Merge pull request #2184 from thaJeztah/19.03_backport_fix_max_replicas_per_node_interpolation

[19.03 backport] Add interpolation type cast for max_replicas_per_node

cli/compose/loader/interpolate.go

@@ -19,6 +19,7 @@ var interpolateTypeCastMapping = map[interp.Path]interp.Cast{
 	servicePath("deploy", "rollback_config", "parallelism"):          toInt,
 	servicePath("deploy", "rollback_config", "max_failure_ratio"):    toFloat,
 	servicePath("deploy", "restart_policy", "max_attempts"):          toInt,
+	servicePath("deploy", "placement", "max_replicas_per_node"):      toInt,
 	servicePath("ports", interp.PathMatchList, "target"):             toInt,
 	servicePath("ports", interp.PathMatchList, "published"):          toInt,
 	servicePath("ulimits", interp.PathMatchAll):                      toInt,

cli/compose/loader/loader_test.go

@@ -582,7 +582,7 @@ volumes:
 
 func TestLoadWithInterpolationCastFull(t *testing.T) {
 	dict, err := ParseYAML([]byte(`
-version: "3.7"
+version: "3.8"
 services:
   web:
     configs:
@@ -604,6 +604,8 @@ services:
         max_failure_ratio: $thefloat
       restart_policy:
         max_attempts: $theint
+      placement:
+        max_replicas_per_node: $theint
     ports:
       - $theint
       - "34567"
@@ -652,7 +654,7 @@ networks:
 	assert.NilError(t, err)
 	expected := &types.Config{
 		Filename: "filename.yml",
-		Version:  "3.7",
+		Version:  "3.8",
 		Services: []types.ServiceConfig{
 			{
 				Name: "web",
@@ -685,6 +687,9 @@ networks:
 					RestartPolicy: &types.RestartPolicy{
 						MaxAttempts: uint64Ptr(555),
 					},
+					Placement: types.Placement{
+						MaxReplicas: 555,
+					},
 				},
 				Ports: []types.ServicePortConfig{
 					{Target: 555, Mode: "ingress", Protocol: "tcp"},