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.
Ways to contribute¶
There are many ways you can contribute to Hyperledger Fabric, both as a user and as a developer.
As a user:
As a developer:
If you can commit to full-time development, either propose a new feature (see Making Feature/Enhancement Proposals) and bring a team to implement it, or join one of the teams working on an existing Epic. If you see an Epic that interests you on the release roadmap, contact the Epic assignee via the Jira work item or on RocketChat.
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 tools, including Gerrit, Jira, RocketChat, and the Wiki (for editing, only).
Hyperledger Fabric is managed under an open governance model as described in our charter. Projects and sub-projects are 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 Fabric project is lead by the project’s top level maintainers. The maintainers are responsible for reviewing and merging all patches submitted for review, and they guide the overall technical direction of the project within the guidelines established by the Hyperledger Technical Steering Committee (TSC).
Becoming a maintainer¶
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, for prolonged inactivity (3 or more months), or for some infraction of the code of conduct or by consistently demonstrating poor judgement. A maintainer removed for inactivity should be restored following a sustained resumption of contributions and reviews (a month or more) demonstrating a renewed commitment to the project.
The Fabric maintainers have settled on a quarterly (approximately) release cadence (see releases). We are also actively considering adopting an LTS (long term support) release process, though the details of this are still being worked out by the maintainers. Follow the discussion on the #fabric-maintainers channel in Chat.
Making Feature/Enhancement Proposals¶
First, take time to 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 or Story, 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 email@example.com 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 included in a subsequent release.
The purpose of the maintainers meeting is to plan for and review the progress of releases, and to discuss the technical and operational direction of the project and sub-projects.
New feature/enhancement proposals as described above should be presented to a maintainers meeting for consideration, feedback and acceptance.
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.
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.
If you are a user and you have found a bug, please submit an issue using JIRA. Before you create a new JIRA issue, please try to search the existing items to be sure no one else has previously reported it. If it has been previously reported, then you might add a comment that you also are interested in seeing the defect fixed.
If the defect is security-related, please follow the Hyperledger security bug reporting process.
If it has not been previously reported, create a new 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 relevant Hyperledger Fabric channel in
Hyperledger Chat. For example, a doc bug should
be broadcast to
#fabric-documentation, a database bug to
and so on…
Submitting your fix¶
If you just submitted a JIRA for a bug you’ve discovered, and would like to provide a fix, we would welcome that gladly! Please assign the JIRA issue to yourself, then you can submit a change request (CR).
If you need help with submitting your first CR, we have created a brief tutorial for you.
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.
Reviewing submitted Change Requests (CRs)¶
Another way to contribute and learn about Hyperledger Fabric is to help the maintainers with the review of the CRs that are open. Indeed maintainers have the difficult role of having to review all the CRs that are being submitted and evaluate whether they should be merged or not. You can review the code and/or documentation changes, test the changes, and tell the submitters and maintainers what you think. Once your review and/or test is complete just reply to the CR with your findings, by adding comments and/or voting. A comment saying something like “I tried it on system X and it works” or possibly “I got an error on system X: xxx ” will help the maintainers in their evaluation. As a result, maintainers will be able to process CRs faster and everybody will gain from it.
Just browse through the open CRs on Gerrit to get started.
As the Fabric project has grown, so too has the backlog of open CRs. One problem that nearly all projects face is effectively managing that backlog and Fabric is no exception. In an effort to keep the backlog of Fabric and related project CRs manageable, we are introducing an aging policy which will be enforced by bots. This is consistent with how other large projects manage their CR backlog.
CR Aging Policy¶
The Fabric project maintainers will automatically monitor all CR activity for delinquency. If a CR has not been updated in 2 weeks, a reminder comment will be added requesting that the CR either be updated to address any outstanding comments or abandoned if it is to be withdrawn. If a delinquent CR goes another 2 weeks without an update, it will be automatically abandoned. If a CR has aged more than 2 months since it was originally submitted, even if it has activity, it will be flagged for maintainer review.
If a submitted CR has passed all validation but has not been reviewed in 72 hours (3 days), it will be flagged to the #fabric-pr-review channel daily until it receives a review comment(s).
This policy applies to all official Fabric projects (fabric, fabric-ca, fabric-samples, fabric-test, fabric-sdk-node, fabric-sdk-java, fabric-chaincode-node, fabric-chaincode-java, fabric-chaincode-evm, fabric-baseimage, and fabric-amcl).
Setting up development environment¶
Next, try building the project in your local development environment to ensure that everything is set up correctly.
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 testor 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 changes. 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.
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 55 (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. See the complete requirements for an acceptable change request.
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.
Note: Each source file must include a license header for the Apache Software License 2.0. See the template of the license header.
We have tried to make it as easy as possible to make contributions. This applies to how we handle the legal aspects of contribution. We use the same approach—the Developer’s Certificate of Origin 1.1 (DCO)—that the Linux® Kernel community uses to manage code contributions.
We simply ask that when submitting a patch for review, the developer must include a sign-off statement in the commit message.
Here is an example Signed-off-by line, which indicates that the submitter accepts the DCO:
Signed-off-by: John Doe <firstname.lastname@example.org>
You can include this automatically when you commit a change to your
local git repository using
git commit -s.