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Python-etcd documentation
=========================
A python client for Etcd https://github.com/coreos/etcd
Installation
------------
Pre-requirements
................
Install etcd
From source
...........
.. code-block:: bash
$ python setup.py install
Usage
-----
Create a client object
......................
.. code-block:: python
import etcd
client = etcd.Client() # this will create a client against etcd server running on localhost on port 4001
client = etcd.Client(port=4002)
client = etcd.Client(host='127.0.0.1', port=4003)
client = etcd.Client(host='127.0.0.1', port=4003, allow_redirect=False) # wont let you run sensitive commands on non-leader machines, default is true
client = etcd.Client(
host='127.0.0.1',
port=4003,
allow_reconnect=True,
protocol='https',)
Set a key
.........
.. code-block:: python
client.write('/nodes/n1', 1)
# with ttl
client.write('/nodes/n2', 2, ttl=4) # sets the ttl to 4 seconds
# create only
client.write('/nodes/n3', 'test', prevExist=False)
# Compare and swap values atomically
client.write('/nodes/n3', 'test2', prevValue='test1') #this fails to write
client.write('/nodes/n3', 'test2', prevIndex=10) #this fails to write
# mkdir
client.write('/nodes/queue', None, dir=True)
# Append a value to a queue dir
client.write('/nodes/queue', 'test', append=True) #will write i.e. /nodes/queue/11
client.write('/nodes/queue', 'test2', append=True) #will write i.e. /nodes/queue/12
You can also atomically update a result:
.. code:: python
result = client.read('/foo')
print(result.value) # bar
result.value += u'bar'
updated = client.update(result) # if any other client wrote '/foo' in the meantime this will fail
print(updated.value) # barbar
Get a key
.........
.. code-block:: python
client.read('/nodes/n2').value
#recursively read a directory
r = client.read('/nodes', recursive=True, sorted=True)
for child in r.children:
print("%s: %s" % (child.key,child.value))
client.read('/nodes/n2', wait=True) #Waits for a change in value in the key before returning.
client.read('/nodes/n2', wait=True, waitIndex=10)
# raises etcd.EtcdKeyNotFound when key not found
try:
client.read('/invalid/path')
except etcd.EtcdKeyNotFound:
# do something
print "error"
Delete a key
............
.. code-block:: python
client.delete('/nodes/n1')
client.delete('/nodes', dir=True) #spits an error if dir is not empty
client.delete('/nodes', recursive=True) #this works recursively
Locking module
~~~~~~~~~~~~~~
.. code:: python
# Initialize the lock object:
# NOTE: this does not acquire a lock yet
client = etcd.Client()
lock = etcd.Lock(client, 'my_lock_name')
# Use the lock object:
lock.acquire(blocking=True, # will block until the lock is acquired
lock_ttl=None) # lock will live until we release it
lock.is_acquired # True
lock.acquire(lock_ttl=60) # renew a lock
lock.release() # release an existing lock
lock.is_acquired # False
# The lock object may also be used as a context manager:
client = etcd.Client()
with etcd.Lock(client, 'customer1') as my_lock:
do_stuff()
my_lock.is_acquired # True
my_lock.acquire(lock_ttl=60)
my_lock.is_acquired # False
Get machines in the cluster
...........................
.. code-block:: python
client.machines
Get leader of the cluster
.........................
.. code-block:: python
client.leader
Development setup
-----------------
To create a buildout,
.. code-block:: bash
$ python bootstrap.py
$ bin/buildout
to test you should have etcd available in your system path:
.. code-block:: bash
$ bin/test
to generate documentation,
.. code-block:: bash
$ cd docs
$ make
Release HOWTO
-------------
To make a release,
1) Update release date/version in NEWS.txt and setup.py
2) Run 'python setup.py sdist'
3) Test the generated source distribution in dist/
4) Upload to PyPI: 'python setup.py sdist register upload'
5) Increase version in setup.py (for next release)
List of contributors at https://github.com/jplana/python-etcd/graphs/contributors
Code documentation
------------------
.. toctree::
:maxdepth: 2
api.rst
|
