Uyuni login less often (#10072)

* Initial implementation of caching the uyuni login token

Signed-off-by: David N Perkins <David.N.Perkins@ibm.com>

discovery/uyuni/uyuni.go

@@ -23,7 +23,6 @@ import (
 	"time"
 
 	"github.com/go-kit/log"
-	"github.com/go-kit/log/level"
 	"github.com/kolo/xmlrpc"
 	"github.com/pkg/errors"
 	"github.com/prometheus/common/config"
@@ -47,6 +46,8 @@ const (
 	uyuniLabelProxyModule    = uyuniMetaLabelPrefix + "proxy_module"
 	uyuniLabelMetricsPath    = uyuniMetaLabelPrefix + "metrics_path"
 	uyuniLabelScheme         = uyuniMetaLabelPrefix + "scheme"
+
+	tokenDuration = 10 * time.Minute
 )
 
 // DefaultSDConfig is the default Uyuni SD configuration.
@@ -96,14 +97,16 @@ type endpointInfo struct {
 // Discovery periodically performs Uyuni API requests. It implements the Discoverer interface.
 type Discovery struct {
 	*refresh.Discovery
-	apiURL       *url.URL
-	roundTripper http.RoundTripper
-	username     string
-	password     string
-	entitlement  string
-	separator    string
-	interval     time.Duration
-	logger       log.Logger
+	apiURL          *url.URL
+	roundTripper    http.RoundTripper
+	username        string
+	password        string
+	token           string
+	tokenExpiration time.Time
+	entitlement     string
+	separator       string
+	interval        time.Duration
+	logger          log.Logger
 }
 
 // Name returns the name of the Config.
@@ -140,16 +143,12 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
-func login(rpcclient *xmlrpc.Client, user, pass string) (string, error) {
+func login(rpcclient *xmlrpc.Client, user, pass string, duration int) (string, error) {
 	var result string
-	err := rpcclient.Call("auth.login", []interface{}{user, pass}, &result)
+	err := rpcclient.Call("auth.login", []interface{}{user, pass, duration}, &result)
 	return result, err
 }
 
-func logout(rpcclient *xmlrpc.Client, token string) error {
-	return rpcclient.Call("auth.logout", token, nil)
-}
-
 func getSystemGroupsInfoOfMonitoredClients(rpcclient *xmlrpc.Client, token, entitlement string) (map[int][]systemGroupID, error) {
 	var systemGroupsInfos []struct {
 		SystemID     int             `xmlrpc:"id"`
@@ -271,12 +270,11 @@ func getSystemGroupNames(systemGroupsIDs []systemGroupID) []string {
 
 func (d *Discovery) getTargetsForSystems(
 	rpcClient *xmlrpc.Client,
-	token string,
 	entitlement string,
 ) ([]model.LabelSet, error) {
 	result := make([]model.LabelSet, 0)
 
-	systemGroupIDsBySystemID, err := getSystemGroupsInfoOfMonitoredClients(rpcClient, token, entitlement)
+	systemGroupIDsBySystemID, err := getSystemGroupsInfoOfMonitoredClients(rpcClient, d.token, entitlement)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to get the managed system groups information of monitored clients")
 	}
@@ -286,12 +284,12 @@ func (d *Discovery) getTargetsForSystems(
 		systemIDs = append(systemIDs, systemID)
 	}
 
-	endpointInfos, err := getEndpointInfoForSystems(rpcClient, token, systemIDs)
+	endpointInfos, err := getEndpointInfoForSystems(rpcClient, d.token, systemIDs)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to get endpoints information")
 	}
 
-	networkInfoBySystemID, err := getNetworkInformationForSystems(rpcClient, token, systemIDs)
+	networkInfoBySystemID, err := getNetworkInformationForSystems(rpcClient, d.token, systemIDs)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to get the systems network information")
 	}
@@ -308,25 +306,27 @@ func (d *Discovery) getTargetsForSystems(
 	return result, nil
 }
 
-func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
+func (d *Discovery) refresh(_ context.Context) ([]*targetgroup.Group, error) {
 	rpcClient, err := xmlrpc.NewClient(d.apiURL.String(), d.roundTripper)
 	if err != nil {
 		return nil, err
 	}
 	defer rpcClient.Close()
 
-	token, err := login(rpcClient, d.username, d.password)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to login to Uyuni API")
-	}
-	defer func() {
-		if err := logout(rpcClient, token); err != nil {
-			level.Debug(d.logger).Log("msg", "Failed to log out from Uyuni API", "err", err)
+	if time.Now().After(d.tokenExpiration) {
+		// Uyuni API takes duration in seconds.
+		d.token, err = login(rpcClient, d.username, d.password, int(tokenDuration.Seconds()))
+		if err != nil {
+			return nil, errors.Wrap(err, "unable to login to Uyuni API")
 		}
-	}()
+		// Login again at half the token lifetime.
+		d.tokenExpiration = time.Now().Add(tokenDuration / 2)
+	}
 
-	targetsForSystems, err := d.getTargetsForSystems(rpcClient, token, d.entitlement)
+	targetsForSystems, err := d.getTargetsForSystems(rpcClient, d.entitlement)
 	if err != nil {
+		// Force the renewal of the token on next refresh.
+		d.tokenExpiration = time.Now()
 		return nil, err
 	}
 

discovery/uyuni/uyuni_test.go

@@ -19,6 +19,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 
@@ -56,3 +57,67 @@ func TestUyuniSDHandleError(t *testing.T) {
 	require.EqualError(t, err, errTesting)
 	require.Equal(t, len(tgs), 0)
 }
+
+func TestUyuniSDLogin(t *testing.T) {
+	var (
+		errTesting  = "unable to get the managed system groups information of monitored clients: request error: bad status code - 500"
+		call        = 0
+		respHandler = func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/xml")
+			switch call {
+			case 0:
+				w.WriteHeader(http.StatusOK)
+				io.WriteString(w, `<?xml version="1.0"?>
+<methodResponse>
+	<params>
+		<param>
+			<value>
+				a token
+			</value>
+		</param>
+	</params>
+</methodResponse>`)
+			case 1:
+				w.WriteHeader(http.StatusInternalServerError)
+				io.WriteString(w, ``)
+			}
+			call++
+		}
+	)
+	tgs, err := testUpdateServices(respHandler)
+
+	require.EqualError(t, err, errTesting)
+	require.Equal(t, len(tgs), 0)
+}
+
+func TestUyuniSDSkipLogin(t *testing.T) {
+	var (
+		errTesting  = "unable to get the managed system groups information of monitored clients: request error: bad status code - 500"
+		respHandler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Header().Set("Content-Type", "application/xml")
+			io.WriteString(w, ``)
+		}
+	)
+
+	// Create a test server with mock HTTP handler.
+	ts := httptest.NewServer(http.HandlerFunc(respHandler))
+	defer ts.Close()
+
+	conf := SDConfig{
+		Server: ts.URL,
+	}
+
+	md, err := NewDiscovery(&conf, nil)
+	if err != nil {
+		t.Error(err)
+	}
+	// simulate a cached token
+	md.token = `a token`
+	md.tokenExpiration = time.Now().Add(time.Minute)
+
+	tgs, err := md.refresh(context.Background())
+
+	require.EqualError(t, err, errTesting)
+	require.Equal(t, len(tgs), 0)
+}