CLSYNC(1)

NAME
clsync - live sync tool, written in GNU C

SYNOPSIS
clsync [ ... ]

DESCRIPTION
clsync executes sync-handler with appropriate arguments on FS events in directory watch-dir using the inotify(7) Linux kernel subsystem. Extended regex-rules to filter what files and directories to sync may be placed in rules-file

OPTIONS
This options can be passed as arguments or to be used in the configuration file. To disable numeric option set to zero:
        =0
To disable string option (for example path to file) set to empty string:
        =
-W, --watch-dir watch-dir
    Root directory to be monitored by clsync. Required.

-S, --sync-handler sync-handler
    Path to sync-handler to be used for syncing by clsync. (see --mode) Required.

-R, --rules-file rules-file
    Path to file with filter rules of objects to be monitored. (see RULES) Is not set by default.

-D, --destination-dir destination-directory
    Defines directory to sync to for modes "rsyncdirect", "rsyncso" and "so". (see --mode) Is not set by default.

-M, --mode mode
    Sets syncing mode. Possible values:
        simple - calls sync-handler for every event
        shell - calls sync-handler for every sync
        rsyncdirect - calls rsync by path sync-handler directly (inflexible and unreliable, should be used only as a proof of concept)
        rsyncshell - calls sync-handler that supposed to run rsync for every sync (recommended mode)
        rsyncso - loads shared object by path sync-handler with dlopen(3) and calls function clsyncapi_rsync function for every sync
        so - loads shared object by path sync-handler with dlopen(3) and calls function clsyncapi_sync function for every sync
    See SYNC HANDLER MODES

    Required.
-b, --background
    Daemonize, forcing clsync to fork() on start. Is not set by default.

-H, --config-file config-file-path
    Use configuration from file config-file-path. (see CONFIGURATION FILE) Is not set by default.

-K, --config-block config-block-name
    Use configuration block with name config-block-name. (see CONFIGURATION FILE) Default value is "default".

-z, --pid-file path-to-pidfile
    Writes pid to file by path path-to-pidfile. Is not set by default.

--status-file status-file-path
    Write status description into file with path status-file-path. Possible statuses:
        starting - initializing subsystems and marking file tree with FS monitor subsystem
        initsync - processing initial syncing
        running - waiting for events or syncing
        rehashing - reloading configuration files
        pthread gc - running threads' garbage collector
        terminating - received signal to die, preparing to die
        exiting - cleaning up [for valgrind(1)]
    Is not set by default.

-u, --uid uid
    Drop user privileges to uid uid with setuid(2) Is not set by default.

-g, --gid gid
    Drop group privileges to gid gid with setgid(2) Is not set by default.

-r, --retries number-of-tries
    Tries limit to sync with sync-handler. clsync will die after number-of-tries tries. To try infinite set "0". Delay between tries is equal to --delay-sync value. Default value is "1".
-p, --pthread
    Use pthreads(7) to parallelize syncing processes. Every sync will be done asynchronous without blocking. If you're running clsync with option --pthread in conjunction with rsync with option --backup, you may catch a bug due to nonatomicity of rsync's file replace operation. (see DIAGNOSTICS) Is not set by default. Don't use this option if not sure.
-Y, --syslog
    Use syslog instead of stderr for logging. Is not set by default.
--one-file-system
    Don't follow to different devices' mount points. This option just adds option "FTS_XDEV" for fts_open(3) function. Warning! If you're using this option (but no --exclude-mount-points) clsync will write neither includes nor excludes of content of mount points.
    This may cause problems e.g. you're using rsync for sync-handler without similar option "--one-file-system". Is not set by default.
-X, --exclude-mount-points
    Forces --one-file-system but also add excludes to do not sync mount points. This requires to do stat(2) syscalls on every dir and can reduce performance. Is not set by default.

-c, --cluster-iface interface-ip
    Not implemented, yet. DANGEROUS OPTION. This functionality wasn't tested well. You can lost your data. Enables inter-node notifing subsystem to prevent sync looping between nodes. This's very useful features that provides ability of birectional sync of the same directory between two or more nodes. interface-ip is an IP-address already assigned to the interface that will be used for multicast notifing. Not enabled by default. To find out the IP-address on interface "eth0", you can use for example next command: ip a s eth0 | awk '{if($1=="inet") {gsub("/.*", "", $2); print $2}}' Is not set by default.

-m, --cluster-ip multicast-ip
    Not implemented yet. Sets IP-address for multicast group. This option can be used only in conjunction with --cluster-interface. Use IP-addresses from 224.0.0.0/4 for this option. Default value is "227.108.115.121". [(128+"c")."l"."s"."y"]

-P, --cluster-port multicast-port
    Not implemented yet. Sets UDP-port number for multicast messages. This option can be used only in conjunction with --cluster-interface. multicast-port should be greater than 0 and less than 65535. Default value is "40079". [("n" << 8) + "c"]

-W, --cluster-timeout cluster-timeout
    Not implemented yet. Sets timeout (in milliseconds) of waiting answer from another nodes of the cluster. If there's no answer from some node, it will be excluded. Default value is "1000". [1 second]

-n, --cluster-node-name cluster-node-name
    Not implemented yet. Sets the name of current node in the cluster. It will be used in action scripts of another nodes (see SYNC HANDLER MODES). Default value is $(uname -n).

-o, --cluster-hash-dl-min hash-dirlevel-min
    Sets minimal directory level for ctime hashing (see CLUSTERING). Default value is "1".

-O, --cluster-hash-dl-max hash-dirlevel-max
    Not implemented yet. Sets maximal directory level for ctime hashing (see CLUSTERING). Default value is "16".

-O, --cluster-scan-dl-max scan-dirlevel-max
    Not implemented yet. Sets maximal directory level for ctime scanning (see CLUSTERING). Default value is "32".

--standby-file standby-file-path
    Sets file to path that should be checked before every sync. If file exists the sync will be suspended until the file is deleted. It may be useful if you need freeze destination directory while running some scripts. Is not set by default.

-k, --timeout-sync sync-timeout
    Sets timeout for syncing processes. clsync will die if syncing process alive more than sync-timeout seconds. Set "0" to disable the timeout. Default value is "86400" ["24 hours"].

-w, --delay-sync additional-delay
    Sets the minimal delay (in seconds) between syncs. Default value is "30".

-t, --delay-collect ordinary-delay
    Sets the delay (in seconds) to collect events about ordinary files and directories. Default value is "30".

-T, --delay-collect-bigfile bigfiles-delay
    Sets the delay (in seconds) to collect events about "big files" (see --threshold-bigfile). Default value is "1800".

-B, --threshold-bigfile filesize-threshold
    Sets file size threshold (in bytes) that separates ordinary files from "big files". Events about "big files" are processed in another queue with a separate collecting delay. This is supposed to be used as a means of unloading IO resources. Default value is "134217728" ["128 MiB"].

-L, --lists-dir tmpdir-path
    Sets directory path to output temporary events-lists files. If this option is enabled, clsync will execute sync-handler once for each aggregated event list, passing the path to a file containing this list (actions "synclist" and "rsynclist"). Otherwise, clsync will execute sync-handler for every file in the aggregated event list (action "sync"). Cannot be used in mode "so". See SYNC HANDLER MODES. Is not set by default.

--have-recursive-sync
    Use action "recursivesync" instead of "synclist" for directories that were just marked (see SYNC HANDLER MODES case shell). Is not set by default.

--synclist-simplify
    Removes the first 3 parameters in list files of action "synclist" (see SYNC HANDLER MODES case shell). Is not set by default.

-A, --auto-add-rules-w
    Forces clsync to create a "w-rule" for every non-"w-rule" (see RULES). Not recommended to use in modes "rsyncdirect", "rsyncshell" and "rsyncso" Is not set by default.

--rsync-inclimit rsync-includes-line-limit
    Sets soft limit for lines count in files by path rsync-listpath. Unfortunately, rsync works very slowly with huge "--include-from" files. So, clsync splits that list with approximately rsync-includes-line-limit lines per list if it's too big, and executes by one rsync instance per list part. Use value "0" to disable the limit. Default value is "20000".

--rsync-prefer-include
    Forces clsync to prefer a "lot of includes" method instead of a "excludes+includes" for rsync on recursive syncing. See cases rsyncshell, rsyncdirect and rsyncso of SYNC HANDLER MODES. This option is not recommended. Is not set by default.

-x, --ignore-exitcode exitcode
    Forces clsync to do not process exitcode exitcode of sync-handler as an error. You can set multiple ignores by passing this option multiple times. Recommended values for rsync case is "24". You can set multiple values with listing a lot of "-x" options (e.g. "-x 23 -x 24") or via commas (e.g. "-x 23,24"). To drop the list use zero exitcode (e.g. "-x 0"). For example you can use "-x 0,23" to drop the list and set "23"-th exitcode to be ignored. Is not set by default (or equally is set to "0").

-U, --dont-unlink-lists
    Do not delete list-files after sync-handler has finished. This may be used for debugging purposes. Is not set by default.

-F, --full-initialsync
    Ignore filter rules from rules-file on initial sync. This may be useful for quick start or e.g. if it's required to sync "/var/log/" tree but not sync every change from there. Is not set by default.

--only-initialsync
    Exit after initial syncing on clsync start. Is not set by default.

--exit-on-no-events
    Exit if there's no events. Works like --only-initialsync, but also syncs events collected while the initial syncing. Unlike --only-initialsync this option uses FS monitor subsystem to monitor for new events while the initial syncing. This may reduce performance. On the other hand this way may be used to be sure, that everything is synced at the moment before clsync will exit. Is not set by default.

--skip-initialsync
    Skip initial syncing on clsync start. Is not set by default.

--exit-hook path-of-exit-hook-program
    Sets path of program to be executed on clsync exit. If this parameter is set, clsync will exec on exit:
        path-of-exit-hook-program label
    The execution will be skipped if syncing process wasn't started. Is not set by default.

-v, --verbose
    This option is supposed to increase verbosity. But at the moment there's no "verbose output" in the code, so the option does nothing. :) Is not set by default.

-d, --debug
    Increases debugging output. This may be supplied multiple times for more debugging information, up to a maximum of three "d" flags (more will do nothing), for example "-d -d -d" or "-d3" (equivalent cases) Is not set by default.

-q, --quiet
    Suppresses error messages. Is not set by default.

-f, --fanotify
    Don't use this option! Switches monitor subsystem to "fanotify" [it's described for future-compatibility]. Is not set by default.

-i, --inotify
    Switches monitor subsystem to "inotify". Is set by default.

-l, --label label
    Sets a label for this instance of clsync. The label will be passed to sync-handler every execution. Default value is "nolabel".

-h, --help
    Outputs options list and exits with exitcode "0". Is not set by default.

-V, --version
    Outputs clsync version and exits with exitcode "0". Is not set by default.

SYNC HANDLER MODES
clsync executes sync-handler that supposed to take care of the actual syncing process. Therefore clsync is only a convenient way to run a syncing script. clsync can run sync-handler in six ways. Which way will be used depends on specified mode (see --mode) case simple
    Executes for every syncing file/dir:
    sync-handler sync label evmask path [nodes] In this case, sync-handler is supposed to non-recursively sync file or directory by path. With evmask it's passed bitmask of events with the file or directory (see "/usr/include/linux/inotify.h"). Not recommended. Not well tested.
case shell
    Executes for every sync (if recursivesync is not used instead):
    sync-handler synclist label listpath [nodes] Executes for initial syncs if option --have-recursive-sync is set:
    sync-handler recursivesync label dirpath [nodes] In this case, sync-handler is supposed to non-recursively sync files and directories from list in a file by path listpath (see below). With evmask it's passed bitmask of events with the file or directory (see "/usr/include/linux/inotify.h"). Also sync-handler is supposed to recursively sync data from directory by path dirpath with manual excluding extra files. Not recommended. Not well tested.
case rsyncdirect
    Executes for every sync:
    sync-handler --inplace -aH --delete-before [--exclude-from rsync-exclude-listpath ] --include-from rsync-listpath --exclude '*' watch-dir/ dest-dir/ In this case, sync-handler is supposed to be a path to rsync binary. Error code "24" from sync-handler will be ignored in this case. This case is supposed to be used only as a proof of concept.
case rsyncshell
    Executes for every sync:
    sync-handler rsynclist label rsync-listpath [nodes] [rsync-exclude-listpath] In this case, sync-handler is supposed to run "rsync" application with parameters: -aH --delete-before --include-from rsync-listpath --exclude '*' if option --rsync-prefer-include is enabled. And with parameters: -aH --delete-before --exclude-from rsync-exclude-listpath --include-from rsync-listpath --exclude '*' if option --rsync-prefer-include is disabled. Recommended case.
case rsyncso
    In this case there's no direct exec*() calling. In this case clsync loads sync-handler as a shared library with dlopen(3) and calls function "int clsyncapi_rsync(const char *inclist, const char *exclist)" from it for every sync.
    inclist is a path to file with rules for "--include-from" option of rsync. This argument is always not NULL.
    exclist is a path to file with rules for "--exclude-from" option of rsync. This argument is NULL if --rsync-prefer-include is set.
    Excludes takes precedence over includes. Also may be defined functions "int clsyncapi_init(options_t *, indexes_t *)" and "int clsyncapi_deinit()" to initialize and deinitialize the syncing process by this shared object. To fork the process should be used function "pid_t clsyncapi_fork(options_t *)" instead of "pid_t fork()" to make clsync be able to kill the child. See example file "clsync-synchandler-rsyncso.c". Recommended case. IMHO, this way is the best.
case so
    In this case there's no direct exec*() calling. In this case clsync loads sync-handler as a shared library with dlopen(3) and calls function "int clsyncapi_sync(int n, api_eventinfo_t *ei)" from it for every sync. n is number of elements of ei. ei is an array of structures with information about what and how to sync (see below). api_eventinfo_t is a structure:
        struct api_eventinfo {
                uint32_t         evmask;    // event bitmask for file/dir
        by path path.
                uint32_t         flags;    // flags of "how to sync" the file/dir
                size_t           path_len;    // strlen(path)
                const char      *path;    // the
        path to file/dir need to be synced
                eventobjtype_t   objtype_old;    // type of object by path
        path before the event.
                eventobjtype_t   objtype_new;    // type of object by path
        path after the event.
        };
        typedef struct api_eventinfo api_eventinfo_t;
    The event bitmask (evmask) values can be learned from "/usr/include/linux/inotify.h". There may be next flags' values (flags):
        enum eventinfo_flags {
                EVIF_NONE        = 0x00000000,    // No modifier
                EVIF_RECURSIVELY = 0x00000001    // sync the file/dir recursively
        };
    Flag "EVIF_RECURSIVELY" may be used if option --have-recursive-sync is set. Is that a file or directory by path path can be determined with objtype_old and objtype_new.
    objtype_old reports about which type was the object by the path before the event.
    objtype_new reports about which type became the object by the path after the event. objtype_old and objtype_new have type eventobjtype_t.
        enum eventobjtype {
                EOT_UNKNOWN     = 0,    // Unknown
                EOT_DOESNTEXIST = 1,    // Doesn't exist (not created yet or already deleted)
                EOT_FILE        = 2,    // File
                EOT_DIR         = 3,    // Directory
        } typedef enum eventobjtype eventobjtype_t;
    Also may be defined functions "int clsyncapi_init(options_t *, indexes_t *)" and "int clsyncapi_deinit()" to initialize and deinitialize the syncing process by this shared object. To fork the process should be used function "pid_t clsyncapi_fork(options_t *)" instead of "pid_t fork()" to make clsync be able to kill the child. See example file "clsync-synchandler-so.c". Recommended case.
About the label see --label.
nodes is comma-separated list of cluster nodes names where to sync to (see --cluster-node-name) The listfile by path listpath contains lines separated by NL (without CR) of next format:
    sync label evmask path
        if option --synclist-simplify is not set
    path
        if option --synclist-simplify is set
    Every lines is supposed to be proceed by external syncer to sync file or directory by path path. With evmask it's passed bitmask of events with the file or directory (see "/usr/include/linux/inotify.h").

RULES
Filter riles can be placed into rules-file with one rule per line. Rule format: [+-][fdw*]regexp + - means include; - - means exclude; f - means file; d - means directory; w - means walking to directory; * - means all. For example: -*^/[Tt]est It's not recommended to use w rules in modes "rsyncdirect", "rsyncshell" and "rsyncso". rsync(1) allows to set syncing and walking only together in "--include" rules ("--files-from" is not appropriate due to problem with syncing files deletions). So there may be problems with clsync's w rules in this cases. More examples: Syncing pwdb files and sshd_config (non-rsync case):
        +f^/passwd$
        +f^/group$
        +f^/shadow$
        +f^/ssh/sshd_config$
        +w^$
        +w^/ssh$
        -*
Syncing pwdb files and sshd_config (non-rsync case with option --auto-add-rules-w):
        +f^/passwd$
        +f^/group$
        +f^/shadow$
        +f^/ssh/sshd_config$
        -*
Syncing pwdb files and sshd_config (rsync case):
        +f^/passwd$
        +f^/group$
        +f^/shadow$
        +f^/ssh/sshd_config$
        +d^$
        +d^/ssh$
        -*
Syncing /srv/lxc tree (rsync case):
        -d/sess(ion)?s?$
        -f/tmp/
        +*

SIGNALS
1 - to reread filter rules 10 - runs threads' GC function 12 - runs full resync 16 - interrupts sleep()/select() and wait() [for debugging and internal uses]

DIAGNOSTICS
Initial rsync process works very slow on clsync start
    Probably there's too huge exclude list is passed to rsync. This can happened if you're excluding with regex in clsync's rules a lot of thousands files. They will be passed to rsync's exclude list one by one. To diagnose it, you can use "-U" option and look into rsync-exclude-listpath file (see SYNC HANDLER case d) To prevent this, it's recommended to write such rules for rsync directly (not via clsync). For example, often problem is with PHP's session files. You shouldn't exclude them in clsync's rules with "-f/sess_.*", but you should exclude it in rsync directly (e.g with «--exclude "sess_*"»).
The following diagnostics may be issued on stderr: Error: Cannot inotify_add_watch() on [...]: No space left on device (errno: 28)
    Not enough inotify watching descriptors is allowed. It can be fixed by increasing value of "sysctl fs.inotify.max_user_watches"
Error: Got non-zero exitcode exitcode [...]
    sync-handler returned non-zero exitcode. Probably, you should process exitcodes in it or your syncer process didn't worked well. I case of using rsync, you can find the exitcodes meanings in man 1 rsync. If exitcode equals to 23 and you're using clsync in conjunction with rsync, this may happend, for example in next cases:
        - Not enough space on destination. - You're running clsync with --pthread and rsync with --backup. See bugreport by URL: https://bugzilla.samba.org/show_bug.cgi?id=10081.
    To confirm the problem, you can try to add "return 0" or "exit 0" into your sync-handler.
To get support see SUPPORT.

CONFIGURATION FILE
clsync supports configuration file. By default clsync tries to read next files (in specified order):
    ~/.clsync.conf
    /etc/clsync/clsync.conf
This may be overrided with option --config-file. clsync reads only one configuration file. In other words, if option --config-file is not set and file ~/.clsync.conf is accessable and parsable, clsync will not try to open /etc/clsync/clsync.conf. Command line options have precedence over config file options. Configuration file is parsed with glib's g_key_file_* API. That means, that config should consits from groups (blocks) of key-value lines as in the example:
    [default]
    background=1
    mode=rsyncshell
    debug=0
    syslog=1
    pid-file=/var/run/clsync.pid
    [test]
    mode=rsyncdirect
    debug=3
Also glib's gkf API doesn't support multiple assignments. If you need to list some values (e.g. exitcodes) just list them with commas in single assignment (e.g. "ignore-exitcode=23,24"). In this example there's 2 blocks are set - "default" and "test". By default clsync uses block with name "default". Block name can be set by option --config-block.

CLUSTERING
Not implemented yet. Don't try to use cluster functionality. Not described yet.

EXAMPLES
Working examples you can try out in "/usr/share/doc/clsync/examples/" directory. Copy this directory somewhere (e.g. into "/tmp"). And try to run "clsync-start-rsync.sh" in there. Any files/directories modifications in "testdir/from" will be synced to "testdir/to" with few seconds delay.

AUTHOR
Dmitry Yu Okunev <dyokunev@ut.mephi.ru> 0x8E30679C

SUPPORT
You can get support on official IRC-channel in Freenode "#clsync" or on github's issue tracking system of repository "https://github.com/xaionaro/clsync". Don't be afraid to ask about clsync configuration, ;).

SEE ALSO
rsync(1), pthreads(7), inotify(7)