More error handling for adb connections. No upgrade needed.

By default we give adb a couple of seconds to succeed with the
connection.

README.md

@@ -5,7 +5,7 @@
 - The MitM is checked to have at least one outbound connection to the upstream websocket.
 
 ## Installation:
-- The script is intended to be installed from a Unix/Linux like environment and depends on having `bash` & `adb` available.
+- The script is intended to be installed from a Unix/Linux like environment and depends on having GNU coreutils, `bash` & `adb` available.
 - All arguments to `nanny.sh` are interpreted as adb reachable addresses.
 - `nanny.sh` handles the connection & installation for you and embeds the nanny script itself: `./nanny.sh host1 host2 host3 192.168.1.21`
 - If you have a range of devices, you can use a bash/zsh range expansion: `./nanny.sh atv0{1..99}`
@@ -37,6 +37,7 @@ The script has a handful of variables set at the top you could customize, but th
 - `log="/sdcard/nanny.log"` # log for all output, cleared for every run of nanny.
 - `connection_min=1` # Number of upsteam ws connections to require. Could optimise to 1+workers.
 - `mitm="com.gocheats.launcher"` # package name of mitm
+- `adb_timeout=2` # Max connection timeout in seconds for ADB. May need to increase if your devices are over WAN
 
 ## Sample session log
 ```

nanny.sh

@@ -16,12 +16,18 @@ cooldown=60 # wait cooldown seconds for mitm before checking
 log="/sdcard/nanny.log" # log for all output, cleared for every run of nanny.
 connection_min=1 # Number of upsteam ws connections to require. Could optimise to 1+workers.
 mitm="com.gocheats.launcher" # package name of mitm
+adb_timeout=2 # Max connection timeout in seconds for ADB. May need to increase if your devices are over WAN
 
 # Nothing to configure below here
 targets=("$@")
 
 for target in "${targets[@]}"; do
+ # The connect may or may not block until connected. No exit value we could use. ¯\_(ツ)_/¯
  adb connect "$target" 
+ # Wait until we have a connection to proceed, with a timeout.
+ timeout "$adb_timeout" adb -s "$target" wait-for-device
+ [[ "$?" -ne 0 ]] && >&2 echo "Failed to connect to $target, skipping." && continue
+ # Connected, render & push the script.
  cat<<EOT | adb -s "$target" shell "su -c 'cat > /data/adb/service.d/nanny.sh && chmod +x /data/adb/service.d/nanny.sh'"
 #!/system/bin/sh
 # ^ says sh, but we assume it to be ash
@@ -86,6 +92,7 @@ while true; do
  echo "RESUME_CHECKS at \$(date +%Y-%m-%dT%T)"
 done
 EOT
-
+ [[ "$?" -ne 0 ]] && >&2 echo "Failed to push script to $target." && continue
+ >&2 echo "Finished with $target."
  done
 >&2 echo "Reboot devices at your leisure to activate Nanny. Check $log to see what's going on."