couchbase / Couchbase Python Client
Programming Languages
======================= Couchbase Python Client
Client for Couchbase_.
.. note::
This is the documentation for the 3.x version of the client. This is
mostly compatible with the older version. Please refer to the
*release25* branch for the older version.
Building and Installing
This only applies to building from source. If you are using a Windows installer then everything (other than the server) is already included. See below for windows snapshot releases.
Also note that these instructions apply to building from source. You can always get the latest supported release version from pypi_.
If you have a recent version of pip, you may use the latest development version by issuing the following incantation
.. code-block:: sh
pip install git+git://github.com/couchbase/couchbase-python-client
Prerequisites
- Couchbase Server (http://couchbase.com/download)
- You may need a C compiler and Python development files, unless a binary wheel is available for your platform. These are available for at least Python 3.7 on Windows, but we will endeavour to add more.
- Git, if a binary wheel is not available.
Building
You will need a few tools installed to be able to build locally. A compiler and CMake (2.8.9 or above), to compile the C extensions that communicate with libcouchbase, git, pip and python's setuptools.
Linux (example is for debian-like linux):
.. code-block:: sh
sudo apt install git-all
sudo apt install python3-dev
sudo apt install python3-pip
sudo apt install python3-setuptools
sudo apt install cmake
sudo apt install build-essential
MacOSX:
.. code-block:: sh
# mac (I'm assuming you use homebrew)
git --version # this will prompt you to install if not already installed
brew install cmake
xcode-select --install
pip3 install setuptools
The following will compile the module locally; you can then test basic functionality including running the examples.
.. code-block:: sh
python setup.py build_ext --inplace
If you have a libcouchbase install already (in, for example,
/opt/local/libcouchbase
), you may build using it by setting PYCBC_BUILD=DISTUTILS
and some add extra directives, like so:
.. code-block:: sh
export PYCBC_BUILD=DISTUTILS
python setup.py build_ext --inplace \
--library-dir /opt/local/libcouchbase/lib \
--include-dir /opt/local/libcouchbase/include
Or you can modify the environment CFLAGS
and LDFLAGS
variables.
.. warning::
If you do not intend to install this module, ensure you set the
``PYTHONPATH`` environment variable to this directory before running
any scripts depending on it. Failing to do so may result in your script
running against an older version of this module (if installed), or
throwing an exception stating that the ``couchbase`` module could not
be found.
^^^^^^^^^^ Installing ^^^^^^^^^^ .. code-block:: sh
pip install .
.. warning::
If you are on *macOS x* you may need to remove the build directory:
`rm -rf ./build` before installing with pip: `pip3 install .`.
Using
Authentication is handled differently depending on what version of Couchbase Server you are using:
Couchbase Server >= 5.0
Role-Based Access Control (RBAC) provides discrete username and passwords for an application that allow fine-grained control. The authenticator is always required.
.. code-block:: pycon
>>> from couchbase.cluster import Cluster, PasswordAuthenticator, ClusterOptions
>>> from couchbase.auth import PasswordAuthenticator
>>> cluster = Cluster('couchbase://localhost', ClusterOptions(PasswordAuthenticator('username', 'password')))
>>> bucket = cluster.bucket('bucket-name')
>>> collection = bucket.default_collection()
Here's an example code snippet which sets a key and then reads it
.. code-block:: pycon
>>> collection.upsert("key", "value")
>>> res = collection.get("key")
>>> res.content
u'value'
>>>
You can also use views
.. code-block:: pycon
>>> resultset = cluster.view_query("beer", "brewery_beers", limit=5)
>>> resultset
View<Design=beer, View=brewery_beers, Query=Query:'limit=5', Rows Fetched=0>
>>> for row in resultset: print row.key
...
[u'21st_amendment_brewery_cafe']
[u'21st_amendment_brewery_cafe', u'21st_amendment_brewery_cafe-21a_ipa']
[u'21st_amendment_brewery_cafe', u'21st_amendment_brewery_cafe-563_stout']
[u'21st_amendment_brewery_cafe', u'21st_amendment_brewery_cafe-amendment_pale_ale']
[u'21st_amendment_brewery_cafe', u'21st_amendment_brewery_cafe-bitter_american']
.. warning:: The gcouchbase API has not yet been fully migrated to version 3, so is omitted for this version.
Twisted API
The Python client now has support for the Twisted async network framework.
To use with Twisted, simply import txcouchbase.cluster
instead of
couchbase.cluster
.. code-block:: python
from twisted.internet import reactor
from txcouchbase.cluster import TxCluster
cluster = TxCluster('couchbase://localhost', ClusterOptions(PasswordAuthenticator('username', 'password')))
bucket = cluster.bucket("default")
cb = bucket.default_collection()
def on_upsert(ret):
print("Set key. Result", ret)
def on_get(ret):
print("Got key. Result", ret)
reactor.stop()
cb.upsert("key", "value").addCallback(on_upsert)
cb.get("key").addCallback(on_get)
reactor.run()
# Output:
# Set key. Result OperationResult<RC=0x0, Key=key, CAS=0x9a78cf56c08c0500>
# Got key. Result ValueResult<RC=0x0, Key=key, Value=u'value', CAS=0x9a78cf56c08c0500, Flags=0x0>
The txcouchbase
API is identical to the couchbase
API, except that where
the synchronous API will block until it receives a result, the async API will
return a Deferred
which will be called later with the result or an appropriate
error.
Asynchronous (Tulip) API
This module also supports Python 3.4/3.5 asynchronous I/O. To use this
functionality, import the couchbase.experimental
module (since this
functionality is considered experimental) and then import the acouchbase
module. The acouchbase
module offers an API similar to the synchronous
client:
.. code-block:: python
import asyncio
from acouchbase.cluster import Cluster, ClusterOptions, PasswordAuthenticator
async def write_and_read(key, value):
cluster = Cluster('couchbase://10.0.0.31/', ClusterOptions(PasswordAuthenticator("username","password")))
cb = cluster.bucket("default")
cb_coll = cb.default_collection()
await cb_coll.connect()
await cb_coll.upsert(key, value)
return await cb_coll.get(key)
loop = asyncio.get_event_loop()
rv = loop.run_until_complete(write_and_read('foo', 'bar'))
print(rv.content)
Other Examples
There are other examples in the examples
directory. To run them from the
source tree, do something like
.. code-block:: sh
PYTHONPATH=$PWD ./examples/bench.py -U couchbase://localhost/default
Building documentation
The documentation is using Sphinx and also needs the numpydoc Sphinx extension. In order for the documentation to build properly, the C extension must have been built, since there are embedded docstrings in there as well.
To build the documentation, go into the docs
directory and run
.. code-block:: sh
make html
The HTML output can be found in docs/build/html/
.
Alternatively, you can also build the documentation (after building the module itself) from the top-level directory:
.. code-block:: sh
python setup.py build_sphinx
Once built, the docs will be in in build/sphinx/html
Testing
For running the tests, you need the standard unittest
module, shipped
with Python. Additionally, the testresources
package is required.
To run them, use either py.test
, unittest
or trial
.
The tests need a running Couchbase instance. For this, a tests.ini
file must be present, containing various connection parameters.
An example of this file may be found in tests.ini.sample
.
You may copy this file to tests.ini
and modify the values as needed.
To run the tests::
nosetests
Support & Additional Resources
If you found an issue, please file it in our JIRA_.
You can ask questions in our forums_ or in the #libcouchbase
channel on
freenode_.
The official documentation
_ can be consulted as well for
general Couchbase concepts and offers a more didactic approach to using the
SDK.
License
The Couchbase Python SDK is licensed under the Apache License 2.0.
.. _Couchbase: http://couchbase.com .. _libcouchbase: https://github.com/couchbase/libcouchbase .. _official documentation: https://docs.couchbase.com/python-sdk/3.0/hello-world/start-using-sdk.html .. _JIRA: http://couchbase.com/issues/browse/pycbc .. _freenode: http://freenode.net/irc_servers.shtml .. _pypi: http://pypi.python.org/pypi/couchbase .. _forums: https://forums.couchbase.com