Welcome to DataHub Actions! The Actions framework makes responding to realtime changes in your Metadata Graph easy, enabling you to seamlessly integrate DataHub into a broader events-based architecture.
For a detailed introduction, check out the original announcement of the DataHub Actions Framework at the DataHub April 2022 Town Hall. For a more in-depth look at use cases and concepts, check out DataHub Actions Concepts.
To get started right away, check out the DataHub Actions Quickstart Guide.
The DataHub Actions CLI commands are an extension of the base datahub CLI commands. We recommend
first installing the datahub CLI:
python3 -m pip install --upgrade pip wheel setuptools
python3 -m pip install --upgrade acryl-datahub
datahub --versionNote that the Actions Framework requires a version of
acryl-datahub>= v0.8.34
Next, simply install the acryl-datahub-actions package from PyPi:
python3 -m pip install --upgrade pip wheel setuptools
python3 -m pip install --upgrade acryl-datahub-actions
datahub actions versionActions are configured using a YAML file, much in the same way DataHub ingestion sources are. An action configuration file consists of the following
- Action Pipeline Name (Should be unique and static)
- Source Configurations
- Transform + Filter Configurations
- Action Configuration
- Pipeline Options (Optional)
- DataHub API configs (Optional - required for select actions)
With each component being independently pluggable and configurable.
# 1. Required: Action Pipeline Name
name: <action-pipeline-name>
# 2. Required: Event Source - Where to source event from.
source:
type: <source-type>
config:
# Event Source specific configs (map)
# 3a. Optional: Filter to run on events (map)
filter:
event_type: <filtered-event-type>
event:
# Filter event fields by exact-match
<filtered-event-fields>
# 3b. Optional: Custom Transformers to run on events (array)
transform:
- type: <transformer-type>
config:
# Transformer-specific configs (map)
# 4. Required: Action - What action to take on events.
action:
type: <action-type>
config:
# Action-specific configs (map)
# 5. Optional: Additional pipeline options (error handling, etc)
options:
retry_count: 0 # The number of times to retry an Action with the same event. (If an exception is thrown). 0 by default.
failure_mode: "CONTINUE" # What to do when an event fails to be processed. Either 'CONTINUE' to make progress or 'THROW' to stop the pipeline. Either way, the failed event will be logged to a failed_events.log file.
failed_events_dir: "/tmp/datahub/actions" # The directory in which to write a failed_events.log file that tracks events which fail to be processed. Defaults to "/tmp/logs/datahub/actions".
# 6. Optional: DataHub API configuration
datahub:
server: "http://localhost:8080" # Location of DataHub API
# token: <your-access-token> # Required if Metadata Service Auth enabledAn simple configuration file for a "Hello World" action, which simply prints all events it receives, is
# 1. Action Pipeline Name
name: "hello_world"
# 2. Event Source: Where to source event from.
source:
type: "kafka"
config:
connection:
bootstrap: ${KAFKA_BOOTSTRAP_SERVER:-localhost:9092}
schema_registry_url: ${SCHEMA_REGISTRY_URL:-http://localhost:8081}
# 3. Action: What action to take on events.
action:
type: "hello_world"We can modify this configuration further to filter for specific events, by adding a "filter" block.
# 1. Action Pipeline Name
name: "hello_world"
# 2. Event Source - Where to source event from.
source:
type: "kafka"
config:
connection:
bootstrap: ${KAFKA_BOOTSTRAP_SERVER:-localhost:9092}
schema_registry_url: ${SCHEMA_REGISTRY_URL:-http://localhost:8081}
# 3. Filter - Filter events that reach the Action
filter:
event_type: "EntityChangeEvent_v1"
event:
category: "TAG"
operation: "ADD"
modifier: "urn:li:tag:pii"
# 4. Action - What action to take on events.
action:
type: "hello_world"To run a new Action, just use the actions CLI command
datahub actions -c <config.yml>
Once the Action is running, you will see
Action Pipeline with name '<action-pipeline-name>' is now running.
You can run multiple actions pipeline within the same command. Simply provide multiple config files by restating the "-c" command line argument.
For example,
datahub actions -c <config-1.yaml> -c <config-2.yaml>
Simply append the --debug flag to the CLI to run your action in debug mode.
datahub actions -c <config.yaml> --debug
Just issue a Control-C as usual. You should see the Actions Pipeline shut down gracefully, with a small summary of processing results.
Actions Pipeline with name '<action-pipeline-name' has been stopped.
Two event types are currently supported. Read more about them below.
Currently, the only event source that is officially supported is kafka, which polls for events
via a Kafka Consumer.
By default, DataHub supports a set of standard actions plugins. These can be found inside the folder
src/datahub-actions/plugins.
Some pre-included Actions include
Notice that we support all actions command using a separate datahub-actions CLI entry point. Feel free
to use this during development.
# Build datahub-actions module
./gradlew datahub-actions:build
# Drop into virtual env
cd datahub-actions && source venv/bin/activate
# Start hello world action
datahub-actions actions -c ../examples/hello_world.yaml
# Start ingestion executor action
datahub-actions actions -c ../examples/executor.yaml
# Start multiple actions
datahub-actions actions -c ../examples/executor.yaml -c ../examples/hello_world.yaml
To develop a new Transformer, check out the Developing a Transformer guide.
To develop a new Action, check out the Developing an Action guide.
Contributing guidelines follow those of the main DataHub project. We are accepting contributions for Actions, Transformers, and general framework improvements (tests, error handling, etc).
Check out the original announcement of the DataHub Actions Framework at the DataHub April 2022 Town Hall.
