chore(docs): add autogenerated flags reference

.github/workflows/release_docs.yaml

@@ -30,14 +30,24 @@ jobs:
           path: docs.konghq.com
           fetch-depth: 0
 
-      - name: Generate docs
+      - name: Generate CRDs reference
         run: |
           ./scripts/apidocs-gen/post-process-for-konghq.sh \
           docs.konghq.com/app/_src/kubernetes-ingress-controller/references/custom-resources-${{ steps.semver_parser.outputs.major }}.${{ steps.semver_parser.outputs.minor }}.x.md
 
+      - name: Generate flags reference
+        run: |
+          go run ./hack/generate-flags-markdown > docs.konghq.com/app/_src/kubernetes-ingress-controller/references/flags-${{ steps.semver_parser.outputs.major }}.${{ steps.semver_parser.outputs.minor }}.x.md
+
       - name: Detect changes
         id: detect-changes
-        run: echo "HAS_CHANGES=$(cd docs.konghq.com && git status --porcelain)" >> $GITHUB_OUTPUT
+        run: |
+          if [[ `cd docs.konghq.com && git status --porcelain` ]]; then
+            echo "Changes detected in docs repo"
+            echo "HAS_CHANGES=true" >> $GITHUB_OUTPUT
+          else
+            echo "No changes detected in docs repo"
+          fi
 
       - name: GPG sign the commits
         uses: crazy-max/ghaction-import-gpg@82a020f1f7f605c65dd2449b392a52c3fcfef7ef

hack/generate-flags-markdown/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/kong/kubernetes-ingress-controller/v2/internal/manager"
+	"github.com/spf13/pflag"
+)
+
+// This program generates markdown documentation for the KIC executable's flags.
+// It skips deprecated and hidden flags.
+func main() {
+	cfg := manager.Config{}
+	flags := cfg.FlagSet()
+
+	markdown := strings.Builder{}
+	markdown.WriteString("---\ntitle: CLI Arguments\n---\n\nVarious settings and configurations of the controller can be tweaked\nusing CLI flags.\n\n## Environment variables\n\nEach flag defined in the table below can also be configured using\nan environment variable. The name of the environment variable is `CONTROLLER_`\nstring followed by the name of flag in uppercase.\n\nFor example, `--ingress-class` can be configured using the following\nenvironment variable:\n\n```\nCONTROLLER_INGRESS_CLASS=kong-foobar\n```\n\nIt is recommended that all the configuration is done via environment variables\nand not CLI flags.\n\n")
+	markdown.WriteString("## Flags\n")
+	markdown.WriteString("| Flag | Type | Description | Default |\n")
+	markdown.WriteString("| ---- | ---- | ----------- | ------- |\n")
+
+	flags.VisitAll(func(flag *pflag.Flag) {
+		// Skip deprecated flags.
+		if flag.Deprecated != "" {
+			return
+		}
+
+		name := fmt.Sprintf("`--%s`", flag.Name)
+		typ := fmt.Sprintf("`%s`", flag.Value.Type())
+
+		description := flag.Usage
+		// Make sure the first letter is capitalized.
+		if first := description[0]; first >= 'a' && first <= 'z' {
+			description = strings.ToUpper(string(first)) + description[1:]
+		}
+		// Make sure the last character is a period.
+		if last := description[len(description)-1]; last != '.' {
+			description += "."
+		}
+
+		defaultValue := ""
+		if flag.DefValue != "" {
+			defaultValue = fmt.Sprintf("`%s`", flag.DefValue)
+		}
+
+		markdown.WriteString(fmt.Sprintf("| %s | %s | %s | %s |\n", name, typ, description, defaultValue))
+	})
+
+	fmt.Println(markdown.String())
+}