update project structure

- move agent to /agent
- change /beszel to /src
- update workflows and docker builds

agent/health/health.go

@@ -0,0 +1,43 @@
+// Package health provides functions to check and update the health of the agent.
+// It uses a file in the temp directory to store the timestamp of the last connection attempt.
+// If the timestamp is older than 90 seconds, the agent is considered unhealthy.
+// NB: The agent must be started with the Start() method to be considered healthy.
+package health
+
+import (
+	"errors"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// healthFile is the path to the health file
+var healthFile = filepath.Join(os.TempDir(), "beszel_health")
+
+// Check checks if the agent is connected by checking the modification time of the health file
+func Check() error {
+	fileInfo, err := os.Stat(healthFile)
+	if err != nil {
+		return err
+	}
+	if time.Since(fileInfo.ModTime()) > 91*time.Second {
+		log.Println("over 90 seconds since last connection")
+		return errors.New("unhealthy")
+	}
+	return nil
+}
+
+// Update updates the modification time of the health file
+func Update() error {
+	file, err := os.Create(healthFile)
+	if err != nil {
+		return err
+	}
+	return file.Close()
+}
+
+// CleanUp removes the health file
+func CleanUp() error {
+	return os.Remove(healthFile)
+}