feat: common labels for all releases in a helmfile (#1415)

This adds `comonLabels` option to helmfile by:

- Adding `CommonLabels` to HelmState
- Changing `markExcludedReleases` and `ListReleases` functions to merge common labels into release labels

Resolves #1266

README.md

@@ -103,6 +103,9 @@ helmDefaults:
   # when using helm 3.2+, automatically create release namespaces if they do not exist (default true)
   createNamespace: true
 
+# these labels will be applied to all releases in a Helmfile. Useful in templating if you have a helmfile per environment or customer and don't want to copy the same label to each release
+commonLabels:
+  hello: world
 
 # The desired states of Helm releases.
 #
@@ -522,6 +525,41 @@ The `selector` parameter can be specified multiple times. Each parameter is reso
 
 In addition to user supplied labels, the name, the namespace, and the chart are available to be used as selectors.  The chart will just be the chart name excluding the repository (Example `stable/filebeat` would be selected using `--selector chart=filebeat`).
 
+`commonLabels` can be used when you want to apply the same label to all releases and use [templating](##Templates) based on that.
+For instance, you install a number of charts on every customer but need to provide different values file per customer.
+
+templates/common.yaml:
+
+```
+templates:
+  nginx: &nginx
+    name: nginx
+    chart: stable/nginx-ingress
+    values:
+    - ../values/common/{{ .Release.Name }}.yaml
+    - ../values/{{ .Release.Labels.customer }}/{{ .Release.Name }}.yaml
+
+  cert-manager: &cert-manager
+    name: cert-manager
+    chart: jetstack/cert-manager
+    values:
+    - ../values/common/{{ .Release.Name }}.yaml
+    - ../values/{{ .Release.Labels.customer }}/{{ .Release.Name }}.yaml
+```
+
+helmfile.yaml:
+
+```
+{{ readFile "templates/common.yaml" }}
+
+commonLabels:
+  customer: company
+
+releases:
+- <<: *nginx
+- <<: *cert-manager
+```
+
 ## Templates
 
 You can use go's text/template expressions in `helmfile.yaml` and `values.yaml.gotmpl` (templated helm values files). `values.yaml` references will be used verbatim. In other words:

pkg/app/app.go

@@ -416,6 +416,12 @@ func (a *App) ListReleases(c ListConfigProvider) error {
 			//var releases m
 			for _, r := range run.state.Releases {
 				labels := ""
+				if r.Labels == nil {
+					r.Labels = map[string]string{}
+				}
+				for k, v := range run.state.CommonLabels {
+					r.Labels[k] = v
+				}
 				for k, v := range r.Labels {
 					labels = fmt.Sprintf("%s,%s:%s", labels, k, v)
 				}

pkg/app/app_test.go

@@ -4,8 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"github.com/google/go-cmp/cmp"
-	"github.com/roboll/helmfile/pkg/remote"
 	"io"
 	"log"
 	"os"
@@ -17,6 +15,9 @@ import (
 	"sync"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
+	"github.com/roboll/helmfile/pkg/remote"
+
 	"github.com/roboll/helmfile/pkg/exectest"
 	"gotest.tools/v3/assert"
 
@@ -4051,6 +4052,8 @@ releases:
 func TestList(t *testing.T) {
 	files := map[string]string{
 		"/path/to/helmfile.d/first.yaml": `
+commonLabels:
+  common: label
 releases:
 - name: myrelease1
   chart: mychart1
@@ -4094,11 +4097,11 @@ releases:
 		assert.NilError(t, err)
 	})
 
-	expected := `NAME      	NAMESPACE	ENABLED	LABELS       
-myrelease1	         	false  	id:myrelease1
-myrelease2	         	true   	             
-myrelease3	         	true   	             
-myrelease4	         	true   	id:myrelease1
+	expected := `NAME      	NAMESPACE	ENABLED	LABELS                    
+myrelease1	         	false  	common:label,id:myrelease1
+myrelease2	         	true   	common:label              
+myrelease3	         	true   	                          
+myrelease4	         	true   	id:myrelease1             
 `
 	assert.Equal(t, expected, out)
 }

pkg/state/state.go

@@ -59,6 +59,7 @@ type HelmState struct {
 	DeprecatedReleases []ReleaseSpec     `yaml:"charts,omitempty"`
 	OverrideNamespace  string            `yaml:"namespace,omitempty"`
 	Repositories       []RepositorySpec  `yaml:"repositories,omitempty"`
+	CommonLabels       map[string]string `yaml:"commonLabels,omitempty"`
 	Releases           []ReleaseSpec     `yaml:"releases,omitempty"`
 	Selectors          []string          `yaml:"-"`
 	ApiVersions        []string          `yaml:"apiVersions,omitempty"`
@@ -1634,14 +1635,14 @@ func (st *HelmState) SelectReleasesWithOverrides() ([]Release, error) {
 	if err != nil {
 		return nil, err
 	}
-	rs, err := markExcludedReleases(st.GetReleasesWithOverrides(), st.Selectors, values)
+	rs, err := markExcludedReleases(st.GetReleasesWithOverrides(), st.Selectors, st.CommonLabels, values)
 	if err != nil {
 		return nil, err
 	}
 	return rs, nil
 }
 
-func markExcludedReleases(releases []ReleaseSpec, selectors []string, values map[string]interface{}) ([]Release, error) {
+func markExcludedReleases(releases []ReleaseSpec, selectors []string, commonLabels map[string]string, values map[string]interface{}) ([]Release, error) {
 	var filteredReleases []Release
 	filters := []ReleaseFilter{}
 	for _, label := range selectors {
@@ -1661,6 +1662,10 @@ func markExcludedReleases(releases []ReleaseSpec, selectors []string, values map
 		// Strip off just the last portion for the name stable/newrelic would give newrelic
 		chartSplit := strings.Split(r.Chart, "/")
 		r.Labels["chart"] = chartSplit[len(chartSplit)-1]
+		//Merge CommonLabels into release labels
+		for k, v := range commonLabels {
+			r.Labels[k] = v
+		}
 		var filterMatch bool
 		for _, f := range filters {
 			if r.Labels == nil {

pkg/state/state_exec_tmpl.go

@@ -83,6 +83,12 @@ func (st *HelmState) ExecuteTemplates() (*HelmState, error) {
 	}
 
 	for i, rt := range st.Releases {
+		if rt.Labels == nil {
+			rt.Labels = map[string]string{}
+		}
+		for k, v := range st.CommonLabels {
+			rt.Labels[k] = v
+		}
 		successFlag := false
 		for it, prev := 0, &rt; it < 6; it++ {
 			tmplData := st.createReleaseTemplateData(prev, vals)