NEW FEATURE: Set JS variables from command line (#913)

* Add ability to specify variables that are passed to js

* Use SplitN to respect a = in value part

* Add JSON parsing for cli variables

* Remove JSON parsing for cli variables

* Add a function to set CLI defaults

* Update static.go

commands/commands.go

@@ -160,6 +160,7 @@ type ExecuteDSLArgs struct {
 	JSFile   string
 	JSONFile string
 	DevMode  bool
+	Variable cli.StringSlice
 }
 
 func (args *ExecuteDSLArgs) flags() []cli.Flag {
@@ -182,6 +183,12 @@ func (args *ExecuteDSLArgs) flags() []cli.Flag {
 			Destination: &args.DevMode,
 			Usage:       "Use helpers.js from disk instead of embedded copy",
 		},
+		&cli.StringSliceFlag{
+			Name:        "variable",
+			Aliases:     []string{"v"},
+			Destination: &args.Variable,
+			Usage:       "Add variable that is passed to JS",
+		},
 	}
 }
 

commands/printIR.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"strings"
 
 	"github.com/urfave/cli/v2"
 
@@ -102,7 +103,7 @@ func ExecuteDSL(args ExecuteDSLArgs) (*models.DNSConfig, error) {
 		return nil, fmt.Errorf("no config specified")
 	}
 
-	dnsConfig, err := js.ExecuteJavascript(args.JSFile, args.DevMode)
+	dnsConfig, err := js.ExecuteJavascript(args.JSFile, args.DevMode, stringSliceToMap(args.Variable))
 	if err != nil {
 		return nil, fmt.Errorf("executing %s: %w", args.JSFile, err)
 	}
@@ -139,3 +140,15 @@ func exit(err error) error {
 	}
 	return cli.NewExitError(err, 1)
 }
+
+// stringSliceToMap converts cli.StringSlice to map[string]string for further processing
+func stringSliceToMap(stringSlice cli.StringSlice) map[string]string {
+	mapString := make(map[string]string, len(stringSlice.Value()))
+	for _, values := range stringSlice.Value() {
+		parts := strings.SplitN(values, "=", 2)
+		if len(parts) == 2 {
+			mapString[parts[0]] = parts[1]
+		}
+	}
+	return mapString
+}

pkg/js/helpers.js

@@ -938,3 +938,12 @@ function require_glob() {
     }
     return files
 }
+
+// Set default values for CLI variables
+function CLI_DEFAULTS(defaults) {
+    for (var key in defaults) {
+        if (typeof this[key] === "undefined") {
+            this[key] = defaults[key]
+        }
+    }
+}

pkg/js/js.go

@@ -25,7 +25,7 @@ import (
 var currentDirectory string
 
 // ExecuteJavascript accepts a javascript string and runs it, returning the resulting dnsConfig.
-func ExecuteJavascript(file string, devMode bool) (*models.DNSConfig, error) {
+func ExecuteJavascript(file string, devMode bool, variables map[string]string) (*models.DNSConfig, error) {
 	script, err := ioutil.ReadFile(file)
 	if err != nil {
 		return nil, err
@@ -40,6 +40,11 @@ func ExecuteJavascript(file string, devMode bool) (*models.DNSConfig, error) {
 	vm.Set("REV", reverse)
 	vm.Set("glob", listFiles) // used for require_glob()
 
+	// add cli variables to otto
+	for key, value := range variables {
+		vm.Set(key, value)
+	}
+
 	helperJs := GetHelpers(devMode)
 	// run helper script to prime vm and initialize variables
 	if _, err := vm.Run(helperJs); err != nil {

pkg/js/static.go

@@ -212,8 +212,8 @@ var _escData = map[string]*_escFile{
 	"/helpers.js": {
 		name:    "helpers.js",
 		local:   "pkg/js/helpers.js",
-		size:    27737,
-		modtime: 0,
+		size:    27948,
+		modtime: 1603735487,
 		compressed: `
 H4sIAAAAAAAC/+x9aXcbN7Lod/2Kis67adJuU4tjzz3UcN5wtGR0Rtsh6VzP1dPjhdggCbuJ7gHQoplY
 +e3vYG2gF0rWmSRfnj8kbKBQKBQKtQAFKCo4Bi4YmYnoaGdnbw/O57DJCsAJESCWhMOcpDhWZauCC2AF
@@ -335,7 +335,8 @@ EHNvmM2WBf1sjPHhu3flA7Gj1mtNdviIsYYhw+tBibQc/cie+7MeT8kMd0gsYT3Q8BxgZIfo0j7XDOU5
 ZoqYRZrdd7rqp/d3PCDNkDJZc5JiHZQOeemHOx50CIUfs67kETGvWWdUsCwFRDdrtInVC86ynUlod3eJ
 beolR5SIzZvZEs8+m0jxKhO4bwkj3Nz5oyr+ZTJMLWiSzdRxIE5giVM1FpcpO85UQjdRocNG0pStKTDC
 P/f8XFaliaamF7fJY1IpDu9gALuf+O6ROdecYaleFCWEztIiwdD7xC173KPl8hMGinadzNChRZrGJWb/
-uX/vJFHjaTlKNLR2FFBLOraq23nc+X8BAAD//9enlT5ZbAAA
+uX/vJFHjaTlKNLR2FFBLOraqs6KMhdsRNmyX/R1fnEsiifR7uWdWL86n7jFsm7lru3fi+hmrC8zV+sqb
+sdKu337Gmzu1ebnrTk12q3rVA3Q41XdNzT3u/L8AAAD///wzemcsbQAA
 `,
 	},
 }