pyramid_zodbconn¶

Overview¶

A package which provides integration between the Pyramid web application server and the ZODB object database.

It will run under CPython 2.5, 2.6, and 2.7. It will not run under PyPy or Jython. It requires ZODB >= 3.10.0.

Installation¶

Install using setuptools, e.g. (within a virtual environment):

$ easy_install pyramid_zodbconn

Setup¶

Once pyramid_zodbconn is installed, you must use the config.include mechanism to include it into your Pyramid project’s configuration. In your Pyramid project’s __init__.py:

config = Configurator(.....)
config.include('pyramid_zodbconn')

Alternately you can use the pyramid.includes configuration value in your .ini file:

[app:myapp]
pyramid.includes = pyramid_zodbconn

Using¶

For pyramid_zodbconn to work properly, you must add at least one setting to your of your Pyramid’s .ini file configuration (or to the settings dictionary if you’re not using ini configuration): zodbconn.uri. For example:

[app:myapp]
...
zodbconn.uri = zeo://localhost:9991?cache_size=25MB
...

The zodbconn.uri parameter is a URL which describes a ZODB database.

Once you’ve both included the pyramid_zodbconn into your configuration via config.include('pyramid_zodbconn') and you’ve added a zodbconn.uri setting to your configuration, you can then use the pyramid_zodbconn.get_connection() API in your Pyramid application, most commonly in a Pyramid root factory:

 from pyramid_zodbconn import get_connection
 from persistent.mapping import PersistentMapping

 class MyModel(PersistentMapping):
     __parent__ = __name__ = None

 def root_factory(request):
     conn = get_connection(request)
     zodb_root = conn.root()
     if not 'app_root' in zodb_root:
         app_root = MyModel()
         zodb_root['app_root'] = app_root
         import transaction
         transaction.commit()
     return zodb_root['app_root']

The pyramid_zodbconn.get_connection() API returns a ZODB connection to the main database you’ve specified via zodbconn.uri in your configuration.

When the request is finalized, the connection you’ve opened via get_connection will be closed.

Named Databases¶

If you need to use more than one ZODB database in your Pyramid application, you can use named databases via configuration. Named databases are specified by zodbconn.uri.thename in settings configuration. For example:

[app:myapp]
...
zodbconn.uri = zeo://localhost:9991?cache_size=25MB
zodbconn.uri.sessions = zeo://localhost:9992?cache_size=100MB
...

Once this is done, you can use pyramid_zodbconn.get_connection() to obtain a reference to each of the named databases:

main_conn = get_connection(request) # main database
sessions_conn = get_connection(request, 'sessions')

The zodbconn.uri.sessions parameter example above is a URI which describes a ZODB database, in the same format as zodbconn.uri. You can combine named and unnamed database configuration in the same application. You must have at least one primary database to use named databases.

Note

Named database support is new as of pyramid_zodbconn 0.3.

URI Schemes¶

The URI schemes currently recognized in the zodbconn.uri setting are file://, zeo://, zconfig:// and memory://. Documentation for these URI scheme syntaxes are below.

`file://` URI scheme¶

The file:// URI scheme can be passed as zodbconn.uri to create a ZODB FileStorage database factory. The path info section of this scheme should point at a filesystem file path that should contain the filestorage data. For example:

file:///my/absolute/path/to/Data.fs

The URI scheme also accepts query string arguments. The query string arguments honored by this scheme are as follows.

Misc¶

demostorage: boolean (if true, wrap FileStorage in a DemoStorage)

Example¶

An example that combines a path with a query string:

file:///my/Data.fs?connection_cache_size=100&blobstorage_dir=/foo/bar

`zeo://` URI scheme¶

The zeo:// URI scheme can be passed as zodbconn.uri to create a ZODB ClientStorage database factory. Either the host and port parts of this scheme should point at a hostname/portnumber combination e.g.:

zeo://localhost:7899

Or the path part should point at a UNIX socket name:

zeo:///path/to/zeo.sock

The URI scheme also accepts query string arguments. The query string arguments honored by this scheme are as follows.

Misc¶

demostorage: boolean (if true, wrap ClientStorage in a DemoStorage)

Connection-related¶

These arguments relate to connections created from the database.

connection_cache_size: integer (default 10000)
connection_pool_size: integer (default 7)

Database-related¶

These arguments relate to the database (as opposed to storage) settings.

database_name: string

Example¶

An example that combines a path with a query string:

zeo://localhost:9001?connection_cache_size=20000

`zconfig://` URI scheme¶

The zconfig:// URI scheme can be passed as zodbconn.uri to create any kind of storage that ZODB can load via ZConfig. The path info section of this scheme should point at a ZConfig file on the filesystem. Use an optional fragment identifier to specify which database to open. This URI scheme does not use query string parameters.

Examples¶

An example ZConfig file:

<zodb>
  <mappingstorage>
  </mappingstorage>
</zodb>

If that configuration file is located at /etc/myapp/zodb.conf, use the following URI to open the database:

zconfig:///etc/myapp/zodb.conf

A ZConfig file can specify more than one database. For example:

<zodb temp1>
  <mappingstorage>
  </mappingstorage>
</zodb>
<zodb temp2>
  <mappingstorage>
  </mappingstorage>
</zodb>

In that case, use a URI with a fragment identifier:

zconfig:///etc/myapp/zodb.conf#temp1

`memory://` URI scheme¶

The memory:// URI scheme can be passed as zodbconn.uri to create a ZODB MappingStorage (memory-based) database factory. The path info section of this scheme should be a storage name. For example:

memory://storagename

However, the storage name is usually omitted, and the most common form is:

memory://

The URI scheme also accepts query string arguments. The query string arguments honored by this scheme are as follows.

Database-related¶

These arguments relate to the database (as opposed to storage) settings.

database_name: string

Connection-related¶

These arguments relate to connections created from the database.

connection_cache_size: integer (default 10000)
connection_pool_size: integer (default 7)

Example¶

An example that combines a dbname with a query string:

memory://storagename?connection_cache_size=100&database_name=fleeb

Events¶

All events are sent via the standard Pyramid registry.notify interface and can be subscribed to using the config.add_subscriber API in Pyramid.

When a connection is opened, the pyramid_zodbconn.ZODBConnectionOpened event is sent.

Just before a connection is closed, the pyramid_zodbconn.ZODBConnectionWillClose event is sent.

When a connection is closed, the pyramid_zodbconn.ZODBConnectionClosed event is sent.

Transfer Log¶

Add the key zodbconn.transferlog to your deployment settings to have pyramid_zodbconn send information about the ZODB stoage loads and stores caused by each request sent to the system. The zodbconn.transferlog key can either be a filename or it can be empty, which indicates that the transfer log should be sent to stdout.

For example:

zodbconn.transferlog = /some/file/transfer.log

The transfer log is written in CSV format. Each line is in the format:

timestamp, request_method, url, elapsed_secs, loads, stores

For example:

"2014-07-02 13:44:18", "GET", "/manage/@@contents", 28.47, 23580, 0
"2014-07-02 13:44:18", "GET", "/manage/auditstream-sse", 0.02, 0, 0
"2014-07-02 13:44:18", "GET", "/sdistatic/css/sdi_bootstrap.css", 0.00, 0, 0
"2014-07-02 13:44:18", "GET", "/sdistatic/js/jquery-2.0.3.js", 0.00, 0, 0
"2014-07-02 13:44:18", "GET", "/sdistatic/js/bootstrap.js", 0.00, 0, 0
"2014-07-02 13:44:18", "GET", "/sdistatic/js/sdi.js", 0.00, 0, 0

If you only want to write transfer log entries for requests that take over a certain amount of time, you can use the zodbconn.transferlog_threshhold setting. It should be an integer representing a number of seconds. If the request consumes more than this number of seconds, a transfer log line will be written, otherwise no transfer log line will be written.

For example:

zodbconn.transferlog_threshhold = 2

More Information¶