Merge pull request #2154 from aws/feat-ua

Modify user agent header syntax and add support for app ID

Author: wty-Bryant

.changelog/750daed90e254d42b50383de16cf6852.json

@@ -0,0 +1,9 @@
+{
+    "id": "750daed9-0e25-4d42-b503-83de16cf6852",
+    "type": "feature",
+    "collapse": true,
+    "description": "Modify user agent syntax and introduce support for optional app identifier in UA header",
+    "modules": [
+        "."
+    ]
+}

aws/config.go

@@ -132,6 +132,14 @@ type Config struct {
 	// `config.LoadDefaultConfig`. You should not populate this structure
 	// programmatically, or rely on the values here within your applications.
 	RuntimeEnvironment RuntimeEnvironment
+
+	// AppId is an optional application specific identifier that can be set.
+	// When set it will be appended to the User-Agent header of every request
+	// in the form of App/{AppId}. This variable is sourced from environment
+	// variable AWS_SDK_UA_APP_ID or the shared config profile attribute sdk_ua_app_id.
+	// See https://docs.aws.amazon.com/sdkref/latest/guide/settings-reference.html for
+	// more information on environment variables and shared config settings.
+	AppID string
 }
 
 // NewConfig returns a new Config pointer that can be chained with builder

aws/middleware/user_agent.go

@@ -59,6 +59,11 @@ func (k SDKAgentKeyType) string() string {
 
 const execEnvVar = `AWS_EXECUTION_ENV`
 
+var validChars = map[rune]bool{
+	'!': true, '#': true, '$': true, '%': true, '&': true, '\'': true, '*': true, '+': true,
+	'-': true, '.': true, '^': true, '_': true, '`': true, '|': true, '~': true,
+}
+
 // requestUserAgent is a build middleware that set the User-Agent for the request.
 type requestUserAgent struct {
 	sdkAgent, userAgent *smithyhttp.UserAgentBuilder
@@ -178,24 +183,24 @@ func getOrAddRequestUserAgent(stack *middleware.Stack) (*requestUserAgent, error
 
 // AddUserAgentKey adds the component identified by name to the User-Agent string.
 func (u *requestUserAgent) AddUserAgentKey(key string) {
-	u.userAgent.AddKey(key)
+	u.userAgent.AddKey(strings.Map(rules, key))
 }
 
 // AddUserAgentKeyValue adds the key identified by the given name and value to the User-Agent string.
 func (u *requestUserAgent) AddUserAgentKeyValue(key, value string) {
-	u.userAgent.AddKeyValue(key, value)
+	u.userAgent.AddKeyValue(strings.Map(rules, key), strings.Map(rules, value))
 }
 
 // AddUserAgentKey adds the component identified by name to the User-Agent string.
 func (u *requestUserAgent) AddSDKAgentKey(keyType SDKAgentKeyType, key string) {
 	// TODO: should target sdkAgent
-	u.userAgent.AddKey(keyType.string() + "/" + key)
+	u.userAgent.AddKey(keyType.string() + "/" + strings.Map(rules, key))
 }
 
 // AddUserAgentKeyValue adds the key identified by the given name and value to the User-Agent string.
 func (u *requestUserAgent) AddSDKAgentKeyValue(keyType SDKAgentKeyType, key, value string) {
 	// TODO: should target sdkAgent
-	u.userAgent.AddKeyValue(keyType.string()+"/"+key, value)
+	u.userAgent.AddKeyValue(keyType.string(), strings.Map(rules, key)+"#"+strings.Map(rules, value))
 }
 
 // ID the name of the middleware.
@@ -241,3 +246,16 @@ func updateHTTPHeader(request *smithyhttp.Request, header string, value string)
 	}
 	request.Header[header] = append(request.Header[header][:0], current)
 }
+
+func rules(r rune) rune {
+	switch {
+	case r >= '0' && r <= '9':
+		return r
+	case r >= 'A' && r <= 'Z' || r >= 'a' && r <= 'z':
+		return r
+	case validChars[r]:
+		return r
+	default:
+		return '-'
+	}
+}