Add reference implementation for health & readiness endpoint in IDP

Signed-off-by: Christian Richter <crichter@owncloud.com>

ocis-pkg/shared/healthchecklist.go

@@ -0,0 +1,29 @@
+package shared
+
+import "net"
+
+// Check is a single health-check
+type Check func() error
+
+// RunChecklist runs all the given checks
+func RunChecklist(checks ...Check) error {
+	for _, c := range checks {
+		err := c()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// TCPConnect connects to a given tcp endpoint
+func TCPConnect(host string) Check {
+	return func() error {
+		conn, err := net.Dial("tcp", host)
+		if err != nil {
+			return err
+		}
+		defer conn.Close()
+		return nil
+	}
+}