Merge pull request #177 from tongueroo/rsync-detection

rsync detection, stop on sh fail

lib/jets.rb

@@ -13,6 +13,7 @@
 
 module Jets
   RUBY_VERSION = "2.5.3"
+  class Error < StandardError; end
 
   autoload :Application, "jets/application"
   autoload :AwsInfo, "jets/aws_info"

lib/jets/util.rb

@@ -13,12 +13,26 @@ def cp_r(src, dest)
       # Using rsync to perform the copy.
       src.chop! if src.ends_with?('/')
       dest.chop! if dest.ends_with?('/')
+      check_rsync_installed!
       sh "rsync -a --links --no-specials --no-devices #{src}/ #{dest}/", quiet: true
     end
 
+    @@rsync_installed = false
+    def check_rsync_installed!
+      return if @@rsync_installed # only check once
+      if system "type rsync > /dev/null 2>&1"
+        @@rsync_installed = true
+      else
+        raise Jets::Error.new("Rsync is required. Rsync does not seem to be installed.")
+      end
+    end
+
     def sh(command, quiet: false)
       puts "=> #{command}" unless quiet
       system(command)
+      success = $?.success?
+      raise Jets::Error.new("Command failed: #{command}") unless success
+      success
     end
   end
 end