Add kanvas-render for rendering kanvas.jsonnet.template to kanvas.yaml with some extvars

Author: mumoshu

app/app.go

@@ -3,8 +3,12 @@ package app
 import (
 	"fmt"
 	"os"
+	"path/filepath"
+	"strings"
 	"time"
 
+	"github.com/goccy/go-yaml"
+
 	"github.com/davinci-std/kanvas/plugin"
 
 	"github.com/davinci-std/kanvas/interpreter"
@@ -13,11 +17,17 @@ import (
 )
 
 type App struct {
-	Config  kanvas.Component
+	Config  Config
 	Runtime *kanvas.Runtime
 	Options kanvas.Options
 }
 
+type Config struct {
+	Raw  []byte
+	Path string
+	kanvas.Component
+}
+
 func New(opts kanvas.Options) (*App, error) {
 	// ts is a timestamp in the format of YYYYMMDDHHMMSS
 	now := time.Now()
@@ -28,23 +38,36 @@ func New(opts kanvas.Options) (*App, error) {
 	}
 	opts.TempDir = tempDir
 
-	c, err := kanvas.LoadConfig(opts)
+	path, err := kanvas.DiscoverConfigFile(opts)
+	if err != nil {
+		return nil, err
+	}
+
+	file, err := kanvas.RenderOrReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	c, err := kanvas.LoadConfig(path, file)
 	if err != nil {
 		return nil, err
 	}
 
 	r := kanvas.NewRuntime()
 
 	return &App{
-		Config:  *c,
+		Config: Config{
+			Raw:       file,
+			Path:      path,
+			Component: *c,
+		},
 		Runtime: r,
 		Options: opts,
 	}, nil
-
 }
 
 func (a *App) newWorkflow() (*kanvas.Workflow, error) {
-	return kanvas.NewWorkflow(a.Config, a.Options)
+	return kanvas.NewWorkflow(a.Config.Component, a.Options)
 }
 
 // Diff shows the diff between the desired state and the current state
@@ -82,6 +105,29 @@ func (a *App) Export(format, dir, kanvasContainerImage string) error {
 	return e.Export(format, dir, kanvasContainerImage)
 }
 
+func (a *App) Render(dir string) error {
+	path := filepath.Base(a.Config.Path)
+
+	const ext = ".template.jsonnet"
+	if strings.HasSuffix(path, ext) {
+		path = path[:len(path)-len(ext)]
+	} else {
+		path = path[:len(path)-len(filepath.Ext(path))]
+	}
+	path = filepath.Join(dir, path+".yaml")
+
+	yamlData, err := yaml.JSONToYAML(a.Config.Raw)
+	if err != nil {
+		return fmt.Errorf("unable to convert json to yaml: %w", err)
+	}
+
+	if err := os.WriteFile(path, yamlData, 0644); err != nil {
+		return fmt.Errorf("unable to write to %s: %w", path, err)
+	}
+
+	return nil
+}
+
 func (a *App) Output(format, op, target string) error {
 	wf, err := a.newWorkflow()
 	if err != nil {

cmd/root.go

@@ -95,6 +95,24 @@ func Root() *cobra.Command {
 		cmd.AddCommand(export)
 	}
 
+	{
+		var (
+			renderDir string
+		)
+		render := &cobra.Command{
+			Use:   "export",
+			Short: "Render the kanvas.template.jsonnet to kanvas.yaml",
+			RunE: func(cmd *cobra.Command, args []string) error {
+				return run(cmd, opts, func(a *app.App) error {
+					cmd.SilenceUsage = true
+					return a.Render(renderDir)
+				})
+			},
+		}
+		render.Flags().StringVarP(&renderDir, "dir", "d", "", "Writes the rendered kanvas.yaml to this directory")
+		cmd.AddCommand(render)
+	}
+
 	{
 		var (
 			target string

convention.go

@@ -3,12 +3,14 @@ package kanvas
 import (
 	"fmt"
 	"os"
+	"strings"
 )
 
 const (
-	defaultConfigFileBase    = "kanvas"
-	DefaultConfigFileYAML    = defaultConfigFileBase + ".yaml"
-	DefaultConfigFileJsonnet = defaultConfigFileBase + ".jsonnet"
+	defaultConfigFileBase            = "kanvas"
+	DefaultConfigFileYAML            = defaultConfigFileBase + ".yaml"
+	DefaultConfigFileJsonnet         = defaultConfigFileBase + ".jsonnet"
+	DefaultConfigFileTemplateJsonnet = defaultConfigFileBase + ".template.jsonnet"
 )
 
 // DiscoverConfigFile returns the path to the config file to use.
@@ -22,27 +24,27 @@ func DiscoverConfigFile(opts Options) (string, error) {
 		return opts.ConfigFile, nil
 	}
 
-	var yamlFound, jsonnetFound bool
+	var (
+		found []string
+	)
 
 	if _, err := os.Stat(DefaultConfigFileYAML); err == nil {
-		yamlFound = true
+		found = append(found, DefaultConfigFileYAML)
 	}
 
 	if _, err := os.Stat(DefaultConfigFileJsonnet); err == nil {
-		jsonnetFound = true
+		found = append(found, DefaultConfigFileJsonnet)
 	}
 
-	if yamlFound && jsonnetFound {
-		return "", fmt.Errorf("both %q and %q exist. Please specify the config file with --config-file", DefaultConfigFileYAML, DefaultConfigFileJsonnet)
+	if _, err := os.Stat(DefaultConfigFileTemplateJsonnet); err == nil {
+		found = append(found, DefaultConfigFileTemplateJsonnet)
 	}
 
-	if yamlFound {
-		return DefaultConfigFileYAML, nil
+	if len(found) > 1 {
+		return "", fmt.Errorf("%d config files %s found. Please specify the config file with --config-file", len(found), strings.Join(found, ", "))
+	} else if len(found) == 0 {
+		return "", fmt.Errorf("unable to find config file")
 	}
 
-	if jsonnetFound {
-		return DefaultConfigFileJsonnet, nil
-	}
-
-	return "", fmt.Errorf("unable to find config file")
+	return found[0], nil
 }

kanvas.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/goccy/go-yaml"
 	"github.com/google/go-jsonnet"
@@ -109,16 +110,23 @@ type Kubernetes struct {
 // The jsonnet file can be used to generate the yaml file.
 // If the file is a jsonnet file, it is compiled to json first.
 // The compiled json is then unmarshalled into the Component struct.
-func LoadConfig(opts Options) (*Component, error) {
+func LoadConfig(path string, file []byte) (*Component, error) {
 	var (
 		config Component
 	)
 
-	path, err := DiscoverConfigFile(opts)
-	if err != nil {
+	if err := yaml.Unmarshal(file, &config); err != nil {
 		return nil, err
 	}
 
+	if config.Dir == "" {
+		config.Dir = filepath.Dir(path)
+	}
+
+	return &config, nil
+}
+
+func RenderOrReadFile(path string) ([]byte, error) {
 	file, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
@@ -127,6 +135,18 @@ func LoadConfig(opts Options) (*Component, error) {
 	if filepath.Ext(path) == ".jsonnet" {
 		vm := jsonnet.MakeVM()
 
+		if strings.Contains(filepath.Base(path), ".template.") {
+			vm.ExtVar("template", "true")
+
+			if v := os.Getenv("GITHUB_REPOSITORY"); v != "" {
+				splits := strings.Split(v, "/")
+				vm.ExtVar("github_repo_owner", splits[0])
+				vm.ExtVar("github_repo_name", splits[1])
+			} else {
+				return nil, errors.New(".template.jsonnet requires GITHUB_REPOSITORY to be set to OWNER/REPO_NAME for the template to access `std.extVar(\"github_repo_name\")` and `std.extVar(\"github_repo_owner\")`")
+			}
+		}
+
 		json, err := vm.EvaluateAnonymousSnippet(path, string(file))
 		if err != nil {
 			return nil, err
@@ -135,13 +155,5 @@ func LoadConfig(opts Options) (*Component, error) {
 		file = []byte(json)
 	}
 
-	if err := yaml.Unmarshal(file, &config); err != nil {
-		return nil, err
-	}
-
-	if config.Dir == "" {
-		config.Dir = filepath.Dir(path)
-	}
-
-	return &config, nil
+	return file, nil
 }

kanvas_test.go

@@ -0,0 +1,37 @@
+package kanvas
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestRenderOrReadFile(t *testing.T) {
+	v := os.Getenv("GITHUB_REPOSITORY")
+	defer os.Setenv("GITHUB_REPOSITORY", v)
+
+	os.Setenv("GITHUB_REPOSITORY", "owner/repo")
+
+	f, err := RenderOrReadFile("testdata/render_or_read_file_test.template.jsonnet")
+	require.NoError(t, err)
+
+	require.Equal(t, `{
+   "my_repo_name": "repo-suffix1",
+   "my_repo_owner": "owner-suffix2"
+}
+`, string(f))
+}
+
+func TestRenderOrReadFileNoEnv(t *testing.T) {
+	v := os.Getenv("GITHUB_REPOSITORY")
+	defer os.Setenv("GITHUB_REPOSITORY", v)
+
+	os.Setenv("GITHUB_REPOSITORY", "")
+
+	_, err := RenderOrReadFile("testdata/render_or_read_file_test.template.jsonnet")
+	require.Equal(t,
+		".template.jsonnet requires GITHUB_REPOSITORY to be set to OWNER/REPO_NAME for the template to access `std.extVar(\"github_repo_name\")` and `std.extVar(\"github_repo_owner\")`",
+		err.Error(),
+	)
+}

test/jsonnet_env_github_repository/kanvas.template.jsonnet

@@ -0,0 +1,12 @@
+{
+    components: {
+        product1: {
+            appimage: {
+                dir: "/containerimages/app",
+                docker: {
+                    image: "myregistry/" + std.extVar("github_repo_owner") + "-" + std.extVar("github_repo_name"),
+                }
+            }
+        }
+    }
+}

test/jsonnet_env_github_repository/renders/kanvas.yaml

@@ -0,0 +1,6 @@
+components:
+  product1:
+    appimage:
+      dir: /containerimages/app
+      docker:
+        image: myregistry/myowner-myrepo