feat: Helmfile renders *.yaml.gotmpl in a K8s manifests/kustomization directory (#1745)

Related to #494

This feature is mostly a built-in alternative to the `incubator/raw` chart without external dependency and has
access to helmfile's own template functions and template data.

The expected use-case of this feature is to add arbitrary K8s resources to your deployment.

Unlike the original issue raised in #494 this doesn't enable you to add arbitary resources to a release. That's another story. But this would be a good foundation for that, too.

go.mod

@@ -28,7 +28,7 @@ require (
 	github.com/spf13/cobra v1.1.1
 	github.com/tatsushid/go-prettytable v0.0.0-20141013043238-ed2d14c29939
 	github.com/urfave/cli v1.22.5
-	github.com/variantdev/chartify v0.6.0
+	github.com/variantdev/chartify v0.7.0
 	github.com/variantdev/dag v0.0.0-20191028002400-bb0b3c785363
 	github.com/variantdev/vals v0.13.0
 	go.uber.org/multierr v1.6.0

go.sum

@@ -573,6 +573,8 @@ github.com/urfave/cli v1.22.5 h1:lNq9sAHXK2qfdI8W+GRItjCEkI+2oR4d+MEHy1CKXoU=
 github.com/urfave/cli v1.22.5/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
 github.com/variantdev/chartify v0.6.0 h1:QQ00a8Vtuhk6F9jeTZJEXV2g0zRXhYG43xovWZrc3ac=
 github.com/variantdev/chartify v0.6.0/go.mod h1:qF4XzQlkfH/6k2jAi1hLas+lK4zSCa8kY+r5JdmLA68=
+github.com/variantdev/chartify v0.7.0 h1:LQU9bW734CPTIRRx9AG6rIolqW3GgbqaFZQTOCNOfn8=
+github.com/variantdev/chartify v0.7.0/go.mod h1:qF4XzQlkfH/6k2jAi1hLas+lK4zSCa8kY+r5JdmLA68=
 github.com/variantdev/dag v0.0.0-20191028002400-bb0b3c785363 h1:KrfQBEUn+wEOQ/6UIfoqRDvn+Q/wZridQ7t0G1vQqKE=
 github.com/variantdev/dag v0.0.0-20191028002400-bb0b3c785363/go.mod h1:pH1TQsNSLj2uxMo9NNl9zdGy01Wtn+/2MT96BrKmVyE=
 github.com/variantdev/vals v0.13.0 h1:zdtTBjoWKkUGdFauxETkDVjqWXdjUNwI+ggWcUmpxv8=

pkg/state/helmx.go

@@ -2,12 +2,13 @@ package state
 
 import (
 	"fmt"
-	"github.com/roboll/helmfile/pkg/helmexec"
-	"github.com/roboll/helmfile/pkg/remote"
-	"github.com/variantdev/chartify"
 	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/roboll/helmfile/pkg/helmexec"
+	"github.com/roboll/helmfile/pkg/remote"
+	"github.com/variantdev/chartify"
 )
 
 type Dependency struct {
@@ -195,6 +196,8 @@ func (st *HelmState) PrepareChartify(helm helmexec.Interface, release *ReleaseSp
 		filesNeedCleaning = append(filesNeedCleaning, generatedFiles...)
 
 		chartify.Opts.ValuesFiles = generatedFiles
+		chartify.Opts.TemplateData = st.newReleaseTemplateData(release)
+		chartify.Opts.TemplateFuncs = st.newReleaseTemplateFuncMap(dir)
 
 		return chartify, clean, nil
 	}

pkg/state/state.go

@@ -2428,10 +2428,22 @@ func (st *HelmState) flagsForLint(helm helmexec.Interface, release *ReleaseSpec,
 	return flags, files, nil
 }
 
-func (st *HelmState) RenderReleaseValuesFileToBytes(release *ReleaseSpec, path string) ([]byte, error) {
+func (st *HelmState) newReleaseTemplateData(release *ReleaseSpec) releaseTemplateData {
 	vals := st.Values()
 	templateData := st.createReleaseTemplateData(release, vals)
 
+	return templateData
+}
+
+func (st *HelmState) newReleaseTemplateFuncMap(dir string) template.FuncMap {
+	r := tmpl.NewFileRenderer(st.readFile, dir, nil)
+
+	return r.Context.CreateFuncMap()
+}
+
+func (st *HelmState) RenderReleaseValuesFileToBytes(release *ReleaseSpec, path string) ([]byte, error) {
+	templateData := st.newReleaseTemplateData(release)
+
 	r := tmpl.NewFileRenderer(st.readFile, filepath.Dir(path), templateData)
 	rawBytes, err := r.RenderToBytes(path)
 	if err != nil {

pkg/tmpl/context_tmpl.go

@@ -6,7 +6,7 @@ import (
 	"text/template"
 )
 
-func (c *Context) newTemplate() *template.Template {
+func (c *Context) CreateFuncMap() template.FuncMap {
 	aliased := template.FuncMap{}
 
 	aliases := map[string]string{
@@ -27,6 +27,12 @@ func (c *Context) newTemplate() *template.Template {
 		funcMap[name] = f
 	}
 
+	return funcMap
+}
+
+func (c *Context) newTemplate() *template.Template {
+	funcMap := c.CreateFuncMap()
+
 	tmpl := template.New("stringTemplate").Funcs(funcMap)
 	if c.preRender {
 		tmpl = tmpl.Option("missingkey=zero")