Clarify and clean up template contract for status (#149)

* Clarify and clean up template contract for status Ring was passing a mix of time.Time and formatted string for the time: unified to pass always time.Time, and decide what to do when rendering. This will allow us some extra customisation if replacing the template with a non-default one. Also replaced the "Unhealthy" state by "UNHEALTHY" in the template, because the rest of states are uppercase. Not replacing the constant value because it's being used for metrics and we'd have to fix the recording rules in all the downstream projects. Changed how heartbeat time is rendered: rendering the duration since the heartbeat and the time in parenthesis: heartbeats are so common that showing a date doesn't make sense, and since they're usually few seconds away, the "duration ago" is what makes more sense IMO. Signed-off-by: Oleg Zaytsev <[email protected]> * Update CHANGELOG.md Signed-off-by: Oleg Zaytsev <[email protected]> * Use only 2 decimals for percentage We don't need 4 Signed-off-by: Oleg Zaytsev <[email protected]> * Add 'Content-Type: text/html' header Signed-off-by: Oleg Zaytsev <[email protected]>
grafana · Mar 30, 2022 · 8de36ff · 8de36ff
1 parent fc0ae59
commit 8de36ff
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Showing 4 changed files with 36 additions and 47 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -22,6 +22,7 @@
 * [CHANGE] ring/client: It's now possible to set different value than `consul` as default KV store. #120
 * [CHANGE] Lifecycler: Default value of lifecycler's `final-sleep` is now `0s` (i.e. no sleep). #121
 * [CHANGE] Lifecycler: It's now possible to change default value of lifecycler's `final-sleep`. #121
+* [CHANGE] Minor cosmetic changes in ring and memberlist HTTP status templates. #149
 * [ENHANCEMENT] Add middleware package. #38
 * [ENHANCEMENT] Add the ring package #45
 * [ENHANCEMENT] Add limiter package. #41

diff --git a/kv/memberlist/kv_init_service.go b/kv/memberlist/kv_init_service.go
@@ -171,21 +171,14 @@ func (kvs *KVInitService) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if strings.Contains(accept, "application/json") {
 		w.Header().Set("Content-Type", "application/json")
 
-		data, err := json.Marshal(v)
-		if err != nil {
+		if err := json.NewEncoder(w).Encode(v); err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
 		}
-
-		// We ignore errors here, because we cannot do anything about them.
-		// Write will trigger sending Status code, so we cannot send a different status code afterwards.
-		// Also this isn't internal error, but error communicating with client.
-		_, _ = w.Write(data)
 		return
 	}
 
-	err := defaultPageTemplate.Execute(w, v)
-	if err != nil {
+	w.Header().Set("Content-Type", "text/html")
+	if err := defaultPageTemplate.Execute(w, v); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 	}
 }
@@ -226,7 +219,6 @@ func viewKey(w http.ResponseWriter, store map[string]valueDesc, key string, form
 }
 
 func formatValue(w http.ResponseWriter, val interface{}, format string) {
-
 	w.WriteHeader(200)
 	w.Header().Add("content-type", "text/plain")
 

diff --git a/ring/http.go b/ring/http.go
@@ -17,26 +17,36 @@ import (
 var defaultPageContent string
 var defaultPageTemplate = template.Must(template.New("webpage").Funcs(template.FuncMap{
 	"mod": func(i, j int) bool { return i%j == 0 },
+	"humanFloat": func(f float64) string {
+		return fmt.Sprintf("%.2g", f)
+	},
+	"timeOrEmptyString": func(t time.Time) string {
+		if t.IsZero() {
+			return ""
+		}
+		return t.Format(time.RFC3339Nano)
+	},
+	"durationSince": func(t time.Time) string { return time.Since(t).Truncate(time.Millisecond).String() },
 }).Parse(defaultPageContent))
 
-type ingesterDesc struct {
-	ID                  string   `json:"id"`
-	State               string   `json:"state"`
-	Address             string   `json:"address"`
-	HeartbeatTimestamp  string   `json:"timestamp"`
-	RegisteredTimestamp string   `json:"registered_timestamp"`
-	Zone                string   `json:"zone"`
-	Tokens              []uint32 `json:"tokens"`
-	NumTokens           int      `json:"-"`
-	Ownership           float64  `json:"-"`
-}
-
 type httpResponse struct {
 	Ingesters  []ingesterDesc `json:"shards"`
 	Now        time.Time      `json:"now"`
 	ShowTokens bool           `json:"-"`
 }
 
+type ingesterDesc struct {
+	ID                  string    `json:"id"`
+	State               string    `json:"state"`
+	Address             string    `json:"address"`
+	HeartbeatTimestamp  time.Time `json:"timestamp"`
+	RegisteredTimestamp time.Time `json:"registered_timestamp"`
+	Zone                string    `json:"zone"`
+	Tokens              []uint32  `json:"tokens"`
+	NumTokens           int       `json:"-"`
+	Ownership           float64   `json:"-"`
+}
+
 type ringAccess interface {
 	casRing(ctx context.Context, f func(in interface{}) (out interface{}, retry bool, err error)) error
 	getRing(context.Context) (*Desc, error)
@@ -85,7 +95,7 @@ func (h *ringPageHandler) handle(w http.ResponseWriter, req *http.Request) {
 	}
 	_, ownedTokens := ringDesc.countTokens()
 
-	ingesterIDs := []string{}
+	var ingesterIDs []string
 	for id := range ringDesc.Ingesters {
 		ingesterIDs = append(ingesterIDs, id)
 	}
@@ -95,24 +105,17 @@ func (h *ringPageHandler) handle(w http.ResponseWriter, req *http.Request) {
 	var ingesters []ingesterDesc
 	for _, id := range ingesterIDs {
 		ing := ringDesc.Ingesters[id]
-		heartbeatTimestamp := time.Unix(ing.Timestamp, 0)
 		state := ing.State.String()
 		if !ing.IsHealthy(Reporting, h.heartbeatPeriod, now) {
-			state = unhealthy
-		}
-
-		// Format the registered timestamp.
-		registeredTimestamp := ""
-		if ing.RegisteredTimestamp != 0 {
-			registeredTimestamp = ing.GetRegisteredAt().String()
+			state = "UNHEALTHY"
 		}
 
 		ingesters = append(ingesters, ingesterDesc{
 			ID:                  id,
 			State:               state,
 			Address:             ing.Addr,
-			HeartbeatTimestamp:  heartbeatTimestamp.String(),
-			RegisteredTimestamp: registeredTimestamp,
+			HeartbeatTimestamp:  time.Unix(ing.Timestamp, 0).UTC(),
+			RegisteredTimestamp: ing.GetRegisteredAt().UTC(),
 			Tokens:              ing.Tokens,
 			Zone:                ing.Zone,
 			NumTokens:           len(ing.Tokens),
@@ -138,8 +141,8 @@ func renderHTTPResponse(w http.ResponseWriter, v httpResponse, t *template.Templ
 		return
 	}
 
-	err := t.Execute(w, v)
-	if err != nil {
+	w.Header().Set("Content-Type", "text/html")
+	if err := t.Execute(w, v); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 	}
 }
@@ -161,14 +164,7 @@ func (h *ringPageHandler) forget(ctx context.Context, id string) error {
 func writeJSONResponse(w http.ResponseWriter, v httpResponse) {
 	w.Header().Set("Content-Type", "application/json")
 
-	data, err := json.Marshal(v)
-	if err != nil {
+	if err := json.NewEncoder(w).Encode(v); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
 	}
-
-	// We ignore errors here, because we cannot do anything about them.
-	// Write will trigger sending Status code, so we cannot send a different status code afterwards.
-	// Also this isn't internal error, but error communicating with client.
-	_, _ = w.Write(data)
 }
diff --git a/ring/status.gohtml b/ring/status.gohtml
@@ -35,10 +35,10 @@
             <td>{{ .Zone }}</td>
             <td>{{ .State }}</td>
             <td>{{ .Address }}</td>
-            <td>{{ .RegisteredTimestamp }}</td>
-            <td>{{ .HeartbeatTimestamp }}</td>
+            <td>{{ .RegisteredTimestamp | timeOrEmptyString }}</td>
+            <td>{{ .HeartbeatTimestamp | durationSince }} ago ({{ .HeartbeatTimestamp.Format "15:04:05.999" }})</td>
             <td>{{ .NumTokens }}</td>
-            <td>{{ .Ownership }}%</td>
+            <td>{{ .Ownership | humanFloat }}%</td>
             <td>
                 <button name="forget" value="{{ .ID }}" type="submit">Forget</button>
             </td>