From 261faaec0eec395cf40ece7d0cdf2a33f4c279b6 Mon Sep 17 00:00:00 2001
From: Oleg Kalachev <okalachev@gmail.com>
Date: Fri, 14 May 2021 12:05:23 +0300
Subject: [PATCH] Add waitfile script to wait for a file before starting a node

---
 clover/launch/mavros.launch | 2 +-
 clover/src/waitfile         | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100755 clover/src/waitfile

diff --git a/clover/launch/mavros.launch b/clover/launch/mavros.launch
index cb958447..9c255a27 100644
--- a/clover/launch/mavros.launch
+++ b/clover/launch/mavros.launch
@@ -8,7 +8,7 @@
     <arg name="distance_sensor_remap" default="rangefinder/range"/>
     <arg name="usb_device" default="/dev/px4fmu"/>
     <arg name="prefix" default="" unless="$(eval fcu_conn == 'usb')"/>
-    <arg name="prefix" default="bash -c 'while [ ! -e $(arg usb_device) ]; do sleep 1; done; $0 $@'" if="$(eval fcu_conn == 'usb')"/>
+    <arg name="prefix" default="rosrun clover waitfile $(arg usb_device)"/>
 
     <node pkg="mavros" type="mavros_node" name="mavros" launch-prefix="$(arg prefix)" required="false" clear_params="true" respawn="$(arg respawn)" unless="$(eval fcu_conn == 'none')" respawn_delay="1" output="screen">
         <!-- UART connection -->
diff --git a/clover/src/waitfile b/clover/src/waitfile
new file mode 100755
index 00000000..2052e42e
--- /dev/null
+++ b/clover/src/waitfile
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+# $ ./waitfile <file> <command> <args...> 
+# wait until <file> appears and then invoke <command> with <args>
+
+echo "wait for file $1 to ${@:2}"
+while [ ! -e "$1" ]; do sleep 1; done;
+echo "file $1 appeared, run ${@:2}"
+"${@:2}"