component/dis: Check if instance alive

internal/component/dis/info.go

@@ -1,26 +1,70 @@
 package dis
 
 import (
+	"encoding/json"
 	"net/http"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
 	"github.com/tkw1536/goprogram/stream"
+	"golang.org/x/sync/errgroup"
 )
 
-func (dis Dis) info(io stream.IOStream) (http.Handler, error) {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		all, err := dis.Instances.All()
-		if err != nil {
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte("internal server error"))
-			io.EPrintln(err)
-			return
-		}
-
-		for _, wk := range all {
-			w.WriteHeader(http.StatusOK)
-			w.Write([]byte(wk.Slug))
-			w.Write([]byte("\n"))
-		}
-
-	}), nil
+func (dis *Dis) info(io stream.IOStream) (http.Handler, error) {
+	return http.HandlerFunc(dis.handleDis), nil
+}
+
+const disLimit = 2
+
+func (dis *Dis) handleDis(w http.ResponseWriter, r *http.Request) {
+	// make sure the user is authorized
+	if !dis.authDis(r) {
+		w.Header().Add("WWW-Authenticate", `Basic realm="WissKI Distillery Admin"`)
+		w.WriteHeader(http.StatusUnauthorized)
+		w.Write([]byte("Unauthorized"))
+		return
+	}
+
+	// create a new error group
+	var errgroup errgroup.Group
+	errgroup.SetLimit(disLimit)
+
+	// list all the instances
+	all, err := dis.Instances.All()
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("internal server error"))
+		return
+	}
+
+	// get all of their info!
+	infos := make([]instances.Info, len(all))
+	for i, instance := range all {
+		{
+			i := i
+			instance := instance
+
+			errgroup.Go(func() (err error) {
+				infos[i], err = instance.Info()
+				return err
+			})
+		}
+	}
+
+	// if some info call failed
+	if err := errgroup.Wait(); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("internal server error"))
+		w.Write([]byte("\n"))
+		return
+	}
+
+	// and return the json
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(infos)
+}
+
+func (dis *Dis) authDis(r *http.Request) bool {
+	user, pass, ok := r.BasicAuth()
+	return ok && user == dis.Config.DisAdminUser && pass == dis.Config.DisAdminPassword
 }