as xmlschema:
+        etree.XMLSchema(etree.parse(xmlschema)).assertValid(etree.parse("inventory.xml"))
+        # After successfuly validation of the inventory.xml, remove it (not removed files make the test fail):
+        os.unlink("inventory.xml")

tests/unit/test_xapidb_filter.py

@@ -1,11 +1,13 @@
 # This uses the deprecated imp module because it has to run with Python2.7 for now:
-import imp  # pylint: disable=deprecated-module
+import imp  # pylint: disable=deprecated-module  # pyright: ignore[reportMissingImports]
 import os
+import sys
 import xml.dom.minidom
 
+import pytest
+
 
 testdir = os.path.dirname(__file__)
-bugtool = imp.load_source("bugtool", testdir + "/../../xen-bugtool")
 original = r"""<?xml version="1.0" ?>
 <root>
     <table name="secret">
@@ -53,7 +55,9 @@
 """
 
 
+@pytest.mark.skipif(sys.version_info >= (3,0), reason="requires python2")
 def test_xapi_database_filter():
     """Assert that bugtool.DBFilter().output() filters the xAPI database as expected"""
+    bugtool = imp.load_source("bugtool", testdir + "/../../xen-bugtool")
     filtered = bugtool.DBFilter(original).output()
     assert xml.dom.minidom.parseString(filtered).toprettyxml(indent="    ") == expected