Package: yedb
yedb - rugged embedded and client/server key-value database (Python implementation)Why YEDB?Is it fast?Fast to read, slow to writeIs it smart?NoSo what is YEDB for?YEDB is ultra-reliable, thread-safe and very easy to use.I don't like PythonThere are otherimplementationshttps://www.youtube.com/watch?v=i3hSWjrNqLoYEDB is absolutely reliable rugged key-value database, which can survive in any
power loss, unless the OS file system die. Keys data is saved in the very
reliable way and immediately flushed to disk (this can be disabled to speed
up the engine but is not recommended - why then YEDB is used for).YEDB database objects are absolutely thread-safe.YEDB has built-in tools to automatically repair itself if any keys are broken.If the tools failed to help, YEDB can be easily repaired by a system
administrator, using standard Linux tools.YEDB can automatically validate keys with JSON Schema
(https://json-schema.org/)YEDB has a cool CLIPractical usage:Create a database and start writing continuouslyTurn the power switch offBoot the machine again. The typical result: the latest saved key isn't
survived, but the database is still valid and working. In 99% of cases, the
latest key can be automatically restored with built-in repair tools.We created YEDB to use in our embedded products as config registry trees and
rugged key-value data storage. We use it a lot and hope you'll like it too.Note: YEDB is good on SSDs and SD cards. As it immediately syncs all the data
written, it can work on classic HDDs really slowly.PerformanceModern SSDs give about 200-300 keys/sec written with auto-flush enabled. The
write speed can be 10-15 times faster without it, but we would not recommend
turning auto-flush off, as it is the key feature of YEDB.Reading speed varies:for embedded: 30-40k keys/second (70-100k keys/second when cached).for UNIX/TCP socket: 7-15k keys/secondfor HTTP: 700-800 keys/second. Transport via HTTP is mostly slow because YEDB
client uses synchronous "requests" library (while the default server is
async). To get better results, consider tuning the server manually and use
a custom async client.Quick start# install YEDBpip3installyedb# to use as embedded or client/server - go on. to use CLI - install additional# required librariespip3install"yedb[cli]"# create a new database and go interactiveyedb/path/to/my/database# set a keyyedbsetkey1value1# get the key valueyedbgetkey1Quick client-server setup# Install required system packages
# Debian/Ubuntu: apt-get install -y --no-install-recommends python3 python3-dev gcc
# RedHat/Fedora/CenOS: yum install -y python3 python3-devel gcc
sudo mkdir /opt/yedbd
cd /opt/yedbd && curl https://raw.githubusercontent.com/alttch/yedb-py/main/setup-server.sh | sudo shUse env to specify extra options:YEDBD_BIND - override bind to (tcp://host:port,http://host:portor path to
UNIX socket)YEDBD_SERVICE - system service nameYEDB_PS - CLI promptPIP_EXTRA_OPTIONS - specify pip extra optionsPYTHON - override Python pathPIP - override pip pathEmbeddingfromyedbimportYEDBwithYEDB('/path/to/db',auto_repair=True)asdb:# do some stuff# ORdb=YEDB('/path/to/db')db.open()try:# do some stufffinally:db.close()Client/serverIf socket transport requested, the built-in in server requires "msgpack"
Python moduleIf HTTP transport requested, the built-in server requires "aiohttp" Python
module# listen to tcp://localhost:8870 (default), to bind UNIX socket, specify the# full socket path, to use http transport, specify http://host:port to bind topython3-myedb.server/path/to/dbConnect a clientIf socket transport requested, the built-in in client requires "msgpack"
Python moduleIf HTTP transport requested, the built-in client requires "requests" Python
modulefromyedbimportYEDBwithYEDB('tcp://localhost:8870')asdb:# do some stuff, remember to send all parameters as kwargsYEDB creates thread-local objects. If the software is using permanent threads
or a thread pool, it is recommended to use sessions to correctly drop these
objects at the end of the statement:fromyedbimportYEDBwithYEDB('tcp://localhost:8870')asdb:withdb.session()assession:# do some stuff, remember to send all parameters as kwargssession.key_set(key='key1',value='val1')print(session.key_get(key='key1'))Building own clientYEDB uses JSON RPC (https://www.jsonrpc.org/) as the API protocol. Any method,
listed in yedb.server.METHODS can be called. Payloads can be packed either with
JSON or with MessagePack.If working via UNIX or TCP socket:only MessagePack payload encoding is supportedRequest/response format: PROTO_VER + DATA_FMT + FRAME_LEN(32-bit
little-endian) + frameWhere PROTO_VER = protocol version (0x01) and DATA_FMT = data encoding format
(0x02 for MessagePack, which is the only protocol supported by the
built-in server).Working with complicated data structures (embedded only)fromyedbimportYEDBwithYEDB('/path/to/db')asdb:withdb.key_as_dict('path/to/keydict) as key:key.set('field','value')# If modified, the key is automatically saved at the end of the statement.Data formatsThe default engine data format is JSON
(https://github.com/python-rapidjson/python-rapidjsonis detected and imported
automatically if present)Other possible formats and their benefits:YAML - (requires manually installing "pyyaml" Python module) slow, but key
files are more human-readable and editablemsgpack - (requires manually installing "msgpack" Python module). Fast,
reliable binary serialization format. If used, keys can hold binary values as
well.cbor - similar to msgpack (requires manually installing "cbor" Python module)pickle - native Python pickle binary data serialization format. Is slower
than msgpack/cbor, but keys can hold Python objects and functions as-is.Databases can be easily converted between formats using "yedb" CLI tool or
"convert_fmt" method, unless format-specific features are used (e.g. if keys
have binary data, they can't be converted to JSON properly).YEDB Specifications and Data formatsSeehttps://github.com/alttch/yedbSchema validationAs all keys are serialized values, they can be automatically schema-validated
with JSON Schema (https://json-schema.org/).To create the validation schema for the chosen key, or key group, create a
special key ".schema/path/to", which has to contain the valid JSON Schema.E.g. the schema, stored in the key ".schema/groups/group1" will be used for
validating all keys in "groups/group1", including the group primary key. And
the schema, stored in ".schema/groups/group1/key1" will be used for validating
"groups/group1/key1" only (if key or subgroup schema is present, the parent
schemas are omitted).YEDB also supports a non-standard scheme:{"type":"code.python"}which requires the key to have valid Python code, without syntax errors.If schema validation fails on set or structure "with" statement exit, an
exception yedb.SchemaValidationError is raised.Backup/restoreFull backup: simply backup the database directory with any preferred method.Partial/server backup:Use "dump_keys" / "load_keys" methods. If dump is created with CLI (requires
"msgpack" Python module for that), it has the format:DUMP\_VER + DUMP\_FMT

KEY_LEN(32-bit little-endian) + KEY
KEY_LEN(32-bit little-endian) + KEY
KEY_LEN(32-bit little-endian) + KEY
KEY_LEN(32-bit little-endian) + KEY
....
KEY_LEN(32-bit little-endian) + KEYDebuggingStart client/server with DEBUG=1 env variable:DEBUG=1yedb/path/to/dbto debug when embedded, enable debug loggingimportyedbyedb.debug=TrueAfter, lower the default logging level.Module documentationhttps://yedb-py.readthedocs.io/