feat: config supports variables

.gitignore

@@ -26,6 +26,8 @@ docs/build
 # YAML for testings
 config*.yaml*
 app*.yaml
+variables*.yaml
+variables*.yaml.bak
 
 # IDE
 .idea/

cmd/devstream/apply.go

@@ -19,7 +19,7 @@ DevStream will generate and execute a new plan based on the config file and the
 
 func applyCMDFunc(cmd *cobra.Command, args []string) {
 	log.Info("Apply started.")
-	if err := pluginengine.Apply(configFile, continueDirectly); err != nil {
+	if err := pluginengine.Apply(configFile, varFile, continueDirectly); err != nil {
 		log.Errorf("Apply failed => %s.", err)
 		os.Exit(1)
 	}

cmd/devstream/delete.go

@@ -20,7 +20,7 @@ DevStream will delete everything defined in the config file, regardless of the s
 func deleteCMDFunc(cmd *cobra.Command, args []string) {
 	log.Info("Delete started.")
 
-	if err := pluginengine.Remove(configFile, continueDirectly, isForceDelete); err != nil {
+	if err := pluginengine.Remove(configFile, varFile, continueDirectly, isForceDelete); err != nil {
 		log.Errorf("Delete error: %s.", err)
 		os.Exit(1)
 	}

cmd/devstream/init.go

@@ -16,7 +16,7 @@ var initCMD = &cobra.Command{
 }
 
 func initCMDFunc(cmd *cobra.Command, args []string) {
-	cfg := configloader.LoadConf(configFile)
+	cfg := configloader.LoadConf(configFile, varFile)
 	if cfg == nil {
 		log.Fatal("Failed to load the config file.")
 	}

cmd/devstream/main.go

@@ -13,6 +13,7 @@ import (
 
 var (
 	configFile       string
+	varFile          string
 	pluginDir        string
 	continueDirectly bool
 	isDebug          bool
@@ -41,6 +42,7 @@ func init() {
 	cobra.OnInitialize(initConfig)
 
 	rootCMD.PersistentFlags().StringVarP(&configFile, "config-file", "f", "config.yaml", "config file")
+	rootCMD.PersistentFlags().StringVarP(&varFile, "var-file", "", "variables.yaml", "variables file")
 	rootCMD.PersistentFlags().StringVarP(&pluginDir, "plugin-dir", "d", pluginengine.DefaultPluginDir, "plugins directory")
 	rootCMD.PersistentFlags().BoolVarP(&continueDirectly, "yes", "y", false, "apply/delete directly without confirmation")
 	rootCMD.PersistentFlags().BoolVarP(&isDebug, "debug", "", false, "debug level log")

cmd/devstream/verify.go

@@ -17,7 +17,7 @@ var verifyCMD = &cobra.Command{
 func verifyCMDFunc(cmd *cobra.Command, args []string) {
 	log.Info("Verify started.")
 
-	if pluginengine.Verify(configFile) {
+	if pluginengine.Verify(configFile, varFile) {
 		log.Success("Verify succeeded.")
 	} else {
 		log.Info("Verify finished.")

internal/pkg/configloader/config.go

@@ -48,19 +48,28 @@ func (t *Tool) DeepCopy() *Tool {
 }
 
 // LoadConf reads an input file as a Config struct.
-func LoadConf(fname string) *Config {
-	fileBytes, err := ioutil.ReadFile(fname)
+func LoadConf(configFileName, varFileName string) *Config {
+	configFileBytes, err := ioutil.ReadFile(configFileName)
 	if err != nil {
 		log.Error(err)
 		log.Info("Maybe the default file doesn't exist or you forgot to pass your config file to the \"-f\" option?")
 		log.Info("See \"dtm help\" for more information.")
 		return nil
 	}
 
-	log.Debugf("Config file: \n%s\n", string(fileBytes))
+	log.Debugf("Original config: \n%s\n", string(configFileBytes))
+
+	// handle variables in the config file
+	configFileBytesWithVarsRendered, err := renderVariables(varFileName, configFileBytes)
+	if err != nil {
+		log.Error(err)
+		return nil
+	}
+
+	log.Debugf("Config file after rendering with variables: \n%s\n", string(configFileBytesWithVarsRendered))
 
 	var config Config
-	err = yaml.Unmarshal(fileBytes, &config)
+	err = yaml.Unmarshal(configFileBytesWithVarsRendered, &config)
 	if err != nil {
 		log.Error("Please verify the format of your config file.")
 		log.Errorf("Reading config file failed. %s.", err)

internal/pkg/configloader/variables.go

@@ -0,0 +1,89 @@
+package configloader
+
+import (
+	"bytes"
+	"errors"
+	"html/template"
+	"io/ioutil"
+	"os"
+	"regexp"
+
+	"gopkg.in/yaml.v3"
+
+	"github.com/devstream-io/devstream/pkg/util/log"
+)
+
+const defaultVarFileName = "variables.yaml"
+
+func renderVariables(varFileName string, configFileBytes []byte) ([]byte, error) {
+	// if the var file is default (user didn't overwrite the value with --var-file option)
+	// and the default var file doesn't exist, do nothing
+	// it's OK to not use a var file
+	if defaultVarFileName == varFileName {
+		if _, err := os.Stat(defaultVarFileName); errors.Is(err, os.ErrNotExist) {
+			return configFileBytes, nil
+		}
+	}
+
+	// load variables file
+	variables, err := loadVariablesFilesIntoMap(varFileName)
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+
+	// handle variables format
+	configFileContentString := addDotForVariablesInConfig(string(configFileBytes))
+
+	// render config with variables
+	result, err := renderConfigWithVariables(configFileContentString, variables)
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+
+	return result, nil
+}
+
+func loadVariablesFilesIntoMap(varFileName string) (map[string]interface{}, error) {
+	fileBytes, err := ioutil.ReadFile(varFileName)
+	if err != nil {
+		return nil, err
+	}
+
+	log.Debugf("Variables file: \n%s\n", string(fileBytes))
+
+	variables := make(map[string]interface{})
+	err = yaml.Unmarshal(fileBytes, &variables)
+	if err != nil {
+		return nil, err
+	}
+
+	return variables, nil
+}
+
+// this is because our variables syntax is [[ varName ]]
+// while Go's template is [[ .varName ]]
+func addDotForVariablesInConfig(s string) string {
+	// regex := `\[\[\s*(.*)\s*\]\]`
+	// r := regexp.MustCompile(regex)
+	// return r.ReplaceAllString(s, "[[ .$1 ]]")
+	regex := `\[\[\s*`
+	r := regexp.MustCompile(regex)
+	return r.ReplaceAllString(s, "[[ .")
+}
+
+func renderConfigWithVariables(fileContent string, variables map[string]interface{}) ([]byte, error) {
+	tpl, err := template.New("configfile").Delims("[[", "]]").Parse(fileContent)
+	if err != nil {
+		return nil, err
+	}
+
+	var results bytes.Buffer
+	err = tpl.Execute(&results, variables)
+	if err != nil {
+		return nil, err
+	}
+
+	return results.Bytes(), err
+}

internal/pkg/configloader/variables_test.go

@@ -0,0 +1,37 @@
+package configloader
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAddDotForVariablesInConfigNormal(t *testing.T) {
+	res := addDotForVariablesInConfig("[[varNameA]]")
+	assert.Equal(t, "[[ .varNameA]]", res, "Adding dot for variable names passed.")
+}
+
+func TestAddDotForVariablesInConfigWithSpaces(t *testing.T) {
+	res := addDotForVariablesInConfig("[[  varNameA]]")
+	assert.Equal(t, "[[ .varNameA]]", res, "Adding dot for variable names passed.")
+}
+
+func TestAddDotForVariablesInConfigWithTrailingSpaces(t *testing.T) {
+	res := addDotForVariablesInConfig("[[ varNameA  ]]")
+	assert.Equal(t, "[[ .varNameA  ]]", res, "Adding dot for variable names passed.")
+}
+
+func TestAddDotForVariablesInConfigMultipleVars(t *testing.T) {
+	res := addDotForVariablesInConfig("[[ varNameA ]]/[[ varNameB ]]/[[ varNameC ]]")
+	assert.Equal(t, "[[ .varNameA ]]/[[ .varNameB ]]/[[ .varNameC ]]", res, "Adding dot for variable names passed.")
+}
+
+func TestRenderConfigWithVariables(t *testing.T) {
+	variables := map[string]interface{}{
+		"varNameA": "A",
+		"varNameB": "B",
+	}
+	result, err := renderConfigWithVariables("[[ .varNameA ]]/[[ .varNameB]]", variables)
+	assert.Equal(t, err, nil)
+	assert.Equal(t, string(result), "A/B")
+}

internal/pkg/pluginengine/cmd_apply.go

@@ -11,8 +11,8 @@ import (
 	"github.com/devstream-io/devstream/pkg/util/log"
 )
 
-func Apply(configFile string, continueDirectly bool) error {
-	cfg := configloader.LoadConf(configFile)
+func Apply(configFile, varFile string, continueDirectly bool) error {
+	cfg := configloader.LoadConf(configFile, varFile)
 	if cfg == nil {
 		return fmt.Errorf("failed to load the config file")
 	}

internal/pkg/pluginengine/cmd_delete.go

@@ -11,8 +11,8 @@ import (
 	"github.com/devstream-io/devstream/pkg/util/log"
 )
 
-func Remove(configFile string, continueDirectly bool, isForceDelete bool) error {
-	cfg := configloader.LoadConf(configFile)
+func Remove(configFile, varFile string, continueDirectly bool, isForceDelete bool) error {
+	cfg := configloader.LoadConf(configFile, varFile)
 	if cfg == nil {
 		return fmt.Errorf("failed to load the config file")
 	}

internal/pkg/pluginengine/cmd_verify.go

@@ -8,9 +8,9 @@ import (
 )
 
 // Verify returns true if all the comments in this function are met
-func Verify(configFile string) bool {
+func Verify(configFile, varFile string) bool {
 	// 1. loading config file succeeded
-	cfg := configloader.LoadConf(configFile)
+	cfg := configloader.LoadConf(configFile, varFile)
 	if cfg == nil {
 		return false
 	}