feat: add constraints

cmd/helmify/flags.go

@@ -37,6 +37,7 @@ func ReadFlags() config.Config {
 	flag.BoolVar(&result.VeryVerbose, "vv", false, "Enable very verbose output. Same as verbose but with DEBUG. Example: helmify -vv")
 	flag.BoolVar(&crd, "crd-dir", false, "Enable crd install into 'crds' directory.\nWarning: CRDs placed in 'crds' directory will not be templated by Helm.\nSee https://helm.sh/docs/chart_best_practices/custom_resource_definitions/#some-caveats-and-explanations\nExample: helmify -crd-dir")
 	flag.BoolVar(&result.ImagePullSecrets, "image-pull-secrets", false, "Allows the user to use existing secrets as imagePullSecrets in values.yaml")
+	flag.BoolVar(&result.GenerateDefaults, "generate-defaults", false, "Allows the user to add empty placeholders for tipical customization options in values.yaml. Currently covers: topology constraints, node selectors, tolerances")
 
 	flag.Parse()
 	if h || help {

examples/operator/templates/_helpers.tpl

@@ -60,3 +60,16 @@ Create the name of the service account to use
 {{- default "default" .Values.serviceAccount.name }}
 {{- end }}
 {{- end }}
+
+{{/*
+Renders a value that contains template.
+Usage:
+{{ include "tplvalues.render" ( dict "value" .Values.path.to.the.Value "context" $) }}
+*/}}
+{{- define "tplvalues.render" -}}
+    {{- if typeIs "string" .value }}
+        {{- tpl .value .context }}
+    {{- else }}
+        {{- tpl (.value | toYaml) .context }}
+    {{- end }}
+{{- end -}}

examples/operator/templates/deployment.yaml

@@ -104,10 +104,17 @@ spec:
         runAsNonRoot: true
       serviceAccountName: {{ include "operator.fullname" . }}-controller-manager
       terminationGracePeriodSeconds: 10
+      topologySpreadConstraints:
+      - maxSkew: 1
+        topologyKey: kubernetes.io/hostname
+        whenUnsatisfiable: DoNotSchedule
       volumes:
       - configMap:
           name: {{ include "operator.fullname" . }}-manager-config
         name: manager-config
       - name: secret-volume
         secret:
-          secretName: {{ include "operator.fullname" . }}-secret-ca
+          secretName: {{ include "operator.fullname" . }}-secret-ca
+{{- if .Values.topologySpreadConstraints }}
+      topologySpreadConstraints: {{- include "tplvalues.render" (dict "value" .Values.topologySpreadConstraints "context" $) | nindent 8 }}
+{{- end }}

examples/operator/values.yaml

@@ -21,6 +21,10 @@ controllerManager:
         cpu: 100m
         memory: 20Mi
   replicas: 1
+  topologySpreadConstraints:
+  - maxSkew: 1
+    topologyKey: kubernetes.io/hostname
+    whenUnsatisfiable: DoNotSchedule
 kubernetesClusterDomain: cluster.local
 managerConfig:
   controllerManagerConfigYaml:

pkg/config/config.go

@@ -23,6 +23,9 @@ type Config struct {
 	Crd bool
 	// ImagePullSecrets flag
 	ImagePullSecrets bool
+	// GenerateDefaults enables the generation of empty values placeholders for common customization options of helm chart
+	// current generated values: tolerances, node selectors, topology constraints
+	GenerateDefaults bool
 }
 
 func (c *Config) Validate() error {

pkg/helm/init.go

@@ -99,6 +99,19 @@ Create the name of the service account to use
 {{- default "default" .Values.serviceAccount.name }}
 {{- end }}
 {{- end }}
+
+{{/*
+Renders a value that contains template.
+Usage:
+{{ include "tplvalues.render" ( dict "value" .Values.path.to.the.Value "context" $) }}
+*/}}
+{{- define "tplvalues.render" -}}
+    {{- if typeIs "string" .value }}
+        {{- tpl .value .context }}
+    {{- else }}
+        {{- tpl (.value | toYaml) .context }}
+    {{- end }}
+{{- end -}}
 `
 
 const defaultChartfile = `apiVersion: v2

pkg/processor/constraints/constraint.go

@@ -0,0 +1,67 @@
+package constraints
+
+import (
+	"github.com/arttor/helmify/pkg/helmify"
+	yamlformat "github.com/arttor/helmify/pkg/yaml"
+)
+
+const tolerations = "tolerations"
+const topology = "topologySpreadConstraints"
+const nodeSelector = "nodeSelector"
+
+const topologyExpression = "\n{{- if .Values.topologySpreadConstraints }}\n" +
+	"      topologySpreadConstraints: {{- include \"tplvalues.render\" (dict \"value\" .Values.topologySpreadConstraints \"context\" $) | nindent 8 }}\n" +
+	"{{- end }}\n"
+
+const nodeSelectorExpression = "{{- if .Values.nodeSelector }}\n" +
+	"      nodeSelector: {{- include \"tplvalues.render\" ( dict \"value\" .Values.nodeSelector \"context\" $) | nindent 8 }}\n" +
+	"{{- end }}\n"
+
+const tolerationsExpression = "{{- if .Values.tolerations }}\n" +
+	"      tolerations: {{- include \"tplvalues.render\" (dict \"value\" .Values.tolerations \"context\" .) | nindent 8 }}\n" +
+	"{{- end }}\n"
+
+// ProcessSpecMap adds 'topologyConstraints' to the podSpec in specMap, if it doesn't
+// already has one defined.
+func ProcessSpecMap(name string, specMap map[string]interface{}, values *helmify.Values, defaultEmpty bool) string {
+
+	spec, err := yamlformat.Marshal(specMap, 6)
+	if err != nil {
+		return ""
+	}
+
+	if defaultEmpty {
+		mapConstraintWithEmpty(name, specMap, topology, []interface{}{}, values)
+		mapConstraintWithEmpty(name, specMap, tolerations, []interface{}{}, values)
+		mapConstraintWithEmpty(name, specMap, nodeSelector, map[string]string{}, values)
+		return spec + topologyExpression + nodeSelectorExpression + tolerationsExpression
+	}
+
+	if specMap[topology] != nil {
+		(*values)[name].(map[string]interface{})[topology] = specMap[topology].(interface{})
+		delete(specMap, topology)
+		spec += topologyExpression
+	}
+
+	if specMap[tolerations] != nil {
+		(*values)[name].(map[string]interface{})[tolerations] = specMap[tolerations].(interface{})
+		delete(specMap, tolerations)
+		spec += tolerationsExpression
+	}
+	if specMap[nodeSelector] != nil {
+		(*values)[name].(map[string]interface{})[nodeSelector] = specMap[nodeSelector].(interface{})
+		delete(specMap, nodeSelector)
+		spec += nodeSelectorExpression
+	}
+
+	return spec
+}
+
+func mapConstraintWithEmpty(name string, specMap map[string]interface{}, constraint string, override interface{}, values *helmify.Values) {
+	if specMap[constraint] != nil {
+		(*values)[name].(map[string]interface{})[constraint] = specMap[constraint].(interface{})
+	} else {
+		(*values)[name].(map[string]interface{})[constraint] = override
+	}
+	delete(specMap, constraint)
+}

pkg/processor/constraints/constraint_test.go

@@ -0,0 +1,83 @@
+package constraints
+
+import (
+	"testing"
+
+	"github.com/arttor/helmify/pkg/helmify"
+	"github.com/stretchr/testify/require"
+	v1 "k8s.io/api/core/v1"
+)
+
+const templatedResult = "{{- if .Values.topologySpreadConstraints }}\n" +
+	"      topologySpreadConstraints: {{- include \"tplvalues.render\" (dict \"value\" .Values.topologySpreadConstraints \"context\" $) | nindent 8 }}\n" +
+	"{{- end }}\n" +
+	"{{- if .Values.nodeSelector }}\n" +
+	"      nodeSelector: {{- include \"tplvalues.render\" ( dict \"value\" .Values.nodeSelector \"context\" $) | nindent 8 }}\n" +
+	"{{- end }}\n" +
+	"{{- if .Values.tolerations }}\n" +
+	"      tolerations: {{- include \"tplvalues.render\" (dict \"value\" .Values.tolerations \"context\" .) | nindent 8 }}\n" +
+	"{{- end }}\n"
+
+func TestProcessSpecMap(t *testing.T) {
+
+	tests := []struct {
+		name       string
+		specMap    map[string]interface{}
+		values     *helmify.Values
+		podspec    v1.PodSpec
+		want       string
+		wantValues *helmify.Values
+	}{
+		{name: "no predefined resource returns still a template and to fill in values",
+			specMap: make(map[string]interface{}, 4),
+			values: &helmify.Values{
+				"mydep": map[string]interface{}{},
+			},
+			want: templatedResult,
+			wantValues: &helmify.Values{
+				"mydep": map[string]interface{}{
+					"nodeSelector":              map[string]string{},
+					"tolerations":               []interface{}{},
+					"topologySpreadConstraints": []interface{}{},
+				},
+			},
+		},
+		{name: "predefined resource are added to values, template is the same",
+			values: &helmify.Values{
+				"mydep": map[string]interface{}{},
+			},
+			specMap: map[string]interface{}{
+
+				"topologySpreadConstraints": []v1.TopologySpreadConstraint{
+					{
+						MaxSkew:           0,
+						TopologyKey:       "trtr",
+						WhenUnsatisfiable: "test",
+						LabelSelector:     nil,
+					},
+				},
+			},
+			want: templatedResult,
+			wantValues: &helmify.Values{
+				"mydep": map[string]interface{}{
+					"nodeSelector": map[string]string{},
+					"tolerations":  []interface{}{},
+					"topologySpreadConstraints": []v1.TopologySpreadConstraint{
+						{
+							MaxSkew:           0,
+							TopologyKey:       "trtr",
+							WhenUnsatisfiable: "test",
+						},
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ProcessSpecMap("mydep", tt.specMap, tt.values, true)
+			require.Contains(t, got, tt.want)
+			require.Equal(t, *tt.wantValues, *tt.values)
+		})
+	}
+}

pkg/processor/deployment/deployment.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/arttor/helmify/pkg/cluster"
 	"github.com/arttor/helmify/pkg/processor"
+	"github.com/arttor/helmify/pkg/processor/constraints"
 	"github.com/arttor/helmify/pkg/processor/imagePullSecrets"
 
 	"github.com/arttor/helmify/pkg/helmify"
@@ -164,10 +165,7 @@ func (d deployment) Process(appMeta helmify.AppMetadata, obj *unstructured.Unstr
 		imagePullSecrets.ProcessSpecMap(specMap, &values)
 	}
 
-	spec, err := yamlformat.Marshal(specMap, 6)
-	if err != nil {
-		return true, nil, err
-	}
+	spec := constraints.ProcessSpecMap(nameCamel, specMap, &values, appMeta.Config().GenerateDefaults)
 	spec = strings.ReplaceAll(spec, "'", "")
 
 	return true, &result{

test_data/k8s-operator-kustomize.output

@@ -586,6 +586,13 @@ spec:
       labels:
         control-plane: controller-manager
     spec:
+      topologySpreadConstraints:
+          - maxSkew: 1
+            topologyKey: kubernetes.io/hostname
+            whenUnsatisfiable: DoNotSchedule
+            matchLabelKeys:
+              - app
+              - pod-template-hash
       imagePullSecrets:
         - name: my-operator-secret-registry-credentials
       containers: