core: Adding Sensitive attribute to resource schema

This an effort to address hashicorp/terraform#516.

Adding the Sensitive attribute to the resource schema, opening up the
ability for resource maintainers to mark some fields as sensitive.
Sensitive fields are hidden in the output, and, possibly in the future,
could be encrypted.

builtin/providers/aws/resource_aws_db_instance.go

@@ -46,6 +46,7 @@ func resourceAwsDbInstance() *schema.Resource {
 			"password": &schema.Schema{
 				Type:      schema.TypeString,
 				Optional:  true,
+				Sensitive: true,
 			},
 
 			"engine": &schema.Schema{

command/format_plan.go

@@ -147,26 +147,38 @@ func formatPlanModuleExpand(
 				v = "<computed>"
 			}
 
-			newResource := ""
+			if attrDiff.Sensitive {
+				v = "<sensitive>"
+			}
+
+			updateMsg := ""
 			if attrDiff.RequiresNew && rdiff.Destroy {
-				newResource = opts.Color.Color(" [red](forces new resource)")
+				updateMsg = opts.Color.Color(" [red](forces new resource)")
+			} else if attrDiff.Sensitive && oldValues {
+				updateMsg = opts.Color.Color(" [yellow](attribute changed)")
 			}
 
 			if oldValues {
+				var u string
+				if attrDiff.Sensitive {
+					u = "<sensitive>"
+				} else {
+					u = attrDiff.Old
+				}
 				buf.WriteString(fmt.Sprintf(
 					"    %s:%s %#v => %#v%s\n",
 					attrK,
 					strings.Repeat(" ", keyLen-len(attrK)),
-					attrDiff.Old,
+					u,
 					v,
-					newResource))
+					updateMsg))
 			} else {
 				buf.WriteString(fmt.Sprintf(
 					"    %s:%s %#v%s\n",
 					attrK,
 					strings.Repeat(" ", keyLen-len(attrK)),
 					v,
-					newResource))
+					updateMsg))
 			}
 		}
 

command/hook_ui.go

@@ -103,15 +103,21 @@ func (h *UiHook) PreApply(
 		attrDiff := d.Attributes[attrK]
 
 		v := attrDiff.New
+		u := attrDiff.Old
 		if attrDiff.NewComputed {
 			v = "<computed>"
 		}
 
+		if attrDiff.Sensitive {
+			u = "<sensitive>"
+			v = "<sensitive>"
+		}
+
 		attrBuf.WriteString(fmt.Sprintf(
 			"  %s:%s %#v => %#v\n",
 			attrK,
 			strings.Repeat(" ", keyLen-len(attrK)),
-			attrDiff.Old,
+			u,
 			v))
 	}
 

helper/schema/schema.go

@@ -147,6 +147,12 @@ type Schema struct {
 	//
 	// ValidateFunc currently only works for primitive types.
 	ValidateFunc SchemaValidateFunc
+
+	// Sensitive ensures that the attribute's value does not get displayed in
+	// logs or regular output. It should be used for passwords or other
+	// secret fields. Futrure versions of Terraform may encrypt these
+	// values.
+	Sensitive bool
 }
 
 // SchemaDefaultFunc is a function called to return a default value for
@@ -281,6 +287,11 @@ func (s *Schema) finalizeDiff(
 		d.RequiresNew = true
 	}
 
+	if s.Sensitive {
+		// Set the Sensitive flag so output is hidden in the UI
+		d.Sensitive = true
+	}
+
 	return d
 }
 

terraform/diff.go

@@ -247,22 +247,30 @@ func (d *ModuleDiff) String() string {
 			attrDiff := rdiff.Attributes[attrK]
 
 			v := attrDiff.New
+			u := attrDiff.Old
 			if attrDiff.NewComputed {
 				v = "<computed>"
 			}
 
-			newResource := ""
+			if attrDiff.Sensitive {
+				u = "<sensitive>"
+				v = "<sensitive>"
+			}
+
+			updateMsg := ""
 			if attrDiff.RequiresNew {
-				newResource = " (forces new resource)"
+				updateMsg = " (forces new resource)"
+			} else if attrDiff.Sensitive {
+				updateMsg = " (attribute changed)"
 			}
 
 			buf.WriteString(fmt.Sprintf(
 				"  %s:%s %#v => %#v%s\n",
 				attrK,
 				strings.Repeat(" ", keyLen-len(attrK)),
-				attrDiff.Old,
+				u,
 				v,
-				newResource))
+				updateMsg))
 		}
 	}
 
@@ -284,6 +292,7 @@ type ResourceAttrDiff struct {
 	NewRemoved  bool        // True if this attribute is being removed
 	NewExtra    interface{} // Extra information for the provider
 	RequiresNew bool        // True if change requires new resource
+	Sensitive   bool        // True if the data should not be displayed in UI output
 	Type        DiffAttrType
 }
 

terraform/diff_test.go

@@ -153,6 +153,11 @@ func TestModuleDiff_String(t *testing.T) {
 						New:         "bar",
 						RequiresNew: true,
 					},
+					"secretfoo": &ResourceAttrDiff{
+						Old:       "foo",
+						New:       "bar",
+						Sensitive: true,
+					},
 				},
 			},
 		},
@@ -610,4 +615,5 @@ CREATE: nodeA
   bar:       "foo" => "<computed>"
   foo:       "foo" => "bar"
   longfoo:   "foo" => "bar" (forces new resource)
+  secretfoo: "<sensitive>" => "<sensitive>" (attribute changed)
 `