Adds function to the emitter that logs launch processes

Signed-off-by: Timothy Hitchener <thitchener@pivotal.io>

Author: ForestEckhardt

scribe/emitter.go

@@ -1,8 +1,10 @@
 package scribe
 
 import (
+	"fmt"
 	"io"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/paketo-buildpacks/packit"
@@ -83,3 +85,24 @@ Entries:
 
 	e.Break()
 }
+
+func (e Emitter) LaunchProcesses(processes []packit.Process) {
+	e.Process("Assigning launch processes:")
+
+	for _, process := range processes {
+		p := fmt.Sprintf("%s: %s", process.Type, process.Command)
+
+		if process.Args != nil {
+			p = fmt.Sprintf("%s %s", p, strings.Join(process.Args, " "))
+		}
+
+		// This conditional should be replaced when API 0.6 is supported at which
+		// point any process can be set as default
+		if process.Type == "web" {
+			p = fmt.Sprintf("%s %s", p, "(default)")
+		}
+
+		e.Subprocess(p)
+	}
+	e.Break()
+}

scribe/emitter_test.go

@@ -189,4 +189,31 @@ func testEmitter(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 	})
+
+	context("LaunchProcesses", func() {
+		it("prints a list of launch processes", func() {
+			emitter.LaunchProcesses([]packit.Process{
+				{
+					Type:    "some-type",
+					Command: "some-command",
+				},
+				{
+					Type:    "web",
+					Command: "web-command",
+				},
+				{
+					Type:    "some-other-type",
+					Command: "some-other-command",
+					Args:    []string{"some", "args"},
+				},
+			})
+
+			Expect(buffer.String()).To(Equal(`  Assigning launch processes:
+    some-type: some-command
+    web: web-command (default)
+    some-other-type: some-other-command some args
+
+`), buffer.String())
+		})
+	})
 }