Merge pull request #5 from usedatabrew/feat/env-variables

Feat/env variables

public/stream/config_loader.go

@@ -2,12 +2,24 @@ package stream
 
 import (
 	"blink/config"
+	"os"
+	"regexp"
+	"strings"
+
 	"gopkg.in/yaml.v3"
 )
 
+var (
+	envRegex        = regexp.MustCompile(`\${[0-9A-Za-z_.]+(:((\${[^}]+})|[^}])*)?}`)
+	escapedEnvRegex = regexp.MustCompile(`\${({[0-9A-Za-z_.]+(:((\${[^}]+})|[^}])*)?})}`)
+)
+
 func ReadInitConfigFromYaml(configBytes []byte) (config.Configuration, error) {
+	replacedBytes := replaceEnvVariables(configBytes, os.LookupEnv)
+
 	conf := config.Configuration{}
-	err := yaml.Unmarshal(configBytes, &conf)
+	err := yaml.Unmarshal(replacedBytes, &conf)
+
 	config.ValidateConfigSchema(conf)
 	return conf, err
 }
@@ -17,7 +29,25 @@ func ReadDriverConfig[T any](driverConfig interface{}, targetConfig T) (T, error
 	if err != nil {
 		return targetConfig, err
 	}
-	err = yaml.Unmarshal(marshaled, &targetConfig)
+
+	replacedBytes := replaceEnvVariables(marshaled, os.LookupEnv)
+
+	err = yaml.Unmarshal(replacedBytes, &targetConfig)
 
 	return targetConfig, err
 }
+
+func replaceEnvVariables(config []byte, lookupFn func(string) (string, bool)) []byte {
+	replaced := envRegex.ReplaceAllFunc(config, func(content []byte) []byte {
+		var value string
+		if len(content) > 3 {
+			varName := string(content[2 : len(content)-1])
+			value, _ = lookupFn(varName)
+			value = strings.ReplaceAll(value, "\n", "\\n")
+		}
+		return []byte(value)
+	})
+	replaced = escapedEnvRegex.ReplaceAll(replaced, []byte("$$$1"))
+
+	return replaced
+}