Contributions Welcome!

We welcome contributions to Hyperledger in many forms, and there’s always plenty to do!

First things first, please review the Hyperledger Code of Conduct before participating. It is important that we keep things civil.

Install prerequisites

Before we begin, if you haven’t already done so, you may wish to check that you have all the prerequisites installed on the platform(s) on which you’ll be developing blockchain applications and/or operating Hyperledger Fabric.

Getting a Linux Foundation account

In order to participate in the development of the Hyperledger Fabric project, you will need a Linux Foundation account. You will need to use your LF ID to access to all the Hyperledger community development tools, including Gerrit, Jira and the Wiki (for editing, only).

Setting up your SSH key

For Gerrit, before you can submit any change set for review, you will need to register your public SSH key. Login to Gerrit with your LFID, and click on your name in the upper right-hand corner of your browser window and then click ‘Settings’. In the left-hand margin, you should see a link for ‘SSH Public Keys’. Copy-n-paste your public SSH key into the window and press ‘Add’.

Getting help

If you are looking for something to work on, or need some expert assistance in debugging a problem or working out a fix to an issue, our community is always eager to help. We hang out on Chat, IRC (#hyperledger on freenode.net) and the mailing lists. Most of us don’t bite :grin: and will be glad to help. The only silly question is the one you don’t ask. Questions are in fact a great way to help improve the project as they highlight where our documentation could be clearer.

Requirements and Use Cases

We have a Requirements WG that is documenting use cases and from those use cases deriving requirements. If you are interested in contributing to this effort, please feel free to join the discussion in chat.

Reporting bugs

If you are a user and you find a bug, please submit an issue using JIRA. Please try to provide sufficient information for someone else to reproduce the issue. One of the project’s maintainers should respond to your issue within 24 hours. If not, please bump the issue with a comment and request that it be reviewed. You can also post to the #fabric-maintainers channel in chat.

Fixing issues and working stories

Review the issues list and find something that interests you. You could also check the “help-wanted” list. It is wise to start with something relatively straight forward and achievable, and that no one is already assigned. If no one is assigned, then assign the issue to yourself. Please be considerate and rescind the assignment if you cannot finish in a reasonable time, or add a comment saying that you are still actively working the issue if you need a little more time.

Making Feature/Enhancement Proposals

Review JIRA. to be sure that there isn’t already an open (or recently closed) proposal for the same function. If there isn’t, to make a proposal we recommend that you open a JIRA Epic, Story or Improvement, whichever seems to best fit the circumstance and link or inline a “one pager” of the proposal that states what the feature would do and, if possible, how it might be implemented. It would help also to make a case for why the feature should be added, such as identifying specific use case(s) for which the feature is needed and a case for what the benefit would be should the feature be implemented. Once the JIRA issue is created, and the “one pager” either attached, inlined in the description field, or a link to a publicly accessible document is added to the description, send an introductory email to the hyperledger-fabric@lists.hyperledger.org mailing list linking the JIRA issue, and soliciting feedback.

Discussion of the proposed feature should be conducted in the JIRA issue itself, so that we have a consistent pattern within our community as to where to find design discussion.

Getting the support of three or more of the Hyperledger Fabric maintainers for the new feature will greatly enhance the probability that the feature’s related CRs will be merged.

Working with a local clone and Gerrit

We are using Gerrit to manage code contributions. If you are unfamiliar, please review this document before proceeding.

After you have familiarized yourself with Gerrit, and maybe played around with the lf-sandbox project, you should be ready to set up your local development environment.

Next, try building the project in your local development environment to ensure that everything is set up correctly.

The Logging Control document describes how to tweak the logging levels of various components within Hyperledger Fabric. Finally, every source file needs to include a license header: modified to include a copyright statement for the principle author(s).

What makes a good change request?

  • One change at a time. Not five, not three, not ten. One and only one. Why? Because it limits the blast area of the change. If we have a regression, it is much easier to identify the culprit commit than if we have some composite change that impacts more of the code.

  • Include a link to the JIRA story for the change. Why? Because a) we want to track our velocity to better judge what we think we can deliver and when and b) because we can justify the change more effectively. In many cases, there should be some discussion around a proposed change and we want to link back to that from the change itself.

  • Include unit and integration tests (or changes to existing tests) with every change. This does not mean just happy path testing, either. It also means negative testing of any defensive code that it correctly catches input errors. When you write code, you are responsible to test it and provide the tests that demonstrate that your change does what it claims. Why? Because without this we have no clue whether our current code base actually works.

  • Unit tests should have NO external dependencies. You should be able to run unit tests in place with go test or equivalent for the language. Any test that requires some external dependency (e.g. needs to be scripted to run another component) needs appropriate mocking. Anything else is not unit testing, it is integration testing by definition. Why? Because many open source developers do Test Driven Development. They place a watch on the directory that invokes the tests automagically as the code is changed. This is far more efficient than having to run a whole build between code changes. See this definition of unit testing for a good set of criteria to keep in mind for writing effective unit tests.

  • Minimize the lines of code per CR. Why? Maintainers have day jobs, too. If you send a 1,000 or 2,000 LOC change, how long do you think it takes to review all of that code? Keep your changes to < 200-300 LOC, if possible. If you have a larger change, decompose it into multiple independent changess. If you are adding a bunch of new functions to fulfill the requirements of a new capability, add them separately with their tests, and then write the code that uses them to deliver the capability. Of course, there are always exceptions. If you add a small change and then add 300 LOC of tests, you will be forgiven;-) If you need to make a change that has broad impact or a bunch of generated code (protobufs, etc.). Again, there can be exceptions.

    Note: large change requests, e.g. those with more than 300 LOC are more likely than not going to receive a -2, and you’ll be asked to refactor the change to conform with this guidance.

  • Do not stack change requests (e.g. submit a CR from the same local branch as your previous CR) unless they are related. This will minimize merge conflicts and allow changes to be merged more quickly. If you stack requests your subsequent requests may be held up because of review comments in the preceding requests.

  • Write a meaningful commit message. Include a meaningful 50 (or less) character title, followed by a blank line, followed by a more comprehensive description of the change. Each change MUST include the JIRA identifier corresponding to the change (e.g. [FAB-1234]). This can be in the title but should also be in the body of the commit message.

    Note that Gerrit will automatically create a hyperlink to the JIRA item.

e.g.

[FAB-1234] fix foobar() panic

Fix [FAB-1234] added a check to ensure that when foobar(foo string) is called,
that there is a non-empty string argument.

Finally, be responsive. Don’t let a change request fester with review comments such that it gets to a point that it requires a rebase. It only further delays getting it merged and adds more work for you - to remediate the merge conflicts.

Communication

We use RocketChat for communication and Google Hangouts™ for screen sharing between developers. Our development planning and prioritization is done in JIRA, and we take longer running discussions/decisions to the mailing list.

Maintainers

The project’s maintainers are responsible for reviewing and merging all patches submitted for review and they guide the over-all technical direction of the project within the guidelines established by the Hyperledger Technical Steering Committee (TSC).

Becoming a maintainer

This project is managed under an open governance model as described in our charter. Projects or sub-projects will be lead by a set of maintainers. New sub-projects can designate an initial set of maintainers that will be approved by the top-level project’s existing maintainers when the project is first approved. The project’s maintainers will, from time-to-time, consider adding or removing a maintainer. An existing maintainer can submit a change set to the MAINTAINERS.rst file. A nominated Contributor may become a Maintainer by a majority approval of the proposal by the existing Maintainers. Once approved, the change set is then merged and the individual is added to (or alternatively, removed from) the maintainers group. Maintainers may be removed by explicit resignation, or for some infraction of the code of conduct or by consistently demonstrating poor judgement.