zc.zkzeo 0.2.1

Including a zc.monitor monitoring server

The zc.monitor package provides a simple extensible command server for gathering monitoring data or providing run-time control of servers. If zc.monitor is in the Python path, zc.zkzeo can start a monitor server and make it’s address available as the monitor property of of a server’s ephemeral port. To request this, we use a monitor-server option in the zookeeper section:

<zeo>
   address 127.0.0.1
</zeo>

<zookeeper>
   connection zookeeper.example.com:2181
   path /databases/demo
   monitor-server 127.0.0.1
</zookeeper>

<filestorage>
   path demo.fs
</filestorage>

The value is the address to listen on.

With the configuration above, if we started the server and looked at the ZooKeeper tree for ‘/databases/demo’ using the zc.zk package, we’d see something like the following:

>>> import zc.zk
>>> zk = zc.zk.ZooKeeper('zookeeper.example.com:2181')
>>> zk.print_tree('/databases/demo')
/demo
  /127.0.0.1:64211
    monitor = u'127.0.0.1:11976'
    pid = 5082

Some notes on the monitor server:

• A monitor server won’t be useful unless you’ve registered some command plugins.

• zc.monitor isn’t a dependency of zc.zkzeoc and won’t be in the Python path unless you install it.

Defining ZEO clients with Python

From Python, use zc.zkzeo.client:

>>> import zc.zkzeo
>>> client = zc.zkzeo.client(
...     'zookeeper.example.com:2181', '/databases/demo',
...     max_disconnect_poll=1)

You pass a ZooKeeper connection string and a path. The Client constructor will create a client storage with addresses found as sub-nodes of the given path and it will adjust the client-storage addresses as nodes are added and removed as children of the path.

You can pass all other ZEO.ClientStorage.ClientStorage arguments, except the address, as additional positional and keyword arguments.

>>> db = zc.zkzeo.DB(
...     'zookeeper.example.com:2181', '/databases/demo',
...     max_disconnect_poll=1)

>>> conn = zc.zkzeo.connection(
...     'zookeeper.example.com:2181', '/databases/demo',
...     max_disconnect_poll=1)

Defining ZEO clients in configuration files

In configuration files, use a zkzeoclient storage section:

%import zc.zkzeo

<zodb>
   <zkzeoclient>
      zookeeper zookeeper.example.com:2181
      server /databases/demo
      max-disconnect-poll 1
   </zkzeoclient>
</zodb>

The options for zkzeoclient are the same as for the standard ZODB zeoclient section, except:

• There’s an extra required zookeeper option used to provide a ZooKeeper connection string.

• There can be only one server option and it is used to supply the path in ZooKeeper where addresses may be found.

0.2.1 (2011-12-14)

• Fixed bug: The path key on the zookeeper server-configuration section was required, and shouldn’t have been.

0.2.0 (2011-12-13)

• Register the host name from the ZEO address setting with ZooKeeper. (This is often an empty string, which zc.zk turns into the fully-quelified domain name.)

• Fixed bug in handling the monitor-server. The actuall address setting was ignored.

0.1.1 (2011-12-12)

• Fixed a packaging bug.

0.1.0 (2011-12-11)

Initial release.