esdb-py

EventStoreDB Python gRPC client

NOTE: This project is still work in progress

• Completed features
• Installation
• Development
• Usage
  • Append/Read
  • Batch append
  • Transient subscription to all events with filtering
  • Persistent subscriptions

Completed features

• secure connection
• basic auth
• connection string parsing
• streams
  • append
  • batch append (v21.10+)
  • delete
  • read stream
  • read all with stream/event type filters (v21.10+)
  • transient subscriptions
  • tombstone
  • filtering
• persistent subscriptions
  • create
  • read stream
  • read all with filter (v21.10+)
  • update
  • delete
  • list
  • info
  • reply parked events
• CRUD for projections
• users

Installation

Using pip:

pip install esdb

Using poetry:

poetry add esdb

Development

1. Install poetry
2. Create virtualenv (i.e. using pyenv):

pyenv install 3.10.5
pyenv virtualenv 3.10.5 esdb-py
pyenv local esdb-py

3. Install deps with poetry install
4. Start eventstore in docker: make run-esdb
5. Run the tests: pytest tests

Usage

Have a look at tests for more examples.

Discovery and node preferences

from esdb import ESClient
from esdb.client import Preference

client = ESClient(
  endpoint="localhost:2112",
  discover=True,  # Discover the available nodes via gossip
  node_preference=Preference.FOLLOWER,  # Connect to a preferred node type
)

Append/Read

import asyncio
import datetime
import uuid

from esdb import ESClient

# For insecure connection without basic auth:
# client = ESClient("localhost:2113", insecure=True)
with open("certs/ca/ca.crt", "rb") as fh:
    root_cert = fh.read()

client = ESClient(
    "localhost:2111",
    root_certificates=root_cert,
    username="admin",
    password="changeit",
    keepalive_time_ms=5000,
    keepalive_timeout_ms=10000,
)

stream = f"test-{str(uuid.uuid4())}"


async def streams():
    async with client.connect() as conn:
        for i in range(10):
            append_result = await conn.streams.append(
                stream=stream,
                event_type="test_event",
                data={"i": i, "ts": datetime.datetime.utcnow().isoformat()},
            )

        print("Forwards!")
        async for result in conn.streams.read(stream=stream, count=10):
            print(result.data)

        print("Backwards!")
        async for result in conn.streams.read(stream=stream, count=10, backwards=True):
            print(result.data)

        print("Forwards start from middle!")
        async for result in conn.streams.read(stream=stream, count=10, revision=5):
            print(result.data)

        print("Backwards start from middle!")
        async for result in conn.streams.read(stream=stream, count=10, backwards=True, revision=5):
            print(result.data)

        # Create a transient subscription to a stream
        async for result in conn.streams.read(stream=stream, subscribe=True):
            print(result.data)


asyncio.run(streams())

Batch append

import asyncio
import uuid

from esdb import ESClient
from esdb.streams import Message


async def batch_append():
    # Batch append is not supported on EventStore < v21.10
    stream = str(uuid.uuid4())
    messages: list[Message] = [
        Message(event_type="one", data={"item": 1}),
        Message(event_type="one", data={"item": 2}),
        Message(event_type="one", data={"item": 3}),
        Message(event_type="two", data={"item": 1}),
        Message(event_type="two", data={"item": 2}),
        Message(event_type="two", data={"item": 3}),
    ]
    async with ESClient("localhost:2113", insecure=True).connect() as conn:
        response = await conn.streams.batch_append(stream=stream, messages=messages)
        assert response.current_revision == 5
        events = [e async for e in conn.streams.read(stream=stream, count=50)]
        assert len(events) == 6


asyncio.run(batch_append())

Transient subscription to all events with filtering

import uuid
import asyncio

from esdb import ESClient
from esdb.shared import Filter


async def filters():
    async with ESClient("localhost:2113", insecure=True).connect() as conn:
        for i in range(10):
            await conn.streams.append(stream=str(uuid.uuid4()), event_type=f"prefix-{i}", data=b"")
        async for event in conn.streams.read_all(
                subscribe=True,  # subscribe will wait for events, use count=<n> to read <n> events and stop
                filter_by=Filter(
                    kind=Filter.Kind.EVENT_TYPE,
                    regex="^prefix-",
                    # Checkpoint only required when subscribe=True, it's not needed when using count=<int>
                    checkpoint_interval_multiplier=1000,
                ),
        ):
            print(event)


asyncio.run(filters())

Persistent subscriptions

import asyncio
from esdb import ESClient
from esdb.shared import Filter
from esdb.subscriptions import SubscriptionSettings, NackAction

client = ESClient("localhost:2113", insecure=True)

stream = "stream-foo"
group = "group-bar"


async def persistent():
    async with client.connect() as conn:
        # emit some events to the same stream
        for i in range(50):
            await conn.streams.append(stream, "foobar", {"i": i})

        # create a subscription
        await conn.subscriptions.create_stream_subscription(
            stream=stream,
            group_name=group,
            settings=SubscriptionSettings(
                max_subscriber_count=50,
                read_batch_size=5,
                live_buffer_size=10,
                history_buffer_size=10,
                consumer_strategy=SubscriptionSettings.ConsumerStrategy.ROUND_ROBIN,
                checkpoint=SubscriptionSettings.DurationType(
                    type=SubscriptionSettings.DurationType.Type.MS,
                    value=10000,
                ),
            ),
        )

        # Only supported on EventStore v21.10+
        await conn.subscriptions.create_all_subscription(
            group_name="subscription_group",
            filter_by=Filter(kind=Filter.Kind.EVENT_TYPE, regex="^some_type$", checkpoint_interval_multiplier=200),
            settings=SubscriptionSettings(
                read_batch_size=50,
                live_buffer_size=100,
                history_buffer_size=100,
                max_retry_count=2,
                checkpoint=SubscriptionSettings.DurationType(
                    type=SubscriptionSettings.DurationType.Type.MS,
                    value=10000,
                ),
            ),
        )

    async with client.connect() as conn:
        sub = conn.subscriptions.subscribe(stream=stream, group_name=group, buffer_size=5)
        async for event in sub:
            try:
                # do work with event
                print(event)
                await sub.ack([event])
            except Exception as err:
                await sub.nack([event], NackAction.RETRY, reason=str(err))


asyncio.run(persistent())