api: fix panic in 'consul acl set-agent-token' (#5533)

api: fix panic in 'consul acl set-agent-token'

Fixes #5531

api/agent.go

@@ -2,7 +2,9 @@ package api
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 )
@@ -1000,12 +1002,20 @@ func (a *Agent) updateTokenOnce(target, token string, q *WriteOptions) (*WriteMe
 	r := a.c.newRequest("PUT", fmt.Sprintf("/v1/agent/token/%s", target))
 	r.setWriteOptions(q)
 	r.obj = &AgentToken{Token: token}
-	rtt, resp, err := requireOK(a.c.doRequest(r))
+
+	rtt, resp, err := a.c.doRequest(r)
 	if err != nil {
-		return nil, resp.StatusCode, err
+		return nil, 0, err
 	}
-	resp.Body.Close()
+	defer resp.Body.Close()
 
 	wm := &WriteMeta{RequestTime: rtt}
+
+	if resp.StatusCode != 200 {
+		var buf bytes.Buffer
+		io.Copy(&buf, resp.Body)
+		return wm, resp.StatusCode, fmt.Errorf("Unexpected response code: %d (%s)", resp.StatusCode, buf.Bytes())
+	}
+
 	return wm, resp.StatusCode, nil
 }

api/agent_test.go

@@ -3,6 +3,9 @@ package api
 import (
 	"fmt"
 	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"net/http/httputil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -1243,8 +1246,8 @@ func TestAPI_AgentUpdateToken(t *testing.T) {
 	c, s := makeACLClient(t)
 	defer s.Stop()
 
+	t.Run("deprecated", func(t *testing.T) {
 		agent := c.Agent()
-
 		if _, err := agent.UpdateACLToken("root", nil); err != nil {
 			t.Fatalf("err: %v", err)
 		}
@@ -1260,7 +1263,10 @@ func TestAPI_AgentUpdateToken(t *testing.T) {
 		if _, err := agent.UpdateACLReplicationToken("root", nil); err != nil {
 			t.Fatalf("err: %v", err)
 		}
+	})
 
+	t.Run("new with no fallback", func(t *testing.T) {
+		agent := c.Agent()
 		if _, err := agent.UpdateDefaultACLToken("root", nil); err != nil {
 			t.Fatalf("err: %v", err)
 		}
@@ -1276,6 +1282,89 @@ func TestAPI_AgentUpdateToken(t *testing.T) {
 		if _, err := agent.UpdateReplicationACLToken("root", nil); err != nil {
 			t.Fatalf("err: %v", err)
 		}
+	})
+
+	t.Run("new with fallback", func(t *testing.T) {
+		// Respond with 404 for the new paths to trigger fallback.
+		failer := func(w http.ResponseWriter, req *http.Request) {
+			w.WriteHeader(404)
+		}
+		notfound := httptest.NewServer(http.HandlerFunc(failer))
+		defer notfound.Close()
+
+		raw := c // real consul client
+
+		// Set up a reverse proxy that will send some requests to the
+		// 404 server and pass everything else through to the real Consul
+		// server.
+		director := func(req *http.Request) {
+			req.URL.Scheme = "http"
+
+			switch req.URL.Path {
+			case "/v1/agent/token/default",
+				"/v1/agent/token/agent",
+				"/v1/agent/token/agent_master",
+				"/v1/agent/token/replication":
+				req.URL.Host = notfound.URL[7:] // Strip off "http://".
+			default:
+				req.URL.Host = raw.config.Address
+			}
+		}
+		proxy := httptest.NewServer(&httputil.ReverseProxy{Director: director})
+		defer proxy.Close()
+
+		// Make another client that points at the proxy instead of the real
+		// Consul server.
+		config := raw.config
+		config.Address = proxy.URL[7:] // Strip off "http://".
+		c, err := NewClient(&config)
+		require.NoError(t, err)
+
+		agent := c.Agent()
+
+		_, err = agent.UpdateDefaultACLToken("root", nil)
+		require.NoError(t, err)
+
+		_, err = agent.UpdateAgentACLToken("root", nil)
+		require.NoError(t, err)
+
+		_, err = agent.UpdateAgentMasterACLToken("root", nil)
+		require.NoError(t, err)
+
+		_, err = agent.UpdateReplicationACLToken("root", nil)
+		require.NoError(t, err)
+	})
+
+	t.Run("new with 403s", func(t *testing.T) {
+		failer := func(w http.ResponseWriter, req *http.Request) {
+			w.WriteHeader(403)
+		}
+		authdeny := httptest.NewServer(http.HandlerFunc(failer))
+		defer authdeny.Close()
+
+		raw := c // real consul client
+
+		// Make another client that points at the proxy instead of the real
+		// Consul server.
+		config := raw.config
+		config.Address = authdeny.URL[7:] // Strip off "http://".
+		c, err := NewClient(&config)
+		require.NoError(t, err)
+
+		agent := c.Agent()
+
+		_, err = agent.UpdateDefaultACLToken("root", nil)
+		require.Error(t, err)
+
+		_, err = agent.UpdateAgentACLToken("root", nil)
+		require.Error(t, err)
+
+		_, err = agent.UpdateAgentMasterACLToken("root", nil)
+		require.Error(t, err)
+
+		_, err = agent.UpdateReplicationACLToken("root", nil)
+		require.Error(t, err)
+	})
 }
 
 func TestAPI_AgentConnectCARoots_empty(t *testing.T) {