ACME DNS challenges

vendor/github.com/xenolf/lego/platform/config/env/env.go

@@ -1,11 +1,15 @@
 package env
 
 import (
+	"errors"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/xenolf/lego/log"
 )
 
 // Get environment variables
@@ -14,7 +18,7 @@ func Get(names ...string) (map[string]string, error) {
 
 	var missingEnvVars []string
 	for _, envVar := range names {
-		value := os.Getenv(envVar)
+		value := GetOrFile(envVar)
 		if value == "" {
 			missingEnvVars = append(missingEnvVars, envVar)
 		}
@@ -28,10 +32,72 @@ func Get(names ...string) (map[string]string, error) {
 	return values, nil
 }
 
+// GetWithFallback Get environment variable values
+// The first name in each group is use as key in the result map
+//
+//	// LEGO_ONE="ONE"
+//	// LEGO_TWO="TWO"
+//	env.GetWithFallback([]string{"LEGO_ONE", "LEGO_TWO"})
+//	// => "LEGO_ONE" = "ONE"
+//
+// ----
+//
+//	// LEGO_ONE=""
+//	// LEGO_TWO="TWO"
+//	env.GetWithFallback([]string{"LEGO_ONE", "LEGO_TWO"})
+//	// => "LEGO_ONE" = "TWO"
+//
+// ----
+//
+//	// LEGO_ONE=""
+//	// LEGO_TWO=""
+//	env.GetWithFallback([]string{"LEGO_ONE", "LEGO_TWO"})
+//	// => error
+//
+func GetWithFallback(groups ...[]string) (map[string]string, error) {
+	values := map[string]string{}
+
+	var missingEnvVars []string
+	for _, names := range groups {
+		if len(names) == 0 {
+			return nil, errors.New("undefined environment variable names")
+		}
+
+		value, envVar := getOneWithFallback(names[0], names[1:]...)
+		if len(value) == 0 {
+			missingEnvVars = append(missingEnvVars, envVar)
+			continue
+		}
+		values[envVar] = value
+	}
+
+	if len(missingEnvVars) > 0 {
+		return nil, fmt.Errorf("some credentials information are missing: %s", strings.Join(missingEnvVars, ","))
+	}
+
+	return values, nil
+}
+
+func getOneWithFallback(main string, names ...string) (string, string) {
+	value := GetOrFile(main)
+	if len(value) > 0 {
+		return value, main
+	}
+
+	for _, name := range names {
+		value := GetOrFile(name)
+		if len(value) > 0 {
+			return value, main
+		}
+	}
+
+	return "", main
+}
+
 // GetOrDefaultInt returns the given environment variable value as an integer.
 // Returns the default if the envvar cannot be coopered to an int, or is not found.
 func GetOrDefaultInt(envVar string, defaultValue int) int {
-	v, err := strconv.Atoi(os.Getenv(envVar))
+	v, err := strconv.Atoi(GetOrFile(envVar))
 	if err != nil {
 		return defaultValue
 	}
@@ -53,7 +119,7 @@ func GetOrDefaultSecond(envVar string, defaultValue time.Duration) time.Duration
 // GetOrDefaultString returns the given environment variable value as a string.
 // Returns the default if the envvar cannot be find.
 func GetOrDefaultString(envVar string, defaultValue string) string {
-	v := os.Getenv(envVar)
+	v := GetOrFile(envVar)
 	if len(v) == 0 {
 		return defaultValue
 	}
@@ -64,10 +130,34 @@ func GetOrDefaultString(envVar string, defaultValue string) string {
 // GetOrDefaultBool returns the given environment variable value as a boolean.
 // Returns the default if the envvar cannot be coopered to a boolean, or is not found.
 func GetOrDefaultBool(envVar string, defaultValue bool) bool {
-	v, err := strconv.ParseBool(os.Getenv(envVar))
+	v, err := strconv.ParseBool(GetOrFile(envVar))
 	if err != nil {
 		return defaultValue
 	}
 
 	return v
 }
+
+// GetOrFile Attempts to resolve 'key' as an environment variable.
+// Failing that, it will check to see if '<key>_FILE' exists.
+// If so, it will attempt to read from the referenced file to populate a value.
+func GetOrFile(envVar string) string {
+	envVarValue := os.Getenv(envVar)
+	if envVarValue != "" {
+		return envVarValue
+	}
+
+	fileVar := envVar + "_FILE"
+	fileVarValue := os.Getenv(fileVar)
+	if fileVarValue == "" {
+		return envVarValue
+	}
+
+	fileContents, err := ioutil.ReadFile(fileVarValue)
+	if err != nil {
+		log.Printf("Failed to read the file %s (defined by env var %s): %s", fileVarValue, fileVar, err)
+		return ""
+	}
+
+	return string(fileContents)
+}