Add handling for license requests in OSS (#9963)

This changes the license-fetching endpoint to respond with 204 in
OSS instead of 501. It closes #9827.

api/operator.go

@@ -1,6 +1,8 @@
 package api
 
 import (
+	"encoding/json"
+	"errors"
 	"io"
 	"io/ioutil"
 	"strconv"
@@ -297,10 +299,26 @@ func (op *Operator) LicensePut(license string, q *WriteOptions) (*WriteMeta, err
 }
 
 func (op *Operator) LicenseGet(q *QueryOptions) (*LicenseReply, *QueryMeta, error) {
+	req, err := op.c.newRequest("GET", "/v1/operator/license")
+	if err != nil {
+		return nil, nil, err
+	}
+
 	var reply LicenseReply
-	qm, err := op.c.query("/v1/operator/license", &reply, q)
+	_, resp, err := op.c.doRequest(req)
 	if err != nil {
 		return nil, nil, err
 	}
-	return &reply, qm, nil
+	defer resp.Body.Close()
+
+	if resp.StatusCode == 204 {
+		return nil, nil, errors.New("Nomad Enterprise only endpoint")
+	}
+
+	err = json.NewDecoder(resp.Body).Decode(&reply)
+	if err == nil {
+		return &reply, nil, nil
+	}
+
+	return nil, nil, err
 }

command/agent/http.go

@@ -314,6 +314,7 @@ func (s *HTTPServer) registerHandlers(enableDebug bool) {
 
 	s.mux.HandleFunc("/v1/search", s.wrap(s.SearchRequest))
 
+	s.mux.HandleFunc("/v1/operator/license", s.wrap(s.LicenseRequest))
 	s.mux.HandleFunc("/v1/operator/raft/", s.wrap(s.OperatorRequest))
 	s.mux.HandleFunc("/v1/operator/autopilot/configuration", s.wrap(s.OperatorAutopilotConfiguration))
 	s.mux.HandleFunc("/v1/operator/autopilot/health", s.wrap(s.OperatorServerHealth))

command/agent/http_oss.go

@@ -16,8 +16,6 @@ func (s *HTTPServer) registerEnterpriseHandlers() {
 	s.mux.HandleFunc("/v1/quota/", s.wrap(s.entOnly))
 	s.mux.HandleFunc("/v1/quota", s.wrap(s.entOnly))
 
-	s.mux.HandleFunc("/v1/operator/license", s.wrap(s.entOnly))
-
 	s.mux.HandleFunc("/v1/recommendation", s.wrap(s.entOnly))
 	s.mux.HandleFunc("/v1/recommendations", s.wrap(s.entOnly))
 	s.mux.HandleFunc("/v1/recommendations/apply", s.wrap(s.entOnly))

command/agent/operator_endpoint_oss.go

@@ -0,0 +1,20 @@
+// +build !ent
+
+package agent
+
+import (
+	"net/http"
+)
+
+func (s *HTTPServer) LicenseRequest(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
+	switch req.Method {
+	case "GET":
+		resp.WriteHeader(http.StatusNoContent)
+		return nil, nil
+	case "PUT":
+		return nil, CodedError(501, ErrEntOnly)
+	default:
+		return nil, CodedError(405, ErrInvalidMethod)
+	}
+
+}