chore: migrate to Go 1.26 and controller-gen v0.21.0 (#822)

Upstream k8s.io dependencies have moved past Go 1.24; Renovate PRs
touching them now drag the go directive forward. This aligns the
operator with k8sgpt-ai/k8sgpt#1689.

- go.mod: go 1.26.3, toolchain go1.26.5
- controller-gen: v0.16.0 -> v0.21.0 (v0.16.0 fails to compile under
  go1.26 via its x/tools v0.24.0 dependency)
- regenerate CRDs/deepcopy; also picks up previously ungenerated
  DeploymentLabels/DeploymentAnnotations schema entries
- CI workflows: Go pins -> 1.26 (release.yaml/build_container.yaml
  envs were stale at 1.19/1.21)
- Dockerfile builder image: golang:1.26-alpine3.23

Signed-off-by: Alex Jones <alexsimonjones@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: AlexsJones

.github/workflows/build_container.yaml

@@ -13,7 +13,7 @@ on:
       - "**.md"
 
 env:
-  GO_VERSION: "~1.21"
+  GO_VERSION: "~1.26"
   IMAGE_NAME: "k8sgpt-operator"
 defaults:
   run:

.github/workflows/release.yaml

@@ -8,7 +8,7 @@ on:
   workflow_dispatch:
 env:
   # Default minimum version of Go to support.
-  DEFAULT_GO_VERSION: 1.19
+  DEFAULT_GO_VERSION: 1.26
   REGISTRY: ghcr.io
   GITHUB_PAGES_BRANCH: gh_pages
 

.github/workflows/test.yaml

@@ -6,7 +6,7 @@ on:
       - main
 
 env:
-    GO_VERSION: "~1.24"
+    GO_VERSION: "~1.26"
 
 jobs:
   build:

Dockerfile

@@ -1,5 +1,5 @@
 # Build the manager binary
-FROM --platform=$BUILDPLATFORM golang:1.24-alpine3.21 AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26-alpine3.23 AS builder
 
 ARG TARGETOS
 ARG TARGETARCH

Makefile

@@ -173,7 +173,7 @@ ENVTEST ?= $(LOCALBIN)/setup-envtest
 
 ## Tool Versions
 KUSTOMIZE_VERSION ?= v3.8.7
-CONTROLLER_TOOLS_VERSION ?= v0.16.0
+CONTROLLER_TOOLS_VERSION ?= v0.21.0
 
 KUSTOMIZE_INSTALL_SCRIPT ?= "https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/hack/install_kustomize.sh"
 .PHONY: kustomize

api/v1alpha1/zz_generated.deepcopy.go

@@ -3,7 +3,7 @@ apiVersion: apiextensions.k8s.io/v1
 kind: CustomResourceDefinition
 metadata:
   annotations:
-    controller-gen.kubebuilder.io/version: v0.16.0
+    controller-gen.kubebuilder.io/version: v0.21.0
   name: k8sgpts.core.k8sgpt.ai
 spec:
   group: core.k8sgpt.ai
@@ -352,6 +352,20 @@ spec:
                       type: string
                   type: object
                 type: array
+              deploymentAnnotations:
+                additionalProperties:
+                  type: string
+                description: |-
+                  DeploymentAnnotations allows adding custom annotations to the K8sGPT Deployment
+                  for integration with monitoring systems and other infrastructure components.
+                type: object
+              deploymentLabels:
+                additionalProperties:
+                  type: string
+                description: |-
+                  DeploymentLabels allows adding custom labels to the K8sGPT Deployment for
+                  organizational tracking, monitoring, logging, and cost allocation purposes.
+                type: object
               extraOptions:
                 properties:
                   backstage:

config/crd/bases/core.k8sgpt.ai_k8sgpts.yaml

@@ -3,7 +3,7 @@ apiVersion: apiextensions.k8s.io/v1
 kind: CustomResourceDefinition
 metadata:
   annotations:
-    controller-gen.kubebuilder.io/version: v0.16.0
+    controller-gen.kubebuilder.io/version: v0.21.0
   name: mutations.core.k8sgpt.ai
 spec:
   group: core.k8sgpt.ai

config/crd/bases/core.k8sgpt.ai_mutations.yaml

@@ -3,7 +3,7 @@ apiVersion: apiextensions.k8s.io/v1
 kind: CustomResourceDefinition
 metadata:
   annotations:
-    controller-gen.kubebuilder.io/version: v0.16.0
+    controller-gen.kubebuilder.io/version: v0.21.0
   name: results.core.k8sgpt.ai
 spec:
   group: core.k8sgpt.ai

config/crd/bases/core.k8sgpt.ai_results.yaml

@@ -1,8 +1,8 @@
 module github.com/k8sgpt-ai/k8sgpt-operator
 
-go 1.24.0
+go 1.26.3
 
-toolchain go1.24.5
+toolchain go1.26.5
 
 require (
 	buf.build/gen/go/k8sgpt-ai/k8sgpt/grpc/go v1.5.1-20241118152629-1379a5a1889d.2