Adds scribe.Emitter object

- Adds function that prints out dependency information as well as
deprecation warnings

Signed-off-by: Forest Eckhardt <[email protected]>

scribe/emitter.go

@@ -0,0 +1,43 @@
+package scribe
+
+import (
+	"io"
+	"time"
+
+	"github.com/paketo-buildpacks/packit"
+	"github.com/paketo-buildpacks/packit/postal"
+)
+
+type Emitter struct {
+	// Logger is embedded and therefore delegates all of its functions to the
+	// Emitter.
+	Logger
+}
+
+func NewEmitter(output io.Writer) Emitter {
+	return Emitter{
+		Logger: NewLogger(output),
+	}
+}
+
+func (e Emitter) SelectedDependency(entry packit.BuildpackPlanEntry, dependency postal.Dependency, now time.Time) {
+	source, ok := entry.Metadata["version-source"].(string)
+	if !ok {
+		source = "<unknown>"
+	}
+
+	e.Subprocess("Selected %s version (using %s): %s", dependency.Name, source, dependency.Version)
+
+	if (dependency.DeprecationDate != time.Time{}) {
+		deprecationDate := dependency.DeprecationDate
+		switch {
+		case (deprecationDate.Add(-30*24*time.Hour).Before(now) && deprecationDate.After(now)):
+			e.Action("Version %s of %s will be deprecated after %s.", dependency.Version, dependency.Name, dependency.DeprecationDate.Format("2006-01-02"))
+			e.Action("Migrate your application to a supported version of %s before this time.", dependency.Name)
+		case (deprecationDate == now || deprecationDate.Before(now)):
+			e.Action("Version %s of %s is deprecated.", dependency.Version, dependency.Name)
+			e.Action("Migrate your application to a supported version of %s.", dependency.Name)
+		}
+	}
+	e.Break()
+}

scribe/emitter_test.go

@@ -0,0 +1,121 @@
+package scribe_test
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	"github.com/paketo-buildpacks/packit"
+	"github.com/paketo-buildpacks/packit/postal"
+	"github.com/paketo-buildpacks/packit/scribe"
+	"github.com/sclevine/spec"
+
+	. "github.com/onsi/gomega"
+)
+
+func testEmitter(t *testing.T, context spec.G, it spec.S) {
+	var (
+		Expect = NewWithT(t).Expect
+
+		buffer  *bytes.Buffer
+		emitter scribe.Emitter
+	)
+
+	it.Before(func() {
+		buffer = bytes.NewBuffer(nil)
+		emitter = scribe.NewEmitter(buffer)
+	})
+
+	context("SelectedDependency", func() {
+		it("prints details about the selected dependency", func() {
+			entry := packit.BuildpackPlanEntry{
+				Metadata: map[string]interface{}{"version-source": "some-source"},
+			}
+			dependency := postal.Dependency{
+				Name:    "Some Dependency",
+				Version: "some-version",
+			}
+
+			emitter.SelectedDependency(entry, dependency, time.Now())
+			Expect(buffer.String()).To(Equal("    Selected Some Dependency version (using some-source): some-version\n\n"))
+		})
+
+		context("when the version source is missing", func() {
+			it("prints details about the selected dependency", func() {
+				dependency := postal.Dependency{
+					Name:    "Some Dependency",
+					Version: "some-version",
+				}
+
+				emitter.SelectedDependency(packit.BuildpackPlanEntry{}, dependency, time.Now())
+				Expect(buffer.String()).To(Equal("    Selected Some Dependency version (using <unknown>): some-version\n\n"))
+			})
+		})
+
+		context("when it is within 30 days of the deprecation date", func() {
+			it("returns a warning that the dependency will be deprecated after the deprecation date", func() {
+				deprecationDate, err := time.Parse(time.RFC3339, "2021-04-01T00:00:00Z")
+				Expect(err).NotTo(HaveOccurred())
+				now := deprecationDate.Add(-29 * 24 * time.Hour)
+
+				entry := packit.BuildpackPlanEntry{
+					Metadata: map[string]interface{}{"version-source": "some-source"},
+				}
+				dependency := postal.Dependency{
+					DeprecationDate: deprecationDate,
+					Name:            "Some Dependency",
+					Version:         "some-version",
+				}
+
+				emitter.SelectedDependency(entry, dependency, now)
+				Expect(buffer.String()).To(ContainSubstring("    Selected Some Dependency version (using some-source): some-version\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Version some-version of Some Dependency will be deprecated after 2021-04-01.\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Migrate your application to a supported version of Some Dependency before this time.\n\n"))
+			})
+		})
+
+		context("when it is on the the deprecation date", func() {
+			it("returns a warning that the version of the dependency is no longer supported", func() {
+				deprecationDate, err := time.Parse(time.RFC3339, "2021-04-01T00:00:00Z")
+				Expect(err).NotTo(HaveOccurred())
+				now := deprecationDate
+
+				entry := packit.BuildpackPlanEntry{
+					Metadata: map[string]interface{}{"version-source": "some-source"},
+				}
+				dependency := postal.Dependency{
+					DeprecationDate: deprecationDate,
+					Name:            "Some Dependency",
+					Version:         "some-version",
+				}
+
+				emitter.SelectedDependency(entry, dependency, now)
+				Expect(buffer.String()).To(ContainSubstring("    Selected Some Dependency version (using some-source): some-version\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Version some-version of Some Dependency is deprecated.\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Migrate your application to a supported version of Some Dependency.\n\n"))
+			})
+		})
+
+		context("when it is after the the deprecation date", func() {
+			it("returns a warning that the version of the dependency is no longer supported", func() {
+				deprecationDate, err := time.Parse(time.RFC3339, "2021-04-01T00:00:00Z")
+				Expect(err).NotTo(HaveOccurred())
+				now := deprecationDate.Add(24 * time.Hour)
+
+				entry := packit.BuildpackPlanEntry{
+					Metadata: map[string]interface{}{"version-source": "some-source"},
+				}
+				dependency := postal.Dependency{
+					DeprecationDate: deprecationDate,
+					Name:            "Some Dependency",
+					Version:         "some-version",
+				}
+
+				emitter.SelectedDependency(entry, dependency, now)
+				Expect(buffer.String()).To(ContainSubstring("    Selected Some Dependency version (using some-source): some-version\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Version some-version of Some Dependency is deprecated.\n"))
+				Expect(buffer.String()).To(ContainSubstring("      Migrate your application to a supported version of Some Dependency.\n\n"))
+			})
+		})
+	})
+}

scribe/init_test.go

@@ -11,6 +11,7 @@ func TestUnitScribe(t *testing.T) {
 	suite := spec.New("scribe", spec.Report(report.Terminal{}))
 	suite("Bar", testBar)
 	suite("Color", testColor)
+	suite("Emitter", testEmitter)
 	suite("FormattedList", testFormattedList)
 	suite("FormattedMap", testFormattedMap)
 	suite("Logger", testLogger)