CDBx - CDB Reimplementation for Python

cdbx is a CDB reimplementation for Python.

Supported python versions are Python 2.7 and Python 3.3 and above.

Documentation

Examples

Note that everything going in and out of the CDB is bytes. This is more relevant for Python 3. Keys and values which are passed as (unicode) strings, are converted to bytes using the ASCII codec. However, keys and values retrieved from the CDB are always bytes.

# simple file write
import cdbx

cdb = cdbx.CDB.make('somefile')
cdb.add('key', 'value')
# ...
cdb = cdb.commit()
print(cdb['key'])
# atomic file write (original cdbmake behaviour)
import os
import cdbx

cdb = cdbx.CDB.make('somefile.tmp')
cdb.add('key', 'value')
# ...
cdb.commit().close()
os.rename('somefile.tmp', 'somefile')
cdb = cdbx.CDB('somefile')
print(cdb['key'])
# CDB within tempfile
import tempfile
import cdbx

cdb = cdbx.CDB.make(tempfile.TemporaryFile())
cdb.add('key', 'value')
# ...
cdb = cdb.commit()
print(cdb['key'])

cdb.close()  # or going out-of-scope, or del cdb

# now it's gone
print(cdb['key'])
IOError: I/O operation on a closed file

Rationale, Advocacy, Key Features

CDB as a concept is a great idea for various reasons. It’s fast, it’s a simple, portable file format and all operations can be done using one open file descriptor.

There are, of course, other interfaces to CDB (most notably python-cdb, which I have been using for a long time).

cdbx tries to solve a few problems with those for me:

  • support for Python 3
  • better interface for CDB creation - you only need a file descriptor if you want to. This is important if you want to create a CDB within a single temporary file.
  • all operations are independent from each other (multiple accesses at the same time are possible). Thanks to the GIL it should be even thread safe. This has not been tested yet, though.
  • more natural interface for the main CDB class in general
  • better error handling (especially with regard to python) in some places
  • Since it’s a complete reimplementation, the licensing issue (people claim to have with public domain software [cdb]) does not apply.

Development Status

Beta.

There are some features to add and some cleanups to do before a stable release.

Download

Current Stable Version

Integrity Check

There are hashes (MD5, SHA1 and SHA256) of the download packages stored in the digests file. In order to check the integrity of the downloaded file, use a tool like md5sum (or sha1sum, sha256sum accordingly), e.g.:

$ md5sum -c cdbx-0.1.0.digests
cdbx-0.1.0.tar.bz2: OK
cdbx-0.1.0.tar.gz: OK
cdbx-0.1.0.tar.xz: OK
cdbx-0.1.0.zip: OK

In order to check the integrity of the digest file itself, you can check the PGP signature of that file. The file is signed by André Malo, Key-ID 0x8103A37E:

$ gpg --verify cdbx-0.1.0.digests
gpg: Signature made Thu Jun 23 22:14:18 2016 CEST using DSA key ID 8103A37E
gpg: Good signature from "Andre Malo <nd@apache.org>"
gpg:                 aka "Andr\xe9\x20Malo <nd@perlig.de>"
gpg:                 aka "Andre Malo <ndparker@gmx.net>"

License

cdbx is available under the terms and conditions of the “Apache License, Version 2.0.” You’ll find the detailed licensing terms in the root directory of the source distribution package or online at http://www.apache.org/licenses/LICENSE-2.0.

Bugs

No bugs, of course. ;-) But if you’ve found one or have an idea how to improve cdbx, feel free to send a pull request on github or send a mail to <cdbx-bugs@perlig.de>.

Author Information

cdbx was written and is maintained by André Malo.