Added prepull.

docker/prepullImage.go

@@ -0,0 +1,78 @@
+package docker
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/docker/docker/api/types/swarm"
+)
+
+func prepullImage(w http.ResponseWriter, r *http.Request){
+	if r.Method != http.MethodPost{
+		w.WriteHeader(http.StatusMethodNotAllowed);
+		fmt.Fprint(w, "Method Not Allowed");
+		return;
+	}
+
+	if !bearerAuth(w, r){return;}
+
+	sc, err := ApiClient.ServiceCreate(context.Background(), swarm.ServiceSpec{
+		Annotations: swarm.Annotations{
+			Name: theConfig.Constants.PrepullImageServiceName, 
+			Labels: map[string]string{"blazena.prepull": "true"},
+		},
+		Mode: swarm.ServiceMode{
+			GlobalJob: &swarm.GlobalJob{},
+		},
+		TaskTemplate: swarm.TaskSpec{
+			ContainerSpec: &swarm.ContainerSpec{
+				Image: theConfig.BlazenaImageUrl, 
+				Command: []string{"sleep", "1s"},
+			},
+		},
+	}, swarm.ServiceCreateOptions{
+		QueryRegistry: true,
+		EncodedRegistryAuth: theConfig.EncodedRegistryAuth,
+	});
+
+	if err != nil {
+		slog.Error("Failed to create prepull service", slog.Any("propagatedError", err));
+		os.Exit(3);
+	}
+
+	slog.Info("Started Prepull of blazena image.");
+
+	go func(){
+	CHECKLOOP: for {
+		time.Sleep(3*time.Second);
+		tasks, err := ApiClient.TaskList(context.Background(), swarm.TaskListOptions{});
+
+		if err != nil {
+			slog.Error("Failed to list tasks.", slog.Any("propagatedError", err));
+			os.Exit(3);
+		}
+
+		for _, task := range tasks {
+			if task.ServiceID != sc.ID {continue};
+
+			if task.Status.State != "complete" {
+				time.Sleep(1*time.Second);
+				continue CHECKLOOP
+			};
+		}
+
+		err = ApiClient.ServiceRemove(context.Background(), sc.ID);
+
+		if err != nil {
+			slog.Warn("Failed to remove prepull service.", slog.Any("propagatedError", err));
+		}
+
+		slog.Info("Prepull Finished");
+		break CHECKLOOP;
+	}
+	}();
+}