view contrib/automation/hgautomation/__init__.py @ 42284:195dcc10b3d7

automation: move image operations to own functions

An upcoming commit will need this functionality with slightly different
values and it is enough code to not want to duplicate. Let's refactor
into standalone functions so it can be reused.

Differential Revision: https://phab.mercurial-scm.org/D6318

# __init__.py - High-level automation interfaces
#
# Copyright 2019 Gregory Szorc <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

# no-check-code because Python 3 native.

import pathlib
import secrets

from .aws import (
    AWSConnection,
)


class HGAutomation:
    """High-level interface for Mercurial automation.

    Holds global state, provides access to other primitives, etc.
    """

    def __init__(self, state_path: pathlib.Path):
        self.state_path = state_path

        state_path.mkdir(exist_ok=True)

    def default_password(self):
        """Obtain the default password to use for remote machines.

        A new password will be generated if one is not stored.
        """
        p = self.state_path / 'default-password'

        try:
            with p.open('r', encoding='ascii') as fh:
                data = fh.read().strip()

                if data:
                    return data

        except FileNotFoundError:
            pass

        password = secrets.token_urlsafe(24)

        with p.open('w', encoding='ascii') as fh:
            fh.write(password)
            fh.write('\n')

        p.chmod(0o0600)

        return password

    def aws_connection(self, region: str, ensure_ec2_state: bool=True):
        """Obtain an AWSConnection instance bound to a specific region."""

        return AWSConnection(self, region, ensure_ec2_state=ensure_ec2_state)