Add helmfile template --show-only (#1494)

Add a `--show-only` parameter to the `helmfile template` command to pass
on to the `helm template` command.

Signed-off-by: Jim Barber <jim.barber@healthengine.com.au>

cmd/template.go

@@ -47,6 +47,7 @@ func NewTemplateCmd(globalCfg *config.GlobalImpl) *cobra.Command {
 	f.StringVar(&templateOptions.PostRenderer, "post-renderer", "", `pass --post-renderer to "helm template" or "helm upgrade --install"`)
 	f.StringArrayVar(&templateOptions.PostRendererArgs, "post-renderer-args", nil, `pass --post-renderer-args to "helm template" or "helm upgrade --install"`)
 	f.StringVar(&templateOptions.KubeVersion, "kube-version", "", `pass --kube-version to "helm template". Overrides kubeVersion in helmfile.yaml`)
+	f.StringArrayVar(&templateOptions.ShowOnly, "show-only", nil, `pass --show-only to "helm template"`)
 
 	return cmd
 }

pkg/app/app.go

@@ -1964,6 +1964,7 @@ func (a *App) template(r *Run, c TemplateConfigProvider) (bool, []error) {
 			PostRenderer:      c.PostRenderer(),
 			PostRendererArgs:  c.PostRendererArgs(),
 			KubeVersion:       c.KubeVersion(),
+			ShowOnly:          c.ShowOnly(),
 		}
 		return st.TemplateReleases(helm, c.OutputDir(), c.Values(), args, c.Concurrency(), c.Validate(), opts)
 	})

pkg/app/app_template_test.go

@@ -24,6 +24,7 @@ func TestTemplate(t *testing.T) {
 		skipNeeds              bool
 		includeNeeds           bool
 		includeTransitiveNeeds bool
+		showOnly               []string
 	}
 
 	type testcase struct {
@@ -131,6 +132,7 @@ releases:
 				skipNeeds:              tc.fields.skipNeeds,
 				includeNeeds:           tc.fields.includeNeeds,
 				includeTransitiveNeeds: tc.fields.includeTransitiveNeeds,
+				showOnly:               tc.fields.showOnly,
 			})
 
 			var gotErr string
@@ -304,6 +306,18 @@ releases:
 			error:     "err: no releases found that matches specified selector(app=test_non_existent) and environment(default), in any helmfile",
 		})
 	})
+
+	t.Run("show-only", func(t *testing.T) {
+		check(t, testcase{
+			fields: fields{
+				showOnly: []string{"templates/resources.yaml"},
+			},
+			selectors: []string{"name=logging"},
+			templated: []exectest.Release{
+				{Name: "logging", Flags: []string{"--show-only", "templates/resources.yaml", "--namespace", "kube-system"}},
+			},
+		})
+	})
 }
 
 func TestTemplate_StrictParsing(t *testing.T) {

pkg/app/app_test.go

@@ -2189,6 +2189,10 @@ func (c configImpl) KubeVersion() string {
 	return c.kubeVersion
 }
 
+func (c configImpl) ShowOnly() []string {
+	return nil
+}
+
 type applyConfig struct {
 	args    string
 	cascade string
@@ -2230,6 +2234,7 @@ type applyConfig struct {
 	postRendererArgs        []string
 	kubeVersion             string
 	suppressOutputLineRegex []string
+	showOnly                []string
 
 	// template-only options
 	includeCRDs, skipTests       bool
@@ -2406,6 +2411,10 @@ func (a applyConfig) KubeVersion() string {
 	return a.kubeVersion
 }
 
+func (a applyConfig) ShowOnly() []string {
+	return a.showOnly
+}
+
 type depsConfig struct {
 	skipRepos              bool
 	includeTransitiveNeeds bool

pkg/app/config.go

@@ -233,6 +233,7 @@ type TemplateConfigProvider interface {
 	OutputDir() string
 	IncludeCRDs() bool
 	KubeVersion() string
+	ShowOnly() []string
 
 	DAGConfig
 

pkg/app/testdata/app_template_test/show-only

@@ -0,0 +1,113 @@
+processing file "helmfile.yaml" in directory "."
+changing working directory to "/path/to"
+first-pass rendering starting for "helmfile.yaml.part.0": inherited=&{default  map[] map[]}, overrode=<nil>
+first-pass uses: &{default  map[] map[]}
+first-pass rendering output of "helmfile.yaml.part.0":
+ 0: 
+ 1: releases:
+ 2: - name: logging
+ 3:   chart: incubator/raw
+ 4:   namespace: kube-system
+ 5: 
+ 6: - name: kubernetes-external-secrets
+ 7:   chart: incubator/raw
+ 8:   namespace: kube-system
+ 9:   needs:
+10:   - kube-system/logging
+11: 
+12: - name: external-secrets
+13:   chart: incubator/raw
+14:   namespace: default
+15:   labels:
+16:     app: test
+17:   needs:
+18:   - kube-system/kubernetes-external-secrets
+19: 
+20: - name: my-release
+21:   chart: incubator/raw
+22:   namespace: default
+23:   labels:
+24:     app: test
+25:   needs:
+26:   - default/external-secrets
+27: 
+28: 
+29: # Disabled releases are treated as missing
+30: - name: disabled
+31:   chart: incubator/raw
+32:   namespace: kube-system
+33:   installed: false
+34: 
+35: - name: test2
+36:   chart: incubator/raw
+37:   needs:
+38:   - kube-system/disabled
+39: 
+40: - name: test3
+41:   chart: incubator/raw
+42:   needs:
+43:   - test2
+44: 
+
+first-pass produced: &{default  map[] map[]}
+first-pass rendering result of "helmfile.yaml.part.0": {default  map[] map[]}
+vals:
+map[]
+defaultVals:[]
+second-pass rendering result of "helmfile.yaml.part.0":
+ 0: 
+ 1: releases:
+ 2: - name: logging
+ 3:   chart: incubator/raw
+ 4:   namespace: kube-system
+ 5: 
+ 6: - name: kubernetes-external-secrets
+ 7:   chart: incubator/raw
+ 8:   namespace: kube-system
+ 9:   needs:
+10:   - kube-system/logging
+11: 
+12: - name: external-secrets
+13:   chart: incubator/raw
+14:   namespace: default
+15:   labels:
+16:     app: test
+17:   needs:
+18:   - kube-system/kubernetes-external-secrets
+19: 
+20: - name: my-release
+21:   chart: incubator/raw
+22:   namespace: default
+23:   labels:
+24:     app: test
+25:   needs:
+26:   - default/external-secrets
+27: 
+28: 
+29: # Disabled releases are treated as missing
+30: - name: disabled
+31:   chart: incubator/raw
+32:   namespace: kube-system
+33:   installed: false
+34: 
+35: - name: test2
+36:   chart: incubator/raw
+37:   needs:
+38:   - kube-system/disabled
+39: 
+40: - name: test3
+41:   chart: incubator/raw
+42:   needs:
+43:   - test2
+44: 
+
+merged environment: &{default  map[] map[]}
+WARNING: release test2 needs disabled, but disabled is not installed due to installed: false. Either mark disabled as installed or remove disabled from test2's needs
+1 release(s) matching name=logging found in helmfile.yaml
+
+processing 1 groups of releases in this order:
+GROUP RELEASES
+1     default/kube-system/logging
+
+processing releases in group 1/1: default/kube-system/logging
+changing working directory back to "/path/to"

pkg/config/template.go

@@ -38,6 +38,8 @@ type TemplateOptions struct {
 	PostRendererArgs []string
 	// KubeVersion is the kube-version flag
 	KubeVersion string
+	// Propagate '--show-only` to helm template
+	ShowOnly []string
 }
 
 // NewTemplateOptions creates a new Apply
@@ -137,3 +139,8 @@ func (t *TemplateImpl) PostRendererArgs() []string {
 func (t *TemplateImpl) KubeVersion() string {
 	return t.TemplateOptions.KubeVersion
 }
+
+// ShowOnly returns the ShowOnly.
+func (t *TemplateImpl) ShowOnly() []string {
+	return t.TemplateOptions.ShowOnly
+}

pkg/state/helmx.go

@@ -119,6 +119,20 @@ func (st *HelmState) appendCascadeFlags(flags []string, helm helmexec.Interface,
 	return flags
 }
 
+// append show-only flags to helm flags
+func (st *HelmState) appendShowOnlyFlags(flags []string, showOnly []string) []string {
+	showOnlyFlags := []string{}
+	if len(showOnly) != 0 {
+		showOnlyFlags = showOnly
+	}
+	for _, arg := range showOnlyFlags {
+		if arg != "" {
+			flags = append(flags, "--show-only", arg)
+		}
+	}
+	return flags
+}
+
 type Chartify struct {
 	Opts  *chartify.ChartifyOpts
 	Clean func()

pkg/state/helmx_test.go

@@ -249,3 +249,30 @@ func TestAppendSuppressOutputLineRegexFlags(t *testing.T) {
 		})
 	}
 }
+
+func TestAppendShowOnlyFlags(t *testing.T) {
+	tests := []struct {
+		name         string
+		templateOpts []string
+		expected     []string
+	}{
+		{
+			name:         "cli template show only with 1 file",
+			templateOpts: []string{"templates/config.yaml"},
+			expected:     []string{"--show-only", "templates/config.yaml"},
+		},
+		{
+			name:         "cli template show only with 2 files",
+			templateOpts: []string{"templates/config.yaml", "templates/resources.yaml"},
+			expected:     []string{"--show-only", "templates/config.yaml", "--show-only", "templates/resources.yaml"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			st := &HelmState{}
+			got := st.appendShowOnlyFlags([]string{}, tt.templateOpts)
+			require.Equalf(t, tt.expected, got, "appendShowOnlyFlags() = %v, want %v", got, tt.expected)
+		})
+	}
+}

pkg/state/state.go

@@ -1437,6 +1437,7 @@ type TemplateOpts struct {
 	PostRenderer      string
 	PostRendererArgs  []string
 	KubeVersion       string
+	ShowOnly          []string
 }
 
 type TemplateOpt interface{ Apply(*TemplateOpts) }
@@ -2691,15 +2692,18 @@ func (st *HelmState) flagsForTemplate(helm helmexec.Interface, release *ReleaseS
 	postRenderer := ""
 	var postRendererArgs []string
 	kubeVersion := ""
+	var showOnly []string
 	if opt != nil {
 		postRenderer = opt.PostRenderer
 		postRendererArgs = opt.PostRendererArgs
 		kubeVersion = opt.KubeVersion
+		showOnly = opt.ShowOnly
 	}
 	flags = st.appendPostRenderFlags(flags, release, postRenderer)
 	flags = st.appendPostRenderArgsFlags(flags, release, postRendererArgs)
 	flags = st.appendApiVersionsFlags(flags, release, kubeVersion)
 	flags = st.appendChartDownloadTLSFlags(flags, release)
+	flags = st.appendShowOnlyFlags(flags, showOnly)
 
 	common, files, err := st.namespaceAndValuesFlags(helm, release, workerIndex)
 	if err != nil {