contrib/dockerlib.sh

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/dockerlib.sh	Wed May 06 10:45:07 2015 -0400
@@ -0,0 +1,19 @@
+#!/bin/sh -eu
+
+# This function exists to set up the DOCKER variable and verify that
+# it's the binary we expect. It also verifies that the docker service
+# is running on the system and we can talk to it.
+function checkdocker() {
+  if which docker.io >> /dev/null 2>&1 ; then
+    DOCKER=docker.io
+  elif which docker >> /dev/null 2>&1 ; then
+    DOCKER=docker
+  else
+    echo "Error: docker must be installed"
+    exit 1
+  fi
+
+  $DOCKER -h 2> /dev/null | grep -q Jansens && { echo "Error: $DOCKER is the Docking System Tray - install docker.io instead"; exit 1; }
+  $DOCKER version | grep -q "^Client version:" || { echo "Error: unexpected output from \"$DOCKER version\""; exit 1; }
+  $DOCKER version | grep -q "^Server version:" || { echo "Error: could not get docker server version - check it is running and your permissions"; exit 1; }
+}