Add support for HTTP Method HEAD

checks_test.go

@@ -28,9 +28,9 @@ func TestTCPDialCheck(t *testing.T) {
 }
 
 func TestHTTPGetCheck(t *testing.T) {
-	assert.NoError(t, HTTPGetCheck("https://heptio.com", 5*time.Second)())
-	assert.Error(t, HTTPGetCheck("http://heptio.com", 5*time.Second)(), "redirect should fail")
-	assert.Error(t, HTTPGetCheck("https://heptio.com/nonexistent", 5*time.Second)(), "404 should fail")
+	assert.NoError(t, HTTPGetCheck("https://heptio.cloud.vmware.com", 5*time.Second)())
+	assert.Error(t, HTTPGetCheck("http://heptio.cloud.vmware.com", 5*time.Second)(), "redirect should fail")
+	assert.Error(t, HTTPGetCheck("https://heptio.cloud.vmware.com/nonexistent", 5*time.Second)(), "404 should fail")
 }
 
 func TestDatabasePingCheck(t *testing.T) {

handler.go

@@ -73,7 +73,8 @@ func (s *basicHandler) collectChecks(checks map[string]Check, resultsOut map[str
 }
 
 func (s *basicHandler) handle(w http.ResponseWriter, r *http.Request, checks ...map[string]Check) {
-	if r.Method != http.MethodGet {
+
+	if r.Method != http.MethodGet && r.Method != http.MethodHead {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 		return
 	}
@@ -88,6 +89,10 @@ func (s *basicHandler) handle(w http.ResponseWriter, r *http.Request, checks ...
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	w.WriteHeader(status)
 
+	if r.Method == http.MethodHead {
+		return
+	}
+
 	// unless ?full=1, return an empty body. Kubernetes only cares about the
 	// HTTP status code, so we won't waste bytes on the full body.
 	if r.URL.Query().Get("full") != "1" {

handler_test.go

@@ -120,6 +120,42 @@ func TestNewHandler(t *testing.T) {
 			expect:     http.StatusServiceUnavailable,
 			expectBody: "{}\n",
 		},
+		{
+			name:       "HEAD with no checks, /live should succeed",
+			method:     "HEAD",
+			path:       "/live",
+			live:       true,
+			ready:      true,
+			expect:     http.StatusOK,
+			expectBody: "",
+		},
+		{
+			name:       "HEAD with no checks, /ready should succeed",
+			method:     "HEAD",
+			path:       "/ready",
+			live:       true,
+			ready:      true,
+			expect:     http.StatusOK,
+			expectBody: "",
+		},
+		{
+			name:       "HEAD with a failing liveness check, /live should fail",
+			method:     "HEAD",
+			path:       "/live",
+			live:       false,
+			ready:      true,
+			expect:     http.StatusServiceUnavailable,
+			expectBody: "",
+		},
+		{
+			name:       "HEAD with a failing liveness check, /ready should fail",
+			method:     "HEAD",
+			path:       "/ready",
+			live:       false,
+			ready:      true,
+			expect:     http.StatusServiceUnavailable,
+			expectBody: "",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {