address changes

tools/expand_template/main.go

@@ -12,26 +12,6 @@ import (
 	"golang.org/x/exp/maps"
 )
 
-var STATUS_REGEX = regexp.MustCompile(`(?m)^([^\s]+)\s+([^\n ]*)$`)
-
-func parseStatusFile(statusFilePath string) (map[string]string, error) {
-	statusFile, err := os.ReadFile(statusFilePath)
-	if err != nil {
-		return nil, err
-	}
-
-	matches := STATUS_REGEX.FindAllStringSubmatch(string(statusFile), -1)
-
-	results := map[string]string{}
-
-	for _, match := range matches {
-		results[match[1]] = match[2]
-	}
-
-	return results, nil
-
-}
-
 func main() {
 	args := os.Args[1:]
 
@@ -52,19 +32,19 @@ func main() {
 	substitutions := map[string]string{}
 	substitutionJson, err := os.ReadFile(args[2])
 	if err != nil {
-		log.Fatal(err)
+		log.Fatal(fmt.Errorf("failed to read substitutions file: %w", err))
 	}
 	if err := json.Unmarshal(substitutionJson, &substitutions); err != nil {
-		log.Fatal(err)
+		log.Fatal(fmt.Errorf("failed to parse substitutions file: %w", err))
 	}
 
 	volatileStatus, err := parseStatusFile(args[3])
 	if err != nil {
-		log.Fatal(err)
+		log.Fatal(fmt.Errorf("failed to parse volatile status file: %w", err))
 	}
 	stableStatus, err := parseStatusFile(args[4])
 	if err != nil {
-		log.Fatal(err)
+		log.Fatal(fmt.Errorf("failed to parse stable status file: %w", err))
 	}
 
 	statuses := map[string]string{}
@@ -80,7 +60,7 @@ func main() {
 
 	contentBytes, err := os.ReadFile(args[0])
 	if err != nil {
-		log.Fatal(err)
+		log.Fatal(fmt.Errorf("failed to read the template file: %w", err))
 	}
 	content := string(contentBytes)
 
@@ -92,5 +72,30 @@ func main() {
 	if executable {
 		mode = 0o777
 	}
-	os.WriteFile(args[1], []byte(content), mode)
+	err = os.WriteFile(args[1], []byte(content), mode)
+	if err != nil {
+		log.Fatal(fmt.Errorf("failed to write output file: %w", err))
+	}
+}
+
+// captures every `KEY VALUE` line in the status file.
+// for explanation see: https://regex101.com/r/B28NN7/1
+var STATUS_REGEX = regexp.MustCompile(`(?m)^([^\s]+)\s+([^\n ]*)$`)
+
+func parseStatusFile(statusFilePath string) (map[string]string, error) {
+	statusFile, err := os.ReadFile(statusFilePath)
+	if err != nil {
+		return nil, err
+	}
+
+	matches := STATUS_REGEX.FindAllStringSubmatch(string(statusFile), -1)
+
+	results := map[string]string{}
+
+	for _, match := range matches {
+		results[match[1]] = match[2]
+	}
+
+	return results, nil
+
 }