From d39057d242965b08ead49899bf5fa9429b163067 Mon Sep 17 00:00:00 2001
From: Chris Sosa <sosa@chromium.org>
Date: Tue, 1 Mar 2011 15:16:16 -0800
Subject: [PATCH] Wait until we can initiate contact with the update engine
 before starting update.

Change-Id: I2f741d7866192300946299f9050717721c2a644d

BUG=chromium-os:12605
TEST=Changed impl of check_status to return 1 and made sure timeout got inc'd
correctly and aborted.  Also checked to make sure if status returned 0 i.e.
update_engine_client --status returned 0, we would continue.

Review URL: http://codereview.chromium.org/6594089
---
 image_to_live.sh | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/image_to_live.sh b/image_to_live.sh
index a7710dcfe6..a61726a35e 100755
--- a/image_to_live.sh
+++ b/image_to_live.sh
@@ -307,12 +307,30 @@ function status_thread {
   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.