Implement extends

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

tests/fixtures/extends/circle-1.yml

@@ -0,0 +1,12 @@
+foo:
+  image: busybox
+bar:
+  image: busybox
+web:
+  extends:
+    file: circle-2.yml
+    service: web
+baz:
+  image: busybox
+quux:
+  image: busybox

tests/fixtures/extends/circle-2.yml

@@ -0,0 +1,12 @@
+foo:
+  image: busybox
+bar:
+  image: busybox
+web:
+  extends:
+    file: circle-1.yml
+    service: web
+baz:
+  image: busybox
+quux:
+  image: busybox

tests/fixtures/extends/common.yml

@@ -0,0 +1,6 @@
+web:
+  image: busybox
+  command: /bin/true
+  environment:
+    - FOO=1
+    - BAR=1

tests/fixtures/extends/docker-compose.yml

@@ -0,0 +1,16 @@
+myweb:
+  extends:
+    file: common.yml
+    service: web
+  command: sleep 300
+  links:
+    - "mydb:db"
+  environment:
+    # leave FOO alone
+    # override BAR
+    BAR: "2"
+    # add BAZ
+    BAZ: "2"
+mydb:
+  image: busybox
+  command: sleep 300

tests/fixtures/extends/nested-intermediate.yml

@@ -0,0 +1,6 @@
+webintermediate:
+  extends:
+    file: common.yml
+    service: web
+  environment:
+    - "FOO=2"

tests/fixtures/extends/nested.yml

@@ -0,0 +1,6 @@
+myweb:
+  extends:
+    file: nested-intermediate.yml
+    service: webintermediate
+  environment:
+    - "BAR=2"