Healthcheck (#51)

* healthcheck

* Fix error message on exit

Dockerfile

@@ -12,6 +12,7 @@ COPY internal internal
 # Build service in seperate stage.
 FROM base as builder
 RUN CGO_ENABLED=0 go build ./cmd/icc
+RUN CGO_ENABLED=0 go build ./cmd/healthcheck
 
 
 # Development build.
@@ -34,7 +35,9 @@ LABEL org.opencontainers.image.licenses="MIT"
 LABEL org.opencontainers.image.source="https://github.com/OpenSlides/openslides-icc-service"
 
 COPY --from=builder /root/icc .
+COPY --from=builder /root/healthcheck .
 EXPOSE 9007
 ENV MESSAGING redis
 ENV AUTH ticket
 ENTRYPOINT ["/icc"]
+HEALTHCHECK CMD ["/healthcheck"]

cmd/healthcheck/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Printf("Error: %v", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	port, found := os.LookupEnv("ICC_PORT")
+	if !found {
+		port = "9007"
+	}
+
+	resp, err := http.Get("http://localhost:" + port + "/system/icc/health")
+	if err != nil {
+		return fmt.Errorf("sending request: %w", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("health returned status %s", resp.Status)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return fmt.Errorf("reading response body: %w", err)
+	}
+
+	expect := `{"healthy":true}`
+	got := strings.TrimSpace(string(body))
+	if got != expect {
+		return fmt.Errorf("got `%s`, expected `%s`", body, expect)
+	}
+
+	return nil
+}

internal/icchttp/http.go

@@ -107,7 +107,7 @@ func HandleHealth(mux *http.ServeMux) {
 		"/system/icc/health",
 		func(w http.ResponseWriter, r *http.Request) {
 			w.Header().Set("Content-Type", "application/octet-stream")
-			fmt.Fprintln(w, `{"healthy": true}`)
+			fmt.Fprintln(w, `{"healthy":true}`)
 		},
 	)
 }

internal/run/run.go

@@ -147,6 +147,10 @@ func secret(name string, getSecret func(name string) (string, error), dev bool)
 
 func buildErrHandler() func(err error) {
 	return func(err error) {
+		if errors.Is(err, context.Canceled) {
+			return
+		}
+
 		var closing interface {
 			Closing()
 		}