agent: add "http_config"

This patch adds an "http_config" object to the config file
and moves the "http_api_response_headers" option there.

"http_api_response_headers" is now deprecated in favor of
"http_config.response_headers"

agent/config.go

@@ -129,6 +129,12 @@ type DNSConfig struct {
 	RecursorTimeoutRaw string        `mapstructure:"recursor_timeout" json:"-"`
 }
 
+// HTTPConfig is used to fine tune the Http sub-system.
+type HTTPConfig struct {
+	// ResponseHeaders are used to add HTTP header response fields to the HTTP API responses.
+	ResponseHeaders map[string]string `mapstructure:"response_headers"`
+}
+
 // RetryJoinEC2 is used to configure discovery of instances via Amazon's EC2 api
 type RetryJoinEC2 struct {
 	// The AWS region to look for instances in
@@ -365,6 +371,9 @@ type Config struct {
 	// Domain is the DNS domain for the records. Defaults to "consul."
 	Domain string `mapstructure:"domain"`
 
+	// HTTP configuration
+	HTTPConfig HTTPConfig `mapstructure:"http_config"`
+
 	// Encryption key to use for the Serf communication
 	EncryptKey string `mapstructure:"encrypt" json:"-"`
 
@@ -706,9 +715,6 @@ type Config struct {
 	// send with the update check. This is used to deduplicate messages.
 	DisableAnonymousSignature bool `mapstructure:"disable_anonymous_signature"`
 
-	// HTTPAPIResponseHeaders are used to add HTTP header response fields to the HTTP API responses.
-	HTTPAPIResponseHeaders map[string]string `mapstructure:"http_api_response_headers"`
-
 	// AEInterval controls the anti-entropy interval. This is how often
 	// the agent attempts to reconcile its local state with the server's
 	// representation of our state. Defaults to every 60s.
@@ -759,11 +765,12 @@ type Config struct {
 
 	// deprecated fields
 	// keep them exported since otherwise the error messages don't show up
-	DeprecatedAtlasInfrastructure string `mapstructure:"atlas_infrastructure" json:"-"`
-	DeprecatedAtlasToken          string `mapstructure:"atlas_token" json:"-"`
-	DeprecatedAtlasACLToken       string `mapstructure:"atlas_acl_token" json:"-"`
-	DeprecatedAtlasJoin           bool   `mapstructure:"atlas_join" json:"-"`
-	DeprecatedAtlasEndpoint       string `mapstructure:"atlas_endpoint" json:"-"`
+	DeprecatedAtlasInfrastructure    string            `mapstructure:"atlas_infrastructure" json:"-"`
+	DeprecatedAtlasToken             string            `mapstructure:"atlas_token" json:"-"`
+	DeprecatedAtlasACLToken          string            `mapstructure:"atlas_acl_token" json:"-"`
+	DeprecatedAtlasJoin              bool              `mapstructure:"atlas_join" json:"-"`
+	DeprecatedAtlasEndpoint          string            `mapstructure:"atlas_endpoint" json:"-"`
+	DeprecatedHTTPAPIResponseHeaders map[string]string `mapstructure:"http_api_response_headers"`
 }
 
 // IncomingHTTPSConfig returns the TLS configuration for HTTPS
@@ -1368,6 +1375,19 @@ func DecodeConfig(r io.Reader) (*Config, error) {
 		result.TLSCipherSuites = ciphers
 	}
 
+	// This is for backwards compatibility.
+	// HTTPAPIResponseHeaders has been replaced with HTTPConfig.ResponseHeaders
+	if len(result.DeprecatedHTTPAPIResponseHeaders) > 0 {
+		fmt.Fprintln(os.Stderr, "==> DEPRECATION: http_api_response_headers is deprecated and "+
+			"is no longer used. Please use http_config.response_headers instead.")
+		if result.HTTPConfig.ResponseHeaders == nil {
+			result.HTTPConfig.ResponseHeaders = make(map[string]string)
+		}
+		for field, value := range result.DeprecatedHTTPAPIResponseHeaders {
+			result.HTTPConfig.ResponseHeaders[field] = value
+		}
+		result.DeprecatedHTTPAPIResponseHeaders = nil
+	}
 	return &result, nil
 }
 
@@ -1974,12 +1994,12 @@ func MergeConfig(a, b *Config) *Config {
 		result.SessionTTLMin = b.SessionTTLMin
 		result.SessionTTLMinRaw = b.SessionTTLMinRaw
 	}
-	if len(b.HTTPAPIResponseHeaders) != 0 {
-		if result.HTTPAPIResponseHeaders == nil {
-			result.HTTPAPIResponseHeaders = make(map[string]string)
+	if len(b.HTTPConfig.ResponseHeaders) > 0 {
+		if result.HTTPConfig.ResponseHeaders == nil {
+			result.HTTPConfig.ResponseHeaders = make(map[string]string)
 		}
-		for field, value := range b.HTTPAPIResponseHeaders {
-			result.HTTPAPIResponseHeaders[field] = value
+		for field, value := range b.HTTPConfig.ResponseHeaders {
+			result.HTTPConfig.ResponseHeaders[field] = value
 		}
 	}
 	if len(b.Meta) != 0 {

agent/config_test.go

@@ -332,7 +332,11 @@ func TestDecodeConfig(t *testing.T) {
 		},
 		{
 			in: `{"http_api_response_headers":{"a":"b","c":"d"}}`,
-			c:  &Config{HTTPAPIResponseHeaders: map[string]string{"a": "b", "c": "d"}},
+			c:  &Config{HTTPConfig: HTTPConfig{ResponseHeaders: map[string]string{"a": "b", "c": "d"}}},
+		},
+		{
+			in: `{"http_config":{"response_headers":{"a":"b","c":"d"}}}`,
+			c:  &Config{HTTPConfig: HTTPConfig{ResponseHeaders: map[string]string{"a": "b", "c": "d"}}},
 		},
 		{
 			in: `{"key_file":"a"}`,
@@ -1389,8 +1393,10 @@ func TestMergeConfig(t *testing.T) {
 		},
 		DisableUpdateCheck:        true,
 		DisableAnonymousSignature: true,
-		HTTPAPIResponseHeaders: map[string]string{
-			"Access-Control-Allow-Origin": "*",
+		HTTPConfig: HTTPConfig{
+			ResponseHeaders: map[string]string{
+				"Access-Control-Allow-Origin": "*",
+			},
 		},
 		UnixSockets: UnixSocketConfig{
 			UnixSocketPermissions{

agent/http.go

@@ -162,7 +162,7 @@ func (s *HTTPServer) handler(enableDebug bool) http.Handler {
 // wrap is used to wrap functions to make them more convenient
 func (s *HTTPServer) wrap(handler func(resp http.ResponseWriter, req *http.Request) (interface{}, error)) http.HandlerFunc {
 	return func(resp http.ResponseWriter, req *http.Request) {
-		setHeaders(resp, s.agent.config.HTTPAPIResponseHeaders)
+		setHeaders(resp, s.agent.config.HTTPConfig.ResponseHeaders)
 		setTranslateAddr(resp, s.agent.config.TranslateWanAddrs)
 
 		// Obfuscate any tokens from appearing in the logs

agent/http_test.go

@@ -241,7 +241,7 @@ func TestHTTPAPI_TranslateAddrHeader(t *testing.T) {
 func TestHTTPAPIResponseHeaders(t *testing.T) {
 	t.Parallel()
 	cfg := TestConfig()
-	cfg.HTTPAPIResponseHeaders = map[string]string{
+	cfg.HTTPConfig.ResponseHeaders = map[string]string{
 		"Access-Control-Allow-Origin": "*",
 		"X-XSS-Protection":            "1; mode=block",
 	}

website/source/docs/agent/options.html.md

@@ -199,7 +199,7 @@ will exit with an error at startup.
   - Shared credentials file (`~/.aws/credentials` or the path specified by `AWS_SHARED_CREDENTIALS_FILE`)
   - ECS task role metadata (container-specific).
   - EC2 instance role metadata.
-  
+
   The only required IAM permission is `ec2:DescribeInstances`, and it is recommended you make a dedicated
   key used only for auto-joining.
 
@@ -437,7 +437,7 @@ Consul will not enable TLS for the HTTP API unless the `https` port has been ass
   "allow" or "deny"; defaults to "allow". The default policy controls the behavior of a token when
   there is no matching rule. In "allow" mode, ACLs are a blacklist: any operation not specifically
   prohibited is allowed. In "deny" mode, ACLs are a whitelist: any operation not
-  specifically allowed is blocked. *Note*: this will not take effect until you've set `acl_datacenter` 
+  specifically allowed is blocked. *Note*: this will not take effect until you've set `acl_datacenter`
   to enable ACL support.
 
 * <a name="acl_down_policy"></a><a href="#acl_down_policy">`acl_down_policy`</a> - Either
@@ -745,6 +745,30 @@ Consul will not enable TLS for the HTTP API unless the `https` port has been ass
       }
     ```
 
+  This has been deprecated in Consul 0.9.0. Setting this value will set `http_config.response_headers`
+  instead for backwards compatibility.
+
+* <a name="http_config"></a><a href="#http_config">`http_config`</a>
+  This object allows setting options for the HTTP API.
+  <br><br>
+  The following sub-keys are available:
+
+  * <a name="response_headers"></a><a href="#response_headers">`response_headers`</a>
+    This object allows adding headers to the HTTP API responses.
+    For example, the following config can be used to enable
+    [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing) on
+    the HTTP API endpoints:
+
+      ```javascript
+        {
+          "http_config": {
+            "response_headers": {
+              "Access-Control-Allow-Origin": "*"
+            }
+          }
+        }
+      ```
+
 * <a name="leave_on_terminate"></a><a href="#leave_on_terminate">`leave_on_terminate`</a> If
   enabled, when the agent receives a TERM signal, it will send a `Leave` message to the rest
   of the cluster and gracefully leave. The default behavior for this feature varies based on