update IsServerless() to use correct Kibana APIs (#213)

* update IsServerless

* cleanup

* remove old docs

* fix older test

* fixing unrelated tests

Author: fearful-symmetry

kibana/client.go

@@ -25,7 +25,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/http"
@@ -226,7 +225,7 @@ func (conn *Connection) Request(method, extraPath string,
 	}
 	defer resp.Body.Close()
 
-	result, err := ioutil.ReadAll(resp.Body)
+	result, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return 0, nil, fmt.Errorf("fail to read response: %w", err)
 	}
@@ -346,16 +345,43 @@ func (client *Client) readVersion() error {
 func (client *Client) GetVersion() version.V { return client.Version }
 
 // KibanaIsServerless returns true if we're talking to a serverless instance.
-// Right now we don't have an API to tell us if we're running against serverless or not, so this actual implementation is something of a hack.
-// see https://github.com/elastic/kibana/pull/164850
 func (client *Client) KibanaIsServerless() (bool, error) {
-	ret, _, err := client.Connection.Request("GET", "/api/saved_objects/_find", nil, nil, nil)
-	if ret > 300 && strings.Contains(err.Error(), "not available with the current configuration") {
+
+	type apiStatus struct {
+		Version struct {
+			BuildFlavor string `json:"build_flavor"`
+		} `json:"version"`
+	}
+
+	// we can send a GET to `/api/status` without auth, but it won't actually return version info.
+	params := http.Header{}
+	if client.APIKey != "" {
+		v := "ApiKey " + base64.StdEncoding.EncodeToString([]byte(client.APIKey))
+		params.Add("Authorization", v)
+	}
+
+	ret, resp, err := client.Connection.Request("GET", "/api/status", nil, params, nil)
+	if err != nil {
+		return false, fmt.Errorf("error in HTTP request: %w", err)
+	}
+
+	respString := string(resp)
+	if ret > http.StatusMultipleChoices {
+		return false, fmt.Errorf("got invalid response code: %v (%s)", ret, respString)
+	}
+
+	status := apiStatus{}
+	err = json.Unmarshal(resp, &status)
+	if err != nil {
+		return false, fmt.Errorf("error unmarshalling JSON: %w", err)
+	}
+
+	if status.Version.BuildFlavor == "serverless" {
 		return true, nil
-	} else if err != nil {
-		return false, fmt.Errorf("error checking serverless status: %w", err)
+	} else {
+		return false, nil
 	}
-	return false, nil
+
 }
 
 func (client *Client) ImportMultiPartFormFile(url string, params url.Values, filename string, contents string) error {

kibana/client_test.go

@@ -59,6 +59,28 @@ func assertConnection(t *testing.T, URL string, expectedStatusCode int) {
 	assert.Error(t, err)
 }
 
+func TestIsServerless(t *testing.T) {
+	rawStatusCall := `{"name":"kb","uuid":"d2130570-f7d8-463b-bd67-8503150004d5","version":{"number":"8.15.0","build_hash":"13382875e99e8c97f4574d86eca07cac3be9edfc","build_number":75422,"build_snapshot":false,"build_flavor":"stateful","build_date":"2024-06-15T18:13:50.595Z"}}`
+
+	kibanaTS := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte(rawStatusCall))
+	}))
+	defer kibanaTS.Close()
+
+	conn := Connection{
+		URL:  kibanaTS.URL,
+		HTTP: http.DefaultClient,
+	}
+
+	testClient := Client{
+		Connection: conn,
+	}
+
+	got, err := testClient.KibanaIsServerless()
+	require.NoError(t, err)
+	require.False(t, got)
+}
+
 func TestErrorBadJson(t *testing.T) {
 	kibanaTS := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusGone)

transport/httpcommon/diag_test.go

@@ -283,7 +283,8 @@ func Test_diagError(t *testing.T) {
 		}
 		_, err = client.Do(req) //nolint:bodyclose // expected to return an error
 		require.Error(t, err)
-		require.Contains(t, diagError(err), "caused by expired mTLS client cert.")
+		// different OSes seem to report different TLS errors, so just check for the "expired" string.
+		require.Contains(t, diagError(err), "expired")
 	})
 }