feat: display docker scout hints on build and pull

On `docker build` and `docker pull` commands, display a hint to
`docker scout quickview`.
Hints are disabled if quiet flag is used or if `DOCKER_SCOUT_HINTS`
environment variable is set to a false (according to Go) value:
  `0`, `f`, `F`, `false`, `FALSE`, `False`

In case of a `docker build` the `docker scout quickview` command doesn't
need an argument as it will take the most recently built image by
default.
In case of a `docker pull` the pulled image is extracted from the
command arguments.

Signed-off-by: Yves Brissaud <[email protected]>

Author: eunomie

cli/mobycli/exec.go

@@ -111,6 +111,18 @@ func Exec(_ *cobra.Command) {
 	}
 	commandArgs := os.Args[1:]
 	command := metrics.GetCommand(commandArgs)
+	if (command == "build" || command == "pull") && !metrics.HasQuietFlag(commandArgs) {
+		var image string
+		if command == "pull" {
+			for _, a := range commandArgs[1:] {
+				if !strings.HasPrefix(a, "--") {
+					image = a
+					break
+				}
+			}
+		}
+		displayScoutQuickViewSuggestMsg(image)
+	}
 	if command == "login" && !metrics.HasQuietFlag(commandArgs) {
 		displayPATSuggestMsg(commandArgs)
 	}

cli/mobycli/scout_suggest.go

@@ -0,0 +1,33 @@
+package mobycli
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+
+	"github.com/fatih/color"
+)
+
+const (
+	scoutHintEnvVarName = "DOCKER_SCOUT_HINTS"
+)
+
+func isDockerScoutHintsEnabled() bool {
+	enabled, err := strconv.ParseBool(os.Getenv(scoutHintEnvVarName))
+	return err != nil || enabled
+}
+
+func displayScoutQuickViewSuggestMsg(image string) {
+	if !isDockerScoutHintsEnabled() {
+		return
+	}
+	if len(image) > 0 {
+		image = " " + image
+	}
+	out := os.Stderr
+	b := color.New(color.Bold)
+	_, _ = fmt.Fprintln(out)
+	_, _ = b.Fprintln(out, "What's Next?")
+	_, _ = fmt.Fprintf(out, "  View summary of image vulnerabilities and recommendations → %s", color.CyanString("docker scout quickview%s", image))
+	_, _ = fmt.Fprintln(out)
+}

cli/mobycli/scout_suggest_test.go

@@ -0,0 +1,50 @@
+package mobycli
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestHintsEnabled(t *testing.T) {
+	testCases := []struct {
+		name     string
+		setup    func()
+		expected bool
+	}{
+		{
+			"enabled by default",
+			func() {},
+			true,
+		},
+		{
+			"handle true value",
+			func() {
+				t.Setenv(scoutHintEnvVarName, "t")
+			},
+			true,
+		},
+		{
+			"handle false value",
+			func() {
+				t.Setenv(scoutHintEnvVarName, "FALSE")
+			},
+			false,
+		},
+		{
+			"handle error",
+			func() {
+				t.Setenv(scoutHintEnvVarName, "123")
+			},
+			true,
+		},
+	}
+
+	for _, testCase := range testCases {
+		tc := testCase
+		t.Run(tc.name, func(t *testing.T) {
+			tc.setup()
+			assert.Equal(t, isDockerScoutHintsEnabled(), tc.expected)
+		})
+	}
+}

go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/docker/docker v20.10.7+incompatible
 	github.com/docker/go-connections v0.4.0
 	github.com/docker/go-units v0.5.0
+	github.com/fatih/color v1.7.0
 	github.com/gobwas/ws v1.1.0
 	github.com/golang/mock v1.6.0
 	github.com/golang/protobuf v1.5.2
@@ -100,7 +101,6 @@ require (
 	github.com/docker/go-metrics v0.0.1 // indirect
 	github.com/evanphx/json-patch v4.9.0+incompatible // indirect
 	github.com/exponent-io/jsonpath v0.0.0-20151013193312-d6023ce2651d // indirect
-	github.com/fatih/color v1.7.0 // indirect
 	github.com/form3tech-oss/jwt-go v3.2.2+incompatible // indirect
 	github.com/fvbommel/sortorder v1.0.1 // indirect
 	github.com/go-errors/errors v1.0.1 // indirect