feat: render kustomize into jsonnet (grafana#422)

* feat: render kustomize into jsonnet

* refactor: move ListAsMap

* docs: add TANKA_KUSTOMIZE_PATH to env-vars

docs/docs/env-vars.md

@@ -25,3 +25,8 @@ menu: "References"
 
 **Description**: Path to the `helm` executable  
 **Default**: `$PATH/helm`
+
+### TANKA_KUSTOMIZE_PATH
+
+**Description**: Path to the `kustomize` executable  
+**Default**: `$PATH/kustomize`

pkg/helm/jsonnet.go

@@ -1,14 +1,11 @@
 package helm
 
 import (
-	"bytes"
 	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
-	"text/template"
 
-	"github.com/Masterminds/sprig/v3"
 	"github.com/google/go-jsonnet"
 	"github.com/google/go-jsonnet/ast"
 	"github.com/grafana/tanka/pkg/kubernetes/manifest"
@@ -71,7 +68,7 @@ func NativeFunc(h Helm) *jsonnet.NativeFunction {
 			}
 
 			// convert list to map
-			out, err := listAsMap(list, opts.NameFormat)
+			out, err := manifest.ListAsMap(list, opts.NameFormat)
 			if err != nil {
 				return nil, err
 			}
@@ -98,43 +95,3 @@ func parseOpts(data interface{}) (*JsonnetOpts, error) {
 
 	return &opts, nil
 }
-
-func listAsMap(list manifest.List, nameFormat string) (map[string]interface{}, error) {
-	if nameFormat == "" {
-		nameFormat = DefaultNameFormat
-	}
-
-	tmpl, err := template.New("").
-		Funcs(sprig.TxtFuncMap()).
-		Parse(nameFormat)
-	if err != nil {
-		return nil, fmt.Errorf("Parsing name format: %w", err)
-	}
-
-	out := make(map[string]interface{})
-	for _, m := range list {
-		var buf bytes.Buffer
-		if err := tmpl.Execute(&buf, m); err != nil {
-			return nil, err
-		}
-		name := buf.String()
-
-		if _, ok := out[name]; ok {
-			return nil, ErrorDuplicateName{name: name, format: nameFormat}
-		}
-		out[name] = map[string]interface{}(m)
-	}
-
-	return out, nil
-}
-
-// ErrorDuplicateName means two resources share the same name using the given
-// nameFormat.
-type ErrorDuplicateName struct {
-	name   string
-	format string
-}
-
-func (e ErrorDuplicateName) Error() string {
-	return fmt.Sprintf("Two resources share the same name '%s'. Please adapt the name template '%s'. See https://tanka.dev/helm#two-resources-share-the-same-name", e.name, e.format)
-}

pkg/jsonnet/native/funcs.go

@@ -10,6 +10,7 @@ import (
 	jsonnet "github.com/google/go-jsonnet"
 	"github.com/google/go-jsonnet/ast"
 	"github.com/grafana/tanka/pkg/helm"
+	"github.com/grafana/tanka/pkg/kustomize"
 	"github.com/pkg/errors"
 	yaml "gopkg.in/yaml.v3"
 )
@@ -32,6 +33,7 @@ func Funcs() []*jsonnet.NativeFunction {
 		regexSubst(),
 
 		helm.NativeFunc(helm.ExecHelm{}),
+		kustomize.NativeFunc(kustomize.ExecKustomize{}),
 	}
 }
 

pkg/kubernetes/manifest/errors.go

@@ -66,3 +66,14 @@ func (s SampleString) Indent(n int) string {
 	lines := strings.Split(s.String(), "\n")
 	return indent + strings.Join(lines, "\n"+indent)
 }
+
+// ErrorDuplicateName means two resources share the same name using the given
+// nameFormat.
+type ErrorDuplicateName struct {
+	name   string
+	format string
+}
+
+func (e ErrorDuplicateName) Error() string {
+	return fmt.Sprintf("Two resources share the same name '%s'. Please adapt the name template '%s'.", e.name, e.format)
+}

pkg/kubernetes/manifest/manifest.go

@@ -4,7 +4,9 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"text/template"
 
+	"github.com/Masterminds/sprig/v3"
 	"github.com/pkg/errors"
 	"github.com/stretchr/objx"
 	yaml "gopkg.in/yaml.v2"
@@ -270,3 +272,35 @@ func m2o(m interface{}) objx.Map {
 	}
 	return nil
 }
+
+// DefaultNameFormat to use when no nameFormat is supplied
+const DefaultNameFormat = `{{ print .kind "_" .metadata.name | snakecase }}`
+
+func ListAsMap(list List, nameFormat string) (map[string]interface{}, error) {
+	if nameFormat == "" {
+		nameFormat = DefaultNameFormat
+	}
+
+	tmpl, err := template.New("").
+		Funcs(sprig.TxtFuncMap()).
+		Parse(nameFormat)
+	if err != nil {
+		return nil, fmt.Errorf("Parsing name format: %w", err)
+	}
+
+	out := make(map[string]interface{})
+	for _, m := range list {
+		var buf bytes.Buffer
+		if err := tmpl.Execute(&buf, m); err != nil {
+			return nil, err
+		}
+		name := buf.String()
+
+		if _, ok := out[name]; ok {
+			return nil, ErrorDuplicateName{name: name, format: nameFormat}
+		}
+		out[name] = map[string]interface{}(m)
+	}
+
+	return out, nil
+}

pkg/kubernetes/manifest/manifest_test.go

@@ -90,3 +90,92 @@ spec:
 		t.Error(s)
 	}
 }
+
+func TestListAsMap(t *testing.T) {
+	cases := []struct {
+		name       string
+		list       List
+		result     map[string]interface{}
+		nameFormat string
+		err        error
+	}{
+		{
+			name:       "simple",
+			nameFormat: "", // test it properly defaults to DefaultNameFormat
+			list: List{
+				configMap("foo"),
+				deployment("bar"),
+			},
+			result: map[string]interface{}{
+				"config_map_foo": configMap("foo"),
+				"deployment_bar": deployment("bar"),
+			},
+		},
+		{
+			name: "duplicate-default",
+			list: List{
+				secret("foo", map[string]interface{}{"id": 1}),
+				secret("foo", map[string]interface{}{"id": 2}),
+			},
+			err:    ErrorDuplicateName{name: "secret_foo", format: DefaultNameFormat},
+			result: nil, // expect no result
+		},
+		{
+			name:       "duplicate-custom",
+			nameFormat: `{{ print .metadata.name "_" .data.id }}`,
+			list: List{
+				secret("foo", map[string]interface{}{"id": 1}),
+				secret("foo", map[string]interface{}{"id": 2}),
+			},
+			result: map[string]interface{}{
+				"foo_1": secret("foo", map[string]interface{}{"id": 1}),
+				"foo_2": secret("foo", map[string]interface{}{"id": 2}),
+			},
+			err: nil, // expect no error
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			result, err := ListAsMap(c.list, c.nameFormat)
+			if err != c.err {
+				t.Fatalf("err mismatch: want '%s' but got '%s'", c.err, err)
+			}
+
+			if diff := cmp.Diff(c.result, result); diff != "" {
+				t.Fatal(diff)
+			}
+		})
+	}
+}
+
+func configMap(name string) map[string]interface{} {
+	return map[string]interface{}{
+		"apiVersion": "v1",
+		"kind":       "ConfigMap",
+		"metadata":   map[string]interface{}{"name": name},
+		"data":       map[string]interface{}{},
+	}
+}
+
+func deployment(name string) map[string]interface{} {
+	return map[string]interface{}{
+		"apiVersion": "apps/v1",
+		"kind":       "Deployment",
+		"metadata":   map[string]interface{}{"name": name},
+		"spec":       map[string]interface{}{},
+	}
+}
+
+func secret(name string, data map[string]interface{}) map[string]interface{} {
+	if data == nil {
+		data = map[string]interface{}{}
+	}
+
+	return map[string]interface{}{
+		"apiVersion": "v1",
+		"kind":       "Secret",
+		"metadata":   map[string]interface{}{"name": name},
+		"data":       data,
+	}
+}

pkg/kustomize/build.go

@@ -0,0 +1,40 @@
+package kustomize
+
+import (
+	"bytes"
+	"io"
+	"os"
+
+	"github.com/grafana/tanka/pkg/kubernetes/manifest"
+	"github.com/pkg/errors"
+	yaml "gopkg.in/yaml.v3"
+)
+
+// Build expands a Kustomize into a regular manifest.List using the `kustomize
+// build` command
+func (k ExecKustomize) Build(path string) (manifest.List, error) {
+	cmd := k.cmd("build", path)
+	var buf bytes.Buffer
+	cmd.Stdout = &buf
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Run(); err != nil {
+		return nil, errors.Wrap(err, "Expanding Kustomize")
+	}
+
+	var list manifest.List
+	d := yaml.NewDecoder(&buf)
+	for {
+		var m manifest.Manifest
+		if err := d.Decode(&m); err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, errors.Wrap(err, "Parsing Kustomize output")
+		}
+
+		list = append(list, m)
+	}
+
+	return list, nil
+}