add version package

Added version info to binary.
Added the go version dependency to read executable info.
Original version package from 654e10aaab/version

Makefile

@@ -5,6 +5,21 @@ BUILD_DIR := $(WORKSPACE)/build
 
 export GOBIN=$(BUILD_DIR)
 
+VERSION = $(shell git describe --tags --always --dirty)
+BRANCH = $(shell git rev-parse --abbrev-ref HEAD)
+REVISION = $(shell git rev-parse HEAD)
+REVSHORT = $(shell git rev-parse --short HEAD)
+USER = $(shell whoami)
+NOW	= $(shell date -u +"%Y-%m-%dT%H:%M:%SZ")
+
+BUILD_VERSION = "\
+	-X micromdm.io/v2/pkg/version.appName=${APP_NAME} \
+	-X micromdm.io/v2/pkg/version.version=${VERSION} \
+	-X micromdm.io/v2/pkg/version.branch=${BRANCH} \
+	-X micromdm.io/v2/pkg/version.buildUser=${USER} \
+	-X micromdm.io/v2/pkg/version.buildDate=${NOW} \
+	-X micromdm.io/v2/pkg/version.revision=${REVISION}"
+
 download:
 	@echo "Download dependencies"
 	@go mod download
@@ -14,4 +29,5 @@ install-tools: download
 	@cat cmd/tools/tools.go | grep _ | awk -F'"' '{print $$2}' | xargs -tI % go install %
 
 micromdm:
-	go install -race ./cmd/micromdm
+	$(eval APP_NAME = micromdm)
+	go install -race -ldflags ${BUILD_VERSION} ./cmd/micromdm

cmd/micromdm/micromdm.go

@@ -17,6 +17,7 @@ import (
 	"github.com/peterbourgon/ff/v3/ffcli"
 
 	"micromdm.io/v2/pkg/log"
+	"micromdm.io/v2/pkg/version"
 )
 
 // write a pid so that the server can be restarted with SIGHUP
@@ -42,7 +43,7 @@ func micromdm(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 		ShortUsage: "version [<arg> ...]",
 		ShortHelp:  "Print version information.",
 		Exec: func(_ context.Context, args []string) error {
-			fmt.Println("v2dev")
+			version.PrintFull()
 			return nil
 		},
 	}

go.mod

@@ -9,4 +9,5 @@ require (
 	github.com/oklog/ulid v1.3.1 // indirect
 	github.com/oklog/ulid/v2 v2.0.2
 	github.com/peterbourgon/ff/v3 v3.0.0
+	rsc.io/goversion v1.2.0
 )

go.sum

@@ -360,5 +360,7 @@ honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWh
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
+rsc.io/goversion v1.2.0 h1:SPn+NLTiAG7w30IRK/DKp1BjvpWabYgxlLp/+kx5J8w=
+rsc.io/goversion v1.2.0/go.mod h1:Eih9y/uIBS3ulggl7KNJ09xGSLcuNaLgmvvqa07sgfo=
 sigs.k8s.io/yaml v1.1.0/go.mod h1:UJmg0vDUVViEyp3mgSv9WPwZCDxu4rQW1olrI1uml+o=
 sourcegraph.com/sourcegraph/appdash v0.0.0-20190731080439-ebfcffb1b5c0/go.mod h1:hI742Nqp5OhwiqlzhgfbWU4mW4yO10fP+LoT9WOswdU=

pkg/version/version.go

@@ -0,0 +1,94 @@
+/*
+	Package version provides utilities for displaying version information about a Go application.
+	To use this package, a program would set the package variables at build time, using the
+	-ldflags go build flag.
+	Example:
+		go build -ldflags "-X micromdm.io/v2/pkg/version.version=1.0.0"
+	Available values and defaults to use with ldflags:
+		version   = "unknown"
+		branch    = "unknown"
+		revision  = "unknown"
+		buildDate = "unknown"
+		buildUser = "unknown"
+		appName   = "unknown"
+*/
+package version
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+
+	goversion "rsc.io/goversion/version"
+)
+
+var (
+	version   = "unknown"
+	branch    = "unknown"
+	revision  = "unknown"
+	buildDate = "unknown"
+	buildUser = "unknown"
+	appName   = "micromdm"
+)
+
+// Info holds version and build info about the program.
+type Info struct {
+	Version   string `json:"version"`
+	Branch    string `json:"branch"`
+	Revision  string `json:"revision"`
+	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,
+		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() error {
+	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)
+
+	binary, err := os.Executable()
+	if err != nil {
+		return err
+	}
+
+	binVersion, err := goversion.ReadExe(binary)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("go release: \t%s\n", binVersion.Release)
+	fmt.Println()
+	fmt.Println(binVersion.ModuleInfo)
+	return nil
+}
+
+// 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)
+	})
+}