asyncio-foundationdb 0.10.4.dev0

asyncio drivers for FoundationDB

asyncio-foundationdb

early draft

asyncio drivers for foundationdb tested with CPython 3.9 and PyPy 3.7

Table of Content

• Getting started
• ChangeLog
  • v0.10.x
• import found
• from found import bstore
• from found import nstore
• from found import eavstore
• from found import pstore

Getting started

pip install asyncio-foundationdb

import found


async def get(tx, key):
    out = await found.get(tx, key)

async def set(tx, key, value):
    return found.set(tx, key, value)


db = await found.open()
out = await found.transactional(db, get, b'hello')
assert out is None

await found.transactional(db, set, b'hello', b'world')
out = await found.transactional(db, get, b'hello')
assert out == b'world'

ChangeLog

v0.10.x

• Almost full rewrite
• Remove hooks for the time being
• Port Generic Tuple Store aka. nstore
• Add blob store aka. bstore
• Add Entity-Attribute-Value store aka. eavstore
• Add inverted index store aka. pstore

import found

found.BaseFoundException

All found exceptions inherit that class.

found.FoundException

Exception raised when there is an error foundationdb client driver, or foundationdb server side.

async found.open(cluster_file=None)

Open database.

Coroutine that will open a connection with the cluster specified in the file cluster_file. If cluster_file is not provided the default is /etc/foundationdb/fdb.cluster. Returns a database object.

async found.transactional(db, func, *args, snapshot=False, **kwargs)

Operate a transaction for func.

Coroutine that will operate a transaction against db for func. If snapshot=True then the transaction is read-only. func will receive an appropriate transaction object as first argument, then args, then kwargs. Because of errors transactional might run func several times, hence func should be idempotent.

async found.get(tx, key)

Get the value associated with key.

Coroutine that will fetch the value associated with key inside the database associated with tx. key must be bytes. In case of success, returns bytes. Otherwise, if there is no value associated with key, returns the object None.

found.set(tx, key, value)

Set key to value.

In the database associated with tx, associate key with value. Both key and value must be bytes.

found.pack(tuple)

Serialize python objects tuple into bytes.

found.pack_with_versionstamp(tuple)

Serialize python objects tuple into bytes. tuple may contain found.Versionstamp objects.

found.unpack(bytes)

Deserialize bytes into python objects.

found.Versionstamp(...)

FIXME.

found.clear(tx, key, other=None)

Remove key or keys.

In the database associated with tx, clear the specified key or range of keys.

key and other if provided must be bytes.

If other=None, then clear the association that might exists with key. Otherwise, if other is provided, found.clear will remove any association between key and other but not the association with other if any (that is other is excluded from the range).

async found.query(tx, key, other, *, limit=0, mode=STREAMING_MODE_ITERATOR)

Fetch key-value pairs.

In the database associated with tx, generate at most limit key-value pairs inside the specified range, with the specified order.

If key < other then found.query generates key-value pairs in lexicographic order. Otherwise, if key > other then found.query generates key-value pairs in reverse lexicographic order, that is starting at other until key.

If limit=0, then found.query generates all key-value pairs in the specified bounds. Otherwise if limit > 0 then, it generates at most limit pairs.

The keyword mode can be one the following constant:

• found.STREAMING_MODE_WANT_ALL
• found.STREAMING_MODE_ITERATOR
• found.STREAMING_MODE_EXACT
• found.STREAMING_MODE_SMALL
• found.STREAMING_MODE_MEDIUM
• found.STREAMING_MODE_LARGE
• found.STREAMING_MODE_SERIAL

found.next_prefix(key)

Returns the immediatly next byte sequence that is not prefix of key.

found.lt(key, offset=0)

found.lte(key, offset=0)

found.gt(key, offset=0)

found.gte(key, offset=0)

async found.read_version(tx)

found.set_read_version(tx, version)

found.add(tx, key, param)

found.bit_and(tx, key, param)

found.bit_or(tx, key, param)

found.bit_xor(tx, key, param)

found.max(tx, key, param)

found.byte_max(tx, key, param)

found.min(tx, key, param)

found.byte_min(tx, key, param)

found.set_versionstamped_key(tx, key, param)

found.set_versionstamped_value(tx, key, param)

from found import bstore

bstore.BStoreException

Exception specific to bstore.

bstore.make(name, prefix)

Handle over a bstore called name with prefix.

async bstore.get_or_create(tx, bstore, blob)

bstore.get(tx, bstore, uid)

from found import nstore

nstore.NStoreException

Exception specific to nstore.

nstore.make(name, prefix, n)

Create a handle over a nstore called name with prefix and n columns.

The argument name should be a string, it is really meant to ease debugging. prefix should be a tuple that can be packed with found.pack. Last but not least, n is the number of columns in the returned tuple store (or, if you prefer, the number of tuple items).

It is preferable to store the returned value.

nstore.add(tx, nstore, *items, *, value=b'')

In the database associated with tx, as part of nstore, add items associated with value.

nstore.remove(tx, nstore, *items)

In the database associated with tx, as part of nstore, remove items and the associated value.

async nstore.get(tx, nstore, *items)

In the database associated with tx, as part of nstore, get the value associated with items. If there is no such items in nstore, returns None.

nstore.var(name)

Create a variable called name for use with nstore.query.

async nstore.query(tx, nstore, pattern, *patterns)

In the database associated with tx, as part of nstore, generate mappings that match pattern and patterns. Both pattern and patterns may contain nstore.var that will be replaced with matching values in the generic tuple store.

from found import eavstore

eavstore.make(name, prefix)

Create a handle over an eavstore called name with prefix.

The argument name should be a string, it is really meant to ease debugging. prefix should be a tuple that can be packed with found.pack.

eavstore.create(tx, eavstore, dict)

Store a dictionary.

In the database associated with tx, as part of eavstore, save dict and returns its unique identifier.

async eavstore.get(tx, eavstore, uid)

Fetch a dictionary.

In the database associated with tx, as part of eavstore, retrieve the dictionary associated with uid. If there is no such dictionary, returns an empty dictionary.

eavstore.remove(tx, eavstore, uid)

Clear a dictionary.

In the database associated with tx, as part of eavstore, remove the dictionary associated with uid.

eavstore.update(tx, eavstore, uid, dict)

Update a dictionary.

In the database associated with tx, as part of eavstore, replace the dictionary associated with uid with dict.

async eavstore.query(tx, eavstore, key, value)

Lookup dictionaries according to sppecification.

In the database associated with tx, as part of eavstore, generates unique identifier for dictionaries that have key equal to value.

from found import pstore

pstore.PStoreException

Exception specific to pstore.

pstore.make(name, prefix, pool)

A handle over a pstore called name with prefix, that will use pool.

async pstore.index(tx, store, docuid, counter)

Associates docuid with counter.

Coroutine that associates the identifier docuid with the dict-like counter inside the database associated with tx at store for later retriaval with pstore.search.

counter must be a dict-like mapping string to integers bigger than zero.

async pstore.search(tx, store, keywords, limit)

Return a sorted list of at most limit documents matching keywords.