Add memory swap to swarm

Adds support for setting memory swap settings on Swarm services

* Adds flags `memory-swap` and `memory-swappiness` to `docker service
create` and `docker service update` commands.
* Adds compose fields `memswap_limit` and `mem_swappiness` for `docker
stack` commands.

Signed-off-by: Drew Erny <derny@mirantis.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/compose/convert/service.go

@@ -560,6 +560,10 @@ func convertResources(source composetypes.Resources) (*swarm.ResourceRequirement
 			GenericResources: generic,
 		}
 	}
+	// These fields are themselves pointers -- we can simply assign, no need to
+	// nil-check them. Nil is nil.
+	resources.SwapBytes = source.MemswapLimit
+	resources.MemorySwappiness = source.MemSwappiness
 	return resources, nil
 }
 

cli/compose/convert/service_test.go

@@ -81,6 +81,9 @@ func TestConvertExtraHosts(t *testing.T) {
 }
 
 func TestConvertResourcesFull(t *testing.T) {
+	// create some variables so we can get pointers
+	memswap := int64(72090)
+	swappiness := int64(27)
 	source := composetypes.Resources{
 		Limits: &composetypes.ResourceLimit{
 			NanoCPUs:    "0.003",
@@ -90,6 +93,8 @@ func TestConvertResourcesFull(t *testing.T) {
 			NanoCPUs:    "0.002",
 			MemoryBytes: composetypes.UnitBytes(200000000),
 		},
+		MemswapLimit:  &memswap,
+		MemSwappiness: &swappiness,
 	}
 	resources, err := convertResources(source)
 	assert.NilError(t, err)
@@ -103,6 +108,8 @@ func TestConvertResourcesFull(t *testing.T) {
 			NanoCPUs:    2000000,
 			MemoryBytes: 200000000,
 		},
+		SwapBytes:        &memswap,
+		MemorySwappiness: &swappiness,
 	}
 	assert.Check(t, is.DeepEqual(expected, resources))
 }