To submit a Custom Expectation to Great Expectations for consideration, you complete the following tasks:
To request a documentation change, or a change that doesn't require local testing, see the README in the docs
repository.
To create and submit a custom package to Great Expectations for consideration, see CONTRIBUTING_PACKAGES in the great_expectations
repository.
To submit a code change to Great Expectations for consideration, see CONTRIBUTING_CODE in the great_expectations
repository.
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Great Expectations installed and configured for your environment. See Great Expectations Quickstart.
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A Custom Expectation. See Creating Custom Expectations.
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A GitHub account.
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A working version of Git on your computer. See Getting Started - Installing Git.
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A new SSH (Secure Shell Protocol) key. See Generating a new SSH key and adding it to the ssh-agent.
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The latest Python version installed and configured. See Python downloads.
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Open a browser and go to the Great Expectations repository.
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Click Fork and then Create Fork.
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Click Code and then select the HTTPS or SSH tabs.
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Copy the URL, open a Git terminal, and then run the following command:
git clone <url>
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Run the following command to specify a new remote upstream repository that will be synced with the fork:
git remote add upstream git@github.com:great-expectations/great_expectations.git
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Run the following command to create a branch for your changes:
git checkout -b <branch-name>
Before you submit your Custom Expectation, you need to verify it meets the submission requirements. Great Expectations provides a checklist to help you determine if your Custom Expectation meets the minimum requirements. Your Custom Expectation must meet the first five of the listed requirements to qualify for submission.
To generate the Expectation checklist, add the print_diagnostic_checklist()
instance method to your Custom Expectation. When the instance method runs, it returns results similar to the following:
✔ Has a valid library_metadata object
✔ Has a docstring, including a one-line short description
...
✔ Has at least one positive and negative example case, and all test cases pass
✔ Has core logic and passes tests on at least one Execution Engine
...
✔ Passes all linting checks
✔ Has basic input validation and type checking
✔ Has both statement Renderers: prescriptive and diagnostic
✔ Has core logic that passes tests for all applicable Execution Engines and SQL dialects
...
Has a full suite of tests, as determined by project code standards
Has passed a manual review by a code owner for code standards and style guides
Verifying your Custom Expectation metadata ensures that it is accredited to you and includes an accurate description.
Great Expectations maintains a number of Custom Expectation packages, that contain thematically related Custom Expectations. These packages are located in the Great Expectations contrib directory and on PyPI. If your Custom Expectation fits within one of these packages, you're encouraged to contribute your Custom Expectation directly to one of these packages.
If you're not contributing to a specific package, your Custom Expectation is automatically published in the PyPI great-expectations-experimental package. This package contains all Great Expectations experimental community-contributed Custom Expectations that have not been submitted to other packages.
Confirm the library_metadata
object for your Custom Expectation includes the following information:
contributors
: Identifies the creators of the Custom Expectation.tags
: Identifies the Custom Expectation functionality and domain. For example,statistics
,flexible comparisons
,geography
, and so on.requirements
: Identifies if your Custom Expectation relies on third-party packages.
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Push your changes to the remote fork of your repository.
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Create a pull request from your fork. See Creating a pull request from a fork.
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Add a meaningful title and description for your pull request (PR). Provide a detailed explanation of what you changed and why. To help identify the type of issue you’re submitting, add one of the following identifiers to the pull request (PR) title:
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[BUGFIX] for PRs that address minor bugs without changing behavior.
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[FEATURE] for significant PRs that add a new feature likely to require being added to our feature maturity matrix.
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[MAINTENANCE] for PRs that focus on updating repository settings or related changes.
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[CONTRIB] for the contribution of Custom Expectations and supporting work into the
contrib/
directory. -
[HACKATHON] for submissions to an active Great Expectations Hackathon.
In the section for design review, include a description of any prior discussion or coordination on the features in the PR, such as mentioning the number of the issue where discussion has taken place. For example: Closes #123”, linking to a relevant discuss or slack article, citing a team meeting, or even noting that no discussion is relevant because the issue is small.
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If this is your first Great Expectations contribution, you'll be prompted to complete the Contributor License Agreement (CLA). Complete the CLA and add
@cla-bot check
as a comment to the pull request (PR) to indicate that you’ve completed it. -
Wait for the Continuous Integration (CI) checks to complete and then correct any syntax or formatting issues.
A Great Expectations team member reviews, approves, and merges your PR. Depending on your GitHub notification settings, you'll be notified when there are comments or when your changes are successfully merged.
If your Custom Expectation doesn't meet the minimum requirements in the validation checklist, it is failing testing, or there is a functionality error, you'll be asked to resolve the issues before your Custom Expectation can move forward.
If you are submitting a production Custom Expectation, Great Expectations requires that your Custom Expectation meet or exceed Great Expectation standards for testing and coding.
When your Custom Expectation has successfully passed testing and received approval from a code owner, your contribution is complete. Your custom Expectation will be included in the next release of Great Expectations and an announcement will appear in the release notes
Great Expectations uses a stalebot
to automatically tag issues without activity as stale
, and closes them when a response is not received within a week. To prevent stalebot
from closing an issue, you can add the stalebot-exempt
tag.
Additionally, Great Expectations adds the following tags to indicate issue status:
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The
help wanted
tag identifies useful issues that require help from community contributors to accelerate development. -
The
enhacement
andexpectation-request
tags identify new Great Expectations features that require additional investigation and discussion. -
The
good first issue
tag identifies issues that provide an introduction to the Great Expectations contribution process.