fix #526: adds lookup for GetMetricVersions

This commit adds a lookup to fetch all metrics of a given namespace
without traversing to the leaves and collecting children.

cmd/snapctl/commands.go

@@ -219,7 +219,11 @@ func printFields(tw *tabwriter.Writer, indent bool, width int, fields ...interfa
 		argArray = append(argArray, strings.Repeat(" ", width))
 	}
 	for i, field := range fields {
-		argArray = append(argArray, field)
+		if field != nil {
+			argArray = append(argArray, field)
+		} else {
+			argArray = append(argArray, "")
+		}
 		if i < (len(fields) - 1) {
 			argArray = append(argArray, "\t")
 		}

cmd/snapctl/metric.go

@@ -54,8 +54,8 @@ func listMetrics(ctx *cli.Context) {
 
 	/*
 		NAMESPACE               VERSION
-		/intel/mock/foo        1,2
-		/intel/mock/bar        1
+		/intel/mock/foo         1,2
+		/intel/mock/bar         1
 	*/
 	w := tabwriter.NewWriter(os.Stdout, 0, 8, 1, '\t', 0)
 	metsByVer := make(map[string][]string)
@@ -78,26 +78,23 @@ func listMetrics(ctx *cli.Context) {
 }
 
 func getMetric(ctx *cli.Context) {
-	ns := ctx.String("metric-namespace")
-	ver := ctx.Int("metric-version")
-	if ns == "" {
-		fmt.Println("namespace is required")
+	if !ctx.IsSet("metric-namespace") || !ctx.IsSet("metric-version") {
+		fmt.Println("namespace and version are required")
+		fmt.Println("")
 		cli.ShowCommandHelp(ctx, ctx.Command.Name)
 		return
 	}
-	if ver == 0 {
-		ver = -1
-	}
-	metrics := pClient.FetchMetrics(ns, ver)
-	if metrics.Err != nil {
-		fmt.Println(metrics.Err)
+	ns := ctx.String("metric-namespace")
+	ver := ctx.Int("metric-version")
+	metric := pClient.GetMetric(ns, ver)
+	if metric.Err != nil {
+		fmt.Println(metric.Err)
 		return
 	}
-	metric := metrics.Catalog[0]
 
 	/*
 		NAMESPACE                VERSION         LAST ADVERTISED TIME
-		/intel/mock/foo         2               Wed, 09 Sep 2015 10:01:04 PDT
+		/intel/mock/foo          2               Wed, 09 Sep 2015 10:01:04 PDT
 
 		  Rules for collecting /intel/mock/foo:
 
@@ -109,28 +106,12 @@ func getMetric(ctx *cli.Context) {
 
 	w := tabwriter.NewWriter(os.Stdout, 0, 8, 1, '\t', 0)
 	printFields(w, false, 0, "NAMESPACE", "VERSION", "LAST ADVERTISED TIME")
-	printFields(w, false, 0, metric.Namespace, metric.Version, time.Unix(metric.LastAdvertisedTimestamp, 0).Format(time.RFC1123))
+	printFields(w, false, 0, metric.Metric.Namespace, metric.Metric.Version, time.Unix(metric.Metric.LastAdvertisedTimestamp, 0).Format(time.RFC1123))
 	w.Flush()
-	fmt.Printf("\n  Rules for collecting %s:\n\n", metric.Namespace)
+	fmt.Printf("\n  Rules for collecting %s:\n\n", metric.Metric.Namespace)
 	printFields(w, true, 6, "NAME", "TYPE", "DEFAULT", "REQUIRED", "MINIMUM", "MAXIMUM")
-	for _, rule := range metric.Policy {
-		var def_, min_, max_ interface{}
-		if rule.Default == nil {
-			def_ = ""
-		} else {
-			def_ = rule.Default
-		}
-		if rule.Minimum == nil {
-			min_ = ""
-		} else {
-			min_ = rule.Minimum
-		}
-		if rule.Maximum == nil {
-			max_ = ""
-		} else {
-			max_ = rule.Maximum
-		}
-		printFields(w, true, 6, rule.Name, rule.Type, def_, rule.Required, min_, max_)
+	for _, rule := range metric.Metric.Policy {
+		printFields(w, true, 6, rule.Name, rule.Type, rule.Default, rule.Required, rule.Minimum, rule.Maximum)
 	}
 	w.Flush()
 }

control/control.go

@@ -108,16 +108,17 @@ type managesPlugins interface {
 }
 
 type catalogsMetrics interface {
-	Get([]string, int) (*metricType, serror.SnapError)
+	Get([]string, int) (*metricType, error)
 	Add(*metricType)
 	AddLoadedMetricType(*loadedPlugin, core.Metric)
 	RmUnloadedPluginMetrics(lp *loadedPlugin)
-	Fetch([]string) ([]*metricType, serror.SnapError)
+	GetVersions([]string) ([]*metricType, error)
+	Fetch([]string) ([]*metricType, error)
 	Item() (string, []*metricType)
 	Next() bool
-	Subscribe([]string, int) serror.SnapError
-	Unsubscribe([]string, int) serror.SnapError
-	GetPlugin([]string, int) (*loadedPlugin, serror.SnapError)
+	Subscribe([]string, int) error
+	Unsubscribe([]string, int) error
+	GetPlugin([]string, int) (*loadedPlugin, error)
 }
 
 type managesSigning interface {
@@ -491,7 +492,10 @@ func (p *pluginControl) validateMetricTypeSubscription(mt core.RequestedMetric,
 
 	m, err := p.metricCatalog.Get(mt.Namespace(), mt.Version())
 	if err != nil {
-		serrs = append(serrs, err)
+		serrs = append(serrs, serror.New(err, map[string]interface{}{
+			"name":    core.JoinNamespace(mt.Namespace()),
+			"version": mt.Version(),
+		}))
 		return nil, serrs
 	}
 
@@ -551,7 +555,10 @@ func (p *pluginControl) gatherCollectors(mts []core.Metric) ([]core.Plugin, []se
 	for _, mt := range mts {
 		m, err := p.metricCatalog.Get(mt.Namespace(), mt.Version())
 		if err != nil {
-			serrs = append(serrs, err)
+			serrs = append(serrs, serror.New(err, map[string]interface{}{
+				"name":    core.JoinNamespace(mt.Namespace()),
+				"version": mt.Version(),
+			}))
 			continue
 		}
 		// if the metric subscription is to version -1, we need to carry
@@ -786,6 +793,19 @@ func (p *pluginControl) GetMetric(ns []string, ver int) (core.CatalogedMetric, e
 	return p.metricCatalog.Get(ns, ver)
 }
 
+func (p *pluginControl) GetMetricVersions(ns []string) ([]core.CatalogedMetric, error) {
+	mts, err := p.metricCatalog.GetVersions(ns)
+	if err != nil {
+		return nil, err
+	}
+
+	rmts := make([]core.CatalogedMetric, len(mts))
+	for i, m := range mts {
+		rmts[i] = m
+	}
+	return rmts, nil
+}
+
 func (p *pluginControl) MetricExists(mns []string, ver int) bool {
 	_, err := p.metricCatalog.Get(mns, ver)
 	if err == nil {

control/control_test.go

@@ -556,7 +556,7 @@ type mc struct {
 	e int
 }
 
-func (m *mc) Fetch(ns []string) ([]*metricType, serror.SnapError) {
+func (m *mc) Fetch(ns []string) ([]*metricType, error) {
 	if m.e == 2 {
 		return nil, serror.New(errors.New("test"))
 	}
@@ -567,11 +567,15 @@ func (m *mc) resolvePlugin(mns []string, ver int) (*loadedPlugin, error) {
 	return nil, nil
 }
 
-func (m *mc) GetPlugin([]string, int) (*loadedPlugin, serror.SnapError) {
+func (m *mc) GetPlugin([]string, int) (*loadedPlugin, error) {
 	return nil, nil
 }
 
-func (m *mc) Get(ns []string, ver int) (*metricType, serror.SnapError) {
+func (m *mc) GetVersions([]string) ([]*metricType, error) {
+	return nil, nil
+}
+
+func (m *mc) Get(ns []string, ver int) (*metricType, error) {
 	if m.e == 1 {
 		return &metricType{
 			policy: &mockCDProc{},
@@ -580,14 +584,14 @@ func (m *mc) Get(ns []string, ver int) (*metricType, serror.SnapError) {
 	return nil, serror.New(errorMetricNotFound(ns))
 }
 
-func (m *mc) Subscribe(ns []string, ver int) serror.SnapError {
+func (m *mc) Subscribe(ns []string, ver int) error {
 	if ns[0] == "nf" {
 		return serror.New(errorMetricNotFound(ns))
 	}
 	return nil
 }
 
-func (m *mc) Unsubscribe(ns []string, ver int) serror.SnapError {
+func (m *mc) Unsubscribe(ns []string, ver int) error {
 	if ns[0] == "nf" {
 		return serror.New(errorMetricNotFound(ns))
 	}

control/metrics.go

@@ -208,16 +208,23 @@ func (mc *metricCatalog) Add(m *metricType) {
 	mc.tree.Add(m)
 }
 
-// Get retrieves a loadedPlugin given a namespace and version.
+// Get retrieves a metric given a namespace and version.
 // If provided a version of -1 the latest plugin will be returned.
-func (mc *metricCatalog) Get(ns []string, version int) (*metricType, serror.SnapError) {
+func (mc *metricCatalog) Get(ns []string, version int) (*metricType, error) {
 	mc.mutex.Lock()
 	defer mc.mutex.Unlock()
 	return mc.get(ns, version)
 }
 
+// GetVersions retrieves all versions of a given metric namespace.
+func (mc *metricCatalog) GetVersions(ns []string) ([]*metricType, error) {
+	mc.mutex.Lock()
+	defer mc.mutex.Unlock()
+	return mc.getVersions(ns)
+}
+
 // Fetch transactionally retrieves all metrics which fall under namespace ns
-func (mc *metricCatalog) Fetch(ns []string) ([]*metricType, serror.SnapError) {
+func (mc *metricCatalog) Fetch(ns []string) ([]*metricType, error) {
 	mc.mutex.Lock()
 	defer mc.mutex.Unlock()
 
@@ -260,7 +267,7 @@ func (mc *metricCatalog) Next() bool {
 }
 
 // Subscribe atomically increments a metric's subscription count in the table.
-func (mc *metricCatalog) Subscribe(ns []string, version int) serror.SnapError {
+func (mc *metricCatalog) Subscribe(ns []string, version int) error {
 	mc.mutex.Lock()
 	defer mc.mutex.Unlock()
 
@@ -274,7 +281,7 @@ func (mc *metricCatalog) Subscribe(ns []string, version int) serror.SnapError {
 }
 
 // Unsubscribe atomically decrements a metric's count in the table
-func (mc *metricCatalog) Unsubscribe(ns []string, version int) serror.SnapError {
+func (mc *metricCatalog) Unsubscribe(ns []string, version int) error {
 	mc.mutex.Lock()
 	defer mc.mutex.Unlock()
 
@@ -286,39 +293,43 @@ func (mc *metricCatalog) Unsubscribe(ns []string, version int) serror.SnapError
 	return m.Unsubscribe()
 }
 
-func (mc *metricCatalog) GetPlugin(mns []string, ver int) (*loadedPlugin, serror.SnapError) {
+func (mc *metricCatalog) GetPlugin(mns []string, ver int) (*loadedPlugin, error) {
 	m, err := mc.Get(mns, ver)
 	if err != nil {
 		return nil, err
 	}
 	return m.Plugin, nil
 }
 
-func (mc *metricCatalog) get(ns []string, ver int) (*metricType, serror.SnapError) {
-	mts, err := mc.tree.Get(ns)
+func (mc *metricCatalog) get(ns []string, ver int) (*metricType, error) {
+	mts, err := mc.getVersions(ns)
 	if err != nil {
 		return nil, err
 	}
-	if mts == nil {
-		return nil, serror.New(errMetricNotFound)
-	}
+
 	// a version IS given
 	if ver > 0 {
 		l, err := getVersion(mts, ver)
 		if err != nil {
-			se := serror.New(errorMetricNotFound(ns, ver))
-			se.SetFields(map[string]interface{}{
-				"name":    core.JoinNamespace(ns),
-				"version": ver,
-			})
-			return nil, se
+			return nil, errorMetricNotFound(ns, ver)
 		}
 		return l, nil
 	}
 	// ver is less than or equal to 0 get the latest
 	return getLatest(mts), nil
 }
 
+func (mc *metricCatalog) getVersions(ns []string) ([]*metricType, error) {
+	mts, err := mc.tree.Get(ns)
+	if err != nil {
+		return nil, err
+	}
+	if mts == nil {
+		return nil, errMetricNotFound
+	}
+	return mts, nil
+}
+
 func getMetricKey(metric []string) string {
 	return strings.Join(metric, ".")
 }
@@ -343,11 +354,11 @@ func appendIfMissing(keys []string, ns string) []string {
 	return append(keys, ns)
 }
 
-func getVersion(c []*metricType, ver int) (*metricType, serror.SnapError) {
+func getVersion(c []*metricType, ver int) (*metricType, error) {
 	for _, m := range c {
 		if m.Plugin.Version() == ver {
 			return m, nil
 		}
 	}
-	return nil, serror.New(errMetricNotFound)
+	return nil, errMetricNotFound
 }

control/metrics_test.go

@@ -140,8 +140,6 @@ func TestMetricCatalog(t *testing.T) {
 			mc.Add(m35)
 			_, err := mc.Get([]string{"foo", "bar"}, 7)
 			So(err.Error(), ShouldContainSubstring, "Metric not found:")
-			So(err.Fields()["name"], ShouldEqual, "/foo/bar")
-			So(err.Fields()["version"], ShouldEqual, 7)
 		})
 	})
 	Convey("metricCatalog.Table()", t, func() {
@@ -164,7 +162,6 @@ func TestMetricCatalog(t *testing.T) {
 			_mt, err := mc.Get(ns, -1)
 			So(_mt, ShouldBeNil)
 			So(err.Error(), ShouldContainSubstring, "Metric not found:")
-			So(err.Fields()["name"], ShouldEqual, "/test")
 		})
 	})
 	Convey("metricCatalog.Next()", t, func() {
@@ -243,7 +240,6 @@ func TestSubscribe(t *testing.T) {
 		Convey("then it returns an error", func() {
 			err := mc.Subscribe([]string{"test4"}, -1)
 			So(err.Error(), ShouldContainSubstring, "Metric not found:")
-			So(err.Fields()["name"], ShouldEqual, "/test4")
 		})
 	})
 	Convey("when the metric is in the table", t, func() {
@@ -289,7 +285,6 @@ func TestUnsubscribe(t *testing.T) {
 		Convey("then it returns metric not found error", func() {
 			err := mc.Unsubscribe([]string{"test4"}, -1)
 			So(err.Error(), ShouldContainSubstring, "Metric not found:")
-			So(err.Fields()["name"], ShouldEqual, "/test4")
 		})
 	})
 	Convey("when the metric's count is already 0", t, func() {