feat: options to configure chart upgrade strategy

Signed-off-by: Thuan Vo <thuan.votann@gmail.com>

ct/cmd/install.go

@@ -79,6 +79,9 @@ func addInstallFlags(flags *flag.FlagSet) {
 		(e.g. "--set=name=value"`))
 	flags.Bool("skip-clean-up", false, heredoc.Doc(`
 		Skip resources clean-up. Used if need to continue other flows or keep it around.`))
+	flags.String("upgrade-strategy", "reuse-values", heredoc.Doc(`
+		When --upgrade is used, this flag configures the upgrade strategy for chart values.
+		Available options: reset-values, reuse-values, reset-then-reuse-values`))
 }
 
 func install(cmd *cobra.Command, _ []string) error {

doc/ct_install.md

@@ -77,6 +77,8 @@ ct install [flags]
       --target-branch string                 The name of the target branch used to identify changed charts (default "main")
       --upgrade                              Whether to test an in-place upgrade of each chart from its previous revision if the
                                              current version should not introduce a breaking change according to the SemVer spec
+      --upgrade-strategy string              When --upgrade is used, this flag configures the upgrade strategy for chart values.
+                                             Available options: reset-values, reuse-values, reset-then-reuse-values (default "reuse-values")
       --use-helmignore                       Use .helmignore when identifying changed charts
 ```
 

doc/ct_lint-and-install.md

@@ -72,6 +72,8 @@ ct lint-and-install [flags]
       --target-branch string                 The name of the target branch used to identify changed charts (default "main")
       --upgrade                              Whether to test an in-place upgrade of each chart from its previous revision if the
                                              current version should not introduce a breaking change according to the SemVer spec
+      --upgrade-strategy string              When --upgrade is used, this flag configures the upgrade strategy for chart values.
+                                             Available options: reset-values, reuse-values, reset-then-reuse-values (default "reuse-values")
       --use-helmignore                       Use .helmignore when identifying changed charts
       --validate-chart-schema                Enable schema validation of 'Chart.yaml' using Yamale (default true)
       --validate-maintainers                 Enable validation of maintainer account names in chart.yml.

pkg/chart/chart.go

@@ -267,7 +267,7 @@ func NewTesting(config config.Configuration, extraSetArgs string) (Testing, erro
 
 	testing := Testing{
 		config:           config,
-		helm:             tool.NewHelm(procExec, helmExtraArgs, helmLintExtraArgs, strings.Fields(extraSetArgs)),
+		helm:             tool.NewHelm(procExec, helmExtraArgs, helmLintExtraArgs, strings.Fields(extraSetArgs), config.UpgradeStrategy),
 		git:              tool.NewGit(procExec),
 		kubectl:          tool.NewKubectl(procExec, config.KubectlTimeout),
 		linter:           tool.NewLinter(procExec),

pkg/chart/chart_test.go

@@ -235,14 +235,15 @@ func TestReadAllChartDirectories(t *testing.T) {
 		"test_charts/must-pass-upgrade-install",
 		"test_charts/mutating-deployment-selector",
 		"test_charts/simple-deployment",
+		"test_charts/simple-deployment-v2",
 		"test_charts/simple-deployment-different-selector",
 		"test_charts/mutating-sfs-volumeclaim",
 		"test_chart_at_root",
 	}
 	for _, chart := range actual {
 		assert.Contains(t, expected, chart)
 	}
-	assert.Len(t, actual, 8)
+	assert.Len(t, actual, 9)
 	assert.Nil(t, err)
 }
 

pkg/chart/integration_test.go

@@ -43,7 +43,7 @@ func newTestingHelmIntegration(cfg config.Configuration, extraSetArgs string) Te
 		utils:            util.Utils{},
 		accountValidator: fakeAccountValidator{},
 		linter:           fakeMockLinter,
-		helm:             tool.NewHelm(procExec, extraArgs, extraLintArgs, strings.Fields(extraSetArgs)),
+		helm:             tool.NewHelm(procExec, extraArgs, extraLintArgs, strings.Fields(extraSetArgs), cfg.UpgradeStrategy),
 		kubectl:          tool.NewKubectl(procExec, 30*time.Second),
 	}
 }
@@ -111,6 +111,12 @@ func TestInstallChart(t *testing.T) {
 }
 
 func TestUpgradeChart(t *testing.T) {
+	runUpgradeChartTest(t, tool.ResetValues)
+	runUpgradeChartTest(t, tool.ReuseValues)
+	runUpgradeChartTest(t, tool.ResetThenReuseValues)
+}
+
+func runUpgradeChartTest(t *testing.T, upgradeStrategy string) {
 	type testCase struct {
 		name string
 		old  string
@@ -119,8 +125,9 @@ func TestUpgradeChart(t *testing.T) {
 	}
 
 	cfg := config.Configuration{
-		Debug:   true,
-		Upgrade: true,
+		Debug:           true,
+		Upgrade:         true,
+		UpgradeStrategy: upgradeStrategy,
 	}
 	ct := newTestingHelmIntegration(cfg, "")
 	processError := fmt.Errorf("failed waiting for process: exit status 1")
@@ -152,6 +159,20 @@ func TestUpgradeChart(t *testing.T) {
 		},
 	}
 
+	v2UpgradeCase := testCase{
+		"upgrade nginx to v2 with breaking changes",
+		"test_charts/simple-deployment",
+		"test_charts/simple-deployment-v2",
+		nil,
+	}
+	// Expect chart upgrade with breaking changes to fail
+	// if values are reused
+	if upgradeStrategy == tool.ReuseValues {
+		v2UpgradeCase.err = processError
+	}
+
+	cases = append(cases, v2UpgradeCase)
+
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
 			err := ct.doUpgrade(mustNewChart(tc.old), mustNewChart(tc.new), true)
@@ -165,6 +186,7 @@ func TestUpgradeChart(t *testing.T) {
 			}
 		})
 	}
+
 }
 
 func mustNewChart(chartPath string) *Chart {

pkg/chart/test_charts/simple-deployment-v2/Chart.yaml

@@ -0,0 +1,5 @@
+apiVersion: v1
+appVersion: "2.0"
+description: A Helm chart for Kubernetes
+name: nginx
+version: 0.2.0

pkg/chart/test_charts/simple-deployment-v2/README.md

@@ -0,0 +1,4 @@
+Simple chart with a Deployment (v2) with breaking changes to values file.
+
+The integration test will install first simple-deployment and then try to upgrade
+to simple-deployment-v2, which is expected to pass.

pkg/chart/test_charts/simple-deployment-v2/templates/_helpers.tpl

@@ -0,0 +1,32 @@
+{{/* vim: set filetype=mustache: */}}
+{{/*
+Expand the name of the chart.
+*/}}
+{{- define "nginx.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
+{{/*
+Create a default fully qualified app name.
+We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
+If release name contains chart name it will be used as a full name.
+*/}}
+{{- define "nginx.fullname" -}}
+{{- if .Values.fullnameOverride -}}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" -}}
+{{- else -}}
+{{- $name := default .Chart.Name .Values.nameOverride -}}
+{{- if contains $name .Release.Name -}}
+{{- .Release.Name | trunc 63 | trimSuffix "-" -}}
+{{- else -}}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+{{- end -}}
+{{- end -}}
+
+{{/*
+Create chart name and version as used by the chart label.
+*/}}
+{{- define "nginx.chart" -}}
+{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" -}}
+{{- end -}}

pkg/chart/test_charts/simple-deployment-v2/templates/deployment.yaml

@@ -0,0 +1,33 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: {{ include "nginx.fullname" . }}
+  labels:
+    app.kubernetes.io/name: {{ include "nginx.name" . }}
+    helm.sh/chart: {{ include "nginx.chart" . }}
+    app.kubernetes.io/instance: {{ .Release.Name }}
+    app.kubernetes.io/managed-by: {{ .Release.Service }}
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: {{ include "nginx.name" . }}
+      app.kubernetes.io/instance: {{ .Release.Name }}
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: {{ include "nginx.name" . }}
+        app.kubernetes.io/instance: {{ .Release.Name }}
+    spec:
+      securityContext:
+        {{- toYaml .Values.podSecurityContext | nindent 8 }}
+      containers:
+        - name: {{ .Chart.Name }}
+          image: "{{ .Values.core.image.repository }}:{{ .Values.core.image.tag }}"
+          imagePullPolicy: {{ .Values.core.image.pullPolicy }}
+          ports:
+            - name: http
+              containerPort: 80
+              protocol: TCP
+          securityContext:
+            {{- toYaml .Values.core.securityContext | nindent 12 }}

pkg/chart/test_charts/simple-deployment-v2/values.yaml

@@ -0,0 +1,15 @@
+# Default values for nginx.
+# This is a YAML-formatted file.
+# Declare variables to be passed into your templates.
+
+core:
+  image:
+    repository: nginx
+    tag: stable
+    pullPolicy: IfNotPresent
+  securityContext: {}
+
+podSecurityContext: {}
+
+nameOverride: ""
+fullnameOverride: ""

pkg/config/config.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/mitchellh/go-homedir"
 
+	"github.com/helm/chart-testing/v3/pkg/tool"
 	"github.com/helm/chart-testing/v3/pkg/util"
 	"github.com/spf13/cobra"
 	flag "github.com/spf13/pflag"
@@ -74,6 +75,7 @@ type Configuration struct {
 	PrintLogs               bool          `mapstructure:"print-logs"`
 	GithubGroups            bool          `mapstructure:"github-groups"`
 	UseHelmignore           bool          `mapstructure:"use-helmignore"`
+	UpgradeStrategy         string        `mapstructure:"upgrade-strategy"`
 }
 
 func LoadConfiguration(cfgFile string, cmd *cobra.Command, printConfig bool) (*Configuration, error) {
@@ -139,8 +141,20 @@ func LoadConfiguration(cfgFile string, cmd *cobra.Command, printConfig bool) (*C
 	// Disable upgrade (this does some expensive dependency building on previous revisions)
 	// when neither "install" nor "lint-and-install" have not been specified.
 	cfg.Upgrade = isInstall && cfg.Upgrade
-	if (cfg.TargetBranch == "" || cfg.Remote == "") && cfg.Upgrade {
-		return nil, errors.New("specifying '--upgrade=true' without '--target-branch' or '--remote', is not allowed")
+
+	if cfg.Upgrade {
+		if cfg.TargetBranch == "" || cfg.Remote == "" {
+			return nil, errors.New("specifying '--upgrade=true' without '--target-branch' or '--remote', is not allowed")
+		}
+
+		// Ensure upgrade strategy is valid
+		switch cfg.UpgradeStrategy {
+		case tool.ResetValues:
+		case tool.ReuseValues:
+		case tool.ResetThenReuseValues:
+		default:
+			return nil, fmt.Errorf("invalid upgrade strategy %s specified", cfg.UpgradeStrategy)
+		}
 	}
 
 	chartYamlSchemaPath := cfg.ChartYamlSchema

pkg/config/config_test.go

@@ -62,6 +62,7 @@ func loadAndAssertConfigFromFile(t *testing.T, configFile string) {
 	require.Equal(t, 120*time.Second, cfg.KubectlTimeout)
 	require.Equal(t, true, cfg.SkipCleanUp)
 	require.Equal(t, true, cfg.UseHelmignore)
+	require.Equal(t, "reset-then-reuse-values", cfg.UpgradeStrategy)
 }
 
 func Test_findConfigFile(t *testing.T) {

pkg/config/test_config.json

@@ -33,5 +33,7 @@
     "exclude-deprecated": true,
     "kubectl-timeout": "120s",
     "skip-clean-up": true,
-    "use-helmignore": true
+    "use-helmignore": true,
+    "upgrade-strategy": "reset-then-reuse-values"
+
 }

pkg/config/test_config.yaml

@@ -29,3 +29,4 @@ exclude-deprecated: true
 kubectl-timeout: 120s
 skip-clean-up: true
 use-helmignore: true
+upgrade-strategy: reset-then-reuse-values

pkg/tool/helm.go

@@ -22,18 +22,26 @@ import (
 )
 
 type Helm struct {
-	exec          exec.ProcessExecutor
-	extraArgs     []string
-	lintExtraArgs []string
-	extraSetArgs  []string
+	exec            exec.ProcessExecutor
+	extraArgs       []string
+	lintExtraArgs   []string
+	extraSetArgs    []string
+	upgradeStrategy string
 }
 
-func NewHelm(exec exec.ProcessExecutor, extraArgs, lintExtraArgs, extraSetArgs []string) Helm {
+const (
+	ResetValues          string = "reset-values"
+	ReuseValues          string = "reuse-values"
+	ResetThenReuseValues string = "reset-then-reuse-values"
+)
+
+func NewHelm(exec exec.ProcessExecutor, extraArgs, lintExtraArgs, extraSetArgs []string, upgradeStrategy string) Helm {
 	return Helm{
-		exec:          exec,
-		extraArgs:     extraArgs,
-		lintExtraArgs: lintExtraArgs,
-		extraSetArgs:  extraSetArgs,
+		exec:            exec,
+		extraArgs:       extraArgs,
+		lintExtraArgs:   lintExtraArgs,
+		extraSetArgs:    extraSetArgs,
+		upgradeStrategy: upgradeStrategy,
 	}
 }
 
@@ -76,8 +84,9 @@ func (h Helm) InstallWithValues(chart string, valuesFile string, namespace strin
 }
 
 func (h Helm) Upgrade(chart string, namespace string, release string) error {
+	strategyFlag := fmt.Sprintf("--%s", h.upgradeStrategy)
 	return h.exec.RunProcess("helm", "upgrade", release, chart, "--namespace", namespace,
-		"--reuse-values", "--wait", h.extraArgs, h.extraSetArgs)
+		strategyFlag, "--wait", h.extraArgs, h.extraSetArgs)
 }
 
 func (h Helm) Test(namespace string, release string) error {