Add BuildDate to version structure

Signed-off-by: Mark Anderson <manderson@hashicorp.com>

GNUmakefile

@@ -25,7 +25,9 @@ GIT_COMMIT?=$(shell git rev-parse --short HEAD)
 GIT_COMMIT_YEAR?=$(shell git show -s --format=%cd --date=format:%Y HEAD)
 GIT_DIRTY?=$(shell test -n "`git status --porcelain`" && echo "+CHANGES" || true)
 GIT_IMPORT=github.com/hashicorp/consul/version
-GOLDFLAGS=-X $(GIT_IMPORT).GitCommit=$(GIT_COMMIT)$(GIT_DIRTY)
+DATE_FORMAT="%Y-%m-%dT%H:%M:%SZ" # it's tricky to do an RFC3339 format in a cross platform way, so we hardcode UTC
+GIT_DATE=$(shell git show -s --format=%cd --date=format:"$(DATE_FORMAT)" HEAD) # we're using this for build date because it's stable across platform builds
+GOLDFLAGS=-X $(GIT_IMPORT).GitCommit=$(GIT_COMMIT)$(GIT_DIRTY) -X $(GIT_IMPORT).BuildDate=$(GIT_DATE)
 
 ifeq ($(FORCE_REBUILD),1)
 NOCACHE=--no-cache

command/agent/agent.go

@@ -27,12 +27,19 @@ import (
 )
 
 func New(ui cli.Ui) *cmd {
+	buildDate, err := time.Parse(time.RFC3339, consulversion.BuildDate)
+	if err != nil {
+		ui.Error(fmt.Sprintf("Fatal error with internal time set; check makefile for build date %v %v \n", buildDate, err))
+		return nil
+	}
+
 	c := &cmd{
 		ui:                ui,
 		revision:          consulversion.GitCommit,
 		version:           consulversion.Version,
 		versionPrerelease: consulversion.VersionPrerelease,
 		versionHuman:      consulversion.GetHumanVersion(),
+		buildDate:         buildDate,
 		flags:             flag.NewFlagSet("", flag.ContinueOnError),
 	}
 	config.AddFlags(c.flags, &c.configLoadOpts)
@@ -53,6 +60,7 @@ type cmd struct {
 	version           string
 	versionPrerelease string
 	versionHuman      string
+	buildDate         time.Time
 	configLoadOpts    config.LoadOpts
 	logger            hclog.InterceptLogger
 }
@@ -194,6 +202,7 @@ func (c *cmd) run(args []string) int {
 		segment = "<all>"
 	}
 	ui.Info(fmt.Sprintf("       Version: '%s'", c.versionHuman))
+	ui.Info(fmt.Sprintf("    Build Date: %s", c.buildDate))
 	ui.Info(fmt.Sprintf("       Node ID: '%s'", config.NodeID))
 	ui.Info(fmt.Sprintf("     Node name: '%s'", config.NodeName))
 	if ap := config.PartitionOrEmpty(); ap != "" {

version/version.go

@@ -23,6 +23,9 @@ var (
 	// then it means that it is a final release. Otherwise, this is a pre-release
 	// such as "dev" (in development), "beta", "rc1", etc.
 	VersionPrerelease = "dev"
+
+	// The date/time of the build
+	BuildDate string
 )
 
 // GetHumanVersion composes the parts of the version in a way that's suitable