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Description:

edxeventbuskafka 5.8.1

edX Event Bus - Kafka
Kafka implementation for Open edX event bus.

Overview
This package implements an event bus for Open edX using Kafka.
The event bus acts as a broker between services publishing events and other services that consume these events.
Implementing the event bus will allow for asynchronous messaging across services which greatly improves efficiency as we don’t have to wait for scheduled batch synchronizations.
Additionally, since the services all speak to the event bus, they are independent of one another and can still function if one service crashes.
This package contains both the publishing code, which processes events into messages to send to the broker, and the consumer code,
which polls the broker using a while True loop in order to turn messages back into event data to be emitted.
The actual Kafka host will be configurable.
The goal for event-bus-kafka is to eventually have a flexible event bus that can be easily brought into other apps and repositories to produce and consume arbitrary topics.
Ideally, the event bus itself will also be an abstraction behind which platform maintainers can use non-Kafka implementations (Redis, Pulsar, etc.).
The documentation/ADRs may also be moved to more appropriate places as the process matures.
The repository works together with the openedx/openedx-events repository to make the fully functional event bus.

Documentation
To use this implementation of the Event Bus with openedx-events, you’ll need to ensure that you include the dependency confluent_kafka[avro,schema-registry] (see ADR 5 for an explanation) and set the following Django settings:
EVENT_BUS_KAFKA_BOOTSTRAP_SERVERS: ...
EVENT_BUS_KAFKA_SCHEMA_REGISTRY_URL: ...
EVENT_BUS_TOPIC_PREFIX: ...

# On the producing side:
EVENT_BUS_PRODUCER: edx_event_bus_kafka.create_producer

# On the consuming side:
EVENT_BUS_CONSUMER: edx_event_bus_kafka.KafkaEventConsumer
Optional settings that are worth considering:

EVENT_BUS_KAFKA_CONSUMER_CONSECUTIVE_ERRORS_LIMIT

For manual testing, see docs/how_tos/manual_testing.rst.
Django management commands:

If you need to test event production, use the produce_event management command
To actually run the consumer, use openedx-events’ consume_events management command

OEP-52 documentation: https://open-edx-proposals.readthedocs.io/en/latest/architectural-decisions/oep-0052-arch-event-bus-architecture.html
(TODO: Set up documentation)

Development Workflow

One Time Setup
# Clone the repository
git clone git@github.com:openedx/event-bus-kafka.git
cd event-bus-kafka

# Set up a virtualenv using virtualenvwrapper with the same name as the repo and activate it
mkvirtualenv -p python3.8 event-bus-kafka

Every time you develop something in this repo
# Activate the virtualenv
workon event-bus-kafka

# Grab the latest code
git checkout main
git pull

# Install/update the dev requirements
make requirements

# Run the tests and quality checks (to verify the status before you make any changes)
make validate

# Make a new branch for your changes
git checkout -b <your_github_username>/<short_description>

# Using your favorite editor, edit the code to make your change.
vim …

# Run your new tests
pytest ./path/to/new/tests

# Run all the tests and quality checks
make validate

# Commit all your changes
git commit …
git push

# Open a PR and ask for review.

Installation
This library is not intended to be a direct dependency of any service. Instead, it will likely be installed by some private mechanism. Unless the platform gains new processes for installing private dependencies, upgrades will need to be manually managed via a pin.

License
The code in this repository is licensed under the AGPL 3.0 unless
otherwise noted.
Please see LICENSE.txt for details.

How To Contribute
Contributions are very welcome.
Please read How To Contribute for details.
The pull request description template should be automatically applied if you are creating a pull request from GitHub. Otherwise you
can find it at PULL_REQUEST_TEMPLATE.md.
The issue report template should be automatically applied if you are creating an issue on GitHub as well. Otherwise you
can find it at ISSUE_TEMPLATE.md.

Reporting Security Issues
Please do not report security issues in public. Please email security@openedx.org.

Getting Help
If you’re having trouble, we have discussion forums at https://discuss.openedx.org where you can connect with others in the community.
Our real-time conversations are on Slack. You can request a Slack invitation, then join our community Slack workspace.
For more information about these options, see the Getting Help page.

Change Log

Unreleased

[5.8.1] - 2024-08-02
Changed

Monitoring: Add a custom attribute, kafka_received_message to track whether a message was processed or not.

[5.8.0] - 2024-08-01
Changed

Monitoring: Ensure that we have a root span for each iteration of the consume loop; renamed the trace name to be consumer.consume.

[5.7.0] - 2024-03-22
Changed

Dropped Support for Django 3.2, Django 4.0 and Django 4.1
Added Support for Python 3.12

[5.6.0] - 2024-01-25
Changed

Added client.id to base configuration.

[5.5.0] - 2023-09-21
Changed

Reset edx-django-utils RequestCache before handling each event

[5.4.0] - 2023-08-28
Changed

Changed ordering of certain context assignments in producer code.
Adds custom exceptions for producing and consuming errors.

[5.3.1] - 2023-08-10
Fixed

Constrain openedx-events version to at least 8.5.0 (for EventsMetadata serialization support)

[5.3.0] - 2023-08-08
Changed

Added event_metadata_as_dict to ProducingContext for easier replay from logs

[5.2.0] - 2023-08-03
Changed

Added event_data_as_dict to ProducingContext for easier replay from logs

[5.1.0] - 2023-05-17
Changed

Reconfigured serializers to use topic_record_name_strategy, allowing multiple event types per topic

[5.0.0] - 2023-05-17
Changed

BREAKING CHANGE: Removed deprecated signal argument from consumer initialization

[4.0.1] - 2023-05-10
Fixed

Added signal back as an argument when creating a consumer for compatibility with the openedx-events API

[4.0.0] - 2023-05-10
Changed

Implement openedx-events Event Bus Consumer API.
BREAKING CHANGE: Remove consume_events management command as this command will be provided by openedx_events. To replay events using the
openedx-events version of the management command, pass --extra '{"offset_time": "2023-01-08T06:46:22"}' instead of -o 2023-01-08T06:46:22.
BREAKING Change: offset_timestamp argument has been removed from consume_indefinitely and reset_offsets_and_sleep_indefinitely methods.
It is now added as an optional argument named offset_time to KafkaEventConsumer constructor.

[3.10.0] - 2023-05-05
Changed

Switch from edx-sphinx-theme to sphinx-book-theme since the former is
deprecated
Refactored consumer to manually deserialize messages instead of using DeserializingConsumer
Make signal argument optional in consumer command (take signal from message headers)

[3.9.6] - 2023-02-24
Added

Add function tracing to the event consumption workflow for better monitoring.

[3.9.5] - 2023-02-24
Fixed

consume_events command now loads all public signals so that the consumer can load signals by event_type even if their modules were not already imported

[3.9.4] - 2023-02-16
Fixed

produce_event management command fixed to pass required events_metadata parameter

[3.9.3] - 2023-02-10
Fixed

Include message_id in audit log when message is produced (was None)

[3.9.2] - 2023-02-08
Fixed

Added documentation to all Django settings used in consumer and producer

[3.9.1] - 2023-02-07
There was no version 3.9.0, due to a release issue. (Ignore any v3.9.0 tag.)

Added

Added logging of successful message production, consumption, and processing (not just errors)

[3.8.1] - 2023-02-03
Changed

Require and use openedx-events 5.0.0, which has a breaking API change that affects event bus consumers.

[3.8.0] - 2023-01-31
Added

Producer now passes all metadata fields as headers
Consumer emits events with the original metadata information (from the producer)

[3.7.1] - 2023-01-31
Fixed

Consumer management command exits with useful error message if confluent-kafka library not available.

[3.7.0] - 2023-01-30
Changed

Added reset_offsets_and_sleep_indefinitely method to consumer; relying code should switch to calling this when an offset timestamp is set.
Deprecated the offset_timestamp parameter on the consumer’s consume_indefinitely method, since reset_offsets_and_sleep_indefinitely should be used instead.

[3.6.3] - 2023-01-27
Fixed

In the consumer loop, open new database connection if the old one has closed before processing messages

[3.6.2] - 2023-01-26
Fixed

Reset mode now commits the correct offsets to Kafka.

[3.6.1] - 2023-01-20
Fixed

Added a poll call to force resets to be processed during replay/offset-reset mode.

[3.6.0] - 2023-01-06
Changed

Consumers do not consume events after resetting offsets.

[3.5.1] - 2023-01-06
Fixed

Convert timestamps to millisecond offsets as expected by the Kafka API when replaying by timestamp in the consumer

[3.5.0] - 2023-01-05
Added

New setting EVENT_BUS_KAFKA_CONSUMER_CONSECUTIVE_ERRORS_LIMIT will terminate the consumer if too many errors occur in a row, supporting an automated version of “have you tried turning it off and on again” (as long as consumer will automatically be restarted e.g. by Kubernetes).

[3.4.1] - 2022-12-20
Fixed

Fixed bugs in the event replay/offset handling code for consumers.

[3.4.0] - 2022-12-16
Changed

Kill infinite consumer loop when we see a fatal KafkaError, as recommended in the documentation. See https://github.com/confluentinc/librdkafka/blob/e0b9e92a0b492b5b1a6f1bcf08744928d45bf396/INTRODUCTION.md#fatal-consumer-errors.

[3.3.0] - 2022-12-15
Changed

Added/removed some custom attributes used for monitoring. Search for custom_attribute_name annotations for details.

[3.2.0] - 2022-12-14
Changed

Add timestamp parameter for consumer, allowing the starting offset for consuming to be overridden from the default.

[3.1.0] - 2022-12-07

Added

A variety of custom attributes are now set for monitoring purposes. Search for custom_attribute_name annotations for details.

Changed

Error recording to the log will now include message details when the message is available on the error.

[3.0.0] - 2022-12-02
Changed

BREAKING CHANGE: Make event_metadata parameter required

[2.1.0] - 2022-12-01
Changed

Set CloudEvent headers on events using an optional event_metadata parameter

[2.0.0] - 2022-11-28
Changed

Implement openedx-events Event Bus Producer API
BREAKING CHANGE: Remove caching from get_producer and rename to create_producer, as we now rely on the wrapper in openedx-events to cache that call

Upgrading library from 1.x:

Replace calls to edx_event_bus_kafka.get_producer with openedx_events.event_bus.get_producer
Add Django setting EVENT_BUS_PRODUCER = "edx_event_bus_kafka.create_producer"

These breaking changes are only relevant for the producing side. (This should only include the CMS at the moment.)

[1.10.0] - 2022-11-21
Changed

Improve receiver error log message – mention that stack traces are elsewhere in log

[1.9.0] - 2022-11-15
Changed

Log and record receiver errors the same way as other errors (with offset, partition, etc.)

[1.8.1] - 2022-11-10
Changed

Commit consumer offset asynchronously

[1.8.0] - 2022-11-09
Added

Consumer logs a warning for receivers that fail with an exception

[1.7.0] - 2022-11-04
Changed

Manually manage commits instead of using auto-commit on the consumer
Catch Exception instead of BaseException on both producer and consumer

[1.6.0] - 2022-11-04
Changed

Enhanced error logging in consumer, including telemetry for exceptions
Consumer loop will no longer exit when an error is encountered

[1.5.0] - 2022-11-01
Changed

Log full event data on all producer errors

[1.4.3] - 2022-10-31
Fixed

Upgrade openedx-events and fastavro to bring in a fix for schema creation

[1.4.2] - 2022-10-31
Fixed

Removed proof-of-concept code that logged user-login events

[1.4.1] - 2022-10-28
Fixed

Correct and clarify management command help strings (some copy-paste errors)
Update TODO comments

[1.4.0] - 2022-10-21
Changed

Remove override of auto.offset.reset on consumer (which will default to “latest”). New consumer groups will consume only messages that are sent after the group was initialized.
Remove redundant lookup of signal in consumer loop (should not have any effect)
Explicitly encode message header values as UTF-8 (no change in behavior)

[1.3.0] - 2022-10-20
Changed

Upgrade openedx-events. When AvroSignalSerializer gets event schemas, it will get whatever is currently defined in openedx-events, so this will update the COURSE_CATALOG_EVENT_CHANGED schema (dropping effort field)

[1.2.0] - 2022-10-13
Changed

EVENT_BUS_KAFKA_CONSUMERS_ENABLED now defaults to True instead of False
Removed manual monitoring since New Relic tracks these now.

[1.1.0] - 2022-10-06
Changed

Added monitoring for consumption tasks.

[1.0.0] - 2022-10-03
Changed

Fixed bug in schema registry that was sending schemas to the wrong topic
Bump version to 1.x to acknowledge that this is in use in production

[0.7.0] - 2022-09-08
Changed

Breaking changes EventProducerKafka is now KafkaEventProducer
KafkaEventConsumer is now part of the public API

[0.6.2] - 2022-09-08
Added

Topic names can be autoprefixed by setting EVENT_BUS_TOPIC_PREFIX

[0.6.1] - 2022-09-06
Added

Producer now polls on an interval, improving callback reliability. Configurable with EVENT_BUS_KAFKA_POLL_INTERVAL_SEC.

[0.6.0] - 2022-09-01
Changed

Breaking change: Public API is now defined in edx_event_bus_kafka package and edx_event_bus_kafka.management.commands package; all other modules should be considered unstable and not for external use.

[0.5.1] - 2022-08-31
Fixed

Various lint issues (and missing __init__.py files.)

[0.5.0] - 2022-08-31
Changed

Breaking changes in the producer module, refactored to expose a better API:

Rather than send_to_event_bus(...), relying code should now call get_producer().send(...).
The sync kwarg is gone; to flush and sync messages before shutdown, call get_producer().prepare_for_shutdown() instead.

Clarify that config module is for internal use only.
Implementation changes: Only a single Producer is created, and is used for all signals.

[0.4.4] - 2022-08-26
Fixed

Fixed bug in test module for when confluent-kafka isn’t present

[0.4.3] - 2022-08-24
Fixed

Never evict producers from cache. There wasn’t a real risk of this, but now we can rely on them being long-lived. Addresses remainder of https://github.com/openedx/event-bus-kafka/issues/16.

[0.4.2] - 2022-08-24
Fixed

Properly load auth settings for producer/consumer. (Auth settings were ignored since 0.3.1.)

[0.4.1] - 2022-08-18
Changed

Remove confluent-kafka as a formal dependency of the repository.

Note: This library will not work without confluent-kafka.

Add an ADR to explain why this work was done.

[0.4.0] - 2022-08-15
Changed

Rename settings to have consistent prefix.

KAFKA_CONSUMERS_ENABLED becomes EVENT_BUS_KAFKA_CONSUMERS_ENABLED
CONSUMER_POLL_TIMEOUT becomes EVENT_BUS_KAFKA_CONSUMER_POLL_TIMEOUT
Updates to documentation and tests for various settings previously renamed

[0.3.1] - 2022-08-11
Changed

Refactored consumer to use common configuration.

[0.3.0] - 2022-08-10
Changed

Moved configuration onto separate file.
Updated configuration settings to have EVENT_BUS_KAFKA prefix.

[0.2.0] - 2022-08-09
Fixed

Cache producers so that they don’t lose data.

[0.1.0] - 2022-06-16
Added

First release on PyPI.