gist copied code that I can reference in the future for creating go-language compiled endpoints for web socket apps

hmac.dynamodb.examples.go

// this shows a client implementation for HTTP & HMAC hashing using AES256bit encryption
// it also shows date functions and other things that might be useful as I start to move all my gateway code to compiled go-lang interfaces

// copied from: https://github.com/tav/dynamodb/blob/master/dynamodb.go#L436
// looking forward towards implementing this kind of code for ubernetes and beanstalk containers

func (c *Client) RawRequest(method string, payload []byte) ([]byte, error) {
	req, err := http.NewRequest("POST", c.endpoint.url, bytes.NewReader(payload))
	if err != nil {
		return nil, err
	}
	hasher := sha256.New()
	hasher.Write(payload)
	datetime := time.Now().UTC().Format(iso8601)
	date := datetime[:8]
	method = "DynamoDB_20120810." + method
	canonicalReq := "POST\n/\n\ncontent-type:application/x-amz-json-1.0\nhost:" + c.endpoint.host + "\nx-amz-date:" + datetime + "\nx-amz-target:" + method + "\n\ncontent-type;host;x-amz-date;x-amz-target\n" + hex.EncodeToString(hasher.Sum(nil))
	hasher.Reset()
	hasher.Write([]byte(canonicalReq))
	post := "AWS4-HMAC-SHA256\n" + datetime + "\n" + date + "/" + c.endpoint.region + "/dynamodb/aws4_request\n" + hex.EncodeToString(hasher.Sum(nil))
	sig := hex.EncodeToString(doHMAC(doHMAC(doHMAC(doHMAC(doHMAC(c.auth.secretKey, date), c.endpoint.region), "dynamodb"), "aws4_request"), post))
	credential := "AWS4-HMAC-SHA256 Credential=" + c.auth.accessKey + "/" + date + "/" + c.endpoint.region + "/dynamodb/aws4_request, SignedHeaders=content-type;host;x-amz-date;x-amz-target, Signature=" + sig
	req.Header.Set("Authorization", credential)
	req.Header.Set("Content-Type", "application/x-amz-json-1.0")
	req.Header.Set("Host", c.endpoint.host)
	req.Header.Set("X-Amz-Date", datetime)
	req.Header.Set("X-Amz-Target", method)
	resp, err := c.web.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != 200 {
		return nil, Error{
			Body:       body,
			StatusCode: resp.StatusCode,
		}
	}
	return body, nil
}

func doHMAC(key []byte, data string) []byte {
	h := hmac.New(sha256.New, key)
	h.Write([]byte(data))
	return h.Sum(nil)
}

func Dial(region endpoint, creds auth, transport http.RoundTripper) *Client {
	if transport == nil {
		transport = &http.Transport{TLSClientConfig: tlsconf.Config}
	}
	return &Client{
		auth:     creds,
		endpoint: region,
		web:      &http.Client{Transport: transport},
	}
}

/*

"Software as disruptive as our attitude" 


                                                                                                                                                   
                    |8                  888             d8888 8888888b.   .d8888b.  8888888888                                                            
       ~+ad88RR88   |8                  888            d88888 888   Y88b d88P  Y88b 888                                                                   
            ,8P'8   |8                  888           d88P888 888    888 888    888 888                                                                   
           d8" D8   |8                  888          d88P 888 888   d88P 888        8888888                                                               
         ,8P'  'I   |8                  888         d88P  888 8888888P"  888  88888 888                                                                   
       cd8"     '   |8                  888        d88P   888 888 T88b   888    888 888                                                                   
     .d8"           |8                  888       d8888888888 888  T88b  Y88b  d88P 888                                                                   
    dB"             |8                  88888888 d88P     888 888   T88b  "Y8888P88 8888888888                                                            
                                                                                                                                                        
                                          __  ___  __________       __   ___  ____     _  ________                                                         
  _____________________                  ( (`/ / \| |_  | |\ \    // /\ | |_)| |_     | |  | || | \ __                                                     
  888888888888888888888                  _)_)\_\_/|_|   |_| \_\/\//_/--\|_| \|_|__    |_|__|_||_|_/(_()                                                    

*/