__init__.py

#!/usr/bin/env python
#
# __init__.py - Miscellaneous functions used throughout fsl_ci.
#
# Author: Paul McCarthy <pauldmccarthy@gmail.com>
#


import os.path    as op
import               os
import               io
import               sys
import               errno
import               shlex
import               string
import               time
import               tempfile
import contextlib as ctxlib
import subprocess as sp

import ruamel.yaml as yaml


__version__ = '0.6.14'
"""Current version of the fsl-ci-rules."""


USERNAME = 'fsl-ci-rules'
"""Username to be used for all git interactions which require one. """


EMAIL = 'fsl-ci-rules@git.fmrib.ox.ac.uk'
"""Password to be used for all git interactions which require one. """


def fprint(*args, **kwargs):
    """Print with flush=True. """
    print(*args, **kwargs, flush=True)


@ctxlib.contextmanager
def tempdir():
    """Context manager to create, and change into, a temporary directory, and
    then afterwards delete it and change back to the original working
    directory.
    """
    with tempfile.TemporaryDirectory() as td:
        prevdir = os.getcwd()
        os.chdir(td)
        try:
            yield td
        finally:
            os.chdir(prevdir)


@ctxlib.contextmanager
def indir(dirname):
    """Context manager to change into a directory, and then afterwards
    change back to the original working directory.
    """
    prevdir = os.getcwd()
    os.chdir(dirname)
    try:
        yield
    finally:
        os.chdir(prevdir)


def sprun(cmd, **kwargs):
    """Runs the given command with subprocess.run. """
    fprint(f'Running {cmd}')
    if not kwargs.get('shell', False):
        cmd = shlex.split(cmd)

    # we set stdout/stderr for compatibility
    # with CaptureStdout (see below)
    if 'check'  not in kwargs: kwargs['check']  = True
    if 'stdout' not in kwargs: kwargs['stdout'] = sys.stdout
    if 'stderr' not in kwargs: kwargs['stderr'] = sys.stderr

    return sp.run(cmd, **kwargs)


def is_valid_project_version(version):
    """Return True if the given version/tag is "valid" - it must
    be a sequence of integers, separated by periods, with an optional
    leading 'v'.
    """
    if version.lower().startswith('v'):
        version = version[1:]

    for part in version.split('.'):
        if not all([c in string.digits for c in part]):
            return False
    return True


@ctxlib.contextmanager
def lockdir(dirname):
    """Primitive mechanism by which concurrent access to a directory can be
    prevented. Attempts to create a semaphore file in the directory, but waits
    if that file already exists. Removes the file when finished.
    """

    delay    = 10
    lockfile = op.join(dirname, '.fsl_ci.lockdir')

    while True:
        try:
            fprint(f'Attempting to lock {dirname} for exclusive access.')
            fd = os.open(lockfile, os.O_CREAT | os.O_EXCL | os.O_RDWR)
            break
        except OSError as e:
            if e.errno != errno.EEXIST:
                raise e
            fprint(f'{dirname} is already locked - '
                   f'trying again in {delay} seconds ...')
        time.sleep(10)

    fprint(f'Exclusive access acquired for {dirname} ...')
    try:
        yield

    finally:
        fprint(f'Relinquishing lock on {dirname}')
        os.close( fd)
        os.unlink(lockfile)


def loadyaml(s):
    """Loads a YAML string, returning a dict-like. """
    return yaml.YAML().load(s)


def dumpyaml(o):
    """Dumps the given YAML to a string. """
    s = io.StringIO()
    y = yaml.YAML()
    y.default_flow_style = False
    y.dump(o, s)
    return s.getvalue()


class CaptureStdout:
    """Context manager which captures stdout and stderr. """

    def __init__(self):
        self.tmpdir        = tempfile.TemporaryDirectory()
        self.__mock_stdout = open(op.join(self.tmpdir.name, 'stdout'), 'wt')
        self.__mock_stderr = open(op.join(self.tmpdir.name, 'stderr'), 'wt')


    def __enter__(self):
        if self.tmpdir is None:
            raise RuntimeError('CaptureStdout can only be used once')

        self.__real_stdout = sys.stdout
        self.__real_stderr = sys.stderr
        sys.stdout         = self.__mock_stdout
        sys.stderr         = self.__mock_stderr

        return self

    def __exit__(self, *args, **kwargs):

        sys.stdout = self.__real_stdout
        sys.stderr = self.__real_stderr

        self.__mock_stdout.close()
        self.__mock_stderr.close()

        with open(self.__mock_stdout.name, 'rt') as f:
            self.__mock_stdout = f.read()
        with open(self.__mock_stderr.name, 'rt') as f:
            self.__mock_stderr = f.read()

        self.tmpdir.cleanup()
        self.tmpdir = None

    @property
    def real_stdout(self):
        return self.__real_stdout

    @property
    def real_stderr(self):
        return self.__real_stderr

    @property
    def stdout(self):
        return self.__mock_stdout

    @property
    def stderr(self):
        return self.__mock_stderr


def health_check():
    """Rudimentary health check of the fsl-ci-rules codebase. """
    print(f'fsl-ci-rules version {__version__}')
    import fsl_ci.conda
    import fsl_ci.gitlab
    import fsl_ci.scripts.build_conda_package
    import fsl_ci.scripts.deploy_conda_package
    import fsl_ci.scripts.trigger_package_build
    import fsl_ci.scripts.update_conda_recipe
    import fsl_ci.scripts.run_unit_tests
    import fsl_ci.utils.configure_repositories
    import fsl_ci.utils.create_conda_recipe
    import fsl_ci.utils.fsl_project_dependencies
    import fsl_ci.utils.package_status
    import fsl_ci.utils.set_gitlab_variables
    import fsl_ci.utils.trigger_build
    import fsl_ci.utils.trigger_pipeline