python-etcd Documentation

Transcription

1 python-etcd Documentation Release Jose Plana Jun 25, 2018

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3 Contents 1 Installation Pre-requirements From source Usage Create a client object Set a key Get a key Delete a key Get machines in the cluster Get leader of the cluster Development setup 9 4 Release HOWTO 11 5 Code documentation API Documentation i

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5 python-etcd Documentation, Release An asynchronous python client for Etcd Contents 1

6 python-etcd Documentation, Release Contents

7 CHAPTER 1 Installation 1.1 Pre-requirements Install etcd 1.2 From source $ python setup.py install 3

8 python-etcd Documentation, Release Chapter 1. Installation

9 CHAPTER 2 Usage 2.1 Create a client object import aio_etcd as 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=' ', port=4003) client = etcd.client(host=' ', port=4003, allow_redirect=false) # wont let you run sensitive commands on non-leader machines, default is true client = etcd.client( host=' ', port=4003, allow_reconnect=true, protocol='https',) 2.2 Set a key await client.write('/nodes/n1', 1) # with ttl await client.write('/nodes/n2', 2, ttl=4) # sets the ttl to 4 seconds # create only await client.write('/nodes/n3', 'test', prevexist=false) # Compare and swap values atomically await client.write('/nodes/n3', 'test2', prevvalue='test1') #this fails to write await client.write('/nodes/n3', 'test2', previndex=10) #this fails to write # mkdir await client.write('/nodes/queue', None, dir=true) # Append a value to a queue dir (continues on next page) 5

10 python-etcd Documentation, Release (continued from previous page) await client.write('/nodes/queue', 'test', append=true) #will write i.e. /nodes/queue/ 11 await client.write('/nodes/queue', 'test2', append=true) #will write i.e. /nodes/ queue/12 You can also atomically update a result: result = await client.read('/foo') print(result.value) # bar result.value += u'bar' updated = await client.update(result) # if any other client wrote '/foo' in the meantime this will fail print(updated.value) # barbar 2.3 Get a key (await client.read('/nodes/n2')).value #recursively read a directory r = await client.read('/nodes', recursive=true, sorted=true) for child in r.children: print("%s: %s" % (child.key,child.value)) await client.read('/nodes/n2', wait=true) #Waits for a change in value in the key before returning. await 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" 2.4 Delete a key await client.delete('/nodes/n1') await client.delete('/nodes', dir=true) #spits an error if dir is not empty await client.delete('/nodes', recursive=true) #this works recursively Locking module # Initialize the lock object: # NOTE: this does not acquire a lock yet from aio_etcd.lock import Lock client = etcd.client() lock = etcd.lock(client, 'my_lock_name') # Use the lock object: await lock.acquire(blocking=true, # will block until the lock is acquired (continues on next page) 6 Chapter 2. Usage

11 python-etcd Documentation, Release lock_ttl=none) # lock will live until we release it lock.is_acquired # True await lock.acquire(lock_ttl=60) # renew a lock await lock.release() # release an existing lock lock.is_acquired # False (continued from previous page) # The lock object may also be used as a context manager: # (Python 3.5+) client = etcd.client() async with etcd.lock(client, 'customer1') as my_lock: do_stuff() my_lock.is_acquired # True await my_lock.acquire(lock_ttl=60) my_lock.is_acquired # False 2.5 Get machines in the cluster machines = await client.machines() 2.6 Get leader of the cluster leader_info = await client.leader() 2.5. Get machines in the cluster 7

12 python-etcd Documentation, Release Chapter 2. Usage

13 CHAPTER 3 Development setup To create a buildout, $ python bootstrap.py $ bin/buildout to test you should have etcd available in your system path: $ bin/test to generate documentation, $ cd docs $ make 9

14 python-etcd Documentation, Release Chapter 3. Development setup

15 CHAPTER 4 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 11

16 python-etcd Documentation, Release Chapter 4. Release HOWTO

17 CHAPTER 5 Code documentation 5.1 API Documentation 13