[#158] Support cors

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

CHANGELOG.md

@@ -7,6 +7,7 @@ This document outlines major changes between releases.
 ### Added
 - Support percent-encoding for GET queries (#134)
 - Add `trace_id` to logs (#148)
+- Add `cors` config params (#158)
 
 ### Changed
 - Update go version to 1.22 (#132)

cmd/http-gw/app.go

@@ -97,6 +97,21 @@ type (
 		bufferMaxSizeForPut  uint64
 		namespaceHeader      string
 		defaultNamespaces    []string
+		corsAllowOrigin      string
+		corsAllowMethods     []string
+		corsAllowHeaders     []string
+		corsExposeHeaders    []string
+		corsAllowCredentials bool
+		corsMaxAge           int
+	}
+
+	CORS struct {
+		AllowOrigin      string
+		AllowMethods     []string
+		AllowHeaders     []string
+		ExposeHeaders    []string
+		AllowCredentials bool
+		MaxAge           int
 	}
 )
 
@@ -178,6 +193,12 @@ func (s *appSettings) update(v *viper.Viper, l *zap.Logger) {
 	namespaceHeader := v.GetString(cfgResolveNamespaceHeader)
 	defaultNamespaces := v.GetStringSlice(cfgResolveDefaultNamespaces)
 	indexPage, indexEnabled := fetchIndexPageTemplate(v, l)
+	corsAllowOrigin := v.GetString(cfgCORSAllowOrigin)
+	corsAllowMethods := v.GetStringSlice(cfgCORSAllowMethods)
+	corsAllowHeaders := v.GetStringSlice(cfgCORSAllowHeaders)
+	corsExposeHeaders := v.GetStringSlice(cfgCORSExposeHeaders)
+	corsAllowCredentials := v.GetBool(cfgCORSAllowCredentials)
+	corsMaxAge := fetchCORSMaxAge(v)
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -191,6 +212,12 @@ func (s *appSettings) update(v *viper.Viper, l *zap.Logger) {
 	s.defaultNamespaces = defaultNamespaces
 	s.returnIndexPage = indexEnabled
 	s.indexPageTemplate = indexPage
+	s.corsAllowOrigin = corsAllowOrigin
+	s.corsAllowMethods = corsAllowMethods
+	s.corsAllowHeaders = corsAllowHeaders
+	s.corsExposeHeaders = corsExposeHeaders
+	s.corsAllowCredentials = corsAllowCredentials
+	s.corsMaxAge = corsMaxAge
 }
 
 func (s *appSettings) DefaultTimestamp() bool {
@@ -220,6 +247,29 @@ func (s *appSettings) IndexPageTemplate() string {
 	return s.indexPageTemplate
 }
 
+func (s *appSettings) CORS() CORS {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	allowMethods := make([]string, len(s.corsAllowMethods))
+	copy(allowMethods, s.corsAllowMethods)
+
+	allowHeaders := make([]string, len(s.corsAllowHeaders))
+	copy(allowHeaders, s.corsAllowHeaders)
+
+	exposeHeaders := make([]string, len(s.corsExposeHeaders))
+	copy(exposeHeaders, s.corsExposeHeaders)
+
+	return CORS{
+		AllowOrigin:      s.corsAllowOrigin,
+		AllowMethods:     allowMethods,
+		AllowHeaders:     allowHeaders,
+		ExposeHeaders:    exposeHeaders,
+		AllowCredentials: s.corsAllowCredentials,
+		MaxAge:           s.corsMaxAge,
+	}
+}
+
 func (s *appSettings) ClientCut() bool {
 	s.mu.RLock()
 	defer s.mu.RUnlock()

cmd/http-gw/settings.go

@@ -56,6 +56,8 @@ const (
 
 	defaultReconnectInterval = time.Minute
 
+	defaultCORSMaxAge = 600 // seconds
+
 	cfgServer      = "server"
 	cfgTLSEnabled  = "tls.enabled"
 	cfgTLSCertFile = "tls.cert_file"
@@ -141,6 +143,14 @@ const (
 	cfgResolveNamespaceHeader   = "resolve_bucket.namespace_header"
 	cfgResolveDefaultNamespaces = "resolve_bucket.default_namespaces"
 
+	// CORS.
+	cfgCORSAllowOrigin      = "cors.allow_origin"
+	cfgCORSAllowMethods     = "cors.allow_methods"
+	cfgCORSAllowHeaders     = "cors.allow_headers"
+	cfgCORSExposeHeaders    = "cors.expose_headers"
+	cfgCORSAllowCredentials = "cors.allow_credentials"
+	cfgCORSMaxAge           = "cors.max_age"
+
 	// Command line args.
 	cmdHelp          = "help"
 	cmdVersion       = "version"
@@ -527,6 +537,15 @@ func fetchIndexPageTemplate(v *viper.Viper, l *zap.Logger) (string, bool) {
 	return string(tmpl), true
 }
 
+func fetchCORSMaxAge(v *viper.Viper) int {
+	maxAge := v.GetInt(cfgCORSMaxAge)
+	if maxAge <= 0 {
+		maxAge = defaultCORSMaxAge
+	}
+
+	return maxAge
+}
+
 func fetchServers(v *viper.Viper, log *zap.Logger) []ServerInfo {
 	var servers []ServerInfo
 	seen := make(map[string]struct{})

config/config.env

@@ -126,3 +126,10 @@ HTTP_GW_RESOLVE_BUCKET_DEFAULT_NAMESPACES="" "root"
 # Max attempt to make successful tree request.
 # default value is 0 that means the number of attempts equals to number of nodes in pool.
 HTTP_GW_FROSTFS_TREE_POOL_MAX_ATTEMPTS=0
+
+HTTP_GW_CORS_ALLOW_ORIGIN="*"
+HTTP_GW_CORS_ALLOW_METHODS="GET" "POST"
+HTTP_GW_CORS_ALLOW_HEADERS="*"
+HTTP_GW_CORS_EXPOSE_HEADERS="*"
+HTTP_GW_CORS_ALLOW_CREDENTIALS=false
+HTTP_GW_CORS_MAX_AGE=600

config/config.yaml

@@ -138,3 +138,11 @@ cache:
 resolve_bucket:
   namespace_header: X-Frostfs-Namespace
   default_namespaces: [ "", "root" ]
+
+cors:
+  allow_origin: ""
+  allow_methods: []
+  allow_headers: []
+  expose_headers: []
+  allow_credentials: false
+  max_age: 600

docs/gate-configuration.md

@@ -363,3 +363,27 @@ index_page:
 |-----------------|----------|---------------|---------------|---------------------------------------------------------------------------------|
 | `enabled`       | `bool`   | yes           | `false`       | Flag to enable index_page return if no object with specified S3-name was found. |
 | `template_path` | `string` | yes           | `""`          | Path to .gotmpl file with html template for index_page.                         |
+
+# `cors` section
+
+Parameters for CORS (used in OPTIONS requests and responses in all handlers).
+If values are not set, headers will not be included to response.
+
+```yaml
+cors:
+  allow_origin: "*"
+  allow_methods: ["GET", "HEAD"]
+  allow_headers: ["Authorization"]
+  expose_headers: ["*"]
+  allow_credentials: false
+  max_age: 600
+```
+
+| Parameter           | Type       | SIGHUP reload | Default value | Description                                            |
+|---------------------|------------|---------------|---------------|--------------------------------------------------------|
+| `allow_origin`      | `string`   | yes           |               | Values for `Access-Control-Allow-Origin` headers.      |
+| `allow_methods`     | `[]string` | yes           |               | Values for `Access-Control-Allow-Methods` headers.     |
+| `allow_headers`     | `[]string` | yes           |               | Values for `Access-Control-Allow-Headers` headers.     |
+| `expose_headers`    | `[]string` | yes           |               | Values for `Access-Control-Expose-Headers` headers.    |
+| `allow_credentials` | `bool`     | yes           | `false`       | Values for `Access-Control-Allow-Credentials` headers. |
+| `max_age`           | `int`      | yes           | `600`         | Values for `Access-Control-Max-Age ` headers.          |