Add optionality to inspect-builder

[#127]

Signed-off-by: Danny Joyce <[email protected]>

acceptance/testdata/inspect_builder_output.txt

@@ -17,7 +17,7 @@ Buildpacks:
 
 Detection Order:
   Group #1:
-    [email protected]
+    [email protected]    
     [email protected]
   Group #2:
     [email protected]
@@ -39,7 +39,7 @@ Buildpacks:
 
 Detection Order:
   Group #1:
-    [email protected]
+    [email protected]    
     [email protected]
   Group #2:
     [email protected]

commands/inspect_builder.go

@@ -110,8 +110,25 @@ func logDetectionOrderInfo(logger *logging.Logger, info *pack.BuilderInfo) {
 	logger.Info("\nDetection Order:")
 	for i, group := range info.Groups {
 		logger.Info(fmt.Sprintf("  Group #%d:", i+1))
-		for _, bp := range group.Buildpacks {
-			logger.Info(fmt.Sprintf("    %s@%s", bp.ID, bp.Version))
+		buf := &bytes.Buffer{}
+		tabWriter := new(tabwriter.Writer).Init(buf, 0, 0, 4, ' ', 0)
+		for i, bp := range group.Buildpacks {
+			var optional string
+			if bp.Optional {
+				optional = "(optional)"
+			}
+			if _, err := fmt.Fprintf(tabWriter, "    %s@%s\t%s", bp.ID, bp.Version, optional); err != nil {
+				logger.Error(err.Error())
+			}
+			if i < len(group.Buildpacks)-1 {
+				if _, err := fmt.Fprint(tabWriter, "\n"); err != nil {
+					logger.Error(err.Error())
+				}
+			}
+		}
+		if err := tabWriter.Flush(); err != nil {
+			logger.Error(err.Error())
 		}
+		logger.Info(buf.String())
 	}
 }

commands/inspect_builder_test.go

@@ -121,7 +121,7 @@ ERROR: some local error
 					Buildpacks:           buildpacks,
 					Groups: []builder.GroupMetadata{
 						{Buildpacks: []builder.GroupBuildpack{
-							{ID: "test.bp.one", Version: "1.0.0"},
+							{ID: "test.bp.one", Version: "1.0.0", Optional: true},
 							{ID: "test.bp.two", Version: "2.0.0"},
 						}}},
 				}
@@ -135,7 +135,7 @@ ERROR: some local error
 					Buildpacks:           buildpacks,
 					Groups: []builder.GroupMetadata{
 						{Buildpacks: []builder.GroupBuildpack{{ID: "test.bp.one", Version: "1.0.0"}}},
-						{Buildpacks: []builder.GroupBuildpack{{ID: "test.bp.two", Version: "2.0.0"}}},
+						{Buildpacks: []builder.GroupBuildpack{{ID: "test.bp.two", Version: "2.0.0", Optional: true}}},
 					},
 				}
 				mockClient.EXPECT().InspectBuilder("some/image", true).Return(localInfo, nil)
@@ -177,7 +177,7 @@ Buildpacks:
 
 Detection Order:
   Group #1:
-    [email protected]
+    [email protected]    (optional)
     [email protected]
 `)
 
@@ -203,7 +203,7 @@ Detection Order:
   Group #1:
     [email protected]
   Group #2:
-    [email protected]
+    [email protected]    (optional)
 `)
 			})
 		})