hgext/infinitepush/store.py

phabricator: convert phabhunk and phabchange keys to bytes when finalising

I thought I had included this code already but I'd missed it out.  One of the
disadvantages of attrs is that all the keys are unicode strings on py3, but we
need them to be byte strings.

Differential Revision: https://phab.mercurial-scm.org/D7066

# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

# based on bundleheads extension by Gregory Szorc <[e-mail]>

from __future__ import absolute_import

import abc
import hashlib
import os
import subprocess
import tempfile

from mercurial.pycompat import open
from mercurial import (
    node,
    pycompat,
)
from mercurial.utils import procutil

NamedTemporaryFile = tempfile.NamedTemporaryFile


class BundleWriteException(Exception):
    pass


class BundleReadException(Exception):
    pass


class abstractbundlestore(object):
    """Defines the interface for bundle stores.

    A bundle store is an entity that stores raw bundle data. It is a simple
    key-value store. However, the keys are chosen by the store. The keys can
    be any Python object understood by the corresponding bundle index (see
    ``abstractbundleindex`` below).
    """

    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def write(self, data):
        """Write bundle data to the store.

        This function receives the raw data to be written as a str.
        Throws BundleWriteException
        The key of the written data MUST be returned.
        """

    @abc.abstractmethod
    def read(self, key):
        """Obtain bundle data for a key.

        Returns None if the bundle isn't known.
        Throws BundleReadException
        The returned object should be a file object supporting read()
        and close().
        """


class filebundlestore(object):
    """bundle store in filesystem

    meant for storing bundles somewhere on disk and on network filesystems
    """

    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        self.storepath = ui.configpath(b'scratchbranch', b'storepath')
        if not self.storepath:
            self.storepath = self.repo.vfs.join(
                b"scratchbranches", b"filebundlestore"
            )
        if not os.path.exists(self.storepath):
            os.makedirs(self.storepath)

    def _dirpath(self, hashvalue):
        """First two bytes of the hash are the name of the upper
        level directory, next two bytes are the name of the
        next level directory"""
        return os.path.join(self.storepath, hashvalue[0:2], hashvalue[2:4])

    def _filepath(self, filename):
        return os.path.join(self._dirpath(filename), filename)

    def write(self, data):
        filename = node.hex(hashlib.sha1(data).digest())
        dirpath = self._dirpath(filename)

        if not os.path.exists(dirpath):
            os.makedirs(dirpath)

        with open(self._filepath(filename), b'wb') as f:
            f.write(data)

        return filename

    def read(self, key):
        try:
            with open(self._filepath(key), b'rb') as f:
                return f.read()
        except IOError:
            return None


class externalbundlestore(abstractbundlestore):
    def __init__(self, put_binary, put_args, get_binary, get_args):
        """
        `put_binary` - path to binary file which uploads bundle to external
            storage and prints key to stdout
        `put_args` - format string with additional args to `put_binary`
                     {filename} replacement field can be used.
        `get_binary` - path to binary file which accepts filename and key
            (in that order), downloads bundle from store and saves it to file
        `get_args` - format string with additional args to `get_binary`.
                     {filename} and {handle} replacement field can be used.
        """

        self.put_args = put_args
        self.get_args = get_args
        self.put_binary = put_binary
        self.get_binary = get_binary

    def _call_binary(self, args):
        p = subprocess.Popen(
            pycompat.rapply(procutil.tonativestr, args),
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            close_fds=True,
        )
        stdout, stderr = p.communicate()
        returncode = p.returncode
        return returncode, stdout, stderr

    def write(self, data):
        # Won't work on windows because you can't open file second time without
        # closing it
        # TODO: rewrite without str.format() and replace NamedTemporaryFile()
        # with pycompat.namedtempfile()
        with NamedTemporaryFile() as temp:
            temp.write(data)
            temp.flush()
            temp.seek(0)
            formatted_args = [
                arg.format(filename=temp.name) for arg in self.put_args
            ]
            returncode, stdout, stderr = self._call_binary(
                [self.put_binary] + formatted_args
            )

            if returncode != 0:
                raise BundleWriteException(
                    b'Failed to upload to external store: %s' % stderr
                )
            stdout_lines = stdout.splitlines()
            if len(stdout_lines) == 1:
                return stdout_lines[0]
            else:
                raise BundleWriteException(
                    b'Bad output from %s: %s' % (self.put_binary, stdout)
                )

    def read(self, handle):
        # Won't work on windows because you can't open file second time without
        # closing it
        # TODO: rewrite without str.format() and replace NamedTemporaryFile()
        # with pycompat.namedtempfile()
        with NamedTemporaryFile() as temp:
            formatted_args = [
                arg.format(filename=temp.name, handle=handle)
                for arg in self.get_args
            ]
            returncode, stdout, stderr = self._call_binary(
                [self.get_binary] + formatted_args
            )

            if returncode != 0:
                raise BundleReadException(
                    b'Failed to download from external store: %s' % stderr
                )
            return temp.read()