Workflows

A Workflow is similar to an Airflow dag that lets you encapsulate a set of tasks.

Here is an example of a workflow. Click the plus buttons to understand all the parts of the workflow file.

workflow.py

from datetime import timedelta
from brickflow import Workflow, Cluster, WorkflowPermissions, User, \
    TaskSettings, EmailNotifications, PypiTaskLibrary, MavenTaskLibrary

wf = Workflow(  # (1)!
    "wf_test",  # (2)!
    default_cluster=Cluster.from_existing_cluster("your_existing_cluster_id"),  # (3)!

    # Optional parameters below
    schedule_quartz_expression="0 0/20 0 ? * * *",  # (4)!
    timezone="UTC",  # (5)!
    default_task_settings=TaskSettings(  # (6)!
        email_notifications=EmailNotifications(
            on_start=["email@nike.com"],
            on_success=["email@nike.com"],
            on_failure=["email@nike.com"]
        ),
        timeout_seconds=timedelta(hours=2).seconds
    ),
    libraries=[  # (7)!
        PypiTaskLibrary(package="requests"),
        MavenTaskLibrary(coordinates="com.cronutils:cron-utils:9.2.0"),
    ],
    tags={  # (8)!
        "product_id": "brickflow_demo",
        "slack_channel": "nike-sole-brickflow-support"
    },
    max_concurrent_runs=1,  # (9)!
    permissions=WorkflowPermissions(  # (10)!
        can_manage_run=[User("abc@abc.com")],
        can_view=[User("abc@abc.com")],
        can_manage=[User("abc@abc.com")],
    ),
    prefix="feature-jira-xxx",  # (11)!
    suffix="_qa1",  # (12)!
    common_task_parameters={  # (13)!
        "catalog": "development",
        "database": "your_database"
    },
)


@wf.task()  # (14)!
def task_function(*, test="var"):
    return "hello world"

Workflow definition which constructs the workflow object
Define the workflow name
The default cluster used for all the tasks in the workflow. This is an all-purpose cluster, but you can also create a job cluster
Cron expression in the quartz format
Define the timezone for your workflow. It is defaulted to UTC
Default task setting that can be used for all the tasks
Libraries that need to be installed for all the tasks
Tags for the resulting workflow and other objects created during the workflow.
Define the maximum number of concurrent runs
Define the permissions on the workflow
Prefix for the name of the workflow
Suffix for the name of the workflow
Define the common task parameters that can be used in all the tasks
Define a workflow task and associate it to the workflow

Clusters¶

There are two ways to define the cluster for the workflow or a task

Using an existing cluster¶

existing_cluster

from brickflow import Cluster

default_cluster=Cluster.from_existing_cluster("your_existing_cluster_id")

Use a job cluster¶

job_cluster

from brickflow import Cluster

default_cluster=Cluster(
    name="your_cluster_name",
    spark_version='11.3.x-scala2.12',
    node_type_id='m6g.xlarge',
    driver_node_type_id='m6g.xlarge',
    min_workers=1,
    max_workers=3,
    enable_elastic_disk=True,
    policy_id='your_policy_id',
    aws_attributes={
        "first_on_demand": 1,
        "availability": "SPOT_WITH_FALLBACK",
        "instance_profile_arn": "arn:aws:iam::XXXX:instance-profile/XXXX/group/XX",
        "spot_bid_price_percent": 100,
        "ebs_volume_type": "GENERAL_PURPOSE_SSD",
        "ebs_volume_count": 3,
        "ebs_volume_size": 100
    }
)

Permissions¶

Brickflow provides an opportunity to manage permissions on the workflows. You can provide individual users or to a group or to a ServicePrincipal that can help manage, run or view the workflows.

Below example is for reference

manage_permissions

from brickflow import WorkflowPermissions, User, Group, ServicePrincipal

permissions=WorkflowPermissions(
    can_manage_run=[
        User("abc@abc.com"), 
        Group("app.xyz.team.Developer"), 
        ServicePrincipal("ServicePrinciple_dbx_url.app.xyz.team.Developer")
    ],
    can_view=[User("abc@abc.com")],
    can_manage=[User("abc@abc.com")],
)

Tags¶

Using brickflow, custom tags can be created on the workflow - but there are also some default tags that are created while the job is deployed.

The defaults tags that gets automatically attached to the workflow are below

"brickflow_project_name" : Brickflow Project Name that is referred from the entrypoint.py file
"brickflow_version" : Brickflow Version that is used to deploy the workflow
"databricks_tf_provider_version" : Databricks terraform provider version that is used to deploy the workflow
"deployed_by" : Email id of the profile that is used to deploy the workflow. It can be a user or a service principle. Whichever id is used to deploy the workflow, automatically becomes the owner of the workflow
"environment" : Environment to which the workflow is identified to

Use the below reference to define more tags and attach to the workflow. These can be used for collecting various metrics and build dashboards.

configure_tags

tags={
        "product_id": "brickflow_demo",
        "slack_channel": "nike-sole-brickflow-support"
    }

Schedule¶

Databricks workflows uses Quartz cron expression unlike airflow's unix based cron scheduler. A typical Quartz cron expression have six or seven fields, seperated by spaces

second minute hour day_of_month month day_of_week year(optional)

Below is a sample

quartz_cron_expression

schedule_quartz_expression="0 0/20 0 ? * * *"

Tasksettings¶

Task setting at workflow level can be used to have common setting defined that will be applicable for all the tasks. Below is a sample that can be used for reference and all the parameters in TaskSettings are optional

task_settings

from datetime import timedelta
from brickflow import TaskSettings, EmailNotifications

default_task_settings=TaskSettings(
   email_notifications=EmailNotifications(
      on_start=["email@nike.com"],
      on_success=["email@nike.com"],
      on_failure=["email@nike.com"]
   ),
   timeout_seconds=timedelta(hours=2).seconds,
   max_retries=2,
   min_retry_interval_millis=60000,
   retry_on_timeout=True
)

Libraries¶

Brickflow allows to specify libraries that are need to be installed and used across different tasks. There are many ways to install library from different repositories/sources

libraries

from brickflow import PypiTaskLibrary, MavenTaskLibrary, StorageBasedTaskLibrary, \
    JarTaskLibrary, EggTaskLibrary, WheelTaskLibrary

libraries=[
   PypiTaskLibrary(package="requests"),
   MavenTaskLibrary(coordinates="com.cronutils:cron-utils:9.2.0"),
   StorageBasedTaskLibrary("s3://..."),
   StorageBasedTaskLibrary("dbfs://..."),
   JarTaskLibrary("s3://..."),
   JarTaskLibrary("dbfs://..."),
   EggTaskLibrary("s3://..."),
   EggTaskLibrary("dbfs://..."),
   WheelTaskLibrary("s3://..."),
   WheelTaskLibrary("dbfs://..."),
]

Common task parameters¶

Define the common parameters that can be used in all the tasks. Example could be database name, secrets_id etc

common_task_parameters

common_task_parameters={
        "catalog": "development",
        "database": "your_database"
    }