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zodburi

Overview

A library which parses URIs and converts them to ZODB storage objects and database arguments.

It will run under CPython 3.7+ and pypy3. It will not run under Jython. It requires ZODB >= 5.0.0.

Installation

Install using pip, e.g. (within a virtualenv):

$ pip install zodburi

Using

zodburi has exactly one api: zodburi.resolve_uri. This API obtains a ZODB storage factory and a set of keyword arguments suitable for passing to the ZODB.DB.DB constructor. For example:

from zodburi import resolve_uri

storage_factory, dbkw = resolve_uri(
                  'zeo://localhost:9001?connection_cache_size=20000')

# factory will be an instance of ClientStorageURIResolver
# dbkw will be {'connection_cache_size':20000, 'pool_size':7,
#               'database_name':'unnamed'}

from ZODB.DB import DB
storage = storage_factory()
db = DB(storage, **dbkw)

URI Schemes

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

In addition to those schemes, the relstorage package adds support for postgres://.

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.

FileStorage constructor related

These arguments generally inform the FileStorage constructor about values of the same names.

create

boolean

read_only

boolean

quota

bytesize

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) target size, in number of objects, of each connection's object cache

connection_cache_size_bytes

integer (default 0) target estimated size, in bytes, of each connection's object cache

0 means no limit.

A suffix of KB, MB, or GB may be used to provide units.

connection_historical_cache_size

integer (default 1000) target size, in number of objects, of each historical connection's object cache

connection_historical_cache_size_bytes

integer (default 0) target estimated size, in bytes, of each historical connection's object cache

0 means no limit.

A suffix of KB, MB, or GB may be used to provide units.

connection_historical_pool_size

integer (default 3) expected maximum total number of historical connections simultaneously open

connection_historical_timeout

integer (default 300) maximum age of inactive historical connections

When a historical connection has remained unused in a historical connection pool for more than connection_historical_timeout seconds, it will be discarded and its resources released.

connection_large_record_size

integer (default 16MB) record size limit before suggesting using blobs

When object records are saved that are larger than this, a warning is issued, suggesting that blobs should be used instead.

A suffix of KB, MB, or GB may be used to provide units.

connection_pool_size

integer (default 7) expected maximum number of simultaneously open connections

There is no hard limit (as many connections as are requested will be opened, until system resources are exhausted). Exceeding pool-size connections causes a warning message to be logged, and exceeding twice pool-size connections causes a critical message to be logged.

connection_pool_timeout

integer (default unlimited) maximum age of inactive (non-historical) connections

When a connection has remained unused in a connection pool for more than connection_pool_timeout seconds, it will be discarded and its resources released.

Blob-related

If these arguments exist, they control the blob settings for this storage.

blobstorage_dir

string

blobstorage_layout

string

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.

ClientStorage-constructor related

These arguments generally inform the ClientStorage constructor about values of the same names.

storage

string

cache_size

bytesize

name

string

client

string

debug

boolean

var

string

min_disconnect_poll

integer

max_disconnect_poll

integer

wait_for_server_on_startup (deprecated alias for wait)

boolean

wait

boolean

wait_timeout

integer

read_only

boolean

read_only_fallback

boolean

drop_cache_rather_verify

boolean

username

string

password

string

realm

string

blob_dir

string

shared_blob_dir

boolean

blob_cache_size

bytesize

blob_cache_size_check

integer

client_label

string

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

demo: URI scheme

The demo: URI scheme can be passed as zodbconn.uri to create a DemoStorage database factory. DemoStorage provides an overlay combining base and δ ("delta", or in other words, "changes") storages. The URI scheme contains two parts, base and δ:

demo:(base_uri)/(δ_uri)

an optional fragment specifies arguments for ZODB.DB.DB constructor:

demo:(base_uri)/(δ_uri)#dbkw

Example

An example that combines ZEO with local FileStorage for changes:

demo:(zeo://localhost:9001?storage=abc)/(file:///path/to/Changes.fs)

More Information

api.rst

Reporting Bugs / Development Versions

Visit https://github.com/Pylons/zodburi to download development or tagged versions.

Visit https://github.com/Pylons/zodburi/issues to report bugs.

Indices and tables

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