= applylog, updatelog: log-based updates

== SYNOPSIS

*install/applylog* [ *-c* ] [ *-e* ] [ *-n* ] [ *-s* ] [ *-u* ] [ *-g* ]
[ *-v* ] [ **-T**__ timefile__ ] _clientlog_ _clientroot_ _serverroot_ [
_path_ ... ]

*install/updatelog* [ **-p**__ proto__ ] [ **-r**__ root__ ] [ **-t**__
now gen__ ] [ *-c* ] [ **-x**__ path__ ] _log_ [ _path_ ... ]


These two commands allow distribution of updates (eg, to the Inferno
tree) based on a log of changes since a previous update. Notionally, one
_server_ system is the primary for a set of files, and one or more
_client_ systems maintain replicas of that set, although in some
applications server and client might be the same machine.

_Applylog_ is run on a client, to update the file tree rooted at
_clientroot_. The server's version of the tree is rooted at _serverroot_
on the client, typically by being mounted there (see _bind_(1)).
_Applylog_ takes the current state of the replica from the entries in
_clientlog_, and applies a set of changes represented by log entries
read from its standard input. Those entries are provided by the server.
Each change is examined to see whether the file to which it applies is
in the expected state. If so, the change is applied without comment;
otherwise, there is a conflict caused by a local change to the replica
tree independently from the primary. By default, _applylog_ diagnoses
the conflict and does not apply the change. It accepts the following
options:

*-c*::
  Resolve inconsistencies in favour of the client: leave the replica as
  is.
*-e*::
  Exit with an error status on any error, including inconsistency
  between client and server.
*-n*::
  Print on standard output a list of changes that would be made, and
  list any conflicts, but do not change the tree or update the log.
*-s*::
  Resolve inconsistencies in favour of the server: make the replica
  match the server's state.
*-u*::
  Make file ownership in the replica match that on the server.
*-g*::
  Make group ownership in the replica match that on the server.
*-v*::
  Print a summary of each log entry as it is examined.
**-T**__ timefile__::
  Read a time and sequence number from _timefile_ and apply only log
  entries with stamps greater than that. On successful completion, if
  the *-n* option is not given, update the _timefile_ with the stamp of
  the last log entry processed successfully.

The scope of an update in a tree can be restricted to a particular set
of _paths_ listed on the command line. They should all be relative path
names.

_Updatelog_ is run on a server to produce a sequence of log entries
representing changes to the primary tree since a previous log was
produced. It can also be run on a client to see how its replica state
differs from that recorded in a log. It accepts the following options:

**-p**__ proto__::
  Use _proto_ as the prototype for the file system, as described by
  _proto_(6) (default: */lib/proto/all*).
**-r**__ root__::
  The replica is rooted at _root_ (default: the current directory, *.*).
**-t**__ now gen__::
  Make log entries use time _now_ and initial sequence number _gen_. The
  defaults are the current time and 0.
*-c*::
  Produce output only for content and metadata changes, not additions or
  deletions.
**-x**__ path__::
  Exclude _path_ and its subtrees from consideration.

By default, _updatelog_ produces log entries describing changes,
additions and deletions to all files in _root_ but the scope can be
limited by giving a different _proto_, explicitly listing trees to
consider as _paths_ on the command line, and by giving one or more *-x*
options to exclude particular paths, in any desired combination.

=== Log file format

A log file is a text file with one line representing each change to the
tree. Each line has the form:

_______________________________________________________________________
_time gen verb path serverpath mode uid gid mtime length_ [ _sum_ ... ]
_______________________________________________________________________

where:

________________________________________________________________________________________________________________________________________________________________________________________________
_time, gen_::
  are decimal numbers that order the sequence of requests: _time_ is
  typically the time in seconds of the epoch at which the entry was
  made; _gen_ is a monotonically increasing sequence number

_verb_::
  is an action:
  +
  *a*;;
    add file _path_
  *c*;;
    change the contents of file _path_
  *d*;;
    delete _path_
  *m*;;
    change the metadata (permissions, ownership) for _path_

_path_::
  the name of the file on the client
_serverpath_::
  the name of the file on the server with the contents for _path_, or
  simply

when the server and client file names are the same

_mode, uid, gid, length, mtime_::
  the resulting metadata (except for *d* where the metadata is that for
  the file to be deleted)
_sum_::
  is the MD5 checksum of the file's contents
________________________________________________________________________________________________________________________________________________________________________________________________

== SOURCE

*/appl/cmd/install/applylog.b* +
*/appl/cmd/install/logs.b* +
*/appl/cmd/install/updatelog.b*

== SEE ALSO

_fs_(1), _kfs_(4), _proto_(6)