Wait until we can initiate contact with the update engine before starting update.

image_to_live.sh

 #!/bin/bash
 
 # Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to update an image onto a live running ChromiumOS instance.
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
 # Load common CrOS utilities.  Inside the chroot this file is installed in
@@ skipping 287 matching lines @@
     else
       echo -n "."
     fi
 
     sleep ${timeout}
     current_state="${next_state}"
     next_state="$(get_update_var CURRENT_OP)"
   done
 }
 
+# Pings the update_engine to see if it responds or a max timeout is reached.
+# Returns 1 if max timeout is reached.
+function wait_until_update_engine_is_ready {
+  local wait_timeout=1
+  local max_timeout=60
+  local time_elapsed=0
+  while ! get_update_var CURRENT_OP > /dev/null; do
+    sleep ${wait_timeout}
+    time_elapsed=$(( time_elapsed + wait_timeout ))
+    echo -n "."
+    if [ ${time_elapsed} -gt ${max_timeout} ]; then
+      return 1
+    fi
+  done
+}
 
 function run_auto_update {
   # Truncate the update log so our log file is clean.
   truncate_update_log
 
   local update_args="$(get_update_args "$(get_devserver_url)")"
+  info "Waiting to initiate contact with the update_engine."
+  wait_until_update_engine_is_ready || die "Could not contact update engine."
+
   info "Starting update using args ${update_args}"
 
   # Sets up a secondary thread to track the update progress.
   status_thread &
   local status_thread_pid=$!
   trap "kill ${status_thread_pid} && cleanup" EXIT
 
   # Actually run the update.  This is a blocking call.
   remote_sh "${UPDATER_BIN} ${update_args}"
 
@@ skipping 114 matching lines @@
     local release_description=$(echo ${REMOTE_OUT} | cut -d '=' -f 2)
     info "Update was successful and rebooted to $release_description"
   fi
 
   print_time_elapsed
 
   exit 0
 }
 
 main $@