Obnam, a backup program
=======================

Obnam is a backup program.


Home page
---------

The Obnam home page is at <http://liw.fi/obnam/>, see there
for more information.


Installation
------------

The source tree contains packaging for Debian. Run `debuild -us -uc -i.git` to
build an installation package.

On other systems, using the `setup.py` file should work: run
"python setup.py --help" for advice. If not, please report a bug.
(I've only tested `setup.py` enough for to build the Debian package.)

You need Python 2.6 or 2.7 (Python 3 is not yet supported). You also
need to install my Python B-tree library, and some of my other
libraries and tools, which you can get from:

* <http://liw.fi/larch/>
* <http://liw.fi/ttystatus/>
* <http://liw.fi/coverage-test-runner/> (for automatic tests)
* <http://liw.fi/tracing/>
* <http://liw.fi/cliapp/>
* <http://liw.fi/genbackupdata/>
* <http://liw.fi/summain/>
* <http://liw.fi/cmdtest/>
* <http://liw.fi/seivot/> (for benchmarks)

You also need third party libraries:

* paramiko: <http://www.lag.net/paramiko/>

See debian/control for the full set of build dependencies and runtime
dependencies on a Debian system. (That set actually gets tested. The
above list is maintained manually and may get out of date from time
to time.)

Use
---

To get a quick help summary of options:

    ./obnam --help

To make a backup:

    ./obnam backup --repository /tmp/mybackup $HOME

For more information, see the manual page:

    man -l obnam.1


Hacking
-------

Obnam source code is stored in git for version control purposes;
you can get a copy as follows:

    git clone git://git.liw.fi/obnam

The 'master' branch is the main development one. Any bug fixes and
features should be developed in a dedicated branch, which gets merged
to master when the changes are done and considered good.

To build and run automatic tests:

    ./check
    ./check --fast # unit tests only, no black box tests
    ./check --network # requires ssh access to localhost

`check` is a wrapper around `python setup.py`, but since using that
takes several steps, the script makes things easier.

You need my CoverageTestRunner to run tests, see above for where to get it.
A couple of scripts exist to run benchmarks and profiles:

    ./metadata-speed 10000
    ./obnam-benchmark --size=1m/100k --results /tmp/benchmark-results
    viewprof /tmp/benchmark-results/*/*backup-0.prof
    seivots-summary /tmp/benchmark-results/*/*.seivot | less -S

There are two kinds of results: Python profiling output, and `.seivot`
files.

For the former, `viewprof` is a little helper script I wrote,
around the Python pstats module.
You can use your own, or get mine from extrautils
(<http://liw.fi/extrautils/>). Running the benchmarks under profiling
makes them a little slower (typically around 10% for me, when I've
compared), but that's OK: the absolute numbers of the benchmarks are
less important than the relative ones. It's nice to be able to look at
the profiler output, if a benchmark is surprisingly slow, without
having to re-run it.

`seivots-summary` is a tool to display summaries of the measurements
made during a benchmark run. `seivot` is the tool that makes the
measurements. I typically save a number of benchmark results, so that
I can see how my changes affect performance over time.

If you make any changes, I welcome patches, either as plain diffs,
`git format-patch --cover-letter` mails, or public repositories I can
merge from.

The code layout is roughly like this:

    obnamlib/               # all the real code
    obnamlib/plugins/       # the plugin code (see pluginmgr.py)
    obnam                   # script to invoke obnam
    _obnammodule.c          # wrapper around some system calls

In obnamlib, every code module has a corresponding test module,
and "make check" uses CoverageTestRunner to run them pairwise. For
each pair, test coverage must be 100% or the test will fail.
Mark statements that should not be included in coverage test with
"# pragma: no cover", if you really, really can't write a test.
without-tests lists modules that have no test modules.

If you want to make a new release of Obnam, I recommend following
my release checklist: <http://liw.fi/obnam/release/>.

Feedback
--------

I welcome bug fixes, enhancements, bug reports, suggestions, requests,
and other feedback. I prefer e-mail the mailing list:
see <http://vlists.pepperfish.net/cgi-bin/mailman/listinfo/obnam-flarn.net>
for instructions.

It would be helpful if you can run `make clean check` before submitting
a patch, but it is not strictly required.


Legal stuff
-----------

Most of the code is written by Lars Wirzenius. (Please provide patches
so that can change.)

The code is covered by the GNU General Public License, version 3 or later.

Copyright 2010-2013  Lars Wirzenius

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.