E2E: RDX: Add tests for POST

- For the E2E/BATS testing image: switch to registry.opensuse.org base
  images because that doesn't have pull limits.
- For the same: switch to golang backend instead of python, because we
  already need golang to build for Windows; this leads to smaller images to
  pull.  Also, we don't use python as much in this project.
- Add POST handler for the backend (just returning the POST request body),
  and test it in E2E to ensure `ddClient.extension.vm.service.post` is
  working correctly.

Signed-off-by: Mark Yen <mark.yen@suse.com>

Author: mook-as

.github/actions/spelling/expect.txt

@@ -68,6 +68,7 @@ basedisk
 bassano
 batslib
 bcdfghjklmnpqrstvwxz
+bci
 bellingham
 bindir
 binfmt

bats/tests/extensions/testdata/Dockerfile

@@ -1,19 +1,26 @@
-FROM golang:1 AS builder
+FROM registry.opensuse.org/opensuse/bci/golang:stable AS builder
 WORKDIR /usr/src/app
 COPY bin/dummy.go .
 ENV GOOS=windows
 RUN go build -o /dummy.exe -ldflags '-s -w' dummy.go
 
-FROM python:3-alpine
+FROM registry.opensuse.org/opensuse/bci/golang:stable AS server-builder
+WORKDIR /usr/src/app
+COPY bin/server.go .
+ENV GOOS=linux
+RUN go build -o /server -ldflags '-s -w' server.go
+
+FROM registry.opensuse.org/opensuse/bci/bci-minimal
 ARG variant=basic
 
 ADD ${variant}.json /metadata.json
 ADD extension-icon.svg /extension-icon.svg
 ADD ui /ui/
 ADD bin /bin/
 COPY --from=builder /dummy.exe /bin/
+COPY --from=server-builder /server /bin/
 ADD compose.yaml /compose/
 RUN ln -s does/not/exist /compose/dangling-link
 RUN ln -s compose.yaml /compose/link
 
-ENTRYPOINT ["/usr/local/bin/python3", "/bin/server.py"]
+ENTRYPOINT ["/bin/server"]

bats/tests/extensions/testdata/bin/server.go

@@ -0,0 +1,73 @@
+// command server listens on the Unix socket `/run/guest-services/hello.sock`
+// (see `everything.json`) to exercise the ability for the front end to talk to
+// the back end.
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+const (
+	addr = "/run/guest-services/hello.sock"
+)
+
+// Listen on a port and return the listener
+func listen() (net.Listener, error) {
+	err := os.Remove(addr)
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		slog.Error("failed to remove old socket", "socket", addr, "error", err)
+	}
+	listener, err := net.Listen("unix", addr)
+	if err == nil {
+		return listener, nil
+	}
+	listener, err = net.Listen("tcp", "")
+	if err != nil {
+		return nil, fmt.Errorf("failed to listen on fallback TCP: %w", err)
+	}
+	return listener, nil
+}
+
+// Handle HTTP POST requests
+func handlePost(w http.ResponseWriter, req *http.Request) {
+	_, _ = io.Copy(w, req.Body)
+}
+
+func main() {
+	listener, err := listen()
+	if err != nil {
+		slog.Error("failed to listen", "error", err)
+		os.Exit(1)
+	}
+	http.DefaultServeMux.Handle("GET /", http.FileServer(http.Dir("/")))
+	http.DefaultServeMux.HandleFunc("POST /", handlePost)
+
+	server := &http.Server{}
+	ch := make(chan os.Signal)
+	errCh := make(chan error)
+	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		<-ch
+		errCh <- server.Shutdown(context.Background())
+	}()
+
+	slog.Info("Serving HTTP", "address", listener.Addr().String())
+	err = server.Serve(listener)
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		slog.Error("server closed", "error", err)
+		os.Exit(1)
+	}
+	if err = <-errCh; err != nil {
+		slog.Error("failed to shutdown server", "error", err)
+		os.Exit(1)
+	}
+}

bats/tests/extensions/testdata/bin/server.py

@@ -384,6 +384,13 @@ test.describe.serial('Extensions', () => {
           await expect(result).resolves.toContain('<title>Rancher</title>');
         });
       });
+      test('can post values', async() => {
+        await retry(async() => {
+          const result = evalInView(`ddClient.extension.vm.service.post("/foo", "hello")`);
+
+          await expect(result).resolves.toEqual('hello');
+        });
+      });
     });
   });
 });