refactor: add linter and various fixes

.github/workflows/lint.yml

@@ -0,0 +1,98 @@
+name: Linting
+on:
+  pull_request:
+
+jobs:
+  golangci:
+    name: Lint golang files
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+          repository: ${{github.event.pull_request.head.repo.full_name}}
+          persist-credentials: false
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.23'
+          cache: false
+
+      - name: golangci-lint
+        uses: golangci/[email protected]
+        with:
+          only-new-issues: true
+          version: v1.62.2
+          args: --timeout=900s
+
+  gomodtidy:
+    name: Enforce go.mod tidiness
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+      with:
+        ref: "${{ github.event.pull_request.head.sha }}"
+        repository: ${{github.event.pull_request.head.repo.full_name}}
+        persist-credentials: false
+
+    - name: Setup Go
+      uses: actions/setup-go@v5
+      with:
+        go-version: '1.23'
+
+    - name: Execute go mod tidy and check the outcome
+      working-directory: ./
+      run: |
+        go mod tidy
+        exit_code=$(git diff --exit-code)
+        exit ${exit_code}
+
+    - name: Issue a comment in case the of failure
+      uses: peter-evans/create-or-update-comment@v4
+      with:
+        token: ${{ secrets.GITHUB_TOKEN }}
+        issue-number: ${{ github.event.pull_request.number }}
+        body: |
+          The `go.mod` and/or `go.sum` files appear not to be correctly tidied.
+
+          Please, rerun `go mod tidy` to fix the issues.
+        reactions: confused
+      if: |
+        failure() && github.event.pull_request.head.repo.full_name == github.repository
+
+  shelllint:
+    name: Lint bash files
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+      with:
+        ref: "${{ github.event.pull_request.head.sha }}"
+        repository: ${{github.event.pull_request.head.repo.full_name}}
+        persist-credentials: false
+    - name: Run Shellcheck
+      uses: ludeeus/[email protected]
+      env:
+        # Allow 'source' outside of FILES
+        SHELLCHECK_OPTS: -x
+
+  markdownlint:
+    name: Lint markdown files
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check out code
+      uses: actions/checkout@v4
+      with:
+        ref: "${{ github.event.pull_request.head.sha }}"
+        repository: ${{github.event.pull_request.head.repo.full_name}}
+        persist-credentials: false
+    - name: Lint markdown files
+      uses: avto-dev/markdown-lint@v1
+      with:
+        config: '.markdownlint.yml'
+        args: '**/*.md'
+        ignore: .github/ISSUE_TEMPLATE/*.md

.golangci.yml

@@ -0,0 +1,140 @@
+run:
+  timeout: 10m
+
+linters-settings:
+  exhaustive:
+    check-generated: false
+    default-signifies-exhaustive: true
+
+  lll:
+    line-length: 150
+  gomodguard:
+    blocked:
+      modules:
+        - github.com/go-logr/logr:
+            recommendations:
+              - k8s.io/klog/v2
+  gci:
+    sections:
+    - standard                          # Captures all standard packages if they do not match another section.
+    - default                           # Contains all imports that could not be matched to another section type.
+    - prefix(github.com/liqotech/resource-slice-class-controller-template)  # Groups all imports with the specified Prefix.
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      # Conflicts with govet check-shadowing
+      - sloppyReassign
+  goimports:
+    local-prefixes: github.com/liqotech/resource-slice-class-controller-template
+  govet:
+    enable:
+      - shadow
+      - nilness
+      - nilfunc
+  misspell:
+    locale: US
+  nolintlint:
+    allow-unused: false # report any unused nolint directives
+    require-explanation: true # require an explanation for nolint directives
+    require-specific: true # require nolint directives to be specific about which linter is being skipped
+  dupl:
+    threshold: 300
+
+linters:
+  disable-all: true
+  enable:
+    - asciicheck
+    - bodyclose
+    - copyloopvar
+  # - depguard
+    - dogsled
+    - dupl
+    - errcheck
+    - errorlint
+    - exhaustive
+  # - funlen
+  # - gochecknoglobals
+  # - gochecknoinits
+  # - gocognit
+    - gci
+    - goconst
+    - gocritic
+    - gocyclo
+    - godot
+  # - godox
+  # - goerr113
+    - gofmt
+    - goheader
+    - goimports
+    - gomodguard
+  # - gomnd
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - lll
+  # - maligned
+    - misspell
+    - nakedret
+  # - nestif
+    - noctx
+    - nolintlint
+  # - prealloc
+    - revive
+    - rowserrcheck
+    - staticcheck
+    - stylecheck
+  # - testpackage
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - whitespace
+  # - wsl
+
+issues:
+  #fix: true
+
+  max-issues-per-linter: 0
+  max-same-issues: 0
+
+  # Disable the default exclude patterns (as they disable the mandatory comments)
+  exclude-use-default: false
+  exclude:
+    # errcheck: Almost all programs ignore errors on these functions and in most cases it's ok
+    - Error return value of .((os\.)?std(out|err)\..*|.*Close|.*Flush|os\.Remove(All)?|.*printf?|os\.(Un)?Setenv). is not checked
+
+  exclude-rules:
+    - linters:
+        - govet
+      text: 'declaration of "(err|ctx)" shadows declaration at'
+    - linters:
+        - gosec
+      # Disable the check to test that HTTP clients are not using an insecure TLS connection.
+      # We need it to contact the remote authentication services exposing a self-signed certificate
+      text: TLS InsecureSkipVerify set true.
+    - linters:
+        - errorlint
+      # Disable the check to test errors type assertion on switches.
+      text: type switch on error will fail on wrapped errors. Use errors.As to check for specific errors
+
+    # Exclude the following linters from running on tests files.
+    - path: _test\.go
+      linters:
+        - whitespace
+        - revive  # it does not allow dot imports (e.g. . "github.com/onsi/ginkgo")
+
+  exclude-files:
+    - "zz_generated.*.go"
+
+  exclude-dirs:
+    - "pkg/client"

.markdownlint.yml

@@ -0,0 +1,5 @@
+default: true
+line-length: false
+no-inline-html: false
+no-duplicate-header:
+  siblings_only: true

README.md

@@ -19,12 +19,14 @@ The controller manages the ResourceSlice status updates and conditions, while th
 ## Installation
 
 1. Clone the repository:
+
    ```bash
    git clone https://github.com/liqotech/resource-slice-class-controller-template.git
    cd resource-slice-class-controller-template
    ```
 
 2. Build the controller:
+
    ```bash
    go build -o bin/manager main.go
    ```
@@ -40,13 +42,15 @@ The controller requires a class name to be specified:
 ```
 
 Additional flags:
+
 - `--metrics-bind-address`: The address to bind the metrics endpoint (default: ":8080")
 - `--health-probe-bind-address`: The address to bind the health probe endpoint (default: ":8081")
 - `--leader-elect`: Enable leader election for controller manager
 
 ### Example Implementation
 
 The repository includes an example handler implementation in `example/resourceslice/handler.go` that:
+
 - Generates CPU resources between 1 and 10 cores
 - Generates Memory resources between 1 and 5 GB
 - Allocates 110 pods
@@ -58,56 +62,56 @@ To implement a custom handler for your ResourceSlice class:
 
 1. Create a new type that implements the `handler.Handler` interface:
 
-```go
-package myhandler
+    ```go
+    package myhandler
 
-import (
-    "context"
-    authv1beta1 "github.com/liqotech/liqo/apis/authentication/v1beta1"
-    "github.com/liqotech/resource-slice-classes/pkg/resourceslice/handler"
-    ctrl "sigs.k8s.io/controller-runtime"
-)
+    import (
+        "context"
+        authv1beta1 "github.com/liqotech/liqo/apis/authentication/v1beta1"
+        rshandler "github.com/liqotech/resource-slice-class-controller-template/pkg/resourceslice/handler"
+        ctrl "sigs.k8s.io/controller-runtime"
+    )
 
-type MyHandler struct {}
+    type MyHandler struct {}
 
-func NewMyHandler() handler.Handler {
-    return &MyHandler{}
-}
+    func NewMyHandler() rshandler.Handler {
+        return &MyHandler{}
+    }
 
-func (h *MyHandler) Handle(ctx context.Context, resourceSlice *authv1beta1.ResourceSlice) (ctrl.Result, error) {
-    // Implement your custom resource allocation logic here
-    // Update resourceSlice.Status.Resources with your allocated resources
-
-    return ctrl.Result{}, nil
-}
-```
+    func (h *MyHandler) Handle(ctx context.Context, resourceSlice *authv1beta1.ResourceSlice) (ctrl.Result, error) {
+        // Implement your custom resource allocation logic here
+        // Update resourceSlice.Status.Resources with your allocated resources
+        
+        return ctrl.Result{}, nil
+    }
+    ```
 
 2. Update `main.go` to use your custom handler:
 
-```go
-import (
-    "github.com/your-org/your-module/pkg/myhandler"
-)
-
-func main() {
-    // ...
-
-    // Create your custom handler
-    customHandler := myhandler.NewMyHandler()
-
-    if err = controller.NewResourceSliceReconciler(
-        mgr.GetClient(),
-        mgr.GetScheme(),
-        mgr.GetEventRecorderFor("resource-slice-controller"),
-        className,
-        customHandler,
-    ).SetupWithManager(mgr); err != nil {
+    ```go
+    import (
+        "github.com/your-org/your-module/pkg/myhandler"
+    )
+
+    func main() {
+        // ...
+
+        // Create your custom handler
+        customHandler := myhandler.NewMyHandler()
+
+        if err = controller.NewResourceSliceReconciler(
+            mgr.GetClient(),
+            mgr.GetScheme(),
+            mgr.GetEventRecorderFor("resource-slice-controller"),
+            className,
+            customHandler,
+        ).SetupWithManager(mgr); err != nil {
+            // ...
+        }
+
         // ...
     }
-
-    // ...
-}
-```
+    ```
 
 ## Handler Interface
 
@@ -120,11 +124,13 @@ type Handler interface {
 ```
 
 Your handler implementation should:
+
 1. Implement your resource allocation strategy
 2. Set the allocated resources in `resourceSlice.Status.Resources`
 3. Return appropriate reconciliation results and errors
 
 Note: The controller, not the handler, is responsible for:
+
 - Updating the ResourceSlice status in the API server
 - Managing ResourceSlice conditions
 - Recording events
@@ -150,7 +156,3 @@ Note: The controller, not the handler, is responsible for:
 ## Contributing
 
 Contributions are welcome! Please feel free to submit a Pull Request.
-
-## License
-
-This project is licensed under the Apache License 2.0 - see the LICENSE file for details.