backend: Move environment based configuration into backend

cmd/restic/global.go

@@ -559,24 +559,10 @@ func parseConfig(loc location.Location, opts options.Options) (interface{}, erro
 
 	case "s3":
 		cfg := loc.Config.(s3.Config)
-		if cfg.KeyID == "" {
-			cfg.KeyID = os.Getenv("AWS_ACCESS_KEY_ID")
-		}
 
-		if cfg.Secret.String() == "" {
+		if err := s3.ApplyEnvironment(&cfg); err != nil {
-			cfg.Secret = options.NewSecretString(os.Getenv("AWS_SECRET_ACCESS_KEY"))
+			return nil, err
 		}
-
-		if cfg.KeyID == "" && cfg.Secret.String() != "" {
-			return nil, errors.Fatalf("unable to open S3 backend: Key ID ($AWS_ACCESS_KEY_ID) is empty")
-		} else if cfg.KeyID != "" && cfg.Secret.String() == "" {
-			return nil, errors.Fatalf("unable to open S3 backend: Secret ($AWS_SECRET_ACCESS_KEY) is empty")
-		}
-
-		if cfg.Region == "" {
-			cfg.Region = os.Getenv("AWS_DEFAULT_REGION")
-		}
-
 		if err := opts.Apply(loc.Scheme, &cfg); err != nil {
 			return nil, err
 		}
@@ -586,10 +572,10 @@ func parseConfig(loc location.Location, opts options.Options) (interface{}, erro
 
 	case "gs":
 		cfg := loc.Config.(gs.Config)
-		if cfg.ProjectID == "" {
-			cfg.ProjectID = os.Getenv("GOOGLE_PROJECT_ID")
-		}
 
+		if err := gs.ApplyEnvironment(&cfg); err != nil {
+			return nil, err
+		}
 		if err := opts.Apply(loc.Scheme, &cfg); err != nil {
 			return nil, err
 		}
@@ -599,18 +585,10 @@ func parseConfig(loc location.Location, opts options.Options) (interface{}, erro
 
 	case "azure":
 		cfg := loc.Config.(azure.Config)
-		if cfg.AccountName == "" {
-			cfg.AccountName = os.Getenv("AZURE_ACCOUNT_NAME")
-		}
 
-		if cfg.AccountKey.String() == "" {
+		if err := azure.ApplyEnvironment(&cfg); err != nil {
-			cfg.AccountKey = options.NewSecretString(os.Getenv("AZURE_ACCOUNT_KEY"))
+			return nil, err
 		}
-
-		if cfg.AccountSAS.String() == "" {
-			cfg.AccountSAS = options.NewSecretString(os.Getenv("AZURE_ACCOUNT_SAS"))
-		}
-
 		if err := opts.Apply(loc.Scheme, &cfg); err != nil {
 			return nil, err
 		}
@@ -635,22 +613,9 @@ func parseConfig(loc location.Location, opts options.Options) (interface{}, erro
 	case "b2":
 		cfg := loc.Config.(b2.Config)
 
-		if cfg.AccountID == "" {
+		if err := b2.ApplyEnvironment(&cfg); err != nil {
-			cfg.AccountID = os.Getenv("B2_ACCOUNT_ID")
+			return nil, err
 		}
-
-		if cfg.AccountID == "" {
-			return nil, errors.Fatalf("unable to open B2 backend: Account ID ($B2_ACCOUNT_ID) is empty")
-		}
-
-		if cfg.Key.String() == "" {
-			cfg.Key = options.NewSecretString(os.Getenv("B2_ACCOUNT_KEY"))
-		}
-
-		if cfg.Key.String() == "" {
-			return nil, errors.Fatalf("unable to open B2 backend: Key ($B2_ACCOUNT_KEY) is empty")
-		}
-
 		if err := opts.Apply(loc.Scheme, &cfg); err != nil {
 			return nil, err
 		}

internal/backend/azure/config.go

@@ -1,6 +1,7 @@
 package azure
 
 import (
+	"os"
 	"path"
 	"strings"
 
@@ -53,3 +54,20 @@ func ParseConfig(s string) (interface{}, error) {
 	cfg.Prefix = prefix
 	return cfg, nil
 }
+
+// ApplyEnvironment saves values from the environment to the config.
+func ApplyEnvironment(cfgRaw interface{}) error {
+	cfg := cfgRaw.(*Config)
+	if cfg.AccountName == "" {
+		cfg.AccountName = os.Getenv("AZURE_ACCOUNT_NAME")
+	}
+
+	if cfg.AccountKey.String() == "" {
+		cfg.AccountKey = options.NewSecretString(os.Getenv("AZURE_ACCOUNT_KEY"))
+	}
+
+	if cfg.AccountSAS.String() == "" {
+		cfg.AccountSAS = options.NewSecretString(os.Getenv("AZURE_ACCOUNT_SAS"))
+	}
+	return nil
+}

internal/backend/b2/config.go

@@ -1,6 +1,7 @@
 package b2
 
 import (
+	"os"
 	"path"
 	"regexp"
 	"strings"
@@ -79,3 +80,24 @@ func ParseConfig(s string) (interface{}, error) {
 
 	return cfg, nil
 }
+
+// ApplyEnvironment saves values from the environment to the config.
+func ApplyEnvironment(cfgRaw interface{}) error {
+	cfg := cfgRaw.(*Config)
+	if cfg.AccountID == "" {
+		cfg.AccountID = os.Getenv("B2_ACCOUNT_ID")
+	}
+
+	if cfg.AccountID == "" {
+		return errors.Fatalf("unable to open B2 backend: Account ID ($B2_ACCOUNT_ID) is empty")
+	}
+
+	if cfg.Key.String() == "" {
+		cfg.Key = options.NewSecretString(os.Getenv("B2_ACCOUNT_KEY"))
+	}
+
+	if cfg.Key.String() == "" {
+		return errors.Fatalf("unable to open B2 backend: Key ($B2_ACCOUNT_KEY) is empty")
+	}
+	return nil
+}

internal/backend/gs/config.go

@@ -1,6 +1,7 @@
 package gs
 
 import (
+	"os"
 	"path"
 	"strings"
 
@@ -56,3 +57,12 @@ func ParseConfig(s string) (interface{}, error) {
 	cfg.Prefix = prefix
 	return cfg, nil
 }
+
+// ApplyEnvironment saves values from the environment to the config.
+func ApplyEnvironment(cfgRaw interface{}) error {
+	cfg := cfgRaw.(*Config)
+	if cfg.ProjectID == "" {
+		cfg.ProjectID = os.Getenv("GOOGLE_PROJECT_ID")
+	}
+	return nil
+}

internal/backend/s3/config.go

@@ -2,6 +2,7 @@ package s3
 
 import (
 	"net/url"
+	"os"
 	"path"
 	"strings"
 
@@ -91,3 +92,27 @@ func createConfig(endpoint, bucket, prefix string, useHTTP bool) (interface{}, e
 	cfg.Prefix = prefix
 	return cfg, nil
 }
+
+// ApplyEnvironment saves values from the environment to the config.
+func ApplyEnvironment(cfgRaw interface{}) error {
+	cfg := cfgRaw.(*Config)
+	if cfg.KeyID == "" {
+		cfg.KeyID = os.Getenv("AWS_ACCESS_KEY_ID")
+	}
+
+	if cfg.Secret.String() == "" {
+		cfg.Secret = options.NewSecretString(os.Getenv("AWS_SECRET_ACCESS_KEY"))
+	}
+
+	if cfg.KeyID == "" && cfg.Secret.String() != "" {
+		return errors.Fatalf("unable to open S3 backend: Key ID ($AWS_ACCESS_KEY_ID) is empty")
+	} else if cfg.KeyID != "" && cfg.Secret.String() == "" {
+		return errors.Fatalf("unable to open S3 backend: Secret ($AWS_SECRET_ACCESS_KEY) is empty")
+	}
+
+	if cfg.Region == "" {
+		cfg.Region = os.Getenv("AWS_DEFAULT_REGION")
+	}
+
+	return nil
+}