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Databolt Flow

For data scientists and data engineers, d6tflow is a python library which makes building complex data science workflows easy, fast and intuitive. It is built on top of workflow manager luigi but unlike luigi it is optimized for data science workflows.

Why use d6tflow?

Data science workflows typically look like this.

Sample Data Workflow

The workflow involves chaining together parameterized tasks which pass multiple inputs and outputs between each other. The output data gets stored in multiple dataframes, files and databases but you have to manually keep track of where everything is. And often you want to rerun tasks with different parameters without inadvertently rerunning long-running tasks. The workflows get complex and your code gets messy, difficult to audit and doesn't scale well.

d6tflow to the rescue! With d6tflow you can easily chain together complex data flows and execute them. You can quickly load input and output data for each task. It makes your workflow very clear and intuitive.

When to use d6tflow?

  • Data engineering: when you prepare and analyze data with pandas or dask. That is you load, filter, transform, join data
  • Data science: when you analyze data with ANY ML library including sklearn, pytorch, keras. That is you perform EDA, feature engineering, model training and evaluation

Read more at:

4 Reasons Why Your Machine Learning Code is Probably Bad
How d6tflow is different from airflow/luigi

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What can d6tflow do for you?

  • Data engineering
    • Build a data workflow made up of tasks with dependencies and parameters
    • Check task dependencies and their execution status
    • Execute tasks including dependencies
    • Intelligently continue workflows after failed tasks
    • Intelligently rerun workflow after changing parameters, code or data
    • Intelligently manage parameters between dependencies
    • Save task output to Parquet, CSV, JSON, pickle and in-memory
    • Load task output to pandas dataframe and python objects
    • Quickly share and hand off output data to others
  • Data science
    • Scalable workflows: build an efficient data workflow made up of tasks with dependencies and parameters
    • Experiment tracking: compare model performance with different preprocessing and model selection options
    • Model deployment: d6tflow workflows are easier to deploy to production


Install with pip install d6tflow. To update, run pip install d6tflow -U --no-deps.

You can also clone the repo and run pip install .

Python3 only You might need to call pip3 install d6tflow if you have not set python 3 as default.

To install latest DEV pip install git+git:// or upgrade pip install git+git:// -U --no-deps

Example: Introduction

This is a minial example. Be sure to check out the ML workflow example below.

import d6tflow
import pandas as pd

# define 2 tasks that load raw data
class Task1(d6tflow.tasks.TaskPqPandas):
    def run(self):
        df = pd.DataFrame({'a':range(3)}) # quickly save dataframe

class Task2(Task1):

# define another task that depends on data from task1 and task2
class Task3(d6tflow.tasks.TaskPqPandas):
    multiplier = d6tflow.IntParameter(default=2)
    def run(self):
        df1 = self.input()['upstream1'].load() # quickly load input data
        df2 = self.input()['upstream2'].load() # quickly load input data
        df = df1.join(df2, lsuffix='1', rsuffix='2')
        df['b']=df['a1']*self.multiplier # use task parameter

# Execute task including all its dependencies
* 3 ran successfully:
    - 1 Task1()
    - 1 Task2()
    - 1 Task3(multiplier=2)

# quickly load output data. Task1().outputLoad() also works
   a1  a2  b
0   0   0  0
1   1   1  2
2   2   2  4

# Intelligently rerun workflow after changing parameters
└─--[Task3-{'multiplier': '3'} (PENDING)] => this changed and needs to run
   |--[Task1-{} (COMPLETE)] => this doesn't change and doesn't need to rerun
   └─--[Task2-{} (COMPLETE)] => this doesn't change and doesn't need to rerun

Example: Comparing model performance in ML Workflow

Below is sample output for a machine learning workflow. The goal is to efficiently compare the performance of two ML models.

See the full example here
Interactive mybinder jupyter notebook example


Library usage and reference

Real-life project template

Transition to d6tflow from typical scripts 5 Step Guide to Scalable Deep Learning Pipelines with d6tflow

d6tpipe Integration

To quickly share workflow outputs, we recommend you make use of d6tpipe. See Sharing Workflows and Outputs.

Pro version

Additional features:

  • Integrations for enterprise and cloud storage (SQL, S3)
  • Integrations for distributed copmute (dask, pyspark)
  • Automatically detect data changes
  • Advanced machine learning features

Request demo

Accelerate Data Science

Check out other d6t libraries, including

  • push/pull data: quickly get and share data files like code
  • import data: quickly ingest messy raw CSV and XLS files to pandas, SQL and more
  • join data: quickly combine multiple datasets using fuzzy joins

Get notified

d6tflow is in active development. Join the databolt blog for the latest announcements and tips+tricks.

Collecting Errors Messages and Usage statistics

We have put a lot of effort into making this library useful to you. To help us make this library even better, it collects ANONYMOUS error messages and usage statistics. See d6tcollect for details including how to disable collection. Collection is asynchronous and doesn't impact your code in any way.

It may not catch all errors so if you run into any problems or have any questions, please raise an issue on github.

How To Contribute

Thank you for considering to contribute to the project. First, fork the code repository and then pick an issue that is open. Afterwards follow these steps

  • Create a branch called [issue_no]_yyyymmdd_[feature]
  • Implement the feature
  • Write unit tests for the desired behaviour
  • Create a pull request to merge branch with master

A similar workflow applies to bug-fixes as well. In the case of a fix, just change the feature name with the bug-fix name. And make sure the code passes already written unit tests.


Python library for building highly effective data science workflows




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