Redo the whole thing and make it silly

.github/workflows/push.yml

@@ -0,0 +1,20 @@
+name: CI
+on: [push]
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+
+      - uses: actions/checkout@v1
+
+      - uses: actions/setup-go@v1
+        with:
+          go-version: 1.13
+
+      - run: go test -v ./...
+        env:
+          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+          AWS_REGION: ap-southeast-2

.github/workflows/release.yml

@@ -0,0 +1,20 @@
+name: Release
+on:
+  release:
+    types: [created]
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+
+      - uses: actions/setup-go@v1
+        with:
+          go-version: 1.13
+
+      - uses: goreleaser/goreleaser-action@v1
+        with:
+          version: latest
+          args: release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.goreleaser.yml

@@ -0,0 +1,18 @@
+builds:
+  - env: [CGO_ENABLED=0]
+    goos: [linux]
+    goarch: [amd64]
+archives:
+  - name_template: lambdahttp
+    format: zip
+    files: [none*] # https://github.com/goreleaser/goreleaser/issues/602
+checksum:
+  name_template: 'checksums.txt'
+snapshot:
+  name_template: "{{ .Tag }}-next"
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - '^docs:'
+      - '^test:'

docs/README.md

@@ -0,0 +1,41 @@
+# lambdahttp
+
+Do you yearn for the days of listening on port 80(80) for web traffic? Does this
+new serverless world scare you and make you wonder if you'll have to refactor
+your existing code? Or maybe you have a crusty old binary lying around, have
+lost the source code and are desperate to make it work on AWS Lambda?
+
+If so, `lambdahttp` is for **you**.
+
+## How do I use it?
+
+* Grab the latest zip from the [Releases][releases]
+  tab on GitHub.
+* Add your app to the zip file.
+* Upload the zip to S3.
+* Create a Lambda function from that zip file. Configure it to use a "custom runtime"
+  and specify a shell command as the "handler", e.g. `./myprogram listen --port 8080`.
+* Do the API Gateway / Application Load Balancer dance.
+* Swim in the savings of serverless.
+
+If you app _doesn't_ listen on port 8080, you can specify a different one using
+the `PORT` environment variable. 
+
+Additionally, `lambdahttp` has no real way of knowing when your app is ready to 
+start serving traffic. For this reason, it will continuously make requests to 
+`/ping` until that endpoint returns a `200 OK` - this is how it knows you are 
+good to go. If that path doesn't work for you, specify a different one in the
+`HEALTHCHECK_PATH` environment variable.
+
+## How does it work?
+
+Let me explain through the only kind of diagram I know: a sequence diagram.
+
+![seq-diag](/docs/seq-diag.png)
+
+`lambdahttp` communicates with the Lambda service using the [Lambda runtime interface][runtime]
+and converts these requests into regular HTTP over TCP. It converts the responses back to the
+format expected by Lambda and voilà. Nothing new you need to learn.
+
+[releases]: https://github.com/glassechidna/lambdahttp/releases
+[runtime]: https://docs.aws.amazon.com/lambda/latest/dg/runtimes-api.html

docs/seq-diag.txt

@@ -0,0 +1,16 @@
+@startuml
+participant Browser
+participant "API Gateway" as apigw
+participant Lambda
+participant lambdahttp
+participant "Your app" as app
+
+Browser -> apigw: GET /index HTTP/1.1
+apigw -> Lambda: {"spooky": "json"...}
+Lambda -> lambdahttp: (magic)
+lambdahttp -> app: GET /index HTTP/1.1
+app -> lambdahttp: 200 OK ...
+lambdahttp -> Lambda: (magic)
+Lambda -> apigw: {"more": "aws json"...}
+apigw -> Browser: 200 OK ...
+@enduml

go.mod

@@ -4,6 +4,8 @@ go 1.13
 
 require (
 	github.com/aws/aws-lambda-go v1.13.2
+	github.com/aws/aws-sdk-go v1.25.6
+	github.com/jarcoal/httpmock v1.0.4
 	github.com/pkg/errors v0.8.1
 	github.com/stretchr/testify v1.4.0
 )

go.sum

@@ -1,9 +1,15 @@
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/aws/aws-lambda-go v1.13.2 h1:8lYuRVn6rESoUNZXdbCmtGB4bBk4vcVYojiHjE4mMrM=
 github.com/aws/aws-lambda-go v1.13.2/go.mod h1:4UKl9IzQMoD+QF79YdCuzCwp8VbmG4VAQwij/eHl5CU=
+github.com/aws/aws-sdk-go v1.25.6 h1:Rmg2pgKXoCfNe0KQb4LNSNmHqMdcgBjpMeXK9IjHWq8=
+github.com/aws/aws-sdk-go v1.25.6/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/jarcoal/httpmock v1.0.4 h1:jp+dy/+nonJE4g4xbVtl9QdrUNbn6/3hDT5R4nDIZnA=
+github.com/jarcoal/httpmock v1.0.4/go.mod h1:ATjnClrvW/3tijVmpL/va5Z3aAyGvqU3gCT8nX0Txik=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

main.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"github.com/glassechidna/lambdahttp/pkg/proxy"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func main() {
+	port := port()
+
+	ctx := context.Background()
+	cmdch := make(chan error)
+	go runCmd(ctx, cmdch)
+
+	readych := make(chan error)
+	go waitForHealthy(ctx, readych, port)
+
+	select {
+	case err := <-cmdch:
+		panic(fmt.Sprintf("%+v", err))
+	case err := <-readych:
+		if err != nil {
+			panic(fmt.Sprintf("%+v", err))
+		}
+	}
+
+	go runProxy(ctx, port, cmdch)
+	for {
+		select {
+		case <-ctx.Done():
+			panic("cancelled")
+		case err := <-cmdch:
+			panic(err)
+		}
+	}
+}
+
+func waitForHealthy(ctx context.Context, readych chan error, port int) {
+	path := strings.TrimPrefix(os.Getenv("HEALTHCHECK_PATH"), "/")
+	if path == "" {
+		path = "ping"
+	}
+
+	url := fmt.Sprintf("http://127.0.0.1:%d/%s", port, path)
+
+	waitUntil(ctx, readych, func() bool {
+		resp, err := http.Get(url)
+		return err == nil && resp != nil && resp.StatusCode == 200
+	})
+}
+
+func runProxy(ctx context.Context, port int, cmdch chan error) {
+	runtimeBaseUrl := os.ExpandEnv("http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01")
+
+	proxy := proxy.New(runtimeBaseUrl, port, &http.Client{}, &http.Client{})
+	for {
+		err := proxy.Next(ctx)
+		if err != nil {
+			cmdch <- err
+		}
+	}
+}
+
+func port() int {
+	port, _ := strconv.Atoi(os.Getenv("PORT"))
+	if port == 0 {
+		port = 8080
+		os.Setenv("PORT", "8080")
+	}
+	return port
+}
+
+func runCmd(ctx context.Context, ch chan error) {
+	fmt.Println(os.Getwd())
+
+	subcmd := os.Getenv("_HANDLER")
+	cmd := exec.CommandContext(ctx, "/bin/sh", "-c", subcmd)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	ch <- cmd.Run()
+}
+
+func waitUntil(ctx context.Context, done chan error, condition func() bool) {
+	ticker := time.NewTicker(100 * time.Millisecond)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			done <- ctx.Err()
+		case <-ticker.C:
+			if condition() {
+				done <- nil
+			}
+		}
+	}
+}

pkg/gowrap/request.go

@@ -62,7 +62,11 @@ func urlForRequest(request events.ALBTargetGroupRequest) *url.URL {
 		query[k] = append(query[k], v)
 	}
 
-	u, _ := url.Parse(fmt.Sprintf("%s://%s%s?%s", proto, host, path, query.Encode()))
+	u, err := url.Parse(fmt.Sprintf("%s://%s%s?%s", proto, host, path, query.Encode()))
+	if err != nil {
+		panic(err)
+	}
+
 	return u
 }
 

pkg/proxy/e2e_test.go

@@ -0,0 +1,62 @@
+package proxy
+
+import (
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/lambda"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+func TestEndToEnd(t *testing.T) {
+	if testing.Short() {
+		t.SkipNow()
+	}
+
+	cmd := exec.Command("testdata/e2e.sh")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
+	require.NoError(t, err)
+
+	zip, err := ioutil.ReadFile("../../lambda.zip")
+	require.NoError(t, err)
+
+	sess, err := session.NewSession(aws.NewConfig().WithRegion("ap-southeast-2"))
+	require.NoError(t, err)
+
+	api := lambda.New(sess)
+	updateResp, err := api.UpdateFunctionCode(&lambda.UpdateFunctionCodeInput{
+		FunctionName: aws.String("lambdahttptest"),
+		Publish:      aws.Bool(true),
+		ZipFile:      zip,
+	})
+	require.NoError(t, err)
+
+	payload, err := ioutil.ReadFile("testdata/alb_input.json")
+	require.NoError(t, err)
+
+	invokeResp, err := api.Invoke(&lambda.InvokeInput{
+		FunctionName: updateResp.FunctionArn,
+		Payload:      payload,
+	})
+	require.NoError(t, err)
+
+	expected, err := ioutil.ReadFile("testdata/alb_expected_output.json")
+	assert.NoError(t, err)
+	assert.JSONEq(t, string(expected), normalizeDateInResponse(invokeResp.Payload))
+}
+
+func normalizeDateInResponse(payload []byte) string {
+	response := string(payload)
+	regex := regexp.MustCompile(`"Date":"([^"]+)"`)
+	matches := regex.FindStringSubmatch(response)
+	returnedDate := matches[1]
+	return strings.ReplaceAll(response, returnedDate, "Sun, 06 Oct 2019 06:53:36 GMT")
+}