commit 4eedc518db6964bccc47a8f55c7867c9cde0244e
Author: Max Mehl <mail@mehl.mx>
Date:   Fri May 26 11:04:12 2023 +0200

    initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100755
index 0000000..267fa85
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.seafile_backup.db.json
+__pycache__/
+*.log
diff --git a/functions/__init__.py b/functions/__init__.py
new file mode 100755
index 0000000..e69de29
diff --git a/functions/cachedb.py b/functions/cachedb.py
new file mode 100755
index 0000000..912c48c
--- /dev/null
+++ b/functions/cachedb.py
@@ -0,0 +1,55 @@
+"""Functions for cache DB for seafile mirror"""
+
+import json
+import logging
+from pathlib import Path
+
+
+def db_read(cachefile) -> dict:
+    """Get the cache database file as a dict"""
+    dbpath = Path(cachefile)
+
+    # If DB file exists, return JSON as dict
+    if dbpath.is_file():
+        with open(cachefile, "r", encoding="UTF-8") as dbread:
+            logging.debug("Reading cache file '%s' from disk", cachefile)
+            cachedb = json.load(dbread)
+    else:
+        logging.debug("Cache file '%s' does not exist on disk", cachefile)
+        cachedb = {}
+
+    # Add/Update key containing the local cache file so we can easily access it
+    cachedb["_cachefile"] = cachefile
+
+    return cachedb
+
+
+def db_write(dbdict):
+    """Update/create the cache database file with a dict"""
+    with open(dbdict["_cachefile"], "w", encoding="UTF-8") as dbwrite:
+        logging.debug("Writing cache file '%s' to disk", dbdict["_cachefile"])
+        json.dump(dbdict, dbwrite, indent=2)
+        # Append newline to file
+        dbwrite.write("\n")
+
+
+def db_update(dbdict, libid, **kwargs):
+    """Update the cached key/values for a specific library, and write the cache file"""
+    # Create dict entry for library if it doesn't exist yet
+    if libid not in dbdict:
+        dbdict[libid] = {}
+    for key, value in kwargs.items():
+        logging.debug(
+            "Updating '%s' of library '%s' in in-memory cache dictionary", key, libid
+        )
+        dbdict[libid][key] = value
+
+    db_write(dbdict)
+
+
+def db_get_library_key(dbdict, libid, key):
+    """Get value of requested key from the cache dictionary"""
+    if libid in dbdict and key in dbdict[libid]:
+        return dbdict[libid][key]
+
+    return None
diff --git a/functions/helpers.py b/functions/helpers.py
new file mode 100755
index 0000000..9cfb067
--- /dev/null
+++ b/functions/helpers.py
@@ -0,0 +1,37 @@
+"""Misc helper functions for seafile mirror"""
+
+import logging
+import socket
+import sys
+
+
+def get_lock(process_name):
+    """Get the lock for this program to avoid double-execution"""
+    # Without holding a reference to our socket somewhere it gets garbage
+    # collected when the function exits
+    # pylint: disable=protected-access
+    get_lock._lock_socket = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
+
+    try:
+        # The null byte (\0) means the socket is created
+        # in the abstract namespace instead of being created
+        # on the file system itself.
+        # Works only in Linux
+        # pylint: disable=protected-access
+        get_lock._lock_socket.bind("\0" + process_name)
+    except socket.error:
+        logging.critical("This script is already executed in another instance. Abort.")
+        sys.exit(1)
+
+
+def findstring(text, string):
+    """Check if a certain string exists in an output"""
+    if text.find(string) >= 0:
+        return True
+
+    return False
+
+
+def countlines(string: str) -> int:
+    """Count number of lines in a variable"""
+    return len(string.splitlines())
diff --git a/functions/seafile.py b/functions/seafile.py
new file mode 100755
index 0000000..28e808b
--- /dev/null
+++ b/functions/seafile.py
@@ -0,0 +1,262 @@
+"""Functions specific to Seafile for seafile mirror"""
+
+import datetime
+import logging
+import subprocess
+import sys
+from time import sleep
+
+from .cachedb import db_get_library_key, db_update
+
+# Constants
+# Seafile CLI command
+CMD = "seaf-cli"
+
+
+def sf_runcmd(auth: list, *arguments: str) -> str:
+    """Run a seaf-cli command and return the output (stdout)"""
+    # Build command list
+    # base command (seaf-cli)
+    cmdargs = [CMD]
+
+    # Arguments
+    for arg in arguments:
+        cmdargs.append(arg)
+
+    # Optional authentication as list
+    # "-s", server, "-u", user, "-p", password
+    if auth:
+        cmdargs.extend(["-s", auth[0], "-u", auth[1], "-p", auth[2]])
+
+    # run command
+    ret = subprocess.run(cmdargs, capture_output=True, check=False)
+
+    # check for errors
+    if ret.returncode != 0:
+        logging.error("The command '%s' returned an error: %s", ret.args, ret.stderr)
+        return False
+
+    return ret.stdout.decode("UTF-8")
+
+
+def sf_parse(output: str, fromcommand: str) -> list:
+    """Parse the output of `list` and `status`, return a list of dicts"""
+    libs = []
+    # Read line by line, skip first line
+    for lib in output.splitlines()[1:]:
+        # If list, split is by " ", and structure is name,id,dir
+        if fromcommand == "list":
+            lib = [x.strip() for x in lib.split(" ")]
+            lib = {"name": lib[0], "id": lib[1], "dir": lib[2]}
+            libs.append(lib)
+        # If status, split is by "\t", and structure is name,status,progress
+        elif fromcommand == "status":
+            lib_tmp = [x.strip() for x in lib.split("\t")]
+            lib = {"name": lib_tmp[0], "status": lib_tmp[1]}
+            # Add progress if it exists
+            try:
+                lib["progress"] = lib_tmp[2]
+            except IndexError:
+                lib["progress"] = None
+
+            libs.append(lib)
+
+    return libs
+
+
+def sf_getstatus(libname: str) -> dict:
+    """Return the current status of a library (name, status, progress)"""
+    # Get output of `status` and parse it
+    libsstatus = sf_runcmd(None, "status")
+    libsstatus = sf_parse(libsstatus, "status")
+
+    # In the list of statuses, get the one for the requested library. None if no match
+    status = next((item for item in libsstatus if item["name"] == libname), None)
+
+    # Handle if the library does not appear in `status`. Usually directly after starting to sync it
+    if not status:
+        logging.debug("Status for %s cannot be retrieved", libname)
+        # Construct a status dict
+        status = {"name": libname, "status": None, "progress": None}
+
+    return status
+
+
+def sf_desync_all(cache):
+    """Desync all libraries that are in `list` and `status`"""
+    # Firstly, go through libslist
+    libslist = sf_runcmd(None, "list")
+    libslist = sf_parse(libslist, "list")
+
+    # If libraries found in `list`, desync them
+    if libslist:
+        logging.warning(
+            "There are still %s local synced libraries. Desyncing them...",
+            len(libslist),
+        )
+
+        for lib in libslist:
+            # Check if the cache status of the lib is still `started`. If so,
+            # update the lastsync date
+            if db_get_library_key(cache, lib["id"], "status") == "started":
+                logging.debug(
+                    "Library %s is synced but the cache file hasn't been updated "
+                    "with the last sync date. Setting it to 'now'",
+                    lib["name"],
+                )
+                sf_bump_cache_status(cache, lib["id"], status="synced")
+
+            # Desync library
+            logging.debug("Desyncing library %s stored in %s", lib["name"], lib["dir"])
+            sf_runcmd(None, "desync", "-d", lib["dir"])
+
+    # Secondly, go through libstatus
+    # We cannot desync libraries that are in `status` but not `list`, so error out
+    libsstatus = sf_runcmd(None, "status")
+    libsstatus = sf_parse(libsstatus, "status")
+
+    # If libraries found in `status`, return informative errors and abort
+    if libsstatus:
+        logging.error(
+            "There are still %s local libraries currently downloading but not listed yet:",
+            len(libsstatus),
+        )
+
+        for lib in libsstatus:
+            logging.error(
+                "- %s with the current status '%s' and progress '%s'",
+                lib["name"],
+                lib["status"],
+                lib["progress"],
+            )
+
+        logging.critical(
+            "Exiting application because we cannot resync at least one library, see errors above."
+        )
+        sys.exit(1)
+
+
+def sf_waitforsynced(libname) -> int:
+    """Regularly check status of the library that started to sync"""
+    libsynced = False
+    syncwaitmins = 0
+    nostatus, nostatus_limit = 0, 10
+    while libsynced is not True:
+        libstatus = sf_getstatus(libname)
+        # If we have some status information, act upon it
+        # If not, we already informed about being unable to retrieve it and also wait
+
+        if libstatus["status"]:
+            # Reset status fails
+            nostatus = 0
+            # If synchronised, inform and end loop
+            if libstatus["status"] == "synchronized":
+                logging.debug(
+                    "Library %s has been fully synchronised after %s minutes",
+                    libname,
+                    round(syncwaitmins),
+                )
+                libsynced = True
+
+            # If not synchronised yet, report on status
+            else:
+                logging.debug(
+                    "Library %s is not fully synchronised yet. "
+                    "Current status: %s with progress: %s",
+                    libname,
+                    libstatus["status"],
+                    libstatus["progress"],
+                )
+
+        # Status is None, which is fine a few times. But if it happens too often
+        # (`nostatus_limit`), we'll restart seaf-cli as it's probably hung up
+        else:
+            # Increment number of failed status retrievals
+            nostatus += 1
+            if nostatus >= nostatus_limit:
+                logging.warning(
+                    "Library %s didn't appear in status %s times. Restarting seaf-cli daemon...",
+                    libname,
+                    nostatus_limit,
+                )
+                sf_runcmd(None, "stop")
+                sf_runcmd(None, "start")
+
+        # If library not synced yet or no status available, wait
+        if not libsynced:
+            # Decide how long to wait for next `status` check depending on how
+            # often we tried before
+            if syncwaitmins < 1:
+                # wait 15 seconds for 1 minute in total
+                sleep(15)
+                syncwaitmins += 0.25
+            elif syncwaitmins < 10:
+                # wait 60 seconds for 10 minutes in total
+                sleep(60)
+                syncwaitmins += 1
+            else:
+                # wait 120 seconds
+                sleep(120)
+                syncwaitmins += 2
+
+    return syncwaitmins
+
+
+def sf_bump_cache_status(dbdict, libid, status, duration=0) -> None:
+    """Update the sync state of a library in the cache database"""
+    logging.debug("Updating cache for library '%s' to status '%s'", libid, status)
+    # Library has been successfully synced
+    if status == "synced":
+        lastsync = datetime.datetime.now() - datetime.timedelta(minutes=duration + 2)
+        db_update(
+            dbdict,
+            libid,
+            status=status,
+            lastsync=lastsync.isoformat(),
+        )
+    # Library sync has just been started
+    if status == "started":
+        db_update(dbdict, libid, status=status)
+
+
+def sf_lastsync_old_enough(dbdict, libid, force, resyncinterval) -> bool:
+    """Find out if lastsync time of library is older than resyncinterval"""
+    # Get lastsync key from cache for this library
+    lastsync = db_get_library_key(dbdict, libid, "lastsync")
+    # Check if there actually has been an entry for the last sync
+    if lastsync:
+        # Convert to datetime object
+        lastsync = datetime.datetime.fromisoformat(lastsync)
+        # Test if time difference (hours) is smaller than resyncinterval
+        if datetime.datetime.now() - lastsync < datetime.timedelta(days=resyncinterval):
+            logging.debug(
+                "Last sync of library '%s' is newer than limit (%s days)",
+                libid,
+                resyncinterval,
+            )
+
+            if force:
+                logging.info(
+                    "Last sync of library '%s' is newer than limit (%s days), "
+                    "but sync is enforced.",
+                    libid,
+                    resyncinterval,
+                )
+                return True
+
+            return False
+
+        # time difference is larger than resyncinterval
+        logging.debug(
+            "Last sync of library '%s' is older than limit (%s days)",
+            libid,
+            resyncinterval,
+        )
+        return True
+
+    # The library has never been synced before (lastsync = None)
+    logging.debug(
+        "Library '%s' seems to not have been synced before",
+        libid,
+    )
+    return True
diff --git a/seafile_mirror.py b/seafile_mirror.py
new file mode 100755
index 0000000..e9c642c
--- /dev/null
+++ b/seafile_mirror.py
@@ -0,0 +1,199 @@
+#!/usr/bin/env python3
+"""Handle clean read-only (re-)syncs of Seafile libraries to mirror them"""
+
+import argparse
+import logging
+import shutil
+from pathlib import Path
+from time import sleep
+
+import yaml
+
+from functions.cachedb import db_read
+from functions.helpers import findstring, get_lock
+from functions.seafile import (
+    sf_bump_cache_status,
+    sf_desync_all,
+    sf_lastsync_old_enough,
+    sf_runcmd,
+    sf_waitforsynced,
+)
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("-c", "--configdir", required=True, help="The config directory")
+parser.add_argument(
+    "-d",
+    "--dry",
+    action="store_true",
+    default=False,
+    help="Do not modify anything. Useful for being informed about which "
+    "libraries are due to be synced",
+)
+parser.add_argument(
+    "-f",
+    "--force",
+    action="store_true",
+    default=False,
+    help="Force re-sync of libraries even if they are newer than the configured limit",
+)
+parser.add_argument(
+    "-v",
+    "--verbose",
+    action="store_true",
+    default=False,
+    help="Print and log DEBUG messages",
+)
+
+
+def main():
+    """Main function"""
+    # Logging
+    log = logging.getLogger()
+    logging.basicConfig(
+        encoding="utf-8",
+        format="[%(asctime)s] %(levelname)s: %(message)s",
+        datefmt="%Y-%m-%d %H:%M:%S",
+        # Log to file and stdout
+        handlers=[
+            logging.FileHandler(logfile),
+            logging.StreamHandler(),
+        ],
+    )
+    # Set loglevel based on --verbose flag
+    if args.verbose:
+        log.setLevel(logging.DEBUG)
+    else:
+        log.setLevel(logging.INFO)
+
+    # Get lock for this process
+    get_lock("seafile_backup")
+
+    # Read configfile
+    with open(configfile, "r", encoding="UTF-8") as yamlfile:
+        config = yaml.safe_load(yamlfile)
+
+    # Populate cache dictionary
+    cache = db_read(cachefile)
+
+    # Check if there are still libraries in `list` or `status`. Desync them if
+    # possible. Do not run in dry-run
+    if not args.dry:
+        sf_desync_all(cache)
+
+    # Create list of libraries we handle(d) for final output
+    libsdone = []
+
+    # Go through users in config
+    for access in config:
+        # Setting variables for this server/user/pass combination
+        server = access["server"]
+        user = access["user"]
+        password = access["password"]
+        resyncinterval = access["resync_interval_days"]
+        authlist = [server, user, password]
+
+        logging.info(
+            "Checking all libraries for user %s on server %s for "
+            "whether they are due for a re-sync",
+            user,
+            server,
+        )
+
+        # Get remotely available libraries
+        remotelibs = sf_runcmd(authlist, "list-remote")
+
+        for lib in access["libs"]:
+            # Setting variables for this library
+            libdir = Path(lib["dir"])
+            libname = lib["name"]
+            libid = lib["id"]
+            # Set resync interval if there is a lib-specific setting. Otherwise default
+            libresyncinterval = (
+                lib["resync_interval_days"]
+                if "resync_interval_days" in lib
+                else resyncinterval
+            )
+
+            # Check if last sync of library is older than resync_interval_days
+            if sf_lastsync_old_enough(cache, libid, args.force, libresyncinterval):
+                logging.info(
+                    "Starting to re-sync library %s (%s) to %s", libname, libid, libdir
+                )
+            else:
+                logging.info(
+                    "Local mirror of library %s (%s) at %s is still recent enough. Skipping it.",
+                    libname,
+                    libid,
+                    libdir,
+                )
+                continue
+
+            # Check if desired library exists remotely
+            if findstring(remotelibs, libid):
+                logging.debug("The library %s exists remotely. Continuing...", libname)
+            else:
+                # If the library does not exist remotely, we don't continue
+                # Otherwise, we would delete data which cannot be retrieved again!
+                logging.warning(
+                    "The library %s does not exist remotely. Aborting resyncing this library.",
+                    libname,
+                )
+                # Start next iteration of loop (next library)
+                continue
+
+            if args.dry:
+                logging.info(
+                    "Running in dry run mode. Aborting resync of library %s which would happen now",
+                    libname,
+                )
+                continue
+
+            # Delete libdir if it exists
+            if libdir.exists() and libdir.is_dir():
+                logging.debug("Deleting library directory %s", libdir)
+                shutil.rmtree(libdir)
+            else:
+                logging.debug("Library directory did not exist before: %s", libdir)
+
+            # Re-create directory
+            logging.debug("Creating library directory %s", libdir)
+            Path(libdir).mkdir(parents=True, exist_ok=True)
+
+            # Trigger sync of library
+            logging.debug("Starting to sync library %s to %s", libname, libdir)
+            sf_runcmd(authlist, "sync", "-l", libid, "-d", libdir)
+            sf_bump_cache_status(cache, libid, status="started")
+
+            # Sleep a second to populate `status`
+            sleep(1)
+
+            # Check regularly how the syncing progress is and wait for it to finish
+            syncduration = sf_waitforsynced(libname)
+
+            # Library is synchronised, now we desync it again
+            logging.debug(
+                "Desyncing library %s stored at %s after it has been synced",
+                libname,
+                libdir,
+            )
+            sf_runcmd(None, "desync", "-d", libdir)
+
+            # Update libsdone and cache
+            libsdone.append(libname)
+            sf_bump_cache_status(cache, libid, status="synced", duration=syncduration)
+
+            logging.info(
+                "Library %s (%s) has been re-synced to %s", libname, libid, libdir
+            )
+
+    logging.info("Fully re-synced the following libraries: %s", ", ".join(libsdone))
+
+
+if __name__ == "__main__":
+    args = parser.parse_args()
+    # Set files depending on configdir
+    configdir = args.configdir.rstrip("/") + "/"
+    configfile = configdir + "seafile_mirror.conf.yaml"
+    cachefile = configdir + ".seafile_mirror.db.json"
+    logfile = configdir + "seafile_mirror.log"
+    main()