consul/.github/CONTRIBUTING.md

# Contributing to Consul
>**Note:** We take Consul's security and our users' trust very seriously.
>If you believe you have found a security issue in Consul, please responsibly
>disclose by contacting us at security@hashicorp.com.

**First:** if you're unsure or afraid of _anything_, just ask or submit the
issue or pull request anyways. You won't be yelled at for giving your best
effort. The worst that can happen is that you'll be politely asked to change
something. We appreciate any sort of contributions, and don't want a wall of
rules to get in the way of that.

That said, if you want to ensure that a pull request is likely to be merged, 
talk to us! A great way to do this is in issues themselves. When you want to 
work on an issue, comment on it first and tell us the approach you want to take.

## Getting Started
### Some Ways to Contribute
* Report potential bugs.
* Suggest product enhancements.
* Increase our test coverage.
* Fix a [bug](https://github.com/hashicorp/consul/labels/type/bug).
* Implement a requested [enhancement](https://github.com/hashicorp/consul/labels/type/enhancement).
* Improve our guides and documentation. Consul's [Guides](https://www.consul.io/docs/guides/index.html), [Docs](https://www.consul.io/docs/index.html), and [api godoc](https://godoc.org/github.com/hashicorp/consul/api)
are deployed from this repo.
* Respond to questions about usage on the issue tracker or the Consul section of the [HashiCorp forum]: (https://discuss.hashicorp.com/c/consul)

### Reporting an Issue:
>Note: Issues on GitHub for Consul are intended to be related to bugs or feature requests. 
>Questions should be directed to other community resources such as the: [Mailing List](https://groups.google.com/group/consul-tool/), [FAQ](https://www.consul.io/docs/faq.html), or [Guides](https://www.consul.io/docs/guides/index.html).

* Make sure you test against the latest released version. It is possible we 
already fixed the bug you're experiencing. However, if you are on an older 
version of Consul and feel the issue is critical, do let us know.

* Check existing issues (both open and closed) to make sure it has not been 
reported previously.

* Provide a reproducible test case. If a contributor can't reproduce an issue, 
then it dramatically lowers the chances it'll get fixed.

* Aim to respond promptly to any questions made by the Consul team on your 
issue. Stale issues will be closed.

### Issue Lifecycle

1. The issue is reported.

2. The issue is verified and categorized by a Consul maintainer.
   Categorization is done via tags. For example, bugs are tagged as "bug".

3. Unless it is critical, the issue is left for a period of time (sometimes many
   weeks), giving outside contributors a chance to address the issue.

4. The issue is addressed in a pull request or commit. The issue will be
   referenced in the commit message so that the code that fixes it is clearly
   linked.

5. The issue is closed.

## Building Consul

If you wish to work on Consul itself, you'll first need [Go](https://golang.org)
installed (The version of Go should match the one of our [CI config's](https://github.com/hashicorp/consul/blob/main/.circleci/config.yml) Go image).


Next, clone this repository and then run `make dev`. In a few moments, you'll have a working
`consul` executable in `consul/bin` and `$GOPATH/bin`:

>Note: `make dev` will build for your local machine's os/architecture. If you wish to build for all os/architecture combinations use `make`.

## Making Changes to Consul

The first step to making changes is to fork Consul. Afterwards, the easiest way 
to work on the fork is to set it as a remote of the Consul project:

1. Navigate to `$GOPATH/src/github.com/hashicorp/consul`
2. Rename the existing remote's name: `git remote rename origin upstream`.
3. Add your fork as a remote by running
   `git remote add origin <github url of fork>`. For example:
   `git remote add origin https://github.com/myusername/consul`.
4. Checkout a feature branch: `git checkout -t -b new-feature`
5. Make changes
6. Push changes to the fork when ready to submit PR:
   `git push -u origin new-feature`

By following these steps you can push to your fork to create a PR, but the code on disk still
lives in the spot where the go cli tools are expecting to find it.

>Note: If you make any changes to the code, run `make format` to automatically format the code according to Go standards.

## Testing

Before submitting changes, run **all** tests locally by typing `make test`. 
The test suite may fail if over-parallelized, so if you are seeing stochastic 
failures try `GOTEST_FLAGS="-p 2 -parallel 2" make test`. 

Certain testing patterns such as creating a test `Client` in the `api` pkg 
or a `TestAgent` followed by a session can lead to flaky tests. More generally, 
any tests with components that rely on readiness of other components are often
flaky. 

Our makefile has some tooling built in to help validate the stability of single 
or package-wide tests. By running the `test-flake` goal we spin up a local docker 
container that mirrors a CPU constrained version of our CI environment. Here we can 
surface uncommon failures that are typically hard to reproduce by re-running 
tests multiple times. 

The makefile goal accepts the following variables as arguments:

* **FLAKE_PKG** Target package (required)

* **FLAKE_TEST** Target test

* **FLAKE_CPUS** Amount of CPU resources for container

* **FLAKE_N** Number of times to run tests

Examples:
`make test-flake FLAKE_PKG=connect/proxy`
`make test-flake FLAKE_PKG=connect/proxy FLAKE_TEST=TestUpstreamListener`
`make test-flake FLAKE_PKG=connect/proxy FLAKE_TEST=TestUpstreamListener FLAKE_CPUS=0.15 FLAKE_N=30`

The underlying script dumps the full Consul log output to `test.log` in 
the directory of the target package. In the example above it would be 
located at `consul/connect/proxy/test.log`. 

Historically, the defaults for `FLAKE_CPUS` (0.15) and `FLAKE_N` (30) have been
sufficient to surface a flaky test. If a test is run in this environment and 
it does not fail after 30 iterations, it should be sufficiently stable.

## Vendoring

Consul currently uses Go Modules for vendoring.

Please only apply the minimal vendor changes to get your PR to work. 
Consul does not attempt to track the latest version for each dependency.

## Checklists

Some common changes that many PRs require such as adding config fields, are
documented through checklists.

Please check in `contributing/` for any `checklist-*.md` files that might help
with your change.