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#              C E D A R
#          S O L U T I O N S       "Software done right."
#           S O F T W A R E
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# Copyright (c) 2004-2008,2011,2015 Kenneth J. Pronovici.
# All rights reserved.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License,
# Version 2, as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# Author   : Kenneth J. Pronovici <pronovic@ieee.org>
# Language : Python 3
# Project  : Cedar Backup, release 3
# Purpose  : Implements the standard 'collect' action.
#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

########################################################################
# Module documentation
########################################################################

"""
Implements the standard 'collect' action.
:author: Kenneth J. Pronovici <pronovic@ieee.org>
"""


########################################################################
# Imported modules
########################################################################

import logging
import os
import pickle  # noqa: S403 # we operate on trusted data, so pickle is ok

from CedarBackup3.actions.constants import COLLECT_INDICATOR, DIGEST_EXTENSION
from CedarBackup3.actions.util import writeIndicatorFile
from CedarBackup3.filesystem import BackupFileList, FilesystemList
from CedarBackup3.util import buildNormalizedPath, changeOwnership, displayBytes, isStartOfWeek, pathJoin

########################################################################
# Module-wide constants and variables
########################################################################

logger = logging.getLogger("CedarBackup3.log.actions.collect")


########################################################################
# Public functions
########################################################################

############################
# executeCollect() function
############################


def executeCollect(configPath, options, config):  # noqa: ARG001
    """
    Executes the collect backup action.

    *Note:* When the collect action is complete, we will write a collect
    indicator to the collect directory, so it's obvious that the collect action
    has completed.  The stage process uses this indicator to decide whether a
    peer is ready to be staged.

    Args:
       configPath (String representing a path on disk): Path to configuration file on disk
       options (Options object): Program command-line options
       config (Config object): Program configuration
    Raises:
       ValueError: Under many generic error conditions
       TarError: If there is a problem creating a tar file
    """
    logger.debug("Executing the 'collect' action.")
    if config.options is None or config.collect is None:
        raise ValueError("Collect configuration is not properly filled in.")
    if (config.collect.collectFiles is None or len(config.collect.collectFiles) < 1) and (
        config.collect.collectDirs is None or len(config.collect.collectDirs) < 1
    ):
        raise ValueError("There must be at least one collect file or collect directory.")
    fullBackup = options.full
    logger.debug("Full backup flag is [%s]", fullBackup)
    todayIsStart = isStartOfWeek(config.options.startingDay)
    resetDigest = fullBackup or todayIsStart
    logger.debug("Reset digest flag is [%s]", resetDigest)
    if config.collect.collectFiles is not None:
        for collectFile in config.collect.collectFiles:
            logger.debug("Working with collect file [%s]", collectFile.absolutePath)
            collectMode = _getCollectMode(config, collectFile)
            archiveMode = _getArchiveMode(config, collectFile)
            digestPath = _getDigestPath(config, collectFile.absolutePath)
            tarfilePath = _getTarfilePath(config, collectFile.absolutePath, archiveMode)
            if fullBackup or (collectMode in ["daily", "incr"]) or (collectMode == "weekly" and todayIsStart):
                logger.debug("File meets criteria to be backed up today.")
                _collectFile(config, collectFile.absolutePath, tarfilePath, collectMode, archiveMode, resetDigest, digestPath)
            else:
                logger.debug("File will not be backed up, per collect mode.")
            logger.info("Completed collecting file [%s]", collectFile.absolutePath)
    if config.collect.collectDirs is not None:
        for collectDir in config.collect.collectDirs:
            logger.debug("Working with collect directory [%s]", collectDir.absolutePath)
            collectMode = _getCollectMode(config, collectDir)
            archiveMode = _getArchiveMode(config, collectDir)
            ignoreFile = _getIgnoreFile(config, collectDir)
            linkDepth = _getLinkDepth(collectDir)
            dereference = _getDereference(collectDir)
            recursionLevel = _getRecursionLevel(collectDir)
            (excludePaths, excludePatterns) = _getExclusions(config, collectDir)
            if fullBackup or (collectMode in ["daily", "incr"]) or (collectMode == "weekly" and todayIsStart):
                logger.debug("Directory meets criteria to be backed up today.")
                _collectDirectory(
                    config,
                    collectDir.absolutePath,
                    collectMode,
                    archiveMode,
                    ignoreFile,
                    linkDepth,
                    dereference,
                    resetDigest,
                    excludePaths,
                    excludePatterns,
                    recursionLevel,
                )
            else:
                logger.debug("Directory will not be backed up, per collect mode.")
            logger.info("Completed collecting directory [%s]", collectDir.absolutePath)
    writeIndicatorFile(config.collect.targetDir, COLLECT_INDICATOR, config.options.backupUser, config.options.backupGroup)
    logger.info("Executed the 'collect' action successfully.")


########################################################################
# Private utility functions
########################################################################

##########################
# _collectFile() function
##########################


def _collectFile(config, absolutePath, tarfilePath, collectMode, archiveMode, resetDigest, digestPath):
    """
    Collects a configured collect file.

    The indicated collect file is collected into the indicated tarfile.
    For files that are collected incrementally, we'll use the indicated
    digest path and pay attention to the reset digest flag (basically, the reset
    digest flag ignores any existing digest, but a new digest is always
    rewritten).

    The caller must decide what the collect and archive modes are, since they
    can be on both the collect configuration and the collect file itself.

    Args:
       config: Config object
       absolutePath: Absolute path of file to collect
       tarfilePath: Path to tarfile that should be created
       collectMode: Collect mode to use
       archiveMode: Archive mode to use
       resetDigest: Reset digest flag
       digestPath: Path to digest file on disk, if needed
    """
    backupList = BackupFileList()
    backupList.addFile(absolutePath)
    _executeBackup(config, backupList, absolutePath, tarfilePath, collectMode, archiveMode, resetDigest, digestPath)


###############################
# _collectDirectory() function
###############################


def _collectDirectory(
    config,
    absolutePath,
    collectMode,
    archiveMode,
    ignoreFile,
    linkDepth,
    dereference,
    resetDigest,
    excludePaths,
    excludePatterns,
    recursionLevel,
):
    """
    Collects a configured collect directory.

    The indicated collect directory is collected into the indicated tarfile.
    For directories that are collected incrementally, we'll use the indicated
    digest path and pay attention to the reset digest flag (basically, the reset
    digest flag ignores any existing digest, but a new digest is always
    rewritten).

    The caller must decide what the collect and archive modes are, since they
    can be on both the collect configuration and the collect directory itself.

    Args:
       config: Config object
       absolutePath: Absolute path of directory to collect
       collectMode: Collect mode to use
       archiveMode: Archive mode to use
       ignoreFile: Ignore file to use
       linkDepth: Link depth value to use
       dereference: Dereference flag to use
       resetDigest: Reset digest flag
       excludePaths: List of absolute paths to exclude
       excludePatterns: List of patterns to exclude
       recursionLevel: Recursion level (zero for no recursion)
    """
    if recursionLevel == 0:
        # Collect the actual directory because we're at recursion level 0
        logger.info("Collecting directory [%s]", absolutePath)
        tarfilePath = _getTarfilePath(config, absolutePath, archiveMode)
        digestPath = _getDigestPath(config, absolutePath)

        backupList = BackupFileList()
        backupList.ignoreFile = ignoreFile
        backupList.excludePaths = excludePaths
        backupList.excludePatterns = excludePatterns
        backupList.addDirContents(absolutePath, linkDepth=linkDepth, dereference=dereference)

        _executeBackup(config, backupList, absolutePath, tarfilePath, collectMode, archiveMode, resetDigest, digestPath)
    else:
        # Find all of the immediate subdirectories
        subdirs = FilesystemList()
        subdirs.excludeFiles = True
        subdirs.excludeLinks = True
        subdirs.excludePaths = excludePaths
        subdirs.excludePatterns = excludePatterns
        subdirs.addDirContents(path=absolutePath, recursive=False, addSelf=False)

        # Back up the subdirectories separately
        for subdir in subdirs:
            _collectDirectory(
                config,
                subdir,
                collectMode,
                archiveMode,
                ignoreFile,
                linkDepth,
                dereference,
                resetDigest,
                excludePaths,
                excludePatterns,
                recursionLevel - 1,
            )
            excludePaths.append(subdir)  # this directory is already backed up, so exclude it

        # Back up everything that hasn't previously been backed up
        _collectDirectory(
            config,
            absolutePath,
            collectMode,
            archiveMode,
            ignoreFile,
            linkDepth,
            dereference,
            resetDigest,
            excludePaths,
            excludePatterns,
            0,
        )


############################
# _executeBackup() function
############################


def _executeBackup(config, backupList, absolutePath, tarfilePath, collectMode, archiveMode, resetDigest, digestPath):
    """
    Execute the backup process for the indicated backup list.

    This function exists mainly to consolidate functionality between the
    :any:`_collectFile` and :any:`_collectDirectory` functions.  Those functions build
    the backup list; this function causes the backup to execute properly and
    also manages usage of the digest file on disk as explained in their
    comments.

    For collect files, the digest file will always just contain the single file
    that is being backed up.  This might little wasteful in terms of the number
    of files that we keep around, but it's consistent and easy to understand.

    Args:
       config: Config object
       backupList: List to execute backup for
       absolutePath: Absolute path of directory or file to collect
       tarfilePath: Path to tarfile that should be created
       collectMode: Collect mode to use
       archiveMode: Archive mode to use
       resetDigest: Reset digest flag
       digestPath: Path to digest file on disk, if needed
    """
    if collectMode != "incr":
        logger.debug("Collect mode is [%s]; no digest will be used.", collectMode)
        if len(backupList) == 1 and backupList[0] == absolutePath:  # special case for individual file
            logger.info("Backing up file [%s] (%s).", absolutePath, displayBytes(backupList.totalSize()))
        else:
            logger.info("Backing up %d files in [%s] (%s).", len(backupList), absolutePath, displayBytes(backupList.totalSize()))
        if len(backupList) > 0:
            backupList.generateTarfile(tarfilePath, archiveMode, True)
            changeOwnership(tarfilePath, config.options.backupUser, config.options.backupGroup)
    else:
        if resetDigest:
            logger.debug("Based on resetDigest flag, digest will be cleared.")
            oldDigest = {}
        else:
            logger.debug("Based on resetDigest flag, digest will loaded from disk.")
            oldDigest = _loadDigest(digestPath)
        (removed, newDigest) = backupList.removeUnchanged(oldDigest, captureDigest=True)
        logger.debug("Removed %d unchanged files based on digest values.", removed)
        if len(backupList) == 1 and backupList[0] == absolutePath:  # special case for individual file
            logger.info("Backing up file [%s] (%s).", absolutePath, displayBytes(backupList.totalSize()))
        else:
            logger.info("Backing up %d files in [%s] (%s).", len(backupList), absolutePath, displayBytes(backupList.totalSize()))
        if len(backupList) > 0:
            backupList.generateTarfile(tarfilePath, archiveMode, True)
            changeOwnership(tarfilePath, config.options.backupUser, config.options.backupGroup)
        _writeDigest(config, newDigest, digestPath)


#########################
# _loadDigest() function
#########################


def _loadDigest(digestPath):
    """
    Loads the indicated digest path from disk into a dictionary.

    If we can't load the digest successfully (either because it doesn't exist or
    for some other reason), then an empty dictionary will be returned - but the
    condition will be logged.

    Args:
       digestPath: Path to the digest file on disk

    Returns:
        Dictionary representing contents of digest path
    """
    if not os.path.isfile(digestPath):
        digest = {}
        logger.debug("Digest [%s] does not exist on disk.", digestPath)
    else:
        try:
            with open(digestPath, "rb") as f:
                digest = pickle.load(f, fix_imports=True)  # noqa: S301 # this is trusted data, so pickle is ok
            logger.debug("Loaded digest [%s] from disk: %d entries.", digestPath, len(digest))
        except Exception as e:
            digest = {}
            logger.error("Failed loading digest [%s] from disk: %s", digestPath, e)
    return digest


##########################
# _writeDigest() function
##########################


def _writeDigest(config, digest, digestPath):
    """
    Writes the digest dictionary to the indicated digest path on disk.

    If we can't write the digest successfully for any reason, we'll log the
    condition but won't throw an exception.

    Args:
       config: Config object
       digest: Digest dictionary to write to disk
       digestPath: Path to the digest file on disk
    """
    try:
        with open(digestPath, "wb") as f:
            pickle.dump(digest, f, 0, fix_imports=True)  # be compatible with Python 2
        changeOwnership(digestPath, config.options.backupUser, config.options.backupGroup)
        logger.debug("Wrote new digest [%s] to disk: %d entries.", digestPath, len(digest))
    except Exception as e:
        logger.error("Failed to write digest [%s] to disk: %s", digestPath, e)


########################################################################
# Private attribute "getter" functions
########################################################################

############################
# getCollectMode() function
############################


def _getCollectMode(config, item):
    """
    Gets the collect mode that should be used for a collect directory or file.
    If possible, use the one on the file or directory, otherwise take from collect section.
    Args:
       config: Config object
       item: ``CollectFile`` or ``CollectDir`` object
    Returns:
        Collect mode to use
    """
    if item.collectMode is None:
        collectMode = config.collect.collectMode
    else:
        collectMode = item.collectMode
    logger.debug("Collect mode is [%s]", collectMode)
    return collectMode


#############################
# _getArchiveMode() function
#############################


def _getArchiveMode(config, item):
    """
    Gets the archive mode that should be used for a collect directory or file.
    If possible, use the one on the file or directory, otherwise take from collect section.
    Args:
       config: Config object
       item: ``CollectFile`` or ``CollectDir`` object
    Returns:
        Archive mode to use
    """
    if item.archiveMode is None:
        archiveMode = config.collect.archiveMode
    else:
        archiveMode = item.archiveMode
    logger.debug("Archive mode is [%s]", archiveMode)
    return archiveMode


############################
# _getIgnoreFile() function
############################


def _getIgnoreFile(config, item):
    """
    Gets the ignore file that should be used for a collect directory or file.
    If possible, use the one on the file or directory, otherwise take from collect section.
    Args:
       config: Config object
       item: ``CollectFile`` or ``CollectDir`` object
    Returns:
        Ignore file to use
    """
    if item.ignoreFile is None:
        ignoreFile = config.collect.ignoreFile
    else:
        ignoreFile = item.ignoreFile
    logger.debug("Ignore file is [%s]", ignoreFile)
    return ignoreFile


############################
# _getLinkDepth() function
############################


def _getLinkDepth(item):
    """
    Gets the link depth that should be used for a collect directory.
    If possible, use the one on the directory, otherwise set a value of 0 (zero).
    Args:
       item: ``CollectDir`` object
    Returns:
        Link depth to use
    """
    if item.linkDepth is None:
        linkDepth = 0
    else:
        linkDepth = item.linkDepth
    logger.debug("Link depth is [%d]", linkDepth)
    return linkDepth


############################
# _getDereference() function
############################


def _getDereference(item):
    """
    Gets the dereference flag that should be used for a collect directory.
    If possible, use the one on the directory, otherwise set a value of False.
    Args:
       item: ``CollectDir`` object
    Returns:
        Dereference flag to use
    """
    if item.dereference is None:
        dereference = False
    else:
        dereference = item.dereference
    logger.debug("Dereference flag is [%s]", dereference)
    return dereference


################################
# _getRecursionLevel() function
################################


def _getRecursionLevel(item):
    """
    Gets the recursion level that should be used for a collect directory.
    If possible, use the one on the directory, otherwise set a value of 0 (zero).
    Args:
       item: ``CollectDir`` object
    Returns:
        Recursion level to use
    """
    if item.recursionLevel is None:
        recursionLevel = 0
    else:
        recursionLevel = item.recursionLevel
    logger.debug("Recursion level is [%d]", recursionLevel)
    return recursionLevel


############################
# _getDigestPath() function
############################


def _getDigestPath(config, absolutePath):
    """
    Gets the digest path associated with a collect directory or file.
    Args:
       config: Config object
       absolutePath: Absolute path to generate digest for
    Returns:
        Absolute path to the digest associated with the collect directory or file
    """
    normalized = buildNormalizedPath(absolutePath)
    filename = "%s.%s" % (normalized, DIGEST_EXTENSION)
    digestPath = pathJoin(config.options.workingDir, filename)
    logger.debug("Digest path is [%s]", digestPath)
    return digestPath


#############################
# _getTarfilePath() function
#############################


def _getTarfilePath(config, absolutePath, archiveMode):
    """
    Gets the tarfile path (including correct extension) associated with a collect directory.
    Args:
       config: Config object
       absolutePath: Absolute path to generate tarfile for
       archiveMode: Archive mode to use for this tarfile
    Returns:
        Absolute path to the tarfile associated with the collect directory
    """
    if archiveMode == "tar":
        extension = "tar"
    elif archiveMode == "targz":
        extension = "tar.gz"
    elif archiveMode == "tarbz2":
        extension = "tar.bz2"
    normalized = buildNormalizedPath(absolutePath)
    filename = "%s.%s" % (normalized, extension)
    tarfilePath = pathJoin(config.collect.targetDir, filename)
    logger.debug("Tarfile path is [%s]", tarfilePath)
    return tarfilePath


############################
# _getExclusions() function
############################


def _getExclusions(config, collectDir):
    """
    Gets exclusions (file and patterns) associated with a collect directory.

    The returned files value is a list of absolute paths to be excluded from the
    backup for a given directory.  It is derived from the collect configuration
    absolute exclude paths and the collect directory's absolute and relative
    exclude paths.

    The returned patterns value is a list of patterns to be excluded from the
    backup for a given directory.  It is derived from the list of patterns from
    the collect configuration and from the collect directory itself.

    Args:
       config: Config object
       collectDir: Collect directory object

    Returns:
        Tuple (files, patterns) indicating what to exclude
    """
    paths = []
    if config.collect.absoluteExcludePaths is not None:
        paths.extend(config.collect.absoluteExcludePaths)
    if collectDir.absoluteExcludePaths is not None:
        paths.extend(collectDir.absoluteExcludePaths)
    if collectDir.relativeExcludePaths is not None:
        for relativePath in collectDir.relativeExcludePaths:
            paths.append(pathJoin(collectDir.absolutePath, relativePath))
    patterns = []
    if config.collect.excludePatterns is not None:
        patterns.extend(config.collect.excludePatterns)
    if collectDir.excludePatterns is not None:
        patterns.extend(collectDir.excludePatterns)
    logger.debug("Exclude paths: %s", paths)
    logger.debug("Exclude patterns: %s", patterns)
    return (paths, patterns)
