505 lines
18 KiB
Python
Executable File
505 lines
18 KiB
Python
Executable File
#!/usr/bin/python3
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# This script performs a backup of all user data:
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# 1) System services are stopped.
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# 2) An incremental encrypted backup is made using duplicity.
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# 3) The stopped services are restarted.
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# 4) STORAGE_ROOT/backup/after-backup is executd if it exists.
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import os, os.path, shutil, glob, re, datetime, sys
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import dateutil.parser, dateutil.relativedelta, dateutil.tz
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import rtyaml
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from utils import exclusive_process, load_environment, shell, wait_for_service, fix_boto
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def backup_status(env):
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# Root folder
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backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
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# What is the current status of backups?
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# Query duplicity to get a list of all backups.
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# Use the number of volumes to estimate the size.
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config = get_backup_config(env)
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now = datetime.datetime.now(dateutil.tz.tzlocal())
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# Are backups dissbled?
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if config["target"] == "off":
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return { }
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backups = { }
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backup_cache_dir = os.path.join(backup_root, 'cache')
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def reldate(date, ref, clip):
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if ref < date: return clip
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rd = dateutil.relativedelta.relativedelta(ref, date)
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if rd.months > 1: return "%d months, %d days" % (rd.months, rd.days)
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if rd.months == 1: return "%d month, %d days" % (rd.months, rd.days)
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if rd.days >= 7: return "%d days" % rd.days
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if rd.days > 1: return "%d days, %d hours" % (rd.days, rd.hours)
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if rd.days == 1: return "%d day, %d hours" % (rd.days, rd.hours)
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return "%d hours, %d minutes" % (rd.hours, rd.minutes)
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# Get duplicity collection status and parse for a list of backups.
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def parse_line(line):
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keys = line.strip().split()
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date = dateutil.parser.parse(keys[1]).astimezone(dateutil.tz.tzlocal())
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return {
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"date": keys[1],
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"date_str": date.strftime("%x %X") + " " + now.tzname(),
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"date_delta": reldate(date, now, "the future?"),
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"full": keys[0] == "full",
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"size": 0, # collection-status doesn't give us the size
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"volumes": keys[2], # number of archive volumes for this backup (not really helpful)
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}
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code, collection_status = shell('check_output', [
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"/usr/bin/duplicity",
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"collection-status",
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"--archive-dir", backup_cache_dir,
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"--gpg-options", "--cipher-algo=AES256",
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"--log-fd", "1",
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config["target"],
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],
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get_env(env),
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trap=True)
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if code != 0:
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# Command failed. This is likely due to an improperly configured remote
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# destination for the backups or the last backup job terminated unexpectedly.
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raise Exception("Something is wrong with the backup: " + collection_status)
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for line in collection_status.split('\n'):
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if line.startswith(" full") or line.startswith(" inc"):
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backup = parse_line(line)
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backups[backup["date"]] = backup
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# Look at the target to get the sizes of each of the backups. There is more than one file per backup.
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for fn, size in list_target_files(config):
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m = re.match(r"duplicity-(full|full-signatures|(inc|new-signatures)\.(?P<incbase>\d+T\d+Z)\.to)\.(?P<date>\d+T\d+Z)\.", fn)
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if not m: continue # not a part of a current backup chain
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key = m.group("date")
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backups[key]["size"] += size
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# Ensure the rows are sorted reverse chronologically.
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# This is relied on by should_force_full() and the next step.
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backups = sorted(backups.values(), key = lambda b : b["date"], reverse=True)
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# Get the average size of incremental backups, the size of the
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# most recent full backup, and the date of the most recent
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# backup and the most recent full backup.
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incremental_count = 0
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incremental_size = 0
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first_date = None
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first_full_size = None
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first_full_date = None
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for bak in backups:
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if first_date is None:
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first_date = dateutil.parser.parse(bak["date"])
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if bak["full"]:
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first_full_size = bak["size"]
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first_full_date = dateutil.parser.parse(bak["date"])
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break
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incremental_count += 1
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incremental_size += bak["size"]
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# When will the most recent backup be deleted? It won't be deleted if the next
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# backup is incremental, because the increments rely on all past increments.
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# So first guess how many more incremental backups will occur until the next
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# full backup. That full backup frees up this one to be deleted. But, the backup
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# must also be at least min_age_in_days old too.
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deleted_in = None
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if incremental_count > 0 and first_full_size is not None:
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# How many days until the next incremental backup? First, the part of
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# the algorithm based on increment sizes:
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est_days_to_next_full = (.5 * first_full_size - incremental_size) / (incremental_size/incremental_count)
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est_time_of_next_full = first_date + datetime.timedelta(days=est_days_to_next_full)
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# ...And then the part of the algorithm based on full backup age:
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est_time_of_next_full = min(est_time_of_next_full, first_full_date + datetime.timedelta(days=config["min_age_in_days"]*10+1))
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# It still can't be deleted until it's old enough.
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est_deleted_on = max(est_time_of_next_full, first_date + datetime.timedelta(days=config["min_age_in_days"]))
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deleted_in = "approx. %d days" % round((est_deleted_on-now).total_seconds()/60/60/24 + .5)
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# When will a backup be deleted? Set the deleted_in field of each backup.
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saw_full = False
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for bak in backups:
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if deleted_in:
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# The most recent increment in a chain and all of the previous backups
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# it relies on are deleted at the same time.
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bak["deleted_in"] = deleted_in
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if bak["full"]:
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# Reset when we get to a full backup. A new chain start *next*.
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saw_full = True
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deleted_in = None
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elif saw_full and not deleted_in:
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# We're now on backups prior to the most recent full backup. These are
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# free to be deleted as soon as they are min_age_in_days old.
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deleted_in = reldate(now, dateutil.parser.parse(bak["date"]) + datetime.timedelta(days=config["min_age_in_days"]), "on next daily backup")
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bak["deleted_in"] = deleted_in
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return {
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"backups": backups,
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}
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def should_force_full(config, env):
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# Force a full backup when the total size of the increments
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# since the last full backup is greater than half the size
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# of that full backup.
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inc_size = 0
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for bak in backup_status(env)["backups"]:
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if not bak["full"]:
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# Scan through the incremental backups cumulating
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# size...
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inc_size += bak["size"]
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else:
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# ...until we reach the most recent full backup.
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# Return if we should to a full backup, which is based
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# on the size of the increments relative to the full
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# backup, as well as the age of the full backup.
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if inc_size > .5*bak["size"]:
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return True
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if dateutil.parser.parse(bak["date"]) + datetime.timedelta(days=config["min_age_in_days"]*10+1) < datetime.datetime.now(dateutil.tz.tzlocal()):
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return True
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return False
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else:
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# If we got here there are no (full) backups, so make one.
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# (I love for/else blocks. Here it's just to show off.)
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return True
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def get_passphrase(env):
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# Get the encryption passphrase. secret_key.txt is 2048 random
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# bits base64-encoded and with line breaks every 65 characters.
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# gpg will only take the first line of text, so sanity check that
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# that line is long enough to be a reasonable passphrase. It
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# only needs to be 43 base64-characters to match AES256's key
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# length of 32 bytes.
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backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
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with open(os.path.join(backup_root, 'secret_key.txt')) as f:
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passphrase = f.readline().strip()
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if len(passphrase) < 43: raise Exception("secret_key.txt's first line is too short!")
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return passphrase
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def get_env(env):
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config = get_backup_config(env)
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env = { "PASSPHRASE" : get_passphrase(env) }
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if get_target_type(config) == 's3':
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env["AWS_ACCESS_KEY_ID"] = config["target_user"]
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env["AWS_SECRET_ACCESS_KEY"] = config["target_pass"]
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return env
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def get_target_type(config):
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protocol = config["target"].split(":")[0]
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return protocol
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def perform_backup(full_backup):
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env = load_environment()
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exclusive_process("backup")
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config = get_backup_config(env)
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backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
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backup_cache_dir = os.path.join(backup_root, 'cache')
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backup_dir = os.path.join(backup_root, 'encrypted')
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# Are backups dissbled?
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if config["target"] == "off":
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return
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# In an older version of this script, duplicity was called
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# such that it did not encrypt the backups it created (in
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# backup/duplicity), and instead openssl was called separately
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# after each backup run, creating AES256 encrypted copies of
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# each file created by duplicity in backup/encrypted.
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#
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# We detect the transition by the presence of backup/duplicity
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# and handle it by 'dupliception': we move all the old *un*encrypted
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# duplicity files up out of the backup/duplicity directory (as
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# backup/ is excluded from duplicity runs) in order that it is
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# included in the next run, and we delete backup/encrypted (which
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# duplicity will output files directly to, post-transition).
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old_backup_dir = os.path.join(backup_root, 'duplicity')
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migrated_unencrypted_backup_dir = os.path.join(env["STORAGE_ROOT"], "migrated_unencrypted_backup")
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if os.path.isdir(old_backup_dir):
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# Move the old unencrypted files to a new location outside of
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# the backup root so they get included in the next (new) backup.
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# Then we'll delete them. Also so that they do not get in the
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# way of duplicity doing a full backup on the first run after
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# we take care of this.
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shutil.move(old_backup_dir, migrated_unencrypted_backup_dir)
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# The backup_dir (backup/encrypted) now has a new purpose.
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# Clear it out.
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shutil.rmtree(backup_dir)
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# On the first run, always do a full backup. Incremental
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# will fail. Otherwise do a full backup when the size of
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# the increments since the most recent full backup are
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# large.
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try:
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full_backup = full_backup or should_force_full(config, env)
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except Exception as e:
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# This was the first call to duplicity, and there might
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# be an error already.
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print(e)
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sys.exit(1)
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# Stop services.
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def service_command(service, command, quit=None):
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# Execute silently, but if there is an error then display the output & exit.
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code, ret = shell('check_output', ["/usr/sbin/service", service, command], capture_stderr=True, trap=True)
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if code != 0:
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print(ret)
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if quit:
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sys.exit(code)
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service_command("php5-fpm", "stop", quit=True)
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service_command("postfix", "stop", quit=True)
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service_command("dovecot", "stop", quit=True)
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# Run a backup of STORAGE_ROOT (but excluding the backups themselves!).
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# --allow-source-mismatch is needed in case the box's hostname is changed
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# after the first backup. See #396.
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try:
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shell('check_call', [
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"/usr/bin/duplicity",
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"full" if full_backup else "incr",
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"--verbosity", "warning", "--no-print-statistics",
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"--archive-dir", backup_cache_dir,
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"--exclude", backup_root,
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"--volsize", "250",
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"--gpg-options", "--cipher-algo=AES256",
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env["STORAGE_ROOT"],
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config["target"],
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"--allow-source-mismatch"
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],
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get_env(env))
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finally:
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# Start services again.
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service_command("dovecot", "start", quit=False)
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service_command("postfix", "start", quit=False)
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service_command("php5-fpm", "start", quit=False)
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# Once the migrated backup is included in a new backup, it can be deleted.
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if os.path.isdir(migrated_unencrypted_backup_dir):
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shutil.rmtree(migrated_unencrypted_backup_dir)
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# Remove old backups. This deletes all backup data no longer needed
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# from more than 3 days ago.
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shell('check_call', [
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"/usr/bin/duplicity",
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"remove-older-than",
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"%dD" % config["min_age_in_days"],
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"--verbosity", "error",
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"--archive-dir", backup_cache_dir,
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"--force",
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config["target"]
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],
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get_env(env))
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# From duplicity's manual:
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# "This should only be necessary after a duplicity session fails or is
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# aborted prematurely."
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# That may be unlikely here but we may as well ensure we tidy up if
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# that does happen - it might just have been a poorly timed reboot.
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shell('check_call', [
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"/usr/bin/duplicity",
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"cleanup",
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"--verbosity", "error",
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"--archive-dir", backup_cache_dir,
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"--force",
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config["target"]
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],
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get_env(env))
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# Change ownership of backups to the user-data user, so that the after-bcakup
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# script can access them.
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if get_target_type(config) == 'file':
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shell('check_call', ["/bin/chown", "-R", env["STORAGE_USER"], backup_dir])
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# Execute a post-backup script that does the copying to a remote server.
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# Run as the STORAGE_USER user, not as root. Pass our settings in
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# environment variables so the script has access to STORAGE_ROOT.
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post_script = os.path.join(backup_root, 'after-backup')
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if os.path.exists(post_script):
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shell('check_call',
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['su', env['STORAGE_USER'], '-c', post_script, config["target"]],
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env=env)
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# Our nightly cron job executes system status checks immediately after this
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# backup. Since it checks that dovecot and postfix are running, block for a
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# bit (maximum of 10 seconds each) to give each a chance to finish restarting
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# before the status checks might catch them down. See #381.
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wait_for_service(25, True, env, 10)
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wait_for_service(993, True, env, 10)
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def run_duplicity_verification():
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env = load_environment()
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backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
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config = get_backup_config(env)
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backup_cache_dir = os.path.join(backup_root, 'cache')
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shell('check_call', [
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"/usr/bin/duplicity",
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"--verbosity", "info",
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"verify",
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"--compare-data",
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"--archive-dir", backup_cache_dir,
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"--exclude", backup_root,
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config["target"],
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env["STORAGE_ROOT"],
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], get_env(env))
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def run_duplicity_restore(args):
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env = load_environment()
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config = get_backup_config(env)
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backup_cache_dir = os.path.join(env["STORAGE_ROOT"], 'backup', 'cache')
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shell('check_call', [
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"/usr/bin/duplicity",
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"restore",
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"--archive-dir", backup_cache_dir,
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config["target"],
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] + args,
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get_env(env))
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def list_target_files(config):
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import urllib.parse
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try:
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p = urllib.parse.urlparse(config["target"])
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except ValueError:
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return "invalid target"
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if p.scheme == "file":
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return [(fn, os.path.getsize(os.path.join(p.path, fn))) for fn in os.listdir(p.path)]
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elif p.scheme == "s3":
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# match to a Region
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fix_boto() # must call prior to importing boto
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import boto.s3
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from boto.exception import BotoServerError
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for region in boto.s3.regions():
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if region.endpoint == p.hostname:
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break
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else:
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raise ValueError("Invalid S3 region/host.")
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bucket = p.path[1:].split('/')[0]
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path = '/'.join(p.path[1:].split('/')[1:]) + '/'
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# If no prefix is specified, set the path to '', otherwise boto won't list the files
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if path == '/':
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path = ''
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if bucket == "":
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raise ValueError("Enter an S3 bucket name.")
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# connect to the region & bucket
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try:
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conn = region.connect(aws_access_key_id=config["target_user"], aws_secret_access_key=config["target_pass"])
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bucket = conn.get_bucket(bucket)
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except BotoServerError as e:
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if e.status == 403:
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raise ValueError("Invalid S3 access key or secret access key.")
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elif e.status == 404:
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raise ValueError("Invalid S3 bucket name.")
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elif e.status == 301:
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raise ValueError("Incorrect region for this bucket.")
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raise ValueError(e.reason)
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return [(key.name[len(path):], key.size) for key in bucket.list(prefix=path)]
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else:
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raise ValueError(config["target"])
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def backup_set_custom(env, target, target_user, target_pass, min_age):
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config = get_backup_config(env, for_save=True)
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# min_age must be an int
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if isinstance(min_age, str):
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min_age = int(min_age)
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config["target"] = target
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config["target_user"] = target_user
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config["target_pass"] = target_pass
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config["min_age_in_days"] = min_age
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# Validate.
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try:
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if config["target"] not in ("off", "local"):
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# these aren't supported by the following function, which expects a full url in the target key,
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# which is what is there except when loading the config prior to saving
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list_target_files(config)
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except ValueError as e:
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return str(e)
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write_backup_config(env, config)
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return "OK"
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def get_backup_config(env, for_save=False, for_ui=False):
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backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
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# Defaults.
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config = {
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"min_age_in_days": 3,
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"target": "local",
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}
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# Merge in anything written to custom.yaml.
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try:
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custom_config = rtyaml.load(open(os.path.join(backup_root, 'custom.yaml')))
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if not isinstance(custom_config, dict): raise ValueError() # caught below
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config.update(custom_config)
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except:
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pass
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# When updating config.yaml, don't do any further processing on what we find.
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if for_save:
|
|
return config
|
|
|
|
# When passing this back to the admin to show the current settings, do not include
|
|
# authentication details. The user will have to re-enter it.
|
|
if for_ui:
|
|
for field in ("target_user", "target_pass"):
|
|
if field in config:
|
|
del config[field]
|
|
|
|
# helper fields for the admin
|
|
config["file_target_directory"] = os.path.join(backup_root, 'encrypted')
|
|
config["enc_pw_file"] = os.path.join(backup_root, 'secret_key.txt')
|
|
if config["target"] == "local":
|
|
# Expand to the full URL.
|
|
config["target"] = "file://" + config["file_target_directory"]
|
|
|
|
return config
|
|
|
|
def write_backup_config(env, newconfig):
|
|
backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
|
|
with open(os.path.join(backup_root, 'custom.yaml'), "w") as f:
|
|
f.write(rtyaml.dump(newconfig))
|
|
|
|
if __name__ == "__main__":
|
|
import sys
|
|
if sys.argv[-1] == "--verify":
|
|
# Run duplicity's verification command to check a) the backup files
|
|
# are readable, and b) report if they are up to date.
|
|
run_duplicity_verification()
|
|
|
|
elif sys.argv[-1] == "--status":
|
|
# Show backup status.
|
|
ret = backup_status(load_environment())
|
|
print(rtyaml.dump(ret["backups"]))
|
|
|
|
elif len(sys.argv) >= 2 and sys.argv[1] == "--restore":
|
|
# Run duplicity restore. Rest of command line passed as arguments
|
|
# to duplicity. The restore path should be specified.
|
|
run_duplicity_restore(sys.argv[2:])
|
|
|
|
else:
|
|
# Perform a backup. Add --full to force a full backup rather than
|
|
# possibly performing an incremental backup.
|
|
full_backup = "--full" in sys.argv
|
|
perform_backup(full_backup)
|