Merge pull request #11224 from dekimsey/consul-catalog-filter-support

consul: Initial implemenation of catalog filter support

discovery/consul/consul.go

@@ -113,8 +113,11 @@ type SDConfig struct {
 	Services []string `yaml:"services,omitempty"`
 	// A list of tags used to filter instances inside a service. Services must contain all tags in the list.
 	ServiceTags []string `yaml:"tags,omitempty"`
-	// Desired node metadata.
+	// Desired node metadata. As of Consul 1.14, consider `filter` instead.
 	NodeMeta map[string]string `yaml:"node_meta,omitempty"`
+	// Consul filter string
+	// See https://www.consul.io/api-docs/catalog#filtering-1, for syntax
+	Filter string `yaml:"filter,omitempty"`
 
 	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
 }
@@ -174,6 +177,7 @@ type Discovery struct {
 	watchedServices  []string // Set of services which will be discovered.
 	watchedTags      []string // Tags used to filter instances of a service.
 	watchedNodeMeta  map[string]string
+	watchedFilter    string
 	allowStale       bool
 	refreshInterval  time.Duration
 	finalizer        func()
@@ -218,6 +222,7 @@ func NewDiscovery(conf *SDConfig, logger *slog.Logger, metrics discovery.Discove
 		watchedServices:  conf.Services,
 		watchedTags:      conf.ServiceTags,
 		watchedNodeMeta:  conf.NodeMeta,
+		watchedFilter:    conf.Filter,
 		allowStale:       conf.AllowStale,
 		refreshInterval:  time.Duration(conf.RefreshInterval),
 		clientDatacenter: conf.Datacenter,
@@ -361,13 +366,14 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
 // entire list of services.
 func (d *Discovery) watchServices(ctx context.Context, ch chan<- []*targetgroup.Group, lastIndex *uint64, services map[string]func()) {
 	catalog := d.client.Catalog()
-	d.logger.Debug("Watching services", "tags", strings.Join(d.watchedTags, ","))
+	d.logger.Debug("Watching services", "tags", strings.Join(d.watchedTags, ","), "filter", d.watchedFilter)
 
 	opts := &consul.QueryOptions{
 		WaitIndex:  *lastIndex,
 		WaitTime:   watchTimeout,
 		AllowStale: d.allowStale,
 		NodeMeta:   d.watchedNodeMeta,
+		Filter:     d.watchedFilter,
 	}
 	t0 := time.Now()
 	srvs, meta, err := catalog.Services(opts.WithContext(ctx))

discovery/consul/consul_test.go

@@ -252,6 +252,8 @@ func newServer(t *testing.T) (*httptest.Server, *SDConfig) {
 		case "/v1/catalog/services?index=1&wait=120000ms":
 			time.Sleep(5 * time.Second)
 			response = ServicesTestAnswer
+		case "/v1/catalog/services?filter=NodeMeta.rack_name+%3D%3D+%222304%22&index=1&wait=120000ms":
+			response = ServicesTestAnswer
 		default:
 			t.Errorf("Unhandled consul call: %s", r.URL)
 		}
@@ -369,6 +371,27 @@ func TestAllOptions(t *testing.T) {
 	<-ch
 }
 
+// Watch the test service with a specific tag and node-meta via Filter parameter.
+func TestFilterOption(t *testing.T) {
+	stub, config := newServer(t)
+	defer stub.Close()
+
+	config.Services = []string{"test"}
+	config.Filter = `NodeMeta.rack_name == "2304"`
+	config.Token = "fake-token"
+
+	d := newDiscovery(t, config)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	ch := make(chan []*targetgroup.Group)
+	go func() {
+		d.Run(ctx, ch)
+		close(ch)
+	}()
+	checkOneTarget(t, <-ch)
+	cancel()
+}
+
 func TestGetDatacenterShouldReturnError(t *testing.T) {
 	for _, tc := range []struct {
 		handler    func(http.ResponseWriter, *http.Request)

docs/configuration/configuration.md

@@ -796,14 +796,17 @@ The following meta labels are available on targets during [relabeling](#relabel_
 services:
   [ - <string> ]
 
-# See https://www.consul.io/api/catalog.html#list-nodes-for-service to know more
-# about the possible filters that can be used.
+# A Consul Filter expression used to filter the catalog results
+# See https://www.consul.io/api-docs/catalog#list-services to know more
+# about the filter expressions that can be used.
+[ filter: <string> ]
 
+# The `tags` and `node_meta` fields are deprecated in Consul in favor of `filter`.
 # An optional list of tags used to filter nodes for a given service. Services must contain all tags in the list.
 tags:
   [ - <string> ]
 
-# Node metadata key/value pairs to filter nodes for a given service.
+# Node metadata key/value pairs to filter nodes for a given service. As of Consul 1.14, consider `filter` instead.
 [ node_meta:
   [ <string>: <string> ... ] ]