internal/home: Add a status page on home

internal/component/resolver/prefixes.go

@@ -0,0 +1,50 @@
+package resolver
+
+import (
+	"context"
+	"time"
+
+	"github.com/FAU-CDI/wisski-distillery/pkg/timex"
+	"github.com/tkw1536/goprogram/stream"
+)
+
+// updatePrefixes starts updating prefixes
+func (resolver *Resolver) updatePrefixes(io stream.IOStream, ctx context.Context) {
+	timex.SetInterval(ctx, resolver.RefreshInterval, func(t time.Time) {
+		io.Printf("[%s]: reloading prefixes", t.String())
+		prefixes, _ := resolver.AllPrefixes()
+		resolver.prefixes.Set(prefixes)
+	})
+}
+
+// AllPrefixes returns a list of all prefixes from the server.
+// Prefixes may be cached on the server
+func (resolver *Resolver) AllPrefixes() (map[string]string, error) {
+	instances, err := resolver.Instances.All()
+	if err != nil {
+		return nil, err
+	}
+
+	gPrefixes := make(map[string]string)
+	var lastErr error
+	for _, instance := range instances {
+		if instance.NoPrefix() {
+			continue
+		}
+		url := instance.URL().String()
+
+		// failed to fetch prefixes for this particular instance
+		// => skip it!
+		prefixes, err := instance.PrefixesCached()
+		if err != nil {
+			lastErr = err
+			continue
+		}
+
+		for _, p := range prefixes {
+			gPrefixes[p] = url
+		}
+	}
+
+	return gPrefixes, lastErr
+}