fixing deep merge issue and yaml alias (#387)

fixing deep merge issue and yaml alias

Author: davejrt

lib/puppet/provider/docker_compose/ruby.rb

@@ -12,7 +12,7 @@ def exists?
     compose_services = {}
     compose_containers = []
     resource[:compose_files].each do |file|
-      compose_file = YAML.safe_load(File.read(file))
+      compose_file = YAML.safe_load(File.read(file), [], [], true)
       containers = docker([
                             'ps',
                             '--format',
@@ -24,10 +24,10 @@ def exists?
       compose_containers.uniq!
       case compose_file['version']
       when %r{^2(\.[0-3])?$}, %r{^3(\.[0-6])?$}
-        compose_services = compose_services.deep_merge(compose_file['services'])
+        compose_services.deep_merge!(compose_file['services'])
       # in compose v1 "version" parameter is not specified
       when nil
-        compose_services = compose_services.deep_merge(compose_file)
+        compose_services.deep_merge!(compose_file)
       else
         raise(Puppet::Error, "Unsupported docker compose file syntax version \"#{compose_file['version']}\"!")
       end

spec/spec_helper_acceptance.rb

@@ -75,23 +75,32 @@ def retry_on_error_matching(max_retry_count = 3, retry_wait_interval_secs = 5, e
 
         docker_compose_content_v3 = <<-EOS
 version: "3.4"
+x-images:
+  &default-image
+  alpine:3.8
 services:
   compose_test:
-    image: ubuntu:14.04
+    image: *default-image
     command: /bin/sh -c "while true; do echo hello world; sleep 1; done"
       EOS
         docker_compose_override_v3 = <<-EOS
 version: "3.4"
+x-images:
+  &default-image
+  debian:stable-slim
 services:
   compose_test:
-    image: debian:jessie
+    image: *default-image
     command: /bin/sh -c "while true; do echo hello world; sleep 1; done"
         EOS
         docker_stack_override_v3 = <<-EOS
 version: "3.4"
+x-images:
+  &default-image
+  debian:stable-slim
 services:
   compose_test:
-    image: debian:jessie
+    image: *default-image
     command: /bin/sh -c "while true; do echo hello world; sleep 1; done"
         EOS
         docker_compose_content_v3_windows = <<-EOS