feat: configuration support (#684)

* feat: configuration support

* refactor: include manylinux, minor redesign

* "project global" overrides "default platform"

This allows overriding `repair-wheel-command` in the `[tool.cibuildwheel.global]` section.

* fix: add PyPy images

* refactor: remove global

* fix: support tables and arrays

* docs: add pyproject.toml config to docs

* docs: updates based on feedback

* fix: only join if sensible

* refactor: remove manylinux dict

* docs: examples headers and sections on each

* feat: support changing the config from the command line

* fix: use {package}

* tests: add a few tests and mention config one more place

* Restyle examples tabs to remove indent

* Unrelated docs improvements

* Absorb extra content into the tab

* Make the tabs smaller and to the right

* Copy edits to options

* Fix header ids

* Use fewer [tool.cibuildwheel] headers

* docs: minor additions/fixes

* feat: disallow options on some platforms

* docs: make the examples a tiny bit more tabby

* fix: enforce tables/lists are optionally separate

* Some unrelated fixes to the other tab styling

* Minor fix to tab styling

* Refactor to make code a bit more linear and immutable

* Minor docs changes

Co-authored-by: mayeut <mayeut@users.noreply.github.com>
Co-authored-by: Joe Rickerby <joerick@mac.com>

cibuildwheel/options.py

@@ -0,0 +1,171 @@
+import os
+from pathlib import Path
+from typing import Any, Dict, List, Mapping, Optional, Set, Tuple, Union
+
+import toml
+
+from .typing import PLATFORMS, TypedDict
+from .util import resources_dir
+
+Setting = Union[Dict[str, str], List[str], str]
+
+
+class TableFmt(TypedDict):
+    item: str
+    sep: str
+
+
+class ConfigOptionError(KeyError):
+    pass
+
+
+def _dig_first(*pairs: Tuple[Mapping[str, Any], str]) -> Setting:
+    """
+    Return the first dict item that matches from pairs of dicts and keys.
+    Final result is will throw a KeyError if missing.
+
+    _dig_first((dict1, "key1"), (dict2, "key2"), ...)
+    """
+    (dict_like, key), *others = pairs
+    return dict_like.get(key, _dig_first(*others)) if others else dict_like[key]
+
+
+class ConfigOptions:
+    """
+    Gets options from the environment, config or defaults, optionally scoped
+    by the platform.
+
+    Example:
+      >>> options = ConfigOptions(package_dir, platform='macos')
+      >>> options('cool-color')
+
+      This will return the value of CIBW_COOL_COLOR_MACOS if it exists,
+      otherwise the value of CIBW_COOL_COLOR, otherwise
+      'tool.cibuildwheel.macos.cool-color' or 'tool.cibuildwheel.cool-color'
+      from pyproject.toml, or from cibuildwheel/resources/defaults.toml. An
+      error is thrown if there are any unexpected keys or sections in
+      tool.cibuildwheel.
+    """
+
+    def __init__(
+        self,
+        package_path: Path,
+        config_file: Optional[str] = None,
+        *,
+        platform: str,
+        disallow: Optional[Dict[str, Set[str]]] = None,
+    ) -> None:
+        self.platform = platform
+        self.disallow = disallow or {}
+
+        # Open defaults.toml, loading both global and platform sections
+        defaults_path = resources_dir / "defaults.toml"
+        self.default_options, self.default_platform_options = self._load_file(defaults_path)
+
+        # load the project config file
+        config_options: Dict[str, Any] = {}
+        config_platform_options: Dict[str, Any] = {}
+
+        if config_file is not None:
+            config_path = Path(config_file.format(package=package_path))
+            config_options, config_platform_options = self._load_file(config_path)
+        else:
+            # load pyproject.toml, if it's available
+            pyproject_toml_path = package_path / "pyproject.toml"
+            if pyproject_toml_path.exists():
+                config_options, config_platform_options = self._load_file(pyproject_toml_path)
+
+        # validate project config
+        for option_name in config_options:
+            if not self._is_valid_global_option(option_name):
+                raise ConfigOptionError(f'Option "{option_name}" not supported in a config file')
+
+        for option_name in config_platform_options:
+            if not self._is_valid_platform_option(option_name):
+                raise ConfigOptionError(
+                    f'Option "{option_name}" not supported in the "{self.platform}" section'
+                )
+
+        self.config_options = config_options
+        self.config_platform_options = config_platform_options
+
+    def _is_valid_global_option(self, name: str) -> bool:
+        """
+        Returns True if an option with this name is allowed in the
+        [tool.cibuildwheel] section of a config file.
+        """
+        allowed_option_names = self.default_options.keys() | PLATFORMS
+
+        return name in allowed_option_names
+
+    def _is_valid_platform_option(self, name: str) -> bool:
+        """
+        Returns True if an option with this name is allowed in the
+        [tool.cibuildwheel.<current-platform>] section of a config file.
+        """
+        disallowed_platform_options = self.disallow.get(self.platform, set())
+        if name in disallowed_platform_options:
+            return False
+
+        allowed_option_names = self.default_options.keys() | self.default_platform_options.keys()
+
+        return name in allowed_option_names
+
+    def _load_file(self, filename: Path) -> Tuple[Dict[str, Any], Dict[str, Any]]:
+        """
+        Load a toml file, returns global and platform as separate dicts.
+        """
+        config = toml.load(filename)
+
+        global_options = config.get("tool", {}).get("cibuildwheel", {})
+        platform_options = global_options.get(self.platform, {})
+
+        return global_options, platform_options
+
+    def __call__(
+        self,
+        name: str,
+        *,
+        env_plat: bool = True,
+        sep: Optional[str] = None,
+        table: Optional[TableFmt] = None,
+    ) -> str:
+        """
+        Get and return the value for the named option from environment,
+        configuration file, or the default. If env_plat is False, then don't
+        accept platform versions of the environment variable. If this is an
+        array it will be merged with "sep" before returning. If it is a table,
+        it will be formatted with "table['item']" using {k} and {v} and merged
+        with "table['sep']".
+        """
+
+        if name not in self.default_options and name not in self.default_platform_options:
+            raise ConfigOptionError(f"{name} must be in cibuildwheel/resources/defaults.toml file")
+
+        # Environment variable form
+        envvar = f"CIBW_{name.upper().replace('-', '_')}"
+        plat_envvar = f"{envvar}_{self.platform.upper()}"
+
+        # get the option from the environment, then the config file, then finally the default.
+        # platform-specific options are preferred, if they're allowed.
+        result = _dig_first(
+            (os.environ if env_plat else {}, plat_envvar),  # type: ignore
+            (os.environ, envvar),
+            (self.config_platform_options, name),
+            (self.config_options, name),
+            (self.default_platform_options, name),
+            (self.default_options, name),
+        )
+
+        if isinstance(result, dict):
+            if table is None:
+                raise ConfigOptionError(f"{name} does not accept a table")
+            return table["sep"].join(table["item"].format(k=k, v=v) for k, v in result.items())
+        elif isinstance(result, list):
+            if sep is None:
+                raise ConfigOptionError(f"{name} does not accept a list")
+            return sep.join(result)
+        elif isinstance(result, int):
+            return str(result)
+        else:
+            return result