Thanks for helping us to make KSQL even better!
If you have any questions about how to contribute, either create a GH issue or ask your question in the #ksql channel in our public Confluent Community Slack (account registration is free and self-service).
To build and run KSQL locally, run the following commands:
$ mvn clean package -DskipTests
$ ./bin/ksql-server-start -daemon config/ksql-server.properties
$ ./bin/ksql
This will start the KSQL server in the background and the KSQL CLI in the
foreground. Check the logs
folder for the log files that the server writes
including any errors.
If you would rather have the KSQL server logs spool to the console, then
drop the -daemon
switch, and start the CLI in a second console.
To build and test changes locally, run the following commands:
$ mvn verify
See comments at the top of the docker compose file in the root of the project for instructions on how to build and run docker images.
Report bugs and issues by creating a new GitHub issue. Prior to creating an issue, please search through existing issues so that you are not creating duplicate ones.
Any change to the public API of ksqlDB, especially the SQL syntax, requires a KsqlDB improvement proposal (KLIP) to be raised and approved. See the KLIP Readme for more info.
Code changes are submitted via a pull request (PR). When submitting a PR use the following guidelines:
- Follow the style guide below
- Add/update documentation appropriately for the change you are making. For more information, see the docs readme.
- Non-trivial changes should include unit tests covering the new functionality and potentially function tests.
- All SQL syntax changes and enhancements should come with appropriate function tests.
- Bug fixes should include a unit test or integration test potentially function tests proving the issue is fixed.
- Try to keep pull requests short and submit separate ones for unrelated features.
- Keep formatting changes in separate commits to make code reviews easier and distinguish them from actual code changes.
The project uses GoogleStyle code formatting. You can install this code style into your IDE to make things more automatic:
The project also uses immutable types where ever possible. If adding new type(s), ideally make them immutable.
The project build runs checkstyle and findbugs as part of the build.
You can set up IntelliJ for CheckStyle. First install the CheckStyle IDEA plugin, then:
IntelliJ → Preferences → Tools → CheckStyle
- Add a new configurations file using the '+' button:
Description: Confluent Checks
URL: https://raw.githubusercontent.com/confluentinc/common/master/build-tools/src/main/resources/checkstyle/checkstyle.xml
Ignore invalid certs: true
- (Optional) Make the new configuration active.
- Highlight the newly added 'Confluent Checks' and click the edit button (pencil icon).
- Set properties to match the `checkstyle/checkstyle.properties` file in the repo.
'Confluent Checks' will now be available in the CheckStyle tool window in the IDE and will auto-highlight issues in the code editor.
The project uses [Conventional Commits][https://www.conventionalcommits.org/en/v1.0.0-beta.4/] for commit messages in order to aid in automatic generation of changelogs. As described in the Conventional Commmits specification, commit messages should be of the form:
<type>[optional scope]: <description>
[optional body]
[optional footer]
where the type
is one of
- "fix": for bug fixes
- "feat": for new features
- "refactor": for refactors
- "test": for test-only changes
- "docs": for docs-only changes
- "revert": for reverting other changes
- "perf", "style", "build", "ci", or "chore": as described in the [Angular specification][https://github.com/angular/angular/blob/22b96b9/CONTRIBUTING.md#type] for Conventional Commits.
The (optional) scope is a noun describing the section of the codebase affected by the change. Examples that could make sense for KSQL include "parser", "analyzer", "rest server", "testing tool", "cli", "processing log", and "metrics", to name a few.
The optional body and footer are for specifying additional information, such as linking to issues fixed by the commit or drawing attention to breaking changes.
A commit is a "breaking change" if users should expect different behavior from an existing workflow as a result of the change. Examples of breaking changes include deprecation of existing configs or APIs, changing default behavior of existing configs or query semantics, or the renaming of exposed JMX metrics. Breaking changes must be called out in commit messages, PR descriptions, and upgrade notes:
-
Commit messages for breaking changes must include a line (in the optional body or footer) starting with "BREAKING CHANGE: " followed by an explanation of what the breaking change was. For example,
feat: inherit num partitions and replicas from source topic in CSAS/CTAS BREAKING CHANGE: `CREATE * AS SELECT` queries now create sink topics with partition and replica count equal to those of the source, rather than using values from the properties `ksql.sink.partitions` and `ksql.sink.replicas`. These properties are now deprecated.
-
The breaking change should similarly be called out in the PR description. This description will be copied into the body of the final commit merged into the repo, and picked up by our automatic changelog generation accordingly.
-
[Upgrade notes][https://github.com/confluentinc/ksql/blob/master/docs/installation/upgrading.rst] should also be updated as part of the same PR.
This project has [commitlint][https://github.com/conventional-changelog/commitlint] configured
to ensure that commit messages are of the expected format.
To enable commitlint, simply run npm install
from the root directory of the KSQL repo
(after [installing npm
][https://www.npmjs.com/get-npm].)
Once enabled, commitlint will reject commits with improperly formatted commit messages.
-
Fork the
confluentinc/ksql
repository into your GitHub account: https://github.com/confluentinc/ksql/fork. -
Clone your fork of the GitHub repository, replacing
<username>
with your GitHub username.Use ssh (recommended):
git clone [email protected]:<username>/ksql.git
Or https:
git clone https://github.com/<username>/ksql.git
-
Add a remote to keep up with upstream changes.
git remote add upstream https://github.com/confluentinc/ksql.git
If you already have a copy, fetch upstream changes.
git fetch upstream
-
Create a feature branch to work in.
git checkout -b feature-xxx remotes/upstream/master
-
Work in your feature branch.
git commit -a
-
Periodically rebase your changes
git pull --rebase
-
When done, combine ("squash") related commits into a single one
git rebase -i upstream/master
This will open your editor and allow you to re-order commits and merge them:
- Re-order the lines to change commit order (to the extent possible without creating conflicts)
- Prefix commits using
s
(squash) orf
(fixup) to merge extraneous commits.
-
Submit a pull-request
git push origin feature-xxx
Go to your fork main page
https://github.com/<username>/ksql
If you recently pushed your changes GitHub will automatically pop up a
Compare & pull request
button for any branches you recently pushed to. If you click that button it will automatically offer you to submit your pull-request to theconfluentinc/ksql
repository.- Give your pull-request a meaningful title that conforms to the Conventional Commits specification
as described above for commit messages.
You'll know your title is properly formatted once the
Semantic Pull Request
GitHub check transitions from a status of "pending" to "passed". - In the description, explain your changes and the problem they are solving. Be sure to also call out any breaking changes as described above.
- Give your pull-request a meaningful title that conforms to the Conventional Commits specification
as described above for commit messages.
You'll know your title is properly formatted once the
-
Addressing code review comments
Repeat steps 5. through 7. to address any code review comments and rebase your changes if necessary.
Push your updated changes to update the pull request
git push origin [--force] feature-xxx
--force
may be necessary to overwrite your existing pull request in case your commit history was changed when performing the rebase.Note: Be careful when using
--force
since you may lose data if you are not careful.git push origin --force feature-xxx