feat(aws): support lambda (#334)

vendor/github.com/apex/gateway/Readme.md

@@ -0,0 +1,34 @@
+<img src="http://tjholowaychuk.com:6000/svg/title/APEX/GATEWAY">
+
+Package gateway provides a drop-in replacement for net/http's `ListenAndServe` for use in AWS Lambda & API Gateway, simply swap it out for `gateway.ListenAndServe`. Extracted from [Up](https://github.com/apex/up) which provides additional middleware features and operational functionality.
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/apex/gateway"
+)
+
+func main() {
+	addr := ":" + os.Getenv("PORT")
+	http.HandleFunc("/", hello)
+	log.Fatal(gateway.ListenAndServe(addr, nil))
+}
+
+func hello(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintln(w, "Hello World from Go")
+}
+```
+
+---
+
+[![GoDoc](https://godoc.org/github.com/apex/up-go?status.svg)](https://godoc.org/github.com/apex/gateway)
+![](https://img.shields.io/badge/license-MIT-blue.svg)
+![](https://img.shields.io/badge/status-stable-green.svg)
+
+<a href="https://apex.sh"><img src="http://tjholowaychuk.com:6000/svg/sponsor"></a>

vendor/github.com/apex/gateway/gateway.go

@@ -0,0 +1,33 @@
+// Package gateway provides a drop-in replacement for net/http.ListenAndServe for use in AWS Lambda & API Gateway.
+package gateway
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/aws/aws-lambda-go/events"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+// ListenAndServe is a drop-in replacement for
+// http.ListenAndServe for use within AWS Lambda.
+//
+// ListenAndServe always returns a non-nil error.
+func ListenAndServe(addr string, h http.Handler) error {
+	if h == nil {
+		h = http.DefaultServeMux
+	}
+
+	lambda.Start(func(ctx context.Context, e events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
+		r, err := NewRequest(ctx, e)
+		if err != nil {
+			return events.APIGatewayProxyResponse{}, err
+		}
+
+		w := NewResponse()
+		h.ServeHTTP(w, r)
+		return w.End(), nil
+	})
+
+	return nil
+}

vendor/github.com/apex/gateway/request.go

@@ -0,0 +1,74 @@
+package gateway
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"github.com/aws/aws-lambda-go/events"
+	"github.com/pkg/errors"
+)
+
+// NewRequest returns a new http.Request from the given Lambda event.
+func NewRequest(ctx context.Context, e events.APIGatewayProxyRequest) (*http.Request, error) {
+	// path
+	u, err := url.Parse(e.Path)
+	if err != nil {
+		return nil, errors.Wrap(err, "parsing path")
+	}
+
+	// querystring
+	q := u.Query()
+	for k, v := range e.QueryStringParameters {
+		q.Set(k, v)
+	}
+	u.RawQuery = q.Encode()
+
+	// base64 encoded body
+	body := e.Body
+	if e.IsBase64Encoded {
+		b, err := base64.StdEncoding.DecodeString(body)
+		if err != nil {
+			return nil, errors.Wrap(err, "decoding base64 body")
+		}
+		body = string(b)
+	}
+
+	// new request
+	req, err := http.NewRequest(e.HTTPMethod, u.String(), strings.NewReader(body))
+	if err != nil {
+		return nil, errors.Wrap(err, "creating request")
+	}
+
+	// remote addr
+	req.RemoteAddr = e.RequestContext.Identity.SourceIP
+
+	// header fields
+	for k, v := range e.Headers {
+		req.Header.Set(k, v)
+	}
+
+	// content-length
+	if req.Header.Get("Content-Length") == "" && body != "" {
+		req.Header.Set("Content-Length", strconv.Itoa(len(body)))
+	}
+
+	// custom fields
+	req.Header.Set("X-Request-Id", e.RequestContext.RequestID)
+	req.Header.Set("X-Stage", e.RequestContext.Stage)
+
+	// xray support
+	if traceID := ctx.Value("x-amzn-trace-id"); traceID != nil {
+		req.Header.Set("X-Amzn-Trace-Id", fmt.Sprintf("%v", traceID))
+	}
+
+	// host
+	req.URL.Host = req.Header.Get("Host")
+	req.Host = req.URL.Host
+
+	return req, nil
+}

vendor/github.com/apex/gateway/response.go

@@ -0,0 +1,110 @@
+package gateway
+
+import (
+	"bytes"
+	"encoding/base64"
+	"net/http"
+	"strings"
+
+	"github.com/aws/aws-lambda-go/events"
+)
+
+// ResponseWriter implements the http.ResponseWriter interface
+// in order to support the API Gateway Lambda HTTP "protocol".
+type ResponseWriter struct {
+	out         events.APIGatewayProxyResponse
+	buf         bytes.Buffer
+	header      http.Header
+	wroteHeader bool
+}
+
+// NewResponse returns a new response writer to capture http output.
+func NewResponse() *ResponseWriter {
+	return &ResponseWriter{}
+}
+
+// Header implementation.
+func (w *ResponseWriter) Header() http.Header {
+	if w.header == nil {
+		w.header = make(http.Header)
+	}
+
+	return w.header
+}
+
+// Write implementation.
+func (w *ResponseWriter) Write(b []byte) (int, error) {
+	if !w.wroteHeader {
+		w.WriteHeader(http.StatusOK)
+	}
+
+	// TODO: HEAD? ignore
+
+	return w.buf.Write(b)
+}
+
+// WriteHeader implementation.
+func (w *ResponseWriter) WriteHeader(status int) {
+	if w.wroteHeader {
+		return
+	}
+
+	if w.Header().Get("Content-Type") == "" {
+		w.Header().Set("Content-Type", "text/plain; charset=utf8")
+	}
+
+	w.out.StatusCode = status
+
+	h := make(map[string]string)
+
+	for k, v := range w.Header() {
+		if len(v) > 0 {
+			h[k] = v[len(v)-1]
+		}
+	}
+
+	w.out.Headers = h
+	w.wroteHeader = true
+}
+
+// End the request.
+func (w *ResponseWriter) End() events.APIGatewayProxyResponse {
+	w.out.IsBase64Encoded = isBinary(w.header)
+
+	if w.out.IsBase64Encoded {
+		w.out.Body = base64.StdEncoding.EncodeToString(w.buf.Bytes())
+	} else {
+		w.out.Body = w.buf.String()
+	}
+
+	return w.out
+}
+
+// isBinary returns true if the response reprensents binary.
+func isBinary(h http.Header) bool {
+	if !isTextMime(h.Get("Content-Type")) {
+		return true
+	}
+
+	if h.Get("Content-Encoding") == "gzip" {
+		return true
+	}
+
+	return false
+}
+
+// isTextMime returns true if the content type represents textual data.
+func isTextMime(kind string) bool {
+	switch {
+	case strings.HasSuffix(kind, "svg+xml"):
+		return true
+	case strings.HasPrefix(kind, "text/"):
+		return true
+	case strings.HasPrefix(kind, "application/") && strings.HasSuffix(kind, "json"):
+		return true
+	case strings.HasPrefix(kind, "application/") && strings.HasSuffix(kind, "xml"):
+		return true
+	default:
+		return false
+	}
+}