feat(config): allow overriding config from environment (#10)

README.md

@@ -83,6 +83,17 @@ dependency-mapping = {"package-name"= {"repo"= "https://github.com/example/packa
 > Note: the `dependency-mapping` is merged with the default mapping, so you don't need to specify the default mapping if you want to add a new mapping.
 > Repos urls will be normalized to http(s), with the trailing slash removed.
 
+### From environment
+
+Some settings are overridable by environment variables with the following `SYNC_PRE_COMMIT_LOCK_*` prefixed environment variables:
+
+| `toml` setting                | environment                            | format                            |
+| ------------------------------|----------------------------------------|-----------------------------------|
+| `automatically-install-hooks` | `SYNC_PRE_COMMIT_LOCK_INSTALL`         | `bool` as string (`true`, `1`...) |
+| `disable-sync-from-lock`      | `SYNC_PRE_COMMIT_LOCK_DISABLED`        | `bool` as string (`true`, `1`...) |
+| `ignore`                      | `SYNC_PRE_COMMIT_LOCK_IGNORE`          | comma-separated list              |
+| `pre-commit-config-file`      | `SYNC_PRE_COMMIT_LOCK_PRE_COMMIT_FILE` | `str`                             |
+
 ## Usage
 
 Once installed, and optionally configured, the plugin usage should be transparent, and trigger when you run applicable PDM or Poetry commands, like `pdm lock`, or `poetry lock`.

src/sync_pre_commit_lock/config.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
+import os
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Callable, TypedDict
 
 try:
     # 3.11+
@@ -16,6 +17,16 @@
 
     pass
 
+ENV_PREFIX = "SYNC_PRE_COMMIT_LOCK"
+
+
+def env_as_bool(value: str) -> bool:
+    return (value or "False").lower() in ("true", "1")
+
+
+def env_as_list(value: str) -> list[str]:
+    return [v.strip() for v in (value or "").split(",")]
+
 
 def from_toml(data: dict[str, Any]) -> SyncPreCommitLockConfig:
     fields = {f.metadata.get("toml", f.name): f for f in SyncPreCommitLockConfig.__dataclass_fields__.values()}
@@ -33,13 +44,50 @@ def from_toml(data: dict[str, Any]) -> SyncPreCommitLockConfig:
     )
 
 
+def update_from_env(config: SyncPreCommitLockConfig) -> SyncPreCommitLockConfig:
+    vars = {
+        f.metadata["env"]: f for f in SyncPreCommitLockConfig.__dataclass_fields__.values() if f.metadata.get("env")
+    }
+    for var, specs in vars.items():
+        if value := os.getenv(f"{ENV_PREFIX}_{var}"):
+            caster = specs.metadata.get("cast", lambda v: v)
+            setattr(config, specs.name, caster(value))
+    return config
+
+
+class Metadata(TypedDict, total=False):
+    """Configuration metadata known fields"""
+
+    toml: str
+    """Map the `toml` field"""
+    env: str
+    """Optionnaly map the environment variable suffix"""
+    cast: Callable[[str], Any]
+    """Optionnaly provide a cast function for environment variable"""
+
+
 @dataclass
 class SyncPreCommitLockConfig:
-    automatically_install_hooks: bool = field(default=True, metadata={"toml": "automatically-install-hooks"})
-    disable_sync_from_lock: bool = field(default=False, metadata={"toml": "disable-sync-from-lock"})
-    ignore: list[str] = field(default_factory=list, metadata={"toml": "ignore"})
-    pre_commit_config_file: str = field(metadata={"toml": "pre-commit-config-file"}, default=".pre-commit-config.yaml")
-    dependency_mapping: PackageRepoMapping = field(default_factory=dict, metadata={"toml": "dependency-mapping"})
+    automatically_install_hooks: bool = field(
+        default=True,
+        metadata=Metadata(toml="automatically-install-hooks", env="INSTALL", cast=env_as_bool),
+    )
+    disable_sync_from_lock: bool = field(
+        default=False,
+        metadata=Metadata(toml="disable-sync-from-lock", env="DISABLED", cast=env_as_bool),
+    )
+    ignore: list[str] = field(
+        default_factory=list,
+        metadata=Metadata(toml="ignore", env="IGNORE", cast=env_as_list),
+    )
+    pre_commit_config_file: str = field(
+        default=".pre-commit-config.yaml",
+        metadata=Metadata(toml="pre-commit-config-file", env="PRE_COMMIT_FILE"),
+    )
+    dependency_mapping: PackageRepoMapping = field(
+        default_factory=dict,
+        metadata=Metadata(toml="dependency-mapping"),
+    )
 
 
 def load_config(path: Path | None = None) -> SyncPreCommitLockConfig:
@@ -52,4 +100,4 @@ def load_config(path: Path | None = None) -> SyncPreCommitLockConfig:
     if not tool_dict or len(tool_dict) == 0:
         return SyncPreCommitLockConfig()
 
-    return from_toml(tool_dict)
+    return update_from_env(from_toml(tool_dict))

tests/test_config.py

@@ -1,6 +1,7 @@
 from unittest.mock import MagicMock, patch
 
-from sync_pre_commit_lock.config import SyncPreCommitLockConfig, from_toml, load_config
+import pytest
+from sync_pre_commit_lock.config import SyncPreCommitLockConfig, from_toml, load_config, update_from_env
 from sync_pre_commit_lock.db import RepoInfo
 
 
@@ -23,6 +24,24 @@ def test_from_toml() -> None:
     assert actual_config == expected_config
 
 
+def test_update_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_DISABLED", "1")
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_INSTALL", "false")
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_IGNORE", "a, b")
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_PRE_COMMIT_FILE", ".test-config.yaml")
+    expected_config = SyncPreCommitLockConfig(
+        automatically_install_hooks=False,
+        disable_sync_from_lock=True,
+        ignore=["a", "b"],
+        pre_commit_config_file=".test-config.yaml",
+        dependency_mapping={},
+    )
+
+    actual_config = update_from_env(SyncPreCommitLockConfig())
+
+    assert actual_config == expected_config
+
+
 def test_sync_pre_commit_lock_config() -> None:
     config = SyncPreCommitLockConfig(
         disable_sync_from_lock=True,
@@ -63,3 +82,20 @@ def test_load_config_with_data(mock_from_toml: MagicMock, mock_open: MagicMock,
     mock_path.open.assert_called_once_with("rb")
     mock_load.assert_called_once()
     mock_from_toml.assert_called_once_with({"disable": True})
+
+
+@patch("sync_pre_commit_lock.config.toml.load", return_value={"tool": {"sync-pre-commit-lock": {"ignore": ["fake"]}}})
+@patch("builtins.open", new_callable=MagicMock)
+def test_env_override_config(mock_open: MagicMock, mock_load: MagicMock, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_DISABLED", "true")
+    monkeypatch.setenv("SYNC_PRE_COMMIT_LOCK_IGNORE", "a, b")
+    expected_config = SyncPreCommitLockConfig(
+        disable_sync_from_lock=True,
+        ignore=["a", "b"],
+    )
+    mock_path = MagicMock()
+    mock_path.open = mock_open(read_data="dummy_stream")
+    actual_config = load_config(mock_path)
+
+    assert actual_config == expected_config
+    mock_path.open.assert_called_once_with("rb")