internal/home: Add a status page on home

internal/component/home/public.go

@@ -0,0 +1,90 @@
+package home
+
+import (
+	"bytes"
+	"context"
+	"text/template"
+	"time"
+
+	_ "embed"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/component/instances"
+	"github.com/FAU-CDI/wisski-distillery/pkg/timex"
+	"github.com/tkw1536/goprogram/stream"
+	"golang.org/x/sync/errgroup"
+)
+
+func (home *Home) updateInstances(ctx context.Context, io stream.IOStream) {
+	timex.SetInterval(ctx, home.RefreshInterval, func(t time.Time) {
+		io.Printf("[%s]: reloading instance list", t.String())
+
+		names, _ := home.instanceMap()
+		home.instanceNames.Set(names)
+	})
+}
+
+func (home *Home) instanceMap() (map[string]struct{}, error) {
+	wissKIs, err := home.Instances.All()
+	if err != nil {
+		return nil, err
+	}
+
+	names := make(map[string]struct{}, len(wissKIs))
+	for _, w := range wissKIs {
+		names[w.Slug] = struct{}{}
+	}
+	return names, nil
+}
+
+func (home *Home) updateRender(ctx context.Context, io stream.IOStream) {
+	timex.SetInterval(ctx, home.RefreshInterval, func(t time.Time) {
+		io.Printf("[%s]: reloading home render", t.String())
+
+		bytes, _ := home.homeRender()
+		home.homeBytes.Set(bytes)
+	})
+}
+
+//go:embed "home.html"
+var homeHTMLStr string
+var homeTemplate = template.Must(template.New("home.html").Parse(homeHTMLStr))
+
+func (home *Home) homeRender() ([]byte, error) {
+	var context HomeContext
+
+	// setup a couple of static things
+	context.Time = time.Now().UTC()
+	context.SelfRedirect = home.Config.SelfRedirect.String()
+
+	// find all the WissKIs
+	wissKIs, err := home.Instances.All()
+	if err != nil {
+		return nil, err
+	}
+	context.Instances = make([]instances.WissKIInfo, len(wissKIs))
+
+	// determine their infos
+	var eg errgroup.Group
+	for i, instance := range wissKIs {
+		i := i
+		wissKI := instance
+		eg.Go(func() (err error) {
+			context.Instances[i], err = wissKI.Info(true)
+			return
+		})
+	}
+	eg.Wait()
+
+	// render the template
+	var buffer bytes.Buffer
+	homeTemplate.Execute(&buffer, context)
+	return buffer.Bytes(), nil
+}
+
+type HomeContext struct {
+	Instances []instances.WissKIInfo
+
+	Time time.Time
+
+	SelfRedirect string
+}