Files
esphome/esphome/platformio/extra_script.py
T

259 lines
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Python

"""Run a PlatformIO ``extraScript`` against a captured SCons-env stand-in.
PlatformIO libraries occasionally configure per-target link/build state
via a Python ``extraScript`` declared in ``library.json``'s ``build``
section instead of static fields. The script runs under SCons during
PIO's build and mutates the active ``Environment`` (``env.Append``,
``env.Replace``, …) — chiefly to set ``LIBPATH``/``LIBS`` per chip MCU.
ESPHome's PIO→IDF converter doesn't run SCons, so these scripts were
previously ignored and any library
relying on them failed to link under ``toolchain: esp-idf``. This
module provides a small shim that ``exec``s an extra-script with a
fake ``env`` object, captures the common ``env.Append(...)`` calls,
and returns the captured vars so the caller can fold them back into
the library's generated CMakeLists.
Caveats
-------
* Only the ``env.Append`` API is captured. ``env.Replace``,
``env.Prepend``, ``env.AddPreAction``, SCons file generators, and any
arbitrary I/O are no-ops, logged once per method. Scripts that depend
on those will produce incomplete output.
* Running arbitrary Python from third-party libraries is a non-trivial
trust decision. The shim does no sandboxing — anything in the
script's process can run. Use only with libraries whose source you
trust.
"""
from __future__ import annotations
from collections.abc import Callable
from dataclasses import dataclass, field
import logging
import os
from pathlib import Path
from typing import TYPE_CHECKING
from esphome.core import EsphomeError
if TYPE_CHECKING:
from esphome.platformio.library import ConvertedLibrary
_LOGGER = logging.getLogger(__name__)
def apply_extra_script(
component: ConvertedLibrary,
board_mcu: Callable[[], str],
pio_platform: str,
) -> None:
"""Run a library's PIO ``extraScript`` and fold its captured env vars into
``component.data["build"]["flags"]`` so the backend's -L/-l/-D extraction
picks them up. Shared by the ESP-IDF and ESP8266 Arduino backends.
``board_mcu`` is a callable so a backend whose target lookup needs build
state (the esp32 variant) resolves it only when a script will run.
``pio_platform`` is exposed to the script as PlatformIO's ``PIOPLATFORM``.
"""
extra_script = component.data.get("build", {}).get("extraScript")
if not extra_script:
return
# Resolve and confine to the library's source dir so a malicious
# library.json can't escape (e.g. ``"extraScript": "../../etc/passwd"``).
source_path = component.source_dir
library_root = source_path.resolve()
script_path = (source_path / extra_script).resolve()
if not script_path.is_relative_to(library_root):
# More hostile than a missing script; must not be quieter than it
raise EsphomeError(
f"extraScript {extra_script} of library {component.name} escapes "
"the library directory"
)
if not script_path.is_file():
# A declared-but-absent script is a broken or half-downloaded
# package, not an unsupported script; PlatformIO fails on it too
raise EsphomeError(
f"extraScript {extra_script} of library {component.name} not found"
)
result = run_extra_script(
script_path,
library_dir=source_path,
board_mcu=board_mcu(),
pio_platform=pio_platform,
)
extra_flags = captured_as_build_flags(result, library_dir=source_path)
if not extra_flags:
return
flags = component.data.setdefault("build", {}).setdefault("flags", [])
if isinstance(flags, str):
flags = [flags]
elif not isinstance(flags, list):
# A null/dict value coerced through a list wrapper would inject a
# non-string into the compiler command line; fail naming the library
raise EsphomeError(
f"Library {component.name} has a malformed build.flags "
f"({type(flags).__name__}); expected a string or list"
)
component.data["build"]["flags"] = [*flags, *extra_flags]
# Keys we know how to translate back into ESPHome's build-flag pipeline.
# Other env.Append kwargs are recorded but ignored downstream.
_CAPTURED_KEYS = frozenset({"LIBPATH", "LIBS", "CPPDEFINES", "LINKFLAGS", "CPPFLAGS"})
@dataclass
class ExtraScriptResult:
"""Build-var deltas captured from a PIO extra-script ``env.Append`` call."""
libpath: list[str] = field(default_factory=list)
libs: list[str] = field(default_factory=list)
cppdefines: list[str | tuple[str, str]] = field(default_factory=list)
linkflags: list[str] = field(default_factory=list)
cppflags: list[str] = field(default_factory=list)
class _FakeSConsEnv:
"""Minimal stand-in for SCons ``Environment`` exposed to extra-scripts.
Implements just enough surface area to let scripts query ``BOARD_MCU``
/ ``PIOENV`` and call ``env.Append(LIBPATH=…, LIBS=…, …)``. Every
other env method swallows silently so unrelated calls don't raise
``AttributeError`` and abort the script.
"""
def __init__(self, *, board_mcu: str, pio_env: str, pio_platform: str) -> None:
self._vars: dict[str, str] = {
"BOARD_MCU": board_mcu,
"PIOPLATFORM": pio_platform,
"PIOENV": pio_env,
}
self.result = ExtraScriptResult()
self._warned_methods: set[str] = set()
# ----- SCons env API the common scripts use -----
def get(self, key: str, default: str | None = None) -> str | None:
return self._vars.get(key, default)
def Append(self, **kwargs) -> None: # noqa: N802 (SCons API name)
for key, value in kwargs.items():
if key not in _CAPTURED_KEYS:
# Diagnosable from the build log when a script configures
# something this shim does not translate
_LOGGER.warning(
"PIO extra-script env.Append(%s=...) is not captured; ignoring",
key,
)
continue
items = list(value) if isinstance(value, (list, tuple)) else [value]
bucket = getattr(self.result, key.lower())
bucket.extend(items)
# ----- Everything else is a no-op so unsupported scripts don't crash -----
def __getattr__(self, name: str):
def _noop(*args, **kwargs):
# Once per method: a script whose whole effect is env.Replace()
# must be diagnosable from a normal build log
if name not in self._warned_methods:
self._warned_methods.add(name)
_LOGGER.warning(
"PIO extra-script env.%s(...) is not supported; ignoring", name
)
return _noop
def run_extra_script(
script_path: Path,
*,
library_dir: Path,
board_mcu: str,
pio_platform: str,
) -> ExtraScriptResult:
"""Execute ``script_path`` with a fake SCons env and return captured vars.
``board_mcu`` is the active MCU name (e.g. ``esp32``,
``esp32s3``); it's exposed to the script as PlatformIO's
``BOARD_MCU`` so chip-conditional logic resolves the same way it
would under PIO. The script runs with ``library_dir`` as the
process CWD so relative-path lookups (``join``, ``realpath``,
``open``) resolve against the library tree.
On any exception inside the script we warn and return an empty result
(never a partial capture, which could build wrong-output firmware) —
extra-scripts are best-effort, and an unsupported script shouldn't
block the build.
"""
env = _FakeSConsEnv(
board_mcu=board_mcu,
pio_env=f"esphome_{board_mcu}",
pio_platform=pio_platform,
)
old_cwd = Path.cwd()
try:
# Inside the try: a SyntaxError or bad encoding in a vendored script
# is just as best-effort as a runtime failure
code = compile(
script_path.read_text(encoding="utf-8"), str(script_path), "exec"
)
os.chdir(library_dir)
exec( # noqa: S102 pylint: disable=exec-used
code,
{
"Import": lambda *_args: None, # SCons-side import; harmless here
"env": env,
"__file__": str(script_path),
"__name__": "__pio_extra_script__",
},
)
except (SystemExit, Exception) as e: # noqa: BLE001 # pylint: disable=broad-exception-caught
# Discard any partial capture: folding half a script's flags into the
# build could produce wrong-output firmware that links cleanly. The
# warning plus the resulting loud link error point back here.
_LOGGER.warning(
"PIO extra-script %s (in %s) raised %r; ignoring its output",
script_path,
library_dir.name,
e,
)
return ExtraScriptResult()
finally:
os.chdir(old_cwd)
return env.result
def captured_as_build_flags(
result: ExtraScriptResult, *, library_dir: Path
) -> list[str]:
"""Translate captured env vars into the ``-L`` / ``-l`` / ``-D`` /
raw-flag form ``_generate_cmakelists_txt`` already knows how to consume.
``LIBPATH`` entries are made relative to ``library_dir`` so the
generated CMakeLists is portable; absolute paths outside the library
tree are kept as-is (CMake handles absolute paths in
``target_link_directories`` fine).
"""
flags: list[str] = []
library_root = library_dir.resolve()
for path in result.libpath:
# Anchor relative paths to library_dir (not the current CWD, which
# has been restored by the time we get here). Joining an absolute
# path against library_dir returns the absolute path unchanged.
resolved = (library_dir / path).resolve()
try:
flags.append(f"-L{resolved.relative_to(library_root)}")
except ValueError:
flags.append(f"-L{resolved}")
flags.extend(f"-l{lib}" for lib in result.libs)
for define in result.cppdefines:
if isinstance(define, tuple) and len(define) == 2:
flags.append(f"-D{define[0]}={define[1]}")
else:
flags.append(f"-D{define}")
flags.extend(result.linkflags)
flags.extend(result.cppflags)
return flags