contrib/automation/hgautomation/__init__.py

tests: handle Message-Id email header possible wrapping

The "Message-Id" header will get wrapped with a new line when exceeding
75 characters on Python 3 (see changeset 7d4f2e4899c5 introducing usage
of email.header.Header.encode and respective doc). This will occur in an
unpredictable manner depending on the hostname's length. To make the
test output consistent across Python versions and hostname
configuration, we add a filter to unwrap this header value.

# __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)