Refactor installer and general design patterns (#1895)

* fix: refactor clear_vt100_escape_codes

* fix: check for structure being a dict after handling potential parsing errors

* refactor: use short circuit logic than if-elif-else chains

* fix: use or for nullish moutpoint attribute

* fix: better error handling for JSON from urls and paths

* chore: json_stream_to_structure documentation

* refactor: dry up relative and chroot path for custom command scripts

* refactor: use write_text for pathlib.Path object

* refactor: use sets to find intersection instead of filter and list

* refactor: replace loop with dictionary comprehension in preparing luks partition

* refactor: use walrus operator to check if luks_handler exists

* refactor: use read_text and splitlines for potential Path object

* fix: use keepends in splitlines for compatibility

* fix: use keepends in splitlines for compatibility

* feat: set pacman_conf Path as an attribute of installer

* fix: empty string is a part of any string, avoid tuples

* refactor: use iterator patterns to uncomment multilib and testing blocks

* fix: don't json.loads an already loaded structure

* fix: use fstab_path uniformly in genfstab

* fix: remove unused variable matched

* refactor: create separate class to modify pacman.conf in a single pass

* fix: remove unused attribute pacman_conf from installer

* fix: remove unused attribute pacman_conf from installer

* feat: add persist method for pacman.conf, rewrite only when needed

* fix: use path.write_text for locale.conf

* use `or` operator for nullish new_conf

* refactor: Installer.target is always a pathlib.Path object, do not check for string type

* fix: use Optional[str] in function type definition instead of sumtype of str and None

* fix: mypy type annotation

* fix: make flake8 happy

* chore: move pacman config and repo into pacman module

* refactor: use Pacman object instead of Installer's pacstrap method

* fix: break after first sync

* fix: keep old build script for now

* use nullish operator for base_packages and disk_encryption of Installer

* feat: use shutil.which instead of rolling our own implementation

* fix: check for binary only if list is not empty

* fix: import Enum and fix mypy errors

* refactor: use nullish operator for default values

* refactor: linear search for key in Installer._trace_log only once

* fix: use logs instead of the entirety of self._trace_log when searching for key

* refactor: do not copy slice of bytes for search

* refactor: use rfind only once to iterate over logs, do not raise ValueError in clear_vt100_escape_codes since TYPE_CHECKING will take care of it.

* refactor: try decoding trace log before falling back to strigification

* refactor: use an empty dict as default for callbacks in SysCommand.__init__

* refactor: use nullish or operator for slice start and end when not specified

* refactor: use nullish or operator for SysCommand session

* refactor: use pre-existing decode method in __repr__ for SysCommand

* fix: overindentation

* fix: use shallow copy of callbacks to prevent mutating the key-value relationships of the argument dict

* refactor: use truthy value of self.session is not None for json encoding SysCommand

* refactor: directly assign to SysCommand.session in create_session since it short circuits to True if already present

* refactor: use dict.items() instead of manually retrieving the value using the key

* refactor: user_config_to_json method sounds pretty self explanatory

* refactor: store path validity as boolean for return

* refactor: use pathlib.Path.write_text to write configs to destinations

* fix: cannot use assignment expressions with expression

* fix: use config_output.save for saving both config and creds

* refactor: switch dictionary keys and values for options to avoid redundancy

* refactor: use itertools.takewhile to collect locale.gen entries until the empty line

* refactor: use iterative approach for nvidia driver fix

* refactor: install packages if not nvidia

* refactor: return early if no profile is selected

* refactor: use strip to remove commented lines

* fix: install additional packages only when we have a driver

* fix: path with one command is matched as relative to '.'

* fix: remove translation for debug log

---------

Co-authored-by: Anton Hvornum <anton@hvornum.se>

3 files changed, 127 insertions, 0 deletions

diff --git a/archinstall/lib/pacman/__init__.py b/archinstall/lib/pacman/__init__.py
new file mode 100644
index 00000000..6478f0cc
--- /dev/null
+++ b/archinstall/lib/pacman/__init__.py
@@ -0,0 +1,88 @@
+from pathlib import Path
+import time
+import re
+from typing import TYPE_CHECKING, Any, List, Callable, Union
+from shutil import copy2
+
+from ..general import SysCommand
+from ..output import warn, error, info
+from .repo import Repo
+from .config import Config
+from ..exceptions import RequirementError
+from ..plugins import plugins
+
+if TYPE_CHECKING:
+	_: Any
+
+
+class Pacman:
+
+	def __init__(self, target: Path, silent: bool = False):
+		self.synced = False
+		self.silent = silent
+		self.target = target
+
+	@staticmethod
+	def run(args :str, default_cmd :str = 'pacman') -> SysCommand:
+		"""
+		A centralized function to call `pacman` from.
+		It also protects us from colliding with other running pacman sessions (if used locally).
+		The grace period is set to 10 minutes before exiting hard if another pacman instance is running.
+		"""
+		pacman_db_lock = Path('/var/lib/pacman/db.lck')
+
+		if pacman_db_lock.exists():
+			warn(_('Pacman is already running, waiting maximum 10 minutes for it to terminate.'))
+
+		started = time.time()
+		while pacman_db_lock.exists():
+			time.sleep(0.25)
+
+			if time.time() - started > (60 * 10):
+				error(_('Pre-existing pacman lock never exited. Please clean up any existing pacman sessions before using archinstall.'))
+				exit(1)
+
+		return SysCommand(f'{default_cmd} {args}')
+
+	def ask(self, error_message: str, bail_message: str, func: Callable, *args, **kwargs):
+		while True:
+			try:
+				func(*args, **kwargs)
+				break
+			except Exception as err:
+				error(f'{error_message}: {err}')
+				if not self.silent and input('Would you like to re-try this download? (Y/n): ').lower().strip() in 'y':
+					continue
+				raise RequirementError(f'{bail_message}: {err}')
+
+	def sync(self):
+		if self.synced:
+			return
+		self.ask(
+			'Could not sync a new package database',
+			'Could not sync mirrors',
+			self.run,
+			'-Syy',
+			default_cmd='/usr/bin/pacman'
+		)
+		self.synced = True
+
+	def strap(self, packages: Union[str, List[str]]):
+		self.sync()
+		if isinstance(packages, str):
+			packages = [packages]
+
+		for plugin in plugins.values():
+			if hasattr(plugin, 'on_pacstrap'):
+				if (result := plugin.on_pacstrap(packages)):
+					packages = result
+
+		info(f'Installing packages: {packages}')
+
+		self.ask(
+			'Could not strap in packages',
+			'Pacstrap failed. See /var/log/archinstall/install.log or above message for error details',
+			SysCommand,
+			f'/usr/bin/pacstrap -C /etc/pacman.conf -K {self.target} {" ".join(packages)} --noconfirm',
+			peek_output=True
+		)
diff --git a/archinstall/lib/pacman/config.py b/archinstall/lib/pacman/config.py
new file mode 100644
index 00000000..60d202bc
--- /dev/null
+++ b/archinstall/lib/pacman/config.py
@@ -0,0 +1,33 @@
+import re
+from pathlib import Path
+from shutil import copy2
+from typing import List
+
+from .repo import Repo
+
+
+class Config:
+	def __init__(self, target: Path):
+		self.path = Path("/etc") / "pacman.conf"
+		self.chroot_path = target / "etc" / "pacman.conf"
+		self.patterns: List[re.Pattern] = []
+
+	def enable(self, repo: Repo):
+		self.patterns.append(re.compile(r"^#\s*\[{}\]$".format(repo.value)))
+
+	def apply(self):
+		if not self.patterns:
+			return
+		lines = iter(self.path.read_text().splitlines(keepends=True))
+		with open(self.path, 'w') as f:
+			for line in lines:
+				if any(pattern.match(line) for pattern in self.patterns):
+					# Uncomment this line and the next.
+					f.write(line.lstrip('#'))
+					f.write(next(lines).lstrip('#'))
+				else:
+					f.write(line)
+	
+	def persist(self):
+		if self.patterns:
+			copy2(self.path, self.chroot_path)
diff --git a/archinstall/lib/pacman/repo.py b/archinstall/lib/pacman/repo.py
new file mode 100644
index 00000000..b4106f97
--- /dev/null
+++ b/archinstall/lib/pacman/repo.py
@@ -0,0 +1,6 @@
+from enum import Enum
+
+class Repo(Enum):
+	Multilib = "multilib"
+	Testing = "testing"
+	MultilibTesting = "multilib-testing"