feat: Add /version endpoint reporting build and version info

Makefile

@@ -1,8 +1,15 @@
+BUILD_DATE       := $(shell date -u +'%Y-%m-%dT%H:%M:%SZ')
+BUILD_GIT_COMMIT := $(shell git rev-parse --short HEAD)
+BUILD_GIT_TAG    := $(shell git describe --tags --abbrev=0 | tr -d '\n')
+BUILD_PKG_TAG    = $(shell echo $(BUILD_GIT_TAG) | cut -f1 -d.)
+BUILD_LDFLAGS    := -X 'github.com/mccutchen/go-httpbin/$(BUILD_PKG_TAG)/httpbin.buildDate=$(BUILD_DATE)' -X 'github.com/mccutchen/go-httpbin/$(BUILD_PKG_TAG)/httpbin.buildGitCommit=$(BUILD_GIT_COMMIT)' -X 'github.com/mccutchen/go-httpbin/$(BUILD_PKG_TAG)/httpbin.buildGitTag=$(BUILD_GIT_TAG)'
+
 # The version that will be used in docker tags (e.g. to push a
 # go-httpbin:latest image use `make imagepush VERSION=latest)`
-VERSION    ?= $(shell git rev-parse --short HEAD)
+VERSION    ?= $(BUILD_GIT_TAG)
 DOCKER_TAG ?= mccutchen/go-httpbin:$(VERSION)
 
+
 # Built binaries will be placed here
 DIST_PATH  	  ?= dist
 
@@ -26,15 +33,15 @@ PORT ?= 8080
 # =============================================================================
 build:
 	mkdir -p $(DIST_PATH)
-	CGO_ENABLED=0 go build -ldflags="-s -w" -o $(DIST_PATH)/go-httpbin ./cmd/go-httpbin
+	CGO_ENABLED=0 go build -ldflags="$(BUILD_LDFLAGS) -s -w" -o $(DIST_PATH)/go-httpbin ./cmd/go-httpbin
 .PHONY: build
 
 buildexamples: build
 	./examples/build-all
 .PHONY: buildexamples
 
 buildtests:
-	CGO_ENABLED=0 go test -ldflags="-s -w" -v -c -o $(DIST_PATH)/go-httpbin.test ./httpbin
+	CGO_ENABLED=0 go test -ldflags="$(BUILD_LDFLAGS) -s -w" -v -c -o $(DIST_PATH)/go-httpbin.test ./httpbin
 .PHONY: buildtests
 
 clean:

httpbin/handlers.go

@@ -35,6 +35,13 @@ func (h *HTTPBin) Index(w http.ResponseWriter, r *http.Request) {
 	writeHTML(w, h.indexHTML, http.StatusOK)
 }
 
+// Version echoes build and version info
+func (h *HTTPBin) Version(w http.ResponseWriter, r *http.Request) {
+	writeJSON(http.StatusOK, w, &versionResponse{
+		Version: getVersionInfo(),
+	})
+}
+
 // FormsPost renders an HTML form that submits a request to the /post endpoint
 func (h *HTTPBin) FormsPost(w http.ResponseWriter, _ *http.Request) {
 	writeHTML(w, h.formsPostHTML, http.StatusOK)

httpbin/httpbin.go

@@ -185,6 +185,7 @@ func (h *HTTPBin) Handler() http.Handler {
 	mux.HandleFunc("/unstable", h.Unstable)
 	mux.HandleFunc("/user-agent", h.UserAgent)
 	mux.HandleFunc("/uuid", h.UUID)
+	mux.HandleFunc("/version", h.Version)
 	mux.HandleFunc("/xml", h.XML)
 
 	// existing httpbin endpoints that we do not support

httpbin/responses.go

@@ -13,6 +13,10 @@ const (
 	textContentType   = "text/plain; charset=utf-8"
 )
 
+type versionResponse struct {
+	Version VersionInfo `json:"version"`
+}
+
 type headersResponse struct {
 	Headers http.Header `json:"headers"`
 }

httpbin/version.go

@@ -0,0 +1,31 @@
+package httpbin
+
+import (
+	"fmt"
+	"runtime"
+)
+
+var (
+	// Values set with ldflags -X at build time
+	buildDate      = "" // ISO-8601 format
+	buildGitCommit = ""
+	buildGitTag    = ""
+)
+
+type VersionInfo struct {
+	BuildDate  string `json:"buildDate"`
+	GitCommit  string `json:"gitCommit"`
+	GitVersion string `json:"gitVersion"`
+	GoVersion  string `json:"goVersion"`
+	Platform   string `json:"platform"`
+}
+
+func getVersionInfo() VersionInfo {
+	return VersionInfo{
+		BuildDate:  buildDate,
+		GitCommit:  buildGitCommit,
+		GitVersion: buildGitTag,
+		GoVersion:  runtime.Version(),
+		Platform:   fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH),
+	}
+}