Add option to apply enterprise license at zero's startup.

dgraph/cmd/zero/license.go

@@ -37,3 +37,7 @@ func (n *node) updateEnterpriseState(closer *y.Closer) {
 func (st *state) applyEnterpriseLicense(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNotFound)
 }
+
+func (st *state) applyLicenseFile(path string) error {
+	return nil
+}

dgraph/cmd/zero/license_ee.go

@@ -132,3 +132,15 @@ func (st *state) applyEnterpriseLicense(w http.ResponseWriter, r *http.Request)
 	}
 	x.SetStatus(w, x.Success, "Done")
 }
+
+// applyLicenseFile applies the license file stored at the given path.
+func (st *state) applyLicenseFile(path string) error {
+	content, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+	return st.zero.applyLicense(ctx, bytes.NewReader(content))
+}

dgraph/cmd/zero/run.go

@@ -100,6 +100,7 @@ instances to achieve high-availability.
 	flag.String("datadog.collector", "", "Send opencensus traces to Datadog. As of now, the trace"+
 		" exporter does not support annotation logs and would discard them.")
 	flag.Bool("ludicrous_mode", false, "Run zero in ludicrous mode")
+	flag.String("enterprise_license", "", "Path to the enterprise license file.")
 }
 
 func setupListener(addr string, port int, kind string) (listener net.Listener, err error) {
@@ -240,6 +241,13 @@ func run() {
 	st.serveGRPC(grpcListener, store)
 	st.serveHTTP(httpListener)
 
+	// Apply enterprise license if one was given.
+	if license := Zero.Conf.GetString("enterprise_license"); len(license) > 0 {
+		if err := st.applyLicenseFile(license); err != nil {
+			glog.Warningf("Cannot apply enterprise license file %s", license)
+		}
+	}
+
 	http.HandleFunc("/health", st.pingResponse)
 	http.HandleFunc("/state", st.getState)
 	http.HandleFunc("/removeNode", st.removeNode)

wiki/content/enterprise-features/index.md

@@ -11,10 +11,13 @@ forum](https://discuss.dgraph.io).
 
 **Dgraph enterprise features are enabled by default for 30 days in a new cluster**.
 After the trial period of thirty (30) days, the cluster must obtain a license from Dgraph to
-continue enjoying the enterprise features released in the proprietary code. The license can
-be applied to the cluster by including it as the body of a POST request and calling
-`/enterpriseLicense` HTTP endpoint on any Zero server.
+continue enjoying the enterprise features released in the proprietary code.
 
+The license can be applied to the cluster by including it as the body of a POST
+request and calling `/enterpriseLicense` HTTP endpoint on any Zero server. It
+can also be applied by passing the path to the enterprise license file (using
+the flag `--enterprise_license`) to the `dgraph zero` command used to start the
+server. The second option is useful when the process needs to be automated.
 
 {{% notice "note" %}}
 At the conclusion of your 30-day trial period if a license has not been applied to the cluster,