docs: contribution guide

Contribution guide for samba-operator project, which should allow any
user to provide valid patches for this code base. Defines the minimal
requirements for a pull-request to be classified as valid.

Signed-off-by: Shachar Sharon <[email protected]>

Author: synarete

docs/CONTRIBUTING.md

@@ -0,0 +1,174 @@
+# Contribution Guide
+
+1. [Prerequisites](#prerequisites)
+2. [Build](#build)
+3. [Check](#check)
+4. [Testing](#testing)
+5. [Pull-request](#pull-request)
+6. [License](#license)
+
+Thank you for your time and effort to help us improve samba-operator.
+Here are a few steps to get started, with reference to some useful
+resources.
+
+
+## Prerequisites
+
+Development effort takes place using Linux environment and requires at
+minimum:
+
+1. [Go 1.18](https://golang.org/dl/) installed
+2. [GitHub](https://github.com/) account
+3. Development tools: git, make, and podman or docker
+4. Testing: [minikube](https://minikube.sigs.k8s.io)
+5. [Quay](https://quay.io/) account (optional)
+
+Development collaboration takes place via github's samba-in-kubernetes
+([SINK](https://github.com/samba-in-kubernetes/)) pages and facilities.
+
+The top-level [Makefile](../Makefile) is the entry point for various
+build commands. Few utilities are required during the build process,
+either for bootstrapping the project, building it or checking the
+validity of the source code itself. If not present in your `$PATH`,
+those tools may be installed locally to the project (under the
+local `.bin` directory) using:
+
+```sh
+  $ make build-tools
+  ...
+  $ ls .bin/
+```
+
+## Build
+
+The following section describes how to build and test samba-operator.
+A more detailed description of this process may be found in the
+[developer-notes](./developer-notes.md) document.
+
+Building the samba-operator is a straightforward action with
+`make build`. Upon successful build, the output binary is written to
+`bin/manager`:
+
+```sh
+  $ make build
+  ...
+  $ ls bin/
+  manager
+```
+
+Note that the manager binary alone is not typically executed in a
+Kubernetes cluster. For that we generally build a container image. To
+build an OCI container image including the manager binary, run:
+
+```sh
+  $ make image-build
+```
+
+The name of this image is controlled by the `IMG` and `TAG` variables
+and may be customized to fit your needs. A developer may override those
+as well as some other default Makefile settings via the `devel.mk` file
+at the project's root directory:
+
+```sh
+  $ cp devel.mk.sample devel.mk
+  $ vim devel.mk
+```
+
+## Check
+
+Before submitting any pull request, a developer must ensure that
+his code satisfies the following minimum requirements:
+
+1. Go code conforms to the project's standards.
+2. YAML files conform to the project's standards.
+3. Unit-tests pass without errors.
+
+Use the following commands to check and test your code:
+
+```sh
+  $ make check
+  $ make test
+```
+
+If any of those make rules fail they should first be fixed before any
+other developer will review your patches. Please note that those steps
+are integrated into the project's CI workflow, and therefore must pass
+successfully.
+
+## Testing
+
+Ideally, before submitting any pull request, a developer should test
+any code changes locally. Local clusters are simpler to debug and, if
+one has not had code merged to the project before, it does not require
+approval from the project maintainers. A prerequisite to running the
+samba-operator test suite is a running Kubernetes cluster. Typically
+this will be [minikube](https://minikube.sigs.k8s.io) but other
+Kubernetes implementations can suffice.
+
+An example using minikube with a private container image follows:
+
+```sh
+  $ export IMG=quay.io/my-quay-username/samba-operator:latest
+  $ echo IMG=${IMG} >> devel.mk
+  $ make image-build
+  $ make container-push
+  ...
+  $ minikube start \
+      --driver=kvm2 \
+      --bootstrapper kubeadm \
+      --disk-size 32g \
+      --memory 8192 \
+      --cpus 2 \
+      --insecure-registry "10.0.0.0/24" \
+      --nodes=3 -\
+      --extra-disks=2 \
+      --feature-gates=EphemeralContainers=true
+  ...
+  $ # Ensure cluster has basic functionality:
+  $ kubectl get nodes
+  $ kubectl get pods -A
+  ...
+  $ # Deploy your image:
+  $ make deploy
+  $ kubectl get pods -n samba-operator-system
+  ...
+  $ # Start an AD DC inside k8s to support domain logins in test suite
+  $ ./tests/test-deploy-ad-server.sh
+  $ # Run the test-suite
+  $ ./tests/test.sh
+  ...
+  $ # in case of failure:
+  $ ./tests/post-test-info.sh
+  ...
+  $ make undeploy
+```
+
+## Pull-request
+Finally, you may submit your changes via samba-operator github
+[pull-request](https://github.com/samba-in-kubernetes/samba-operator/pulls).
+Before submitting a pull request, make sure that you provided a valid
+git commit message, which allows other developers to easily review your
+code. In particular, ensure that each git commit include the
+followings:
+
+1. A short topic line (up to 72 characters) with the name of the
+sub-component this commit refers to.
+
+2. A commit-message body which explain why and how this change is
+needed, in a clear and informative manner.
+
+3. The author details, including a valid e-mail address and a
+*Signed-off-by* entry.
+
+Validate your commits with [gitlint](https://jorisroovers.com/gitlint/).
+Even better, you may use the following make rule:
+```sh
+  $ make check-gitlint
+```
+
+## License
+
+Samba-operator is an open-source project, developed under the
+[Apache-2.0](https://www.apache.org/licenses/LICENSE-2.0) license. We
+appreciate any contribution which helps us improve this code base.
+