kes: add Status API to client SDK

This commit adds the `Status` API call
to the client SDK.

The current client API only contains a
subset of the status information exposed
by the server due to API instability.

Signed-off-by: Andreas Auernhammer <[email protected]>

client.go

@@ -139,6 +139,29 @@ func (c *Client) Version(ctx context.Context) (string, error) {
 	return response.Version, nil
 }
 
+// Status returns the current state of the KES server.
+func (c *Client) Status(ctx context.Context) (State, error) {
+	client := retry(c.HTTPClient)
+	resp, err := client.Send(ctx, http.MethodGet, c.Endpoints, "/v1/status", nil)
+	if err != nil {
+		return State{}, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return State{}, parseErrorResponse(resp)
+	}
+
+	type Response struct {
+		Version string        `json:"version"`
+		UpTime  time.Duration `json:"uptime"`
+	}
+	const limit = 1 << 20
+	var response Response
+	if err = json.NewDecoder(io.LimitReader(resp.Body, limit)).Decode(&response); err != nil {
+		return State{}, err
+	}
+	return State(response), nil
+}
+
 // CreateKey creates a new cryptographic key. The key will
 // be generated by the KES server.
 //

integration_test.go

@@ -68,6 +68,24 @@ func TestVersion(t *testing.T) {
 	}
 }
 
+func TestStatus(t *testing.T) {
+	if !*IsIntegrationTest {
+		t.SkipNow()
+	}
+
+	client, err := newClient()
+	if err != nil {
+		t.Fatalf("Failed to create KES client: %v", err)
+	}
+	state, err := client.Status(context.Background())
+	if err != nil {
+		t.Fatalf("Failed to fetch KES server state: %v", err)
+	}
+	if state.UpTime == 0 {
+		t.Fatal("The KES server up time cannot be 0")
+	}
+}
+
 func TestCreateKey(t *testing.T) {
 	if !*IsIntegrationTest {
 		t.SkipNow()

status.go

@@ -0,0 +1,14 @@
+// Copyright 2022 - MinIO, Inc. All rights reserved.
+// Use of this source code is governed by the AGPLv3
+// license that can be found in the LICENSE file.
+
+package kes
+
+import "time"
+
+// State is a KES server status snapshot.
+type State struct {
+	Version string // The KES server version
+
+	UpTime time.Duration // The time the KES server has been up and running
+}