sapling/eden/fs/cli/doctor/problem.py

#!/usr/bin/env python3
# Copyright (c) Facebook, Inc. and its affiliates.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2.

import abc
from enum import IntEnum
from typing import Optional, Set

from eden.fs.cli import ui


class RemediationError(Exception):
    pass


class ProblemSeverity(IntEnum):
    # Note that we intentionally want to be able to compare severity values
    # using < and > operators.
    ADVICE = 3
    ERROR = 10


class ProblemBase(abc.ABC):
    @abc.abstractmethod
    def description(self) -> str:
        "Return the description of this problem."

    def severity(self) -> ProblemSeverity:
        """Return the problem severity.

        Defaults to ERROR if not overridden.
        """
        return ProblemSeverity.ERROR

    def get_manual_remediation_message(self) -> Optional[str]:
        "Return a message explaining how to manually fix this problem."
        return None


class FixableProblem(ProblemBase):
    @abc.abstractmethod
    def dry_run_msg(self) -> str:
        """Return a string to print for dry-run operations."""

    @abc.abstractmethod
    def start_msg(self) -> str:
        """Return a string to print when starting the remediation."""

    @abc.abstractmethod
    def perform_fix(self) -> None:
        """Attempt to automatically fix the problem."""


class Problem(ProblemBase):
    def __init__(
        self,
        description: str,
        remediation: Optional[str] = None,
        severity: ProblemSeverity = ProblemSeverity.ERROR,
    ) -> None:
        self._description = description
        self._remediation = remediation
        self._severity = severity

    def description(self) -> str:
        return self._description

    def severity(self) -> ProblemSeverity:
        return self._severity

    def get_manual_remediation_message(self) -> Optional[str]:
        return self._remediation


class UnexpectedCheckError(Problem):
    """A helper class for reporting about unexpected exceptions that occur
    when running checks."""

    def __init__(self):
        import traceback

        tb = traceback.format_exc()
        description = f"unexpected error while checking for problems: {tb}"
        super().__init__(description)


class ProblemTracker(abc.ABC):
    # using_edenfs will be set to False if EdenFS is not running and there
    # are no configured EdenFS checkouts.
    using_edenfs: bool = True

    def add_problem(self, problem: ProblemBase) -> None:
        """Record a new problem"""


class ProblemFixer(ProblemTracker):
    def __init__(self, out: ui.Output) -> None:
        self._out = out
        self.num_problems = 0
        self.num_fixed_problems = 0
        self.num_failed_fixes = 0
        self.num_manual_fixes = 0
        self.problem_types: Set[str] = set()

    def add_problem(self, problem: ProblemBase) -> None:
        self.num_problems += 1
        problem_class = problem.__class__.__name__
        self.problem_types.add(problem_class)
        self._out.writeln("- Found problem:", fg=self._out.YELLOW)
        self._out.writeln(problem.description())
        if isinstance(problem, FixableProblem):
            self.fix_problem(problem)
        else:
            self.num_manual_fixes += 1
            msg = problem.get_manual_remediation_message()
            if msg:
                self._out.write(msg, end="\n\n")

    def fix_problem(self, problem: FixableProblem) -> None:
        self._out.write(f"{problem.start_msg()}...", flush=True)
        try:
            problem.perform_fix()
            self._out.write("fixed", fg=self._out.GREEN, end="\n\n", flush=True)
            self.num_fixed_problems += 1
        except Exception as ex:
            self._out.writeln("error", fg=self._out.RED)
            self._out.write(f"Failed to fix problem: {ex}", end="\n\n", flush=True)
            self.num_failed_fixes += 1


class DryRunFixer(ProblemFixer):
    def fix_problem(self, problem: FixableProblem) -> None:
        self._out.write(problem.dry_run_msg(), end="\n\n")