xOSDManager.py 17.5 KB
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import os
import pickle
import subprocess

import shutil

import dataDistribution
import div_util
import folder

'''
xOSDManager - a python module to manage OSD selection in XtreemFS
currently only depth (level) 2 subdirectories can be managed
'''


# TODO add support for arbitrary subdirectory level (currently depth=2 is hardcoded, which is fine for GeoMultiSens
# TODO purposes)

class OSDManager(object):
    def __init__(self, path_to_managed_folder, config_file='.das_config', value_map=None, debug=False):

        self.managedFolder = path_to_managed_folder
        self.configFile = config_file
        self.debug = debug

        if value_map is None:

            if not div_util.check_for_executable('xtfsutil'):
                raise ExecutableNotFoundException("No xtfsutil found. Please make sure it is contained in your PATH.")

            output_1 = subprocess.run(["xtfsutil", self.managedFolder], stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                      universal_newlines=True)

            if output_1.stderr.startswith("xtfsutil failed: Path doesn't point to an entity on an XtreemFS volume!"):
                raise NotAXtreemFSVolume("The specified folder '" + path_to_managed_folder +
                                         "' is not part of an XtreemFS volume!")

            if len(output_1.stderr) > 0:
                raise Exception("xtfsutil produced some error: " + output_1.stderr)

            self.pathOnVolume = div_util.removeLeadingTrailingSlashes(
                str(output_1.stdout).split("\n")[0].split()[-1])
            self.pathToMountPoint = self.managedFolder[0:(len(self.managedFolder) - len(self.pathOnVolume) - 1)]

            output_2 = subprocess.run(["xtfsutil", self.pathToMountPoint],
                                      stdout=subprocess.PIPE, universal_newlines=True)

            volume_information = div_util.extractVolumeInformation(output_2.stdout)
            self.volumeName = volume_information[0]
            osd_list = list(map(lambda x: x[0], volume_information[1]))
            self.osdSelectionPolicy = volume_information[2]

            self.dataDistribution = None
            if not self.__read_configuration():
                self.dataDistribution = dataDistribution.DataDistribution()

            self.dataDistribution.addOSDList(osd_list)

        else:
            self.pathOnVolume = value_map['path_on_volume']
            self.pathToMountPoint = value_map['path_to_mount']
            self.volumeName = value_map['volume_name']
            self.osdSelectionPolicy = value_map['osd_selection_policy']
            self.dataDistribution = value_map['data_distribution']

    def __read_configuration(self):
        assert self.dataDistribution is None
        path_to_config = os.path.join(self.managedFolder, self.configFile)
        try:
            f = open(path_to_config, "rb")
            self.dataDistribution = pickle.load(f)
            return True
        except IOError:
            return False

    def __write_configuration(self):
        path_to_config = os.path.join(self.managedFolder, self.configFile)
        f = open(path_to_config, "wb")
        pickle.dump(self.dataDistribution, f)

    '''
    create empty folders and assign OSDs.
    '''

    def create_empty_folders(self, folders):
        average_size = int(self.dataDistribution.getAverageFolderSize())
        if average_size <= 0:
            average_size = 1

        tiles = []

        for input_folder in folders:
            new_tile = folder.Folder(self.path_on_volume(input_folder), average_size, None)
            tiles.append(new_tile)

        new_tiles = self.dataDistribution.addFolders(tiles)

        self.apply_osd_assignments(new_tiles)

        for input_folder in folders:
            os.makedirs(input_folder, exist_ok=True)

        self.__write_configuration()

    '''
    copy a list of given folders into the managed folder, assigning OSDs to new folders and updating
    self.dataDistribution
    '''

    def copy_folders(self, folders, environment='LOCAL', remote_source=None, sshfs_mount_dir='/tmp/sshfs_tmp_mnt'):
        if not div_util.check_for_executable('du'):
            raise ExecutableNotFoundException("No du found. Please make sure it is contained in your PATH.")

        if remote_source is not None:
            if not div_util.check_for_executable('sshfs'):
                raise ExecutableNotFoundException("No sshfs found. Please make sure it is contained in your PATH.")
            if not div_util.check_for_executable('scp'):
                raise ExecutableNotFoundException("No scp found. Please make sure it is contained in your PATH.")
            if not div_util.check_for_executable('fusermount'):
                raise ExecutableNotFoundException("No fusermount found. Please make sure it is contained in your PATH.")

        if remote_source is not None:
            os.makedirs(sshfs_mount_dir)

        new_folders = []

        for input_folder in folders:
            last_2_path_elements = os.path.join(os.path.split(os.path.split(input_folder)[0])[1],
                                                os.path.split(input_folder)[1])
            if remote_source is not None:
                mount_point = os.path.join(sshfs_mount_dir, last_2_path_elements)
                os.makedirs(mount_point)
                subprocess.run(["sshfs", remote_source + ":" + input_folder, mount_point])
                du = subprocess.run(["du", "-s", mount_point], stdout=subprocess.PIPE,
                                    universal_newlines=True)
                subprocess.run(["fusermount", "-uz", mount_point])
                folder_size = int(du.stdout.split()[0])
            else:
                du = subprocess.run(["du", "-s", input_folder], stdout=subprocess.PIPE,
                                    universal_newlines=True)
                folder_size = int(du.stdout.split()[0])

            new_folder = folder.Folder(os.path.join(self.volumeName, self.pathOnVolume, last_2_path_elements),
                                       folder_size,
                                       input_folder)
            if self.debug:
                print("new folder: " + str(new_folder))

            new_folders.append(new_folder)

        if remote_source is not None:
            shutil.rmtree(sshfs_mount_dir)

        new_assignments = self.dataDistribution.addFolders(new_folders)
        self.apply_osd_assignments(new_assignments)

        self.__write_configuration()

        if self.debug:
            print("osd manager after new folders have been added to data distribution:")
            print(str(self))

        self.__copy_data(new_folders, environment, remote_source)

    '''
    update the given (by absolute path) folders, such that the values held by self.dataDistribution
    matches their size on disk.
    if no argument is given, all folders are updated.
    '''

    def update(self, arg_folders=None):

        if arg_folders is not None:
            for folder_for_update in arg_folders:
                if not folder_for_update.startswith(self.managedFolder):
                    raise PathNotManagedException(
                        "The path :" + folder_for_update + "is not managed by this instance of the XtreemFS OSD"
                                                           "manager!")

        folder_size_updates = {}

        folders = arg_folders
        if arg_folders is None:
            folders = self.get_assigned_folders()

        for folder_for_update in folders:
            folder_id = self.path_on_volume(folder_for_update)
            command = ["du", "-s", folder_for_update]
            if self.debug:
                print("executing: " + str(command))
            du = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
            folder_disk_size = int(du.stdout.split()[0])
            folder_size_updates[folder_id] = folder_disk_size

        for folder_for_update, size in folder_size_updates.items():
            self.dataDistribution.update_folder(folder_for_update, size)

        self.__write_configuration()

        if self.debug:
            print(str(self))

    '''
    apply the given assignments to the XtreemFS volume, using xtfsutil.
    the assignments are given as a list containing tuples (tile_id, osd),
    where tile_id is given by applying path_on_volume() onto the absolute path of the folder.
    '''

    def apply_osd_assignments(self, assignments):
        if not div_util.check_for_executable('xtfsutil'):
            raise ExecutableNotFoundException("No xtfsutil found. Please make sure it is contained in your PATH.")

        if self.osdSelectionPolicy is not "1000,1004":
            if self.debug:
                subprocess.run(["xtfsutil", "--set-osp", "prefix", self.pathToMountPoint])
            else:
                subprocess.run(["xtfsutil", "--set-osp", "prefix", self.pathToMountPoint],
                               stdout=subprocess.PIPE, universal_newlines=True)

        for new_tile in assignments:
            if self.debug:
                subprocess.run(["xtfsutil",
                                "--set-pattr", "1004.filenamePrefix", "--value",
                                "add " + new_tile[0] + " " + new_tile[1] + "",
                                self.pathToMountPoint])
            else:
                subprocess.run(["xtfsutil",
                                "--set-pattr", "1004.filenamePrefix", "--value",
                                "add " + new_tile[0] + " " + new_tile[1] + "",
                                self.pathToMountPoint],
                               stdout=subprocess.PIPE, universal_newlines=True)

    '''
    copy data onto XtreemFS volume
    '''

    def __copy_data(self, input_folders, environment, remote_source):
        osd_list = self.dataDistribution.get_osd_list()
        osd_to_folders_map = {}
        for osd in osd_list:
            osd_to_folders_map[osd] = []
        for input_folder in input_folders:
            osd_for_tile = self.dataDistribution.getContainingOSD(input_folder.id).uuid
            osd_to_folders_map[osd_for_tile].append(input_folder)

        if self.debug:
            print("osd to folders map:")
            for key, value in osd_to_folders_map.items():
                print("osd: " + key)
                print("assigned folders:")
                for input_folder in value:
                    print(str(input_folder))

        # trigger the copying!
        if environment is "SLURM":
            assert remote_source is not None
            copy_commands = self.__generate_copy_commands_slurm(osd_to_folders_map, remote_source)
        elif environment is "HU_CLUSTER":
            copy_commands = self.__generate_copy_commands_hu_cluster(osd_to_folders_map)
        else:
            copy_commands = self.__generate_copy_commands_local(osd_to_folders_map)

        for input_folder in input_folders:
            path_to_target_dir = self.get_target_dir(input_folder.id)
            os.makedirs(path_to_target_dir, exist_ok=True)

        self.__execute_copy_commands(copy_commands)

    '''
    generates a list of copy commands, one command for each OSD that receives new data.
    the copy commands are constructed such that they can be executed in a slurm environment (that is, within a slurm job
    allocation) at ZIB.
    each command is a copy command including all new folders for the corresponding OSD, preceded by a srun command
    to execute the copy command locally on the slurm node on which the target OSD resides.
    '''

    def __generate_copy_commands_slurm(self, osd_to_folders_map, remote_source):
        if self.debug:
            print("Using SLURM mode for copying...")

        slurm_hosts = div_util.getSlurmHosts()
        osd_to_host_map = div_util.getOSDToHostnameMap(self.dataDistribution.get_osd_list(), slurm_hosts)

        command_list = []

        for key in osd_to_folders_map.keys():
            host_name = osd_to_host_map[key]
            command = ""
            for copy_folder in osd_to_folders_map[key]:
                command += "srun -N1-1 --nodelist=" + host_name
                command += " scp -rq " + remote_source + ":" + copy_folder.origin
                command += " " + self.get_target_dir(copy_folder.id)
                command += " ;"
            if len(osd_to_folders_map[key]) > 0:
                command_list.append(command)

        return command_list

    '''
    generates a list of copy commands, one command for each OSD that receives new data.
    the copy commands are constructed such that they can be executed on the GeoMultiSens cluster at HU Berlin.
    each command is a copy command including all new folders for the corresponding OSD, preceded by a ssh command
    to execute the copy command locally on the node of the target OSD.
    '''

    def __generate_copy_commands_hu_cluster(self, osd_to_folders_map):
        if self.debug:
            print("Using HU_CLUSTER mode for copying...")

        if not div_util.check_for_executable('xtfsutil'):
            raise ExecutableNotFoundException("No xtfsutil found. Please make sure it is contained in your PATH.")

        xtfsutil = subprocess.run(["xtfsutil", self.pathToMountPoint],
                                  stdout=subprocess.PIPE, universal_newlines=True)
        volume_information = div_util.extractVolumeInformation(xtfsutil.stdout)
        osd_to_ip_address = {}
        for (osd, ip) in volume_information[1]:
            osd_to_ip_address[osd] = ip

        command_list = []

        for key in osd_to_folders_map.keys():
            ip_address = osd_to_ip_address[key]
            command = "ssh " + ip_address + " \'"
            for copy_folder in osd_to_folders_map[key]:
                command += " cp -r"
                command += " " + copy_folder.origin
                command += " " + self.get_target_dir(copy_folder.id)
                command += " ;"
            command += " \' "
            if len(osd_to_folders_map[key]) > 0:
                command_list.append(command)

        return command_list

    '''
    generates a list of copy commands, one command for each OSD that receives new data.
    plain old cp is used for the actual copying.
    '''

    def __generate_copy_commands_local(self, osd_to_folders_map):
        if self.debug:
            print("Using local cp for copying...")

        command_list = []

        for key in osd_to_folders_map.keys():
            command = ""
            for copy_folder in osd_to_folders_map[key]:
                command += "cp -r "
                command += copy_folder.origin
                command += " " + self.get_target_dir(copy_folder.id)
                command += " ; "

            if len(osd_to_folders_map[key]) > 0:
                command_list.append(command)

        return command_list

    '''
    execute, in parallel, a given set of commands. note that the degree of parallelism will match the length of
    command_list.
    '''

    def __execute_copy_commands(self, command_list):
        if self.debug:
            print("Executing copy commands: ")
            for command in command_list:
                print(str(command))
            print("in total " + str(len(command_list)) + " commands.")
        processes = []
        for command in command_list:
            process = subprocess.Popen(command, shell=True)
            processes.append(process)

        for p in processes:
            p.wait()

        if self.debug:
            print("Executing copy commands done.")

    '''
    creates a list of all folders, managed by this XtreemFS OSD manager, that have an assigned OSD.
    '''

    def get_assigned_folders(self):
        assigned_folders = []
        for depth_1_folder in os.listdir(self.managedFolder):
            depth_1_path = os.path.join(self.managedFolder, depth_1_folder)
            if os.path.isdir(depth_1_path):
                for depth_2_folder in os.listdir(depth_1_path):
                    depth_2_path = os.path.join(self.managedFolder, depth_1_folder, depth_2_folder)
                    if os.path.isdir(depth_2_path):
                        assigned_folders.append(depth_2_path)

        return assigned_folders

    '''
    gets the path to the target dir, given the folder_id
    '''
    def get_target_dir(self, folder_id):
        path_on_mount_point = folder_id[len(self.volumeName) + 1:]
        return os.path.split(os.path.join(self.pathToMountPoint, path_on_mount_point))[0]

    '''
    remove the leading part of the path, such that only the part onto the xtreemfs volume remains, including
    the volume itself.
    throws an exception when the path is not managed by this XtreemFS OSD manager.
    '''

    def path_on_volume(self, path):
        if not path.startswith(self.managedFolder):
            raise PathNotManagedException("Path " + path + " is not managed by this instance of the XtreemFS OSD"
                                                           "manager!")
        return os.path.join(self.volumeName, path[len(self.pathToMountPoint) + 1:])

    def __str__(self):
        representation = "pathToMountPoint: " + self.pathToMountPoint + " volumeName: " + self.volumeName + " pathOnVolume: " \
                         + self.pathOnVolume
        representation += ("\nconfigFile: " + self.configFile + "\n")
        representation += self.dataDistribution.description()
        return representation


class ExecutableNotFoundException(Exception):
    """raise this when an external executable can not be found"""


class NotAXtreemFSVolume(Exception):
    """raise this when a path does not point to a folder on a xtreemfs volume"""


class PathNotManagedException(Exception):
    """raise this when a path is handled, that is not managed by xOSDManager"""