Print warnings on stderr for each unsupported features while parsing a compose file for deployment on Kubernetes.

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

cli/command/stack/kubernetes/warnings_test.go

@@ -0,0 +1,78 @@
+package kubernetes
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	composetypes "github.com/docker/cli/cli/compose/types"
+	"github.com/gotestyourself/gotestyourself/golden"
+)
+
+func TestWarnings(t *testing.T) {
+	duration := 5 * time.Second
+	attempts := uint64(3)
+	config := &composetypes.Config{
+		Version: "3.4",
+		Services: []composetypes.ServiceConfig{
+			{
+				Name: "front",
+				Build: composetypes.BuildConfig{
+					Context: "ignored",
+				},
+				ContainerName:  "ignored",
+				CgroupParent:   "ignored",
+				CredentialSpec: composetypes.CredentialSpecConfig{File: "ignored"},
+				DependsOn:      []string{"ignored"},
+				Deploy: composetypes.DeployConfig{
+					UpdateConfig: &composetypes.UpdateConfig{
+						Delay:           5 * time.Second,
+						FailureAction:   "rollback",
+						Monitor:         10 * time.Second,
+						MaxFailureRatio: 0.5,
+					},
+					RestartPolicy: &composetypes.RestartPolicy{
+						Delay:       &duration,
+						MaxAttempts: &attempts,
+						Window:      &duration,
+					},
+				},
+				Devices:       []string{"ignored"},
+				DNSSearch:     []string{"ignored"},
+				DNS:           []string{"ignored"},
+				DomainName:    "ignored",
+				EnvFile:       []string{"ignored"},
+				Expose:        []string{"80"},
+				ExternalLinks: []string{"ignored"},
+				Image:         "dockerdemos/front",
+				Links:         []string{"ignored"},
+				Logging:       &composetypes.LoggingConfig{Driver: "syslog"},
+				MacAddress:    "ignored",
+				Networks:      map[string]*composetypes.ServiceNetworkConfig{"private": {}},
+				NetworkMode:   "ignored",
+				Restart:       "ignored",
+				SecurityOpt:   []string{"ignored"},
+				StopSignal:    "ignored",
+				Ulimits:       map[string]*composetypes.UlimitsConfig{"nproc": {Hard: 65535}},
+				User:          "ignored",
+				Volumes: []composetypes.ServiceVolumeConfig{
+					{
+						Type: "bind",
+						Bind: &composetypes.ServiceVolumeBind{Propagation: "ignored"},
+					},
+					{
+						Type:   "volume",
+						Volume: &composetypes.ServiceVolumeVolume{NoCopy: true},
+					},
+				},
+			},
+		},
+		Networks: map[string]composetypes.NetworkConfig{
+			"global": {},
+		},
+	}
+	var buf bytes.Buffer
+	warnUnsupportedFeatures(&buf, config)
+	warnings := buf.String()
+	golden.Assert(t, warnings, "warnings.golden")
+}