tests: Replace Python test image with Go binary

Signed-off-by: Chris Crone <christopher.crone@docker.com>

tests/composefiles/aci_secrets_resources/web/Dockerfile

@@ -1,3 +1,6 @@
+# syntax=docker/dockerfile:experimental
+
+
 #   Copyright 2020 Docker Compose CLI authors
 
 #   Licensed under the Apache License, Version 2.0 (the "License");
@@ -12,7 +15,11 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
-FROM python:3.8
-WORKDIR /run/secrets
+FROM golang:1.15-alpine AS build
+COPY main.go .
+RUN --mount=type=cache,target=/go/pkg/mod \
+    CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o server main.go
 
-CMD python -m http.server ${PORT:-80}
+FROM alpine
+COPY --from=build /go/server /
+CMD /server "${PORT:-80}" "${DIR:-/run/secrets}"

tests/composefiles/aci_secrets_resources/web/main.go

@@ -0,0 +1,27 @@
+/*
+   Copyright 2020 Docker Compose CLI authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+)
+
+func main() {
+	log.Fatal(http.ListenAndServe(":"+os.Args[1], http.FileServer(http.Dir(os.Args[2]))))
+}