[RFC PATCH v4 1/4] dts: code adjustments for sphinx

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

sphinx-build only imports the Python modules when building the
documentation; it doesn't run DTS. This requires changes that make the
code importable without running it. This means:
* properly guarding argument parsing in the if __name__ == '__main__'
  block.
* the logger used by DTS runner underwent the same treatment so that it
  doesn't create unnecessary log files.
* however, DTS uses the arguments to construct an object holding global
  variables. The defaults for the global variables needed to be moved
  from argument parsing elsewhere.
* importing the remote_session module from framework resulted in
  circular imports because of one module trying to import another
  module. This is fixed by more granular imports.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
---
 dts/framework/config/__init__.py              |  3 -
 dts/framework/dts.py                          | 34 ++++++-
 dts/framework/remote_session/__init__.py      | 41 ++++-----
 .../interactive_remote_session.py             |  0
 .../{remote => }/interactive_shell.py         |  0
 .../{remote => }/python_shell.py              |  0
 .../remote_session/remote/__init__.py         | 27 ------
 .../{remote => }/remote_session.py            |  0
 .../{remote => }/ssh_session.py               |  0
 .../{remote => }/testpmd_shell.py             |  0
 dts/framework/settings.py                     | 92 +++++++++++--------
 dts/framework/test_suite.py                   |  3 +-
 dts/framework/testbed_model/__init__.py       | 12 +--
 dts/framework/testbed_model/common.py         | 29 ++++++
 dts/framework/testbed_model/{hw => }/cpu.py   | 13 +++
 dts/framework/testbed_model/hw/__init__.py    | 27 ------
 .../linux_session.py                          |  4 +-
 dts/framework/testbed_model/node.py           | 22 ++++-
 .../os_session.py                             | 14 +--
 dts/framework/testbed_model/{hw => }/port.py  |  0
 .../posix_session.py                          |  2 +-
 dts/framework/testbed_model/sut_node.py       |  8 +-
 dts/framework/testbed_model/tg_node.py        | 30 +-----
 .../traffic_generator/__init__.py             | 24 +++++
 .../capturing_traffic_generator.py            |  2 +-
 .../{ => traffic_generator}/scapy.py          | 17 +---
 .../traffic_generator.py                      | 16 +++-
 .../testbed_model/{hw => }/virtual_device.py  |  0
 dts/framework/utils.py                        | 53 +----------
 dts/main.py                                   |  3 +-
 30 files changed, 229 insertions(+), 247 deletions(-)
 rename dts/framework/remote_session/{remote => }/interactive_remote_session.py (100%)
 rename dts/framework/remote_session/{remote => }/interactive_shell.py (100%)
 rename dts/framework/remote_session/{remote => }/python_shell.py (100%)
 delete mode 100644 dts/framework/remote_session/remote/__init__.py
 rename dts/framework/remote_session/{remote => }/remote_session.py (100%)
 rename dts/framework/remote_session/{remote => }/ssh_session.py (100%)
 rename dts/framework/remote_session/{remote => }/testpmd_shell.py (100%)
 create mode 100644 dts/framework/testbed_model/common.py
 rename dts/framework/testbed_model/{hw => }/cpu.py (95%)
 delete mode 100644 dts/framework/testbed_model/hw/__init__.py
 rename dts/framework/{remote_session => testbed_model}/linux_session.py (98%)
 rename dts/framework/{remote_session => testbed_model}/os_session.py (97%)
 rename dts/framework/testbed_model/{hw => }/port.py (100%)
 rename dts/framework/{remote_session => testbed_model}/posix_session.py (99%)
 create mode 100644 dts/framework/testbed_model/traffic_generator/__init__.py
 rename dts/framework/testbed_model/{ => traffic_generator}/capturing_traffic_generator.py (99%)
 rename dts/framework/testbed_model/{ => traffic_generator}/scapy.py (96%)
 rename dts/framework/testbed_model/{ => traffic_generator}/traffic_generator.py (80%)
 rename dts/framework/testbed_model/{hw => }/virtual_device.py (100%)

diff --git a/dts/framework/config/__init__.py b/dts/framework/config/__init__.py
index cb7e00ba34..5de8b54bcf 100644
--- a/dts/framework/config/__init__.py
+++ b/dts/framework/config/__init__.py
@@ -324,6 +324,3 @@ def load_config() -> Configuration:
     config: dict[str, Any] = warlock.model_factory(schema, name="_Config")(config_data)
     config_obj: Configuration = Configuration.from_dict(dict(config))
     return config_obj
-
-
-CONFIGURATION = load_config()
diff --git a/dts/framework/dts.py b/dts/framework/dts.py
index f773f0c38d..925a212210 100644
--- a/dts/framework/dts.py
+++ b/dts/framework/dts.py
@@ -3,22 +3,23 @@
 # Copyright(c) 2022-2023 PANTHEON.tech s.r.o.
 # Copyright(c) 2022-2023 University of New Hampshire
 
+import logging
 import sys
 
 from .config import (
-    CONFIGURATION,
     BuildTargetConfiguration,
     ExecutionConfiguration,
     TestSuiteConfig,
+    load_config,
 )
 from .exception import BlockingTestSuiteError
 from .logger import DTSLOG, getLogger
 from .test_result import BuildTargetResult, DTSResult, ExecutionResult, Result
 from .test_suite import get_test_suites
 from .testbed_model import SutNode, TGNode
-from .utils import check_dts_python_version
 
-dts_logger: DTSLOG = getLogger("DTSRunner")
+# dummy defaults to satisfy linters
+dts_logger: DTSLOG | logging.Logger = logging.getLogger("DTSRunner")
 result: DTSResult = DTSResult(dts_logger)
 
 
@@ -30,14 +31,18 @@ def run_all() -> None:
     global dts_logger
     global result
 
+    # create a regular DTS logger and create a new result with it
+    dts_logger = getLogger("DTSRunner")
+    result = DTSResult(dts_logger)
+
     # check the python version of the server that run dts
-    check_dts_python_version()
+    _check_dts_python_version()
 
     sut_nodes: dict[str, SutNode] = {}
     tg_nodes: dict[str, TGNode] = {}
     try:
         # for all Execution sections
-        for execution in CONFIGURATION.executions:
+        for execution in load_config().executions:
             sut_node = sut_nodes.get(execution.system_under_test_node.name)
             tg_node = tg_nodes.get(execution.traffic_generator_node.name)
 
@@ -82,6 +87,25 @@ def run_all() -> None:
     _exit_dts()
 
 
+def _check_dts_python_version() -> None:
+    def RED(text: str) -> str:
+        return f"\u001B[31;1m{str(text)}\u001B[0m"
+
+    if sys.version_info.major < 3 or (
+        sys.version_info.major == 3 and sys.version_info.minor < 10
+    ):
+        print(
+            RED(
+                (
+                    "WARNING: DTS execution node's python version is lower than"
+                    "python 3.10, is deprecated and will not work in future releases."
+                )
+            ),
+            file=sys.stderr,
+        )
+        print(RED("Please use Python >= 3.10 instead"), file=sys.stderr)
+
+
 def _run_execution(
     sut_node: SutNode,
     tg_node: TGNode,
diff --git a/dts/framework/remote_session/__init__.py b/dts/framework/remote_session/__init__.py
index 00b6d1f03a..5e7ddb2b05 100644
--- a/dts/framework/remote_session/__init__.py
+++ b/dts/framework/remote_session/__init__.py
@@ -12,29 +12,24 @@
 
 # pylama:ignore=W0611
 
-from framework.config import OS, NodeConfiguration
-from framework.exception import ConfigurationError
+from framework.config import NodeConfiguration
 from framework.logger import DTSLOG
 
-from .linux_session import LinuxSession
-from .os_session import InteractiveShellType, OSSession
-from .remote import (
-    CommandResult,
-    InteractiveRemoteSession,
-    InteractiveShell,
-    PythonShell,
-    RemoteSession,
-    SSHSession,
-    TestPmdDevice,
-    TestPmdShell,
-)
-
-
-def create_session(
+from .interactive_remote_session import InteractiveRemoteSession
+from .interactive_shell import InteractiveShell
+from .python_shell import PythonShell
+from .remote_session import CommandResult, RemoteSession
+from .ssh_session import SSHSession
+from .testpmd_shell import TestPmdShell
+
+
+def create_remote_session(
     node_config: NodeConfiguration, name: str, logger: DTSLOG
-) -> OSSession:
-    match node_config.os:
-        case OS.linux:
-            return LinuxSession(node_config, name, logger)
-        case _:
-            raise ConfigurationError(f"Unsupported OS {node_config.os}")
+) -> RemoteSession:
+    return SSHSession(node_config, name, logger)
+
+
+def create_interactive_session(
+    node_config: NodeConfiguration, logger: DTSLOG
+) -> InteractiveRemoteSession:
+    return InteractiveRemoteSession(node_config, logger)
diff --git a/dts/framework/remote_session/remote/interactive_remote_session.py b/dts/framework/remote_session/interactive_remote_session.py
similarity index 100%
rename from dts/framework/remote_session/remote/interactive_remote_session.py
rename to dts/framework/remote_session/interactive_remote_session.py
diff --git a/dts/framework/remote_session/remote/interactive_shell.py b/dts/framework/remote_session/interactive_shell.py
similarity index 100%
rename from dts/framework/remote_session/remote/interactive_shell.py
rename to dts/framework/remote_session/interactive_shell.py
diff --git a/dts/framework/remote_session/remote/python_shell.py b/dts/framework/remote_session/python_shell.py
similarity index 100%
rename from dts/framework/remote_session/remote/python_shell.py
rename to dts/framework/remote_session/python_shell.py
diff --git a/dts/framework/remote_session/remote/__init__.py b/dts/framework/remote_session/remote/__init__.py
deleted file mode 100644
index 06403691a5..0000000000
--- a/dts/framework/remote_session/remote/__init__.py
+++ /dev/null
@@ -1,27 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright(c) 2023 PANTHEON.tech s.r.o.
-# Copyright(c) 2023 University of New Hampshire
-
-# pylama:ignore=W0611
-
-from framework.config import NodeConfiguration
-from framework.logger import DTSLOG
-
-from .interactive_remote_session import InteractiveRemoteSession
-from .interactive_shell import InteractiveShell
-from .python_shell import PythonShell
-from .remote_session import CommandResult, RemoteSession
-from .ssh_session import SSHSession
-from .testpmd_shell import TestPmdDevice, TestPmdShell
-
-
-def create_remote_session(
-    node_config: NodeConfiguration, name: str, logger: DTSLOG
-) -> RemoteSession:
-    return SSHSession(node_config, name, logger)
-
-
-def create_interactive_session(
-    node_config: NodeConfiguration, logger: DTSLOG
-) -> InteractiveRemoteSession:
-    return InteractiveRemoteSession(node_config, logger)
diff --git a/dts/framework/remote_session/remote/remote_session.py b/dts/framework/remote_session/remote_session.py
similarity index 100%
rename from dts/framework/remote_session/remote/remote_session.py
rename to dts/framework/remote_session/remote_session.py
diff --git a/dts/framework/remote_session/remote/ssh_session.py b/dts/framework/remote_session/ssh_session.py
similarity index 100%
rename from dts/framework/remote_session/remote/ssh_session.py
rename to dts/framework/remote_session/ssh_session.py
diff --git a/dts/framework/remote_session/remote/testpmd_shell.py b/dts/framework/remote_session/testpmd_shell.py
similarity index 100%
rename from dts/framework/remote_session/remote/testpmd_shell.py
rename to dts/framework/remote_session/testpmd_shell.py
diff --git a/dts/framework/settings.py b/dts/framework/settings.py
index cfa39d011b..bf86861efb 100644
--- a/dts/framework/settings.py
+++ b/dts/framework/settings.py
@@ -6,7 +6,7 @@
 import argparse
 import os
 from collections.abc import Callable, Iterable, Sequence
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Any, TypeVar
 
@@ -22,7 +22,7 @@ def __init__(
             option_strings: Sequence[str],
             dest: str,
             nargs: str | int | None = None,
-            const: str | None = None,
+            const: bool | None = None,
             default: str = None,
             type: Callable[[str], _T | argparse.FileType | None] = None,
             choices: Iterable[_T] | None = None,
@@ -32,6 +32,12 @@ def __init__(
         ) -> None:
             env_var_value = os.environ.get(env_var)
             default = env_var_value or default
+            if const is not None:
+                nargs = 0
+                default = const if env_var_value else default
+                type = None
+                choices = None
+                metavar = None
             super(_EnvironmentArgument, self).__init__(
                 option_strings,
                 dest,
@@ -52,22 +58,28 @@ def __call__(
             values: Any,
             option_string: str = None,
         ) -> None:
-            setattr(namespace, self.dest, values)
+            if self.const is not None:
+                setattr(namespace, self.dest, self.const)
+            else:
+                setattr(namespace, self.dest, values)
 
     return _EnvironmentArgument
 
 
-@dataclass(slots=True, frozen=True)
+@dataclass(slots=True)
 class _Settings:
-    config_file_path: str
-    output_dir: str
-    timeout: float
-    verbose: bool
-    skip_setup: bool
-    dpdk_tarball_path: Path
-    compile_timeout: float
-    test_cases: list
-    re_run: int
+    config_file_path: Path = Path(__file__).parent.parent.joinpath("conf.yaml")
+    output_dir: str = "output"
+    timeout: float = 15
+    verbose: bool = False
+    skip_setup: bool = False
+    dpdk_tarball_path: Path | str = "dpdk.tar.xz"
+    compile_timeout: float = 1200
+    test_cases: list[str] = field(default_factory=list)
+    re_run: int = 0
+
+
+SETTINGS: _Settings = _Settings()
 
 
 def _get_parser() -> argparse.ArgumentParser:
@@ -81,7 +93,8 @@ def _get_parser() -> argparse.ArgumentParser:
     parser.add_argument(
         "--config-file",
         action=_env_arg("DTS_CFG_FILE"),
-        default="conf.yaml",
+        default=SETTINGS.config_file_path,
+        type=Path,
         help="[DTS_CFG_FILE] configuration file that describes the test cases, SUTs "
         "and targets.",
     )
@@ -90,7 +103,7 @@ def _get_parser() -> argparse.ArgumentParser:
         "--output-dir",
         "--output",
         action=_env_arg("DTS_OUTPUT_DIR"),
-        default="output",
+        default=SETTINGS.output_dir,
         help="[DTS_OUTPUT_DIR] Output directory where dts logs and results are saved.",
     )
 
@@ -98,7 +111,7 @@ def _get_parser() -> argparse.ArgumentParser:
         "-t",
         "--timeout",
         action=_env_arg("DTS_TIMEOUT"),
-        default=15,
+        default=SETTINGS.timeout,
         type=float,
         help="[DTS_TIMEOUT] The default timeout for all DTS operations except for "
         "compiling DPDK.",
@@ -108,8 +121,9 @@ def _get_parser() -> argparse.ArgumentParser:
         "-v",
         "--verbose",
         action=_env_arg("DTS_VERBOSE"),
-        default="N",
-        help="[DTS_VERBOSE] Set to 'Y' to enable verbose output, logging all messages "
+        default=SETTINGS.verbose,
+        const=True,
+        help="[DTS_VERBOSE] Specify to enable verbose output, logging all messages "
         "to the console.",
     )
 
@@ -117,8 +131,8 @@ def _get_parser() -> argparse.ArgumentParser:
         "-s",
         "--skip-setup",
         action=_env_arg("DTS_SKIP_SETUP"),
-        default="N",
-        help="[DTS_SKIP_SETUP] Set to 'Y' to skip all setup steps on SUT and TG nodes.",
+        const=True,
+        help="[DTS_SKIP_SETUP] Specify to skip all setup steps on SUT and TG nodes.",
     )
 
     parser.add_argument(
@@ -126,7 +140,7 @@ def _get_parser() -> argparse.ArgumentParser:
         "--snapshot",
         "--git-ref",
         action=_env_arg("DTS_DPDK_TARBALL"),
-        default="dpdk.tar.xz",
+        default=SETTINGS.dpdk_tarball_path,
         type=Path,
         help="[DTS_DPDK_TARBALL] Path to DPDK source code tarball or a git commit ID, "
         "tag ID or tree ID to test. To test local changes, first commit them, "
@@ -136,7 +150,7 @@ def _get_parser() -> argparse.ArgumentParser:
     parser.add_argument(
         "--compile-timeout",
         action=_env_arg("DTS_COMPILE_TIMEOUT"),
-        default=1200,
+        default=SETTINGS.compile_timeout,
         type=float,
         help="[DTS_COMPILE_TIMEOUT] The timeout for compiling DPDK.",
     )
@@ -153,7 +167,7 @@ def _get_parser() -> argparse.ArgumentParser:
         "--re-run",
         "--re_run",
         action=_env_arg("DTS_RERUN"),
-        default=0,
+        default=SETTINGS.re_run,
         type=int,
         help="[DTS_RERUN] Re-run each test case the specified amount of times "
         "if a test failure occurs",
@@ -162,23 +176,21 @@ def _get_parser() -> argparse.ArgumentParser:
     return parser
 
 
-def _get_settings() -> _Settings:
+def set_settings() -> None:
     parsed_args = _get_parser().parse_args()
-    return _Settings(
-        config_file_path=parsed_args.config_file,
-        output_dir=parsed_args.output_dir,
-        timeout=parsed_args.timeout,
-        verbose=(parsed_args.verbose == "Y"),
-        skip_setup=(parsed_args.skip_setup == "Y"),
-        dpdk_tarball_path=Path(
-            DPDKGitTarball(parsed_args.tarball, parsed_args.output_dir)
-        )
+    global SETTINGS
+    SETTINGS.config_file_path = parsed_args.config_file
+    SETTINGS.output_dir = parsed_args.output_dir
+    SETTINGS.timeout = parsed_args.timeout
+    SETTINGS.verbose = parsed_args.verbose
+    SETTINGS.skip_setup = parsed_args.skip_setup
+    SETTINGS.dpdk_tarball_path = (
+        Path(DPDKGitTarball(parsed_args.tarball, parsed_args.output_dir))
         if not os.path.exists(parsed_args.tarball)
-        else Path(parsed_args.tarball),
-        compile_timeout=parsed_args.compile_timeout,
-        test_cases=parsed_args.test_cases.split(",") if parsed_args.test_cases else [],
-        re_run=parsed_args.re_run,
+        else Path(parsed_args.tarball)
     )
-
-
-SETTINGS: _Settings = _get_settings()
+    SETTINGS.compile_timeout = parsed_args.compile_timeout
+    SETTINGS.test_cases = (
+        parsed_args.test_cases.split(",") if parsed_args.test_cases else []
+    )
+    SETTINGS.re_run = parsed_args.re_run
diff --git a/dts/framework/test_suite.py b/dts/framework/test_suite.py
index 3b890c0451..b381990d98 100644
--- a/dts/framework/test_suite.py
+++ b/dts/framework/test_suite.py
@@ -26,8 +26,7 @@
 from .logger import DTSLOG, getLogger
 from .settings import SETTINGS
 from .test_result import BuildTargetResult, Result, TestCaseResult, TestSuiteResult
-from .testbed_model import SutNode, TGNode
-from .testbed_model.hw.port import Port, PortLink
+from .testbed_model import Port, PortLink, SutNode, TGNode
 from .utils import get_packet_summaries
 
 
diff --git a/dts/framework/testbed_model/__init__.py b/dts/framework/testbed_model/__init__.py
index 5cbb859e47..8ced05653b 100644
--- a/dts/framework/testbed_model/__init__.py
+++ b/dts/framework/testbed_model/__init__.py
@@ -9,15 +9,9 @@
 
 # pylama:ignore=W0611
 
-from .hw import (
-    LogicalCore,
-    LogicalCoreCount,
-    LogicalCoreCountFilter,
-    LogicalCoreList,
-    LogicalCoreListFilter,
-    VirtualDevice,
-    lcore_filter,
-)
+from .cpu import LogicalCoreCount, LogicalCoreCountFilter, LogicalCoreList
 from .node import Node
+from .port import Port, PortLink
 from .sut_node import SutNode
 from .tg_node import TGNode
+from .virtual_device import VirtualDevice
diff --git a/dts/framework/testbed_model/common.py b/dts/framework/testbed_model/common.py
new file mode 100644
index 0000000000..9222f57847
--- /dev/null
+++ b/dts/framework/testbed_model/common.py
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2023 PANTHEON.tech s.r.o.
+
+
+class MesonArgs(object):
+    """
+    Aggregate the arguments needed to build DPDK:
+    default_library: Default library type, Meson allows "shared", "static" and "both".
+               Defaults to None, in which case the argument won't be used.
+    Keyword arguments: The arguments found in meson_options.txt in root DPDK directory.
+               Do not use -D with them, for example:
+               meson_args = MesonArgs(enable_kmods=True).
+    """
+
+    _default_library: str
+
+    def __init__(self, default_library: str | None = None, **dpdk_args: str | bool):
+        self._default_library = (
+            f"--default-library={default_library}" if default_library else ""
+        )
+        self._dpdk_args = " ".join(
+            (
+                f"-D{dpdk_arg_name}={dpdk_arg_value}"
+                for dpdk_arg_name, dpdk_arg_value in dpdk_args.items()
+            )
+        )
+
+    def __str__(self) -> str:
+        return " ".join(f"{self._default_library} {self._dpdk_args}".split())
diff --git a/dts/framework/testbed_model/hw/cpu.py b/dts/framework/testbed_model/cpu.py
similarity index 95%
rename from dts/framework/testbed_model/hw/cpu.py
rename to dts/framework/testbed_model/cpu.py
index d1918a12dc..8fe785dfe4 100644
--- a/dts/framework/testbed_model/hw/cpu.py
+++ b/dts/framework/testbed_model/cpu.py
@@ -272,3 +272,16 @@ def filter(self) -> list[LogicalCore]:
             )
 
         return filtered_lcores
+
+
+def lcore_filter(
+    core_list: list[LogicalCore],
+    filter_specifier: LogicalCoreCount | LogicalCoreList,
+    ascending: bool,
+) -> LogicalCoreFilter:
+    if isinstance(filter_specifier, LogicalCoreList):
+        return LogicalCoreListFilter(core_list, filter_specifier, ascending)
+    elif isinstance(filter_specifier, LogicalCoreCount):
+        return LogicalCoreCountFilter(core_list, filter_specifier, ascending)
+    else:
+        raise ValueError(f"Unsupported filter r{filter_specifier}")
diff --git a/dts/framework/testbed_model/hw/__init__.py b/dts/framework/testbed_model/hw/__init__.py
deleted file mode 100644
index 88ccac0b0e..0000000000
--- a/dts/framework/testbed_model/hw/__init__.py
+++ /dev/null
@@ -1,27 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright(c) 2023 PANTHEON.tech s.r.o.
-
-# pylama:ignore=W0611
-
-from .cpu import (
-    LogicalCore,
-    LogicalCoreCount,
-    LogicalCoreCountFilter,
-    LogicalCoreFilter,
-    LogicalCoreList,
-    LogicalCoreListFilter,
-)
-from .virtual_device import VirtualDevice
-
-
-def lcore_filter(
-    core_list: list[LogicalCore],
-    filter_specifier: LogicalCoreCount | LogicalCoreList,
-    ascending: bool,
-) -> LogicalCoreFilter:
-    if isinstance(filter_specifier, LogicalCoreList):
-        return LogicalCoreListFilter(core_list, filter_specifier, ascending)
-    elif isinstance(filter_specifier, LogicalCoreCount):
-        return LogicalCoreCountFilter(core_list, filter_specifier, ascending)
-    else:
-        raise ValueError(f"Unsupported filter r{filter_specifier}")
diff --git a/dts/framework/remote_session/linux_session.py b/dts/framework/testbed_model/linux_session.py
similarity index 98%
rename from dts/framework/remote_session/linux_session.py
rename to dts/framework/testbed_model/linux_session.py
index a3f1a6bf3b..7b60b5353f 100644
--- a/dts/framework/remote_session/linux_session.py
+++ b/dts/framework/testbed_model/linux_session.py
@@ -9,10 +9,10 @@
 from typing_extensions import NotRequired
 
 from framework.exception import RemoteCommandExecutionError
-from framework.testbed_model import LogicalCore
-from framework.testbed_model.hw.port import Port
 from framework.utils import expand_range
 
+from .cpu import LogicalCore
+from .port import Port
 from .posix_session import PosixSession
 
 
diff --git a/dts/framework/testbed_model/node.py b/dts/framework/testbed_model/node.py
index fc01e0bf8e..23efa79c50 100644
--- a/dts/framework/testbed_model/node.py
+++ b/dts/framework/testbed_model/node.py
@@ -12,23 +12,26 @@
 from typing import Any, Callable, Type, Union
 
 from framework.config import (
+    OS,
     BuildTargetConfiguration,
     ExecutionConfiguration,
     NodeConfiguration,
 )
+from framework.exception import ConfigurationError
 from framework.logger import DTSLOG, getLogger
-from framework.remote_session import InteractiveShellType, OSSession, create_session
 from framework.settings import SETTINGS
 
-from .hw import (
+from .cpu import (
     LogicalCore,
     LogicalCoreCount,
     LogicalCoreList,
     LogicalCoreListFilter,
-    VirtualDevice,
     lcore_filter,
 )
-from .hw.port import Port
+from .linux_session import LinuxSession
+from .os_session import InteractiveShellType, OSSession
+from .port import Port
+from .virtual_device import VirtualDevice
 
 
 class Node(ABC):
@@ -69,6 +72,7 @@ def __init__(self, node_config: NodeConfiguration):
     def _init_ports(self) -> None:
         self.ports = [Port(self.name, port_config) for port_config in self.config.ports]
         self.main_session.update_ports(self.ports)
+
         for port in self.ports:
             self.configure_port_state(port)
 
@@ -249,3 +253,13 @@ def skip_setup(func: Callable[..., Any]) -> Callable[..., Any]:
             return lambda *args: None
         else:
             return func
+
+
+def create_session(
+    node_config: NodeConfiguration, name: str, logger: DTSLOG
+) -> OSSession:
+    match node_config.os:
+        case OS.linux:
+            return LinuxSession(node_config, name, logger)
+        case _:
+            raise ConfigurationError(f"Unsupported OS {node_config.os}")
diff --git a/dts/framework/remote_session/os_session.py b/dts/framework/testbed_model/os_session.py
similarity index 97%
rename from dts/framework/remote_session/os_session.py
rename to dts/framework/testbed_model/os_session.py
index 8a709eac1c..19ba9a69d5 100644
--- a/dts/framework/remote_session/os_session.py
+++ b/dts/framework/testbed_model/os_session.py
@@ -10,19 +10,19 @@
 
 from framework.config import Architecture, NodeConfiguration, NodeInfo
 from framework.logger import DTSLOG
-from framework.remote_session.remote import InteractiveShell
-from framework.settings import SETTINGS
-from framework.testbed_model import LogicalCore
-from framework.testbed_model.hw.port import Port
-from framework.utils import MesonArgs
-
-from .remote import (
+from framework.remote_session import (
     CommandResult,
     InteractiveRemoteSession,
+    InteractiveShell,
     RemoteSession,
     create_interactive_session,
     create_remote_session,
 )
+from framework.settings import SETTINGS
+
+from .common import MesonArgs
+from .cpu import LogicalCore
+from .port import Port
 
 InteractiveShellType = TypeVar("InteractiveShellType", bound=InteractiveShell)
 
diff --git a/dts/framework/testbed_model/hw/port.py b/dts/framework/testbed_model/port.py
similarity index 100%
rename from dts/framework/testbed_model/hw/port.py
rename to dts/framework/testbed_model/port.py
diff --git a/dts/framework/remote_session/posix_session.py b/dts/framework/testbed_model/posix_session.py
similarity index 99%
rename from dts/framework/remote_session/posix_session.py
rename to dts/framework/testbed_model/posix_session.py
index 5da0516e05..9a95baa353 100644
--- a/dts/framework/remote_session/posix_session.py
+++ b/dts/framework/testbed_model/posix_session.py
@@ -9,8 +9,8 @@
 from framework.config import Architecture, NodeInfo
 from framework.exception import DPDKBuildError, RemoteCommandExecutionError
 from framework.settings import SETTINGS
-from framework.utils import MesonArgs
 
+from .common import MesonArgs
 from .os_session import OSSession
 
 
diff --git a/dts/framework/testbed_model/sut_node.py b/dts/framework/testbed_model/sut_node.py
index 202aebfd06..2b7e104dcd 100644
--- a/dts/framework/testbed_model/sut_node.py
+++ b/dts/framework/testbed_model/sut_node.py
@@ -15,12 +15,14 @@
     NodeInfo,
     SutNodeConfiguration,
 )
-from framework.remote_session import CommandResult, InteractiveShellType, OSSession
+from framework.remote_session import CommandResult
 from framework.settings import SETTINGS
-from framework.utils import MesonArgs
 
-from .hw import LogicalCoreCount, LogicalCoreList, VirtualDevice
+from .common import MesonArgs
+from .cpu import LogicalCoreCount, LogicalCoreList
 from .node import Node
+from .os_session import InteractiveShellType, OSSession
+from .virtual_device import VirtualDevice
 
 
 class EalParameters(object):
diff --git a/dts/framework/testbed_model/tg_node.py b/dts/framework/testbed_model/tg_node.py
index 27025cfa31..166eb8430e 100644
--- a/dts/framework/testbed_model/tg_node.py
+++ b/dts/framework/testbed_model/tg_node.py
@@ -16,16 +16,11 @@
 
 from scapy.packet import Packet  # type: ignore[import]
 
-from framework.config import (
-    ScapyTrafficGeneratorConfig,
-    TGNodeConfiguration,
-    TrafficGeneratorType,
-)
-from framework.exception import ConfigurationError
-
-from .capturing_traffic_generator import CapturingTrafficGenerator
-from .hw.port import Port
+from framework.config import TGNodeConfiguration
+
 from .node import Node
+from .port import Port
+from .traffic_generator import CapturingTrafficGenerator, create_traffic_generator
 
 
 class TGNode(Node):
@@ -80,20 +75,3 @@ def close(self) -> None:
         """Free all resources used by the node"""
         self.traffic_generator.close()
         super(TGNode, self).close()
-
-
-def create_traffic_generator(
-    tg_node: TGNode, traffic_generator_config: ScapyTrafficGeneratorConfig
-) -> CapturingTrafficGenerator:
-    """A factory function for creating traffic generator object from user config."""
-
-    from .scapy import ScapyTrafficGenerator
-
-    match traffic_generator_config.traffic_generator_type:
-        case TrafficGeneratorType.SCAPY:
-            return ScapyTrafficGenerator(tg_node, traffic_generator_config)
-        case _:
-            raise ConfigurationError(
-                "Unknown traffic generator: "
-                f"{traffic_generator_config.traffic_generator_type}"
-            )
diff --git a/dts/framework/testbed_model/traffic_generator/__init__.py b/dts/framework/testbed_model/traffic_generator/__init__.py
new file mode 100644
index 0000000000..11bfa1ee0f
--- /dev/null
+++ b/dts/framework/testbed_model/traffic_generator/__init__.py
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2023 PANTHEON.tech s.r.o.
+
+from framework.config import ScapyTrafficGeneratorConfig, TrafficGeneratorType
+from framework.exception import ConfigurationError
+from framework.testbed_model.node import Node
+
+from .capturing_traffic_generator import CapturingTrafficGenerator
+from .scapy import ScapyTrafficGenerator
+
+
+def create_traffic_generator(
+    tg_node: Node, traffic_generator_config: ScapyTrafficGeneratorConfig
+) -> CapturingTrafficGenerator:
+    """A factory function for creating traffic generator object from user config."""
+
+    match traffic_generator_config.traffic_generator_type:
+        case TrafficGeneratorType.SCAPY:
+            return ScapyTrafficGenerator(tg_node, traffic_generator_config)
+        case _:
+            raise ConfigurationError(
+                "Unknown traffic generator: "
+                f"{traffic_generator_config.traffic_generator_type}"
+            )
diff --git a/dts/framework/testbed_model/capturing_traffic_generator.py b/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
similarity index 99%
rename from dts/framework/testbed_model/capturing_traffic_generator.py
rename to dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
index ab98987f8e..765378fb4a 100644
--- a/dts/framework/testbed_model/capturing_traffic_generator.py
+++ b/dts/framework/testbed_model/traffic_generator/capturing_traffic_generator.py
@@ -16,9 +16,9 @@
 from scapy.packet import Packet  # type: ignore[import]
 
 from framework.settings import SETTINGS
+from framework.testbed_model.port import Port
 from framework.utils import get_packet_summaries
 
-from .hw.port import Port
 from .traffic_generator import TrafficGenerator
 
 
diff --git a/dts/framework/testbed_model/scapy.py b/dts/framework/testbed_model/traffic_generator/scapy.py
similarity index 96%
rename from dts/framework/testbed_model/scapy.py
rename to dts/framework/testbed_model/traffic_generator/scapy.py
index af0d4dbb25..395d7e9bc0 100644
--- a/dts/framework/testbed_model/scapy.py
+++ b/dts/framework/testbed_model/traffic_generator/scapy.py
@@ -24,16 +24,15 @@
 from scapy.packet import Packet  # type: ignore[import]
 
 from framework.config import OS, ScapyTrafficGeneratorConfig
-from framework.logger import DTSLOG, getLogger
 from framework.remote_session import PythonShell
 from framework.settings import SETTINGS
+from framework.testbed_model.node import Node
+from framework.testbed_model.port import Port
 
 from .capturing_traffic_generator import (
     CapturingTrafficGenerator,
     _get_default_capture_name,
 )
-from .hw.port import Port
-from .tg_node import TGNode
 
 """
 ========= BEGIN RPC FUNCTIONS =========
@@ -191,15 +190,9 @@ class ScapyTrafficGenerator(CapturingTrafficGenerator):
     session: PythonShell
     rpc_server_proxy: xmlrpc.client.ServerProxy
     _config: ScapyTrafficGeneratorConfig
-    _tg_node: TGNode
-    _logger: DTSLOG
-
-    def __init__(self, tg_node: TGNode, config: ScapyTrafficGeneratorConfig):
-        self._config = config
-        self._tg_node = tg_node
-        self._logger = getLogger(
-            f"{self._tg_node.name} {self._config.traffic_generator_type}"
-        )
+
+    def __init__(self, tg_node: Node, config: ScapyTrafficGeneratorConfig):
+        super().__init__(tg_node, config)
 
         assert (
             self._tg_node.config.os == OS.linux
diff --git a/dts/framework/testbed_model/traffic_generator.py b/dts/framework/testbed_model/traffic_generator/traffic_generator.py
similarity index 80%
rename from dts/framework/testbed_model/traffic_generator.py
rename to dts/framework/testbed_model/traffic_generator/traffic_generator.py
index 28c35d3ce4..ea7c3963da 100644
--- a/dts/framework/testbed_model/traffic_generator.py
+++ b/dts/framework/testbed_model/traffic_generator/traffic_generator.py
@@ -12,11 +12,12 @@
 
 from scapy.packet import Packet  # type: ignore[import]
 
-from framework.logger import DTSLOG
+from framework.config import TrafficGeneratorConfig
+from framework.logger import DTSLOG, getLogger
+from framework.testbed_model.node import Node
+from framework.testbed_model.port import Port
 from framework.utils import get_packet_summaries
 
-from .hw.port import Port
-
 
 class TrafficGenerator(ABC):
     """The base traffic generator.
@@ -24,8 +25,17 @@ class TrafficGenerator(ABC):
     Defines the few basic methods that each traffic generator must implement.
     """
 
+    _config: TrafficGeneratorConfig
+    _tg_node: Node
     _logger: DTSLOG
 
+    def __init__(self, tg_node: Node, config: TrafficGeneratorConfig):
+        self._config = config
+        self._tg_node = tg_node
+        self._logger = getLogger(
+            f"{self._tg_node.name} {self._config.traffic_generator_type}"
+        )
+
     def send_packet(self, packet: Packet, port: Port) -> None:
         """Send a packet and block until it is fully sent.
 
diff --git a/dts/framework/testbed_model/hw/virtual_device.py b/dts/framework/testbed_model/virtual_device.py
similarity index 100%
rename from dts/framework/testbed_model/hw/virtual_device.py
rename to dts/framework/testbed_model/virtual_device.py
diff --git a/dts/framework/utils.py b/dts/framework/utils.py
index d27c2c5b5f..07e2d1c076 100644
--- a/dts/framework/utils.py
+++ b/dts/framework/utils.py
@@ -7,7 +7,6 @@
 import json
 import os
 import subprocess
-import sys
 from enum import Enum
 from pathlib import Path
 from subprocess import SubprocessError
@@ -16,6 +15,8 @@
 
 from .exception import ConfigurationError
 
+REGEX_FOR_PCI_ADDRESS = "/[0-9a-fA-F]{4}:[0-9a-fA-F]{2}:[0-9a-fA-F]{2}.[0-9]{1}/"
+
 
 class StrEnum(Enum):
     @staticmethod
@@ -28,25 +29,6 @@ def __str__(self) -> str:
         return self.name
 
 
-REGEX_FOR_PCI_ADDRESS = "/[0-9a-fA-F]{4}:[0-9a-fA-F]{2}:[0-9a-fA-F]{2}.[0-9]{1}/"
-
-
-def check_dts_python_version() -> None:
-    if sys.version_info.major < 3 or (
-        sys.version_info.major == 3 and sys.version_info.minor < 10
-    ):
-        print(
-            RED(
-                (
-                    "WARNING: DTS execution node's python version is lower than"
-                    "python 3.10, is deprecated and will not work in future releases."
-                )
-            ),
-            file=sys.stderr,
-        )
-        print(RED("Please use Python >= 3.10 instead"), file=sys.stderr)
-
-
 def expand_range(range_str: str) -> list[int]:
     """
     Process range string into a list of integers. There are two possible formats:
@@ -77,37 +59,6 @@ def get_packet_summaries(packets: list[Packet]):
     return f"Packet contents: \n{packet_summaries}"
 
 
-def RED(text: str) -> str:
-    return f"\u001B[31;1m{str(text)}\u001B[0m"
-
-
-class MesonArgs(object):
-    """
-    Aggregate the arguments needed to build DPDK:
-    default_library: Default library type, Meson allows "shared", "static" and "both".
-               Defaults to None, in which case the argument won't be used.
-    Keyword arguments: The arguments found in meson_options.txt in root DPDK directory.
-               Do not use -D with them, for example:
-               meson_args = MesonArgs(enable_kmods=True).
-    """
-
-    _default_library: str
-
-    def __init__(self, default_library: str | None = None, **dpdk_args: str | bool):
-        self._default_library = (
-            f"--default-library={default_library}" if default_library else ""
-        )
-        self._dpdk_args = " ".join(
-            (
-                f"-D{dpdk_arg_name}={dpdk_arg_value}"
-                for dpdk_arg_name, dpdk_arg_value in dpdk_args.items()
-            )
-        )
-
-    def __str__(self) -> str:
-        return " ".join(f"{self._default_library} {self._dpdk_args}".split())
-
-
 class _TarCompressionFormat(StrEnum):
     """Compression formats that tar can use.
 
diff --git a/dts/main.py b/dts/main.py
index 43311fa847..060ff1b19a 100755
--- a/dts/main.py
+++ b/dts/main.py
@@ -10,10 +10,11 @@
 
 import logging
 
-from framework import dts
+from framework import dts, settings
 
 
 def main() -> None:
+    settings.set_settings()
     dts.run_all()
 
 
-- 
2.34.1