add variables.py, holds global variables

getmac/variables.py

@@ -0,0 +1,125 @@
+import logging
+import os
+import platform
+import sys
+from typing import Dict, List
+
+
+# TODO: methods to print, dump, etc variables
+# TODO: type validation?
+class VarsClass:
+    pass
+
+
+class Settings(VarsClass):
+    """
+    User-configurable settings.
+    """
+
+    #: Debugging level. Increased value => more output. 4 is roughly the highest.
+    DEBUG: int = 0
+
+    #: UDP port to use for populating the ARP table
+    PORT: int = 55555
+
+    #: User-configurable override to force a specific platform
+    # TODO: This will change to a function argument in 1.0.0
+    OVERRIDE_PLATFORM: str = ""
+
+    #: Force a specific method to be used for all lookups
+    #: Used for debugging and testing
+    FORCE_METHOD: str = ""
+
+
+class Constants(VarsClass):
+    """
+    Platform identifiers and other constants.
+    """
+
+    _UNAME: platform.uname_result = platform.uname()
+    _SYST: str = _UNAME.system
+    WINDOWS: bool = _SYST == "Windows"
+    DARWIN: bool = _SYST == "Darwin"
+    OPENBSD: bool = _SYST == "OpenBSD"
+    FREEBSD: bool = _SYST == "FreeBSD"
+    NETBSD: bool = _SYST == "NetBSD"
+    SOLARIS: bool = _SYST == "SunOS"
+    #: Not including Darwin or Solaris as a "BSD"
+    BSD: bool = OPENBSD or FREEBSD or NETBSD
+
+    #: Windows Subsystem for Linux (WSL)
+    #: WSL1: abstraction layer remapping Linux syscalls to Windows syscalls
+    #: WSL2: fancy Linux VM on Hyper-V
+    WSL1: bool = (
+        _SYST == "Linux"
+        and "Microsoft" in _UNAME.version
+        and "-WSL2" not in _UNAME.release
+    )
+    WSL2: bool = (
+        _SYST == "Linux"
+        and "Microsoft" not in _UNAME.version
+        and "-WSL2" in _UNAME.release
+    )
+    LINUX: bool = _SYST == "Linux" and not WSL1
+
+    #: NOTE: "Linux" methods apply to Android without modifications
+    #: If there's Android-specific stuff then we can add a platform
+    #: identifier for it.
+    ANDROID: bool = (
+        hasattr(sys, "getandroidapilevel") or "ANDROID_STORAGE" in os.environ
+    )
+
+    #: Generic platform identifier used for filtering methods
+    # TODO: change to "wsl1", since WSL2 method should just work like normal linux
+    PLATFORM: str = "wsl" if (LINUX and WSL1) else _SYST.lower()
+
+    MAC_RE_COLON: str = r"([0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){5})"
+    MAC_RE_DASH: str = r"([0-9a-fA-F]{2}(?:-[0-9a-fA-F]{2}){5})"
+    #: On OSX, some MACs in arp output may have a single digit instead of two
+    #: Examples: "18:4f:32:5a:64:5", "14:cc:20:1a:99:0"
+    #: This can also happen on other platforms, like Solaris
+    MAC_RE_SHORT: str = r"([0-9a-fA-F]{1,2}(?::[0-9a-fA-F]{1,2}){5})"
+
+
+class Variables(VarsClass):
+    """
+    Things that can change. Essentially most of the global variables in getmac.
+    """
+
+    #: Get and cache the configured system PATH on import
+    #: The process environment does not change after a process is started
+    PATH: List[str] = os.environ.get("PATH", os.defpath).split(os.pathsep)
+    PATH_STR: str = os.pathsep.join(PATH)
+
+    #: Use a copy of the environment so we don't
+    #: modify the process's current environment.
+    ENV: Dict[str, str] = dict(os.environ)
+
+    #: Cache of commands that have been checked for existence by check_command()
+    CHECK_COMMAND_CACHE: Dict[str, bool] = {}
+
+    #: Configure logging
+    log = logging.getLogger("getmac")  # type: logging.Logger
+    if not log.handlers:
+        log.addHandler(logging.NullHandler())
+
+    def __init__(self) -> None:
+        super().__init__()
+
+        self.ENV["LC_ALL"] = "C"  # Ensure ASCII output so we parse correctly
+
+        if not Constants.WINDOWS:
+            self.PATH.extend(("/sbin", "/usr/sbin"))
+        else:
+            # TODO: Prevent edge case on Windows where our script "getmac.exe"
+            #   gets added to the path ahead of the actual Windows getmac.exe
+            #   This just handles case where it's in a virtualenv, won't work /w global scripts
+            self.PATH = [p for p in self.PATH if "\\getmac\\Scripts" not in p]
+
+        # Build the str after modifications are made
+        self.PATH_STR = os.pathsep.join(self.PATH)
+
+
+settings = Settings()
+consts = Constants()
+gvars = Variables()