Centralized linter (#57)

* Reusable lint method

* New reusable linter

* Reusable Go Lint 1.0

* Fix grammar

.github/workflows/lint-go-reusable.yml

@@ -0,0 +1,38 @@
+# This workflow defines a reusable Go linting flow, using Golangci-lint: https://golangci-lint.run/
+# https://golangci-lint.run/usage/configuration/
+
+name: Lint code (reusable)
+
+on:
+  workflow_call:
+    inputs:
+      go-version:
+        required: true
+        type: string
+        description: "The Go version to use. This can be a specific version. E.g. 1.19 or 1.21.x"
+      lint-config-uri:
+        required: true
+        type: string
+        description: "The URI to the linter config file. This can be a local file or a remote file. E.g. https://raw.githubusercontent.com/kyma-project/eventing-tools/main/config/lint/.golangci.yaml"
+
+jobs:
+  unit:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: ${{ inputs.go-version }} # This can be a specific version. E.g. 1.19 or 1.21.x
+          cache: false # Disable cache to avoid issues with different Go versions
+
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Download linter config
+        run: wget -O .golangci.yaml ${{ inputs.lint-config-uri }} # This can be a remote file only. E.g. https://raw.githubusercontent.com/kyma-project/eventing-tools/main/config/lint/.golangci.yaml
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          version: v1.55
+          args: --timeout=5m --config=./.golangci.yaml --issues-exit-code 1 # Failed if any issues are found

.github/workflows/lint-reusable.yml

@@ -22,4 +22,4 @@ jobs:
         uses: golangci/golangci-lint-action@v3
         with:
           version: v1.55
-          args: --timeout=5m
+          args: --timeout=5m

config/lint/.golangci.yaml

@@ -0,0 +1,168 @@
+linters:
+  enable-all: true
+  disable:
+    - contextcheck # too many false positives
+    - deadcode # deprecated (since v1.49.0) and replaced by 'unused'
+    - depguard # checks if package imports are whitelisted
+    - exhaustivestruct # deprecated (since v1.46.0) and replaced by 'exhaustruct'
+    - exhaustruct # TODO enable and fix, use regex to exclude certain cases
+    - golint # deprecated (since v1.41.0) and replaced by 'revive'
+    - ifshort # deprecated (since v1.48.0)
+    - interfacer # deprecated (since v1.38.0)
+    - lll
+    - maligned # deprecated (since v1.38.0)
+    - nlreturn # too strict and mostly code is not more readable
+    - nosnakecase  # deprecated (since v1.48.1) and replaced by 'revive'
+    - scopelint # deprecated (since v1.39.0) and replaced by 'exportloopref'
+    - structcheck # deprecated (since v1.49.0) and replaced by 'unused'
+    - sqlclosecheck # not needed for this project
+    - varcheck # deprecated (since v1.49.0) and replaced by 'unused'
+    - wsl # too strict and mostly code is not more readable
+    ### disabled for now... will be enabled 1 by 1
+    - dupl
+    - forcetypeassert
+    - gosec
+    - inamedparam
+    - ireturn
+    - maintidx
+    - nolintlint
+    - paralleltest
+    - prealloc
+    - testpackage
+    - tparallel
+    - unconvert
+    - varnamelen
+    - wrapcheck
+    ### Disable linters one by one
+    - gci
+    - tagalign
+    - dupword
+    - gomoddirectives
+    - gofumpt
+    - goerr113
+    - funlen
+    - testifylint
+    - bodyclose
+    - containedctx
+    - thelper
+    - tagliatelle
+    - errchkjson
+    - perfsprint
+    - noctx
+    - godox
+    - goconst
+
+
+linters-settings:
+  stylecheck:
+    dot-import-whitelist:
+      - github.com/onsi/ginkgo/v2
+      - github.com/onsi/gomega
+  revive:
+    enable-all-rules: false
+    severity: error
+    rules:
+      - name: comment-spacings
+        disabled: true
+      - name: dot-imports
+        severity: warning
+        disabled: true
+      - name: line-length-limit
+        severity: warning
+        disabled: true
+        arguments: [ 120 ]
+  funlen:
+    lines: 80
+  cyclop:
+    max-complexity: 20
+  nestif:
+    min-complexity: 6
+  gci:
+    sections:
+      - standard                                             # Standard packages.
+      - default                                              # Imports that could not be matched to another section type.
+      - prefix(github.com/kyma-project/eventing-manager)    # Imports with the specified prefix.
+      - blank                                                # Blank imports.
+      - dot                                                  # Dot imports.
+    custom-order: true
+    skip-generated: true
+  importas:
+    no-unaliased: false
+    no-extra-aliases: true
+    ## Version number must be added as suffix to the package name. As an example check `k8s.io/api/core/v1`
+    ## kubernetes APIs get the prefix `k`. As an example check `kcorev1`
+    ## Eventing Manager APIs get the prefix `em`. As an example check `emeventingv1alpha1`
+    ## Eventing Publisher Proxy APIs get the prefix `epp`. As an example check `eppapi`
+    ## Cloud Events APIs get the prefix `ce`. As an example check `ce`
+    ## Eventing Auth Manager APIs get the prefix `eam`.
+    ## Kyma Metrics Collector APIs get the prefix `kmc`.
+    ## NATS Manager APIs get the prefix `nm`.
+
+    alias:
+      - pkg: "log"
+        alias: log
+      - pkg: k8s.io/api/core/v1
+        alias: kcorev1
+      - pkg: k8s.io/apimachinery/pkg/apis/meta/v1
+        alias: kmetav1
+      - pkg: k8s.io/client-go/dynamic/fake
+        alias: kdynamicfake
+      - pkg: github.com/nats-io/nats.go
+        alias: natsgo
+      - pkg: go.opencensus.io/trace/propagation
+        alias: ocpropagation
+      - pkg: github.com/kyma-project/eventing-publisher-proxy/testing
+        alias: epptestingutils
+      - pkg: github.com/kyma-project/eventing-publisher-proxy/pkg/legacy/api
+        alias: eppapi
+      - pkg: github.com/kyma-project/eventing-publisher-proxy/pkg/nats
+        alias: eppnats
+      - pkg : github.com/kyma-project/eventing-manager/pkg/logger
+        alias: emlogger
+      - pkg: github.com/kyma-project/eventing-manager/api/eventing/v1alpha1
+        alias: emeventingv1alpha1
+      - pkg: github.com/kyma-project/eventing-manager/api/eventing/v1alpha2
+        alias: emeventingv2alpha1
+      - pkg : github.com/cloudevents/sdk-go/v2
+        alias: ce
+      - pkg : github.com/cloudevents/sdk-go/v2/protocol/http
+        alias: cehttp
+      - pkg : github.com/cloudevents/sdk-go/v2/event
+        alias: ceevent
+      - pkg : github.com/cloudevents/sdk-go/v2/client
+        alias: ceclient
+      - pkg : github.com/kyma-project/kyma/components/central-application-gateway/pkg/apis/applicationconnector/v1alpha1
+        alias: kymaappconnv1alpha1
+
+
+
+  ireturn:
+    allow:
+      - anon
+      - error
+      - empty
+      - stdlib
+      - Client
+      - client.Object
+      - (or|er)$
+  wrapcheck:
+    ignorePackageGlobs:
+issues:
+  exclude-rules:
+    - path: "_test\\.go"
+      linters:
+        - wrapcheck
+        - gochecknoglobals
+        - funlen # Table driven unit and integration tests exceed function length by design
+        - maintidx # Table driven unit and integration tests exceed maintainability index by design
+    - linters:
+      - importas
+      text: has alias "" which is not part of config # Ignore false positives that emerged due to https://github.com/julz/importas/issues/15.
+  max-issues-per-linter: 0
+  max-same-issues: 0
+output:
+  sort-results: true
+run:
+  timeout: 15m
+  skip-files:
+    - zz_generated.deepcopy.go