api/v2: Check if cluster peer is nil -> release-0.16

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Next release
+
+* [BUGFIX] Do not populate cluster info if clustering is disabled in API v2 (#1726)
+
 ## 0.16.0 / 2019-01-17
 
 This release introduces a new API v2, fully generated via the OpenAPI project

api/v2/api.go

@@ -129,10 +129,12 @@ func (api *API) getStatusHandler(params general_ops.GetStatusParams) middleware.
 	api.mtx.RLock()
 	defer api.mtx.RUnlock()
 
-	name := api.peer.Name()
-	status := api.peer.Status()
 	original := api.alertmanagerConfig.String()
 	uptime := strfmt.DateTime(api.uptime)
+
+	name := ""
+	status := open_api_models.ClusterStatusStatusDisabled
+
 	resp := open_api_models.AlertmanagerStatus{
 		Uptime: &uptime,
 		VersionInfo: &open_api_models.VersionInfo{
@@ -153,12 +155,25 @@ func (api *API) getStatusHandler(params general_ops.GetStatusParams) middleware.
 		},
 	}
 
-	for _, n := range api.peer.Peers() {
-		address := n.Address()
-		resp.Cluster.Peers = append(resp.Cluster.Peers, &open_api_models.PeerStatus{
-			Name:    &n.Name,
-			Address: &address,
-		})
+	// If alertmanager cluster feature is disabled, then api.peers == nil.
+	if api.peer != nil {
+		name := api.peer.Name()
+		status := api.peer.Status()
+
+		peers := []*open_api_models.PeerStatus{}
+		for _, n := range api.peer.Peers() {
+			address := n.Address()
+			peers = append(peers, &open_api_models.PeerStatus{
+				Name:    &n.Name,
+				Address: &address,
+			})
+		}
+
+		resp.Cluster = &open_api_models.ClusterStatus{
+			Name:   &name,
+			Status: &status,
+			Peers:  peers,
+		}
 	}
 
 	return general_ops.NewGetStatusOK().WithPayload(&resp)

api/v2/api_test.go

@@ -0,0 +1,42 @@
+// Copyright 2019 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2
+
+import (
+	"testing"
+	"time"
+
+	general_ops "github.com/prometheus/alertmanager/api/v2/restapi/operations/general"
+	"github.com/prometheus/alertmanager/config"
+)
+
+// If api.peers == nil, Alertmanager cluster feature is disabled. Make sure to
+// not try to access properties of peer, hence triggering a nil pointer
+// dereference.
+func TestGetStatusHandlerWithNilPeer(t *testing.T) {
+	api := API{
+		uptime:             time.Now(),
+		peer:               nil,
+		alertmanagerConfig: &config.Config{},
+	}
+
+	// Test ensures this method call does not panic.
+	status := api.getStatusHandler(general_ops.GetStatusParams{}).(*general_ops.GetStatusOK)
+
+	c := status.Payload.Cluster
+
+	if c == nil || c.Status == nil || c.Name == nil || c.Peers == nil {
+		t.Fatal("expected cluster {status,name,peers} not to be nil, violating the openapi specification")
+	}
+}

api/v2/openapi.yaml

@@ -226,6 +226,7 @@ definitions:
         type: string
       status:
         type: string
+        enum: ["ready", "settling", "disabled"]
       peers:
         type: array
         minimum: 0

ui/app/src/Data/ClusterStatus.elm

@@ -10,7 +10,7 @@
 -}
 
 
-module Data.ClusterStatus exposing (ClusterStatus, decoder, encoder)
+module Data.ClusterStatus exposing (ClusterStatus, Status(..), decoder, encoder)
 
 import Data.PeerStatus as PeerStatus exposing (PeerStatus)
 import Dict exposing (Dict)
@@ -21,23 +21,62 @@ import Json.Encode as Encode
 
 type alias ClusterStatus =
     { name : String
-    , status : String
+    , status : Status
     , peers : List PeerStatus
     }
 
 
+type Status
+    = Ready
+    | Settling
+    | Disabled
+
+
 decoder : Decoder ClusterStatus
 decoder =
     Decode.succeed ClusterStatus
         |> required "name" Decode.string
-        |> required "status" Decode.string
+        |> required "status" statusDecoder
         |> required "peers" (Decode.list PeerStatus.decoder)
 
 
 encoder : ClusterStatus -> Encode.Value
 encoder model =
     Encode.object
         [ ( "name", Encode.string model.name )
-        , ( "status", Encode.string model.status )
+        , ( "status", statusEncoder model.status )
         , ( "peers", Encode.list PeerStatus.encoder model.peers )
         ]
+
+
+statusDecoder : Decoder Status
+statusDecoder =
+    Decode.string
+        |> Decode.andThen
+            (\str ->
+                case str of
+                    "ready" ->
+                        Decode.succeed Ready
+
+                    "settling" ->
+                        Decode.succeed Settling
+
+                    "disabled" ->
+                        Decode.succeed Disabled
+
+                    other ->
+                        Decode.fail <| "Unknown type: " ++ other
+            )
+
+
+statusEncoder : Status -> Encode.Value
+statusEncoder model =
+    case model of
+        Ready ->
+            Encode.string "ready"
+
+        Settling ->
+            Encode.string "settling"
+
+        Disabled ->
+            Encode.string "disabled"

ui/app/src/Status/Api.elm

@@ -1,6 +1,7 @@
-module Status.Api exposing (getStatus)
+module Status.Api exposing (clusterStatusToString, getStatus)
 
 import Data.AlertmanagerStatus exposing (AlertmanagerStatus)
+import Data.ClusterStatus exposing (Status(..))
 import Json.Decode exposing (Decoder, at, bool, field, int, list, map2, maybe, string)
 import Status.Types exposing (ClusterPeer, ClusterStatus, StatusResponse, VersionInfo)
 import Utils.Api exposing (get, send)
@@ -19,6 +20,19 @@ getStatus apiUrl msg =
     Cmd.map msg <| send request
 
 
+clusterStatusToString : Status -> String
+clusterStatusToString status =
+    case status of
+        Ready ->
+            "ready"
+
+        Settling ->
+            "settling"
+
+        Disabled ->
+            "disabled"
+
+
 decodeStatusResponse : Decoder StatusResponse
 decodeStatusResponse =
     field "data" decodeData