add version command

Closes #72

.gitignore

@@ -1,3 +1,2 @@
 vendor/
-SCEPCACert.pem
-mdm.db
+build/

main.go

@@ -8,6 +8,8 @@ import (
 	"strings"
 	"text/tabwriter"
 	"time"
+
+	"github.com/micromdm/micromdm/version"
 )
 
 func init() {
@@ -21,6 +23,9 @@ func main() {
 	}
 	var run func([]string) error
 	switch strings.ToLower(os.Args[1]) {
+	case "version", "-version":
+		version.Print()
+		return
 	case "serve":
 		run = serve
 	case "dep-token":

release.sh

@@ -0,0 +1,27 @@
+VERSION="$(git describe --tags --always --dirty)"
+NAME=micromdm
+USER=$(whoami)
+BRANCH=$(git rev-parse --abbrev-ref HEAD)
+NOW=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+REVISION=$(git rev-parse HEAD)
+GOVERSION=$(go version | awk '{print $3}')
+
+echo "Building $NAME version $VERSION"
+
+mkdir -p build
+
+build() {
+  echo -n "=> $1-$2: "
+  GOOS=$1 GOARCH=$2 CGO_ENABLED=0 go build -o build/$NAME-$1-$2 -ldflags "\
+      -X github.com/micromdm/micromdm/version.version=${VERSION}\
+      -X github.com/micromdm/micromdm/version.branch=${BRANCH}\
+      -X github.com/micromdm/micromdm/version.buildUser=${USER}\
+      -X github.com/micromdm/micromdm/version.buildDate=${NOW}\
+      -X github.com/micromdm/micromdm/version.revision=${REVISION}\
+      -X github.com/micromdm/micromdm/version.goVersion=${GOVERSION}\
+      " ./*.go
+  du -h build/$NAME-$1-$2
+}
+
+build "darwin" "amd64"
+build "linux" "amd64"

version/version.go

@@ -0,0 +1,69 @@
+// Package version provides utilities for displaying version information.
+package version
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+// go build -ldflags "-X github.com/micromdm/micromdm/version.version=1.0.0"
+var (
+	version   = "unknown"
+	branch    = "unknown"
+	revision  = "unknown"
+	goVersion = "unknown"
+	buildDate = "unknown"
+	buildUser = "unknown"
+	appName   = "micromdm"
+)
+
+// Info holds version and build info about the app.
+type Info struct {
+	Version   string `json:"version"`
+	Branch    string `json:"branch"`
+	Revision  string `json:"revision"`
+	GoVersion string `json:"go_version"`
+	BuildDate string `json:"build_date"`
+	BuildUser string `json:"build_user"`
+}
+
+// Version returns a struct with the current version information.
+func Version() Info {
+	return Info{
+		Version:   version,
+		Branch:    branch,
+		Revision:  revision,
+		GoVersion: goVersion,
+		BuildDate: buildDate,
+		BuildUser: buildUser,
+	}
+}
+
+// Print outputs the app name and version string.
+func Print() {
+	v := Version()
+	fmt.Printf("%s version %s\n", appName, v.Version)
+}
+
+// PrintFull outputs the app name and detailed version information.
+func PrintFull() {
+	v := Version()
+	fmt.Printf("%s - version %s\n", appName, v.Version)
+	fmt.Printf("  branch: \t%s\n", v.Branch)
+	fmt.Printf("  revision: \t%s\n", v.Revision)
+	fmt.Printf("  build date: \t%s\n", v.BuildDate)
+	fmt.Printf("  build user: \t%s\n", v.BuildUser)
+	fmt.Printf("  go version: \t%s\n", v.GoVersion)
+}
+
+// Handler provides an HTTP Handler which returns JSON formatted version info.
+func Handler() http.Handler {
+	v := Version()
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
+		enc := json.NewEncoder(w)
+		enc.SetIndent("", "  ")
+		enc.Encode(v)
+	})
+}