Add headers parameter for HTTP checker

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

configuration/configuration.go

@@ -202,6 +202,8 @@ type HTTPChecker struct {
 	Interval time.Duration `yaml:"interval,omitempty"`
 	// URI is the HTTP URI to check
 	URI string `yaml:"uri,omitempty"`
+	// Headers lists static headers that should be added to all requests
+	Headers http.Header `yaml:"headers"`
 	// Threshold is the number of times a check must fail to trigger an
 	// unhealthy state
 	Threshold int `yaml:"threshold,omitempty"`

docs/configuration.md

@@ -205,6 +205,8 @@ information about each option that appears later in this page.
           interval: 10s
       http:
         - uri: http://server.to.check/must/return/200
+          headers:
+            Authorization: [Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==]
           statuscode: 200
           timeout: 3s
           interval: 10s
@@ -1400,7 +1402,9 @@ The URL to which events should be published.
       yes
     </td>
     <td>
-      Static headers to add to each request.
+      Static headers to add to each request. Each header's name should be a key
+      underneath headers, and each value is a list of payloads for that
+      header name. Note that values must always be lists.
     </td>
   </tr>
   <tr>
@@ -1619,6 +1623,8 @@ Configure the behavior of the Redis connection pool.
           interval: 10s
       http:
         - uri: http://server.to.check/must/return/200
+          headers:
+            Authorization: [Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==]
           statuscode: 200
           timeout: 3s
           interval: 10s
@@ -1766,6 +1772,19 @@ health check will fail.
     <td>
 The URI to check.
 </td>
+  </tr>
+   <tr>
+    <td>
+      <code>headers</code>
+    </td>
+    <td>
+      no
+    </td>
+    <td>
+      Static headers to add to each request. Each header's name should be a key
+      underneath headers, and each value is a list of payloads for that
+      header name. Note that values must always be lists.
+    </td>
   </tr>
   <tr>
     <td>

health/checks/checks.go

@@ -24,12 +24,21 @@ func FileChecker(f string) health.Checker {
 
 // HTTPChecker does a HEAD request and verifies that the HTTP status code
 // returned matches statusCode.
-func HTTPChecker(r string, statusCode int, timeout time.Duration) health.Checker {
+func HTTPChecker(r string, statusCode int, timeout time.Duration, headers http.Header) health.Checker {
 	return health.CheckFunc(func() error {
 		client := http.Client{
 			Timeout: timeout,
 		}
-		response, err := client.Head(r)
+		req, err := http.NewRequest("HEAD", r, nil)
+		if err != nil {
+			return errors.New("error creating request: " + r)
+		}
+		for headerName, headerValues := range headers {
+			for _, headerValue := range headerValues {
+				req.Header.Add(headerName, headerValue)
+			}
+		}
+		response, err := client.Do(req)
 		if err != nil {
 			return errors.New("error while checking: " + r)
 		}

health/checks/checks_test.go

@@ -15,11 +15,11 @@ func TestFileChecker(t *testing.T) {
 }
 
 func TestHTTPChecker(t *testing.T) {
-	if err := HTTPChecker("https://www.google.cybertron", 200, 0).Check(); err == nil {
+	if err := HTTPChecker("https://www.google.cybertron", 200, 0, nil).Check(); err == nil {
 		t.Errorf("Google on Cybertron was expected as not exists")
 	}
 
-	if err := HTTPChecker("https://www.google.pt", 200, 0).Check(); err != nil {
+	if err := HTTPChecker("https://www.google.pt", 200, 0, nil).Check(); err != nil {
 		t.Errorf("Google at Portugal was expected as exists, error:%v", err)
 	}
 }

registry/handlers/app.go

@@ -281,7 +281,7 @@ func (app *App) RegisterHealthChecks(healthRegistries ...*health.Registry) {
 			statusCode = 200
 		}
 
-		checker := checks.HTTPChecker(httpChecker.URI, statusCode, httpChecker.Timeout)
+		checker := checks.HTTPChecker(httpChecker.URI, statusCode, httpChecker.Timeout, httpChecker.Headers)
 
 		if httpChecker.Threshold != 0 {
 			ctxu.GetLogger(app).Infof("configuring HTTP health check uri=%s, interval=%d, threshold=%d", httpChecker.URI, interval/time.Second, httpChecker.Threshold)