Add support for volume consistency in compose format.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

compose/convert/volume.go

@@ -32,6 +32,7 @@ func convertVolumeToMount(
 		Source:      volume.Source,
 		Target:      volume.Target,
 		ReadOnly:    volume.ReadOnly,
+		Consistency: mount.Consistency(volume.Consistency),
 	}
 
 	// Anonymous volumes

compose/loader/full-example.yml

@@ -220,6 +220,10 @@ services:
       - ~/configs:/etc/configs/:ro
       # Named volume
       - datavolume:/var/lib/mysql
+      - type: bind
+        source: ./opt
+        target: /opt
+        consistency: cached
 
     working_dir: /code
 

compose/loader/loader_test.go

@@ -910,6 +910,7 @@ func TestFullExample(t *testing.T) {
 			{Source: workingDir + "/static", Target: "/var/www/html", Type: "bind"},
 			{Source: homeDir + "/configs", Target: "/etc/configs/", Type: "bind", ReadOnly: true},
 			{Source: "datavolume", Target: "/var/lib/mysql", Type: "volume"},
+			{Source: workingDir + "/opt", Target: "/opt", Consistency: "cached", Type: "bind"},
 		},
 		WorkingDir: "/code",
 	}

compose/schema/data/config_schema_v3.2.json

@@ -249,6 +249,7 @@
                   "source": {"type": "string"},
                   "target": {"type": "string"},
                   "read_only": {"type": "boolean"},
+                  "consistency": {"type": "string"},
                   "bind": {
                     "type": "object",
                     "properties": {

compose/types/types.go

@@ -233,6 +233,7 @@ type ServiceVolumeConfig struct {
 	Source      string
 	Target      string
 	ReadOnly    bool `mapstructure:"read_only"`
+	Consistency string
 	Bind        *ServiceVolumeBind
 	Volume      *ServiceVolumeVolume
 }