Appendices - Developing Operators | Operators | OpenShift Container Platform 4.5

Operator project scaffolding layout
- Go-based projects
- helm-based projects

Operator project scaffolding layout

The operator-sdk CLI generates a number of packages for each Operator project. The following sections describes a basic rundown of each generated file and directory.

Go-based projects

Go-based Operator projects (the default type) generated using the operator-sdk new command contain the following directories and files:

File/folders Purpose

File/folders	Purpose
`cmd/`	Contains `manager/main.go` file, which is the main program of the Operator. This instantiates a new manager which registers all custom resource defintitions (CRDs) under `pkg/apis/` and starts all controllers under `pkg/controllers/`.
`pkg/apis/`	Contains the directory tree that defines the APIs of the CRDs. Users are expected to edit the `pkg/apis/<group>/<version>/<kind>_types.go` files to define the API for each resource type and import these packages in their controllers to watch for these resource types.
`pkg/controller`	This `pkg` contains the controller implementations. Users are expected to edit the `pkg/controller/<kind>/<kind>_controller.go` files to define the reconcile logic of the controller for handling a resource type of the specified kind.
`build/`	Contains the Dockerfile and build scripts used to build the Operator.
`deploy/`	Contains various YAML manifests for registering CRDs, setting up RBAC, and deploying the Operator as a deployment.
`Gopkg.toml` `Gopkg.lock`	The Go Dep manifests that describe the external dependencies of this Operator.
`vendor/`	The Golang vendor folder that contains the local copies of the external dependencies that satisfy the imports of this project. Go Dep manages the vendor directly.

cmd/

Contains manager/main.go file, which is the main program of the Operator. This instantiates a new manager which registers all custom resource defintitions (CRDs) under pkg/apis/ and starts all controllers under pkg/controllers/.

pkg/apis/

Contains the directory tree that defines the APIs of the CRDs. Users are expected to edit the pkg/apis/<group>/<version>/<kind>_types.go files to define the API for each resource type and import these packages in their controllers to watch for these resource types.

pkg/controller

This pkg contains the controller implementations. Users are expected to edit the pkg/controller/<kind>/<kind>_controller.go files to define the reconcile logic of the controller for handling a resource type of the specified kind.

build/

Contains the Dockerfile and build scripts used to build the Operator.

deploy/

Contains various YAML manifests for registering CRDs, setting up RBAC, and deploying the Operator as a deployment.

Gopkg.toml
Gopkg.lock

The Go Dep manifests that describe the external dependencies of this Operator.

vendor/

The Golang vendor folder that contains the local copies of the external dependencies that satisfy the imports of this project. Go Dep manages the vendor directly.

helm-based projects

helm-based Operator projects generated using the operator-sdk new --type helm command contain the following directories and files:

File/folders Purpose

File/folders	Purpose
`deploy/`	Contains various YAML manifests for registering CRDs, setting up RBAC, and deploying the Operator as a Deployment.
`helm-charts/<kind>`	Contains a helm chart initialized using the equivalent of the `helm create` command.
`build/`	Contains the Dockerfile and build scripts used to build the Operator.
`watches.yaml`	Contains group/version/kind (GVK) and helm chart location.

deploy/

Contains various YAML manifests for registering CRDs, setting up RBAC, and deploying the Operator as a Deployment.

helm-charts/<kind>

Contains a helm chart initialized using the equivalent of the helm create command.

build/

Contains the Dockerfile and build scripts used to build the Operator.

watches.yaml

Contains group/version/kind (GVK) and helm chart location.