feat. support labels

cmd/prom-proxy/main.go

@@ -13,8 +13,8 @@ import (
 	"github.com/dsrvlabs/prometheus-proxy/config"
 	"github.com/dsrvlabs/prometheus-proxy/converter"
 	"github.com/dsrvlabs/prometheus-proxy/jsonselector"
-	"github.com/dsrvlabs/prometheus-proxy/types"
 	"github.com/dsrvlabs/prometheus-proxy/log"
+	"github.com/dsrvlabs/prometheus-proxy/types"
 )
 
 const (
@@ -26,21 +26,25 @@ const (
 type App struct {
 	config    *types.Config
 	converter converter.Converter
-	gauges    map[string]prometheus.Gauge
+	gauges    map[string]*prometheus.GaugeVec
 }
 
 // Prepare prepares prometheus metrics.
 func (a *App) Prepare() (*http.ServeMux, error) {
-	a.gauges = make(map[string]prometheus.Gauge)
+	a.gauges = make(map[string]*prometheus.GaugeVec)
 
 	rpcs := a.config.RPCFetch
 	for _, rpc := range rpcs {
 		fields := rpc.Fields
+		labels := make([]string, len(rpc.Labels))
+		for i, label := range rpc.Labels {
+			labels[i] = label.Key
+		}
+
 		for _, field := range fields {
-			gauge := prometheus.NewGauge(
-				prometheus.GaugeOpts{
-					Name: field.MetricName,
-				},
+			gauge := prometheus.NewGaugeVec(
+				prometheus.GaugeOpts{Name: field.MetricName},
+				labels,
 			)
 
 			a.gauges[field.MetricName] = gauge
@@ -84,7 +88,12 @@ func (a *App) updateMetrics() {
 				continue
 			}
 
-			gauge.Set(result.Value)
+			labels := make([]string, len(rpc.Labels))
+			for i, label := range rpc.Labels {
+				labels[i] = label.Value
+			}
+
+			gauge.WithLabelValues(labels...).Set(result.Value)
 		}
 	}
 }

cmd/prom-proxy/prom_test.go

@@ -27,6 +27,12 @@ func Test_Prom(t *testing.T) {
 						MetricName: "voting_power",
 					},
 				},
+				Labels: []types.Label{
+					{
+						Key: "hostname",
+						Value: "cosmos-mainnet",
+					},
+				},
 			},
 		},
 	}
@@ -35,6 +41,11 @@ func Test_Prom(t *testing.T) {
 	router, err := app.Prepare()
 	assert.Nil(t, err)
 
+	// Add dummy
+	app.gauges["latest_block_height"].WithLabelValues("cosmos-mainnet").Set(100)
+	app.gauges["voting_power"].WithLabelValues("cosmos-mainnet").Set(100)
+
+	// Test
 	server := httptest.NewServer(router)
 	defer server.Close()
 
@@ -44,9 +55,14 @@ func Test_Prom(t *testing.T) {
 	d, err := io.ReadAll(resp.Body)
 	assert.Nil(t, err)
 
+	// Asserts
 	for _, rpc := range config.RPCFetch {
 		for _, field := range rpc.Fields {
 			assert.Contains(t, string(d), field.MetricName)
 		}
+
+		for _, label := range rpc.Labels {
+			assert.Contains(t, string(d), label.Key)
+		}
 	}
 }

config/config_test.go

@@ -34,6 +34,12 @@ func TestConfig_Load(t *testing.T) {
 								MetricName: "catch_up",
 							},
 						},
+						Labels: []types.Label{
+							{
+								Key:   "hostname",
+								Value: "cosmos-mainnet",
+							},
+						},
 					},
 					{
 						Method: "POST",
@@ -45,6 +51,12 @@ func TestConfig_Load(t *testing.T) {
 								MetricName: "is_syncing",
 							},
 						},
+						Labels: []types.Label{
+							{
+								Key:   "hostname",
+								Value: "ethereum-holesky",
+							},
+						},
 					},
 				},
 			},
@@ -66,6 +78,11 @@ func TestConfig_Load(t *testing.T) {
 					assert.Equal(t, tt.ExpectConfig.RPCFetch[i].Fields[j].Selector, field.Selector)
 					assert.Equal(t, tt.ExpectConfig.RPCFetch[i].Fields[j].MetricName, field.MetricName)
 				}
+
+				for j, label := range rpc.Labels {
+					assert.Equal(t, tt.ExpectConfig.RPCFetch[i].Labels[j].Key, label.Key)
+					assert.Equal(t, tt.ExpectConfig.RPCFetch[i].Labels[j].Value, label.Value)
+				}
 			}
 
 		})

config/fixtures/rpc_config.yaml

@@ -7,10 +7,16 @@ rpc_fetch:
         metric_name: "block_height"
       - selector: ".result.sync_info.catch_up"
         metric_name: "catch_up"
+    labels:
+      - key: "hostname"
+        value: "cosmos-mainnet"
 
   - method: POST
     url: http://localhost:8545
     body: '{"jsonrpc":"2.0","id":83,"result":false}'
     fields:
       - selector: ".result"
         metric_name: "is_syncing"
+    labels:
+      - key: "hostname"
+        value: "ethereum-holesky"

samples/ethereum.yaml

@@ -5,10 +5,16 @@ rpc_fetch:
     fields:
       - selector: ".result"
         metric_name: "is_syncing"
+    labels:
+      - key: "hostname"
+        value: "ethereum-holesky"
 
   - method: POST
     url: https://rpc.flashbots.net
     body: '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":83}'
     fields:
       - selector: ".result"
         metric_name: "block_number"
+    labels:
+      - key: "hostname"
+        value: "ethereum-holesky"

types/config.go

@@ -7,14 +7,21 @@ type Config struct {
 
 // RPCFetchConfig is a struct that holds conversion configuration for RPC response into Prometheus.
 type RPCFetchConfig struct {
-	Method string `yaml:"method,omitempty"`
-	URL    string `yaml:"url,omitempty"`
-	Body   string `yaml:"body,omitempty"`
+	Method string  `yaml:"method,omitempty"`
+	URL    string  `yaml:"url,omitempty"`
+	Body   string  `yaml:"body,omitempty"`
 	Fields []Field `yaml:"fields,omitempty"`
+	Labels []Label `yaml:"labels,omitempty"`
 }
 
 // Field is a struct that holds the configuration for a field in the response.
 type Field struct {
 	Selector   string `yaml:"selector,omitempty"`
 	MetricName string `yaml:"metric_name,omitempty"`
 }
+
+// Label is a struct that holds the configuration for a label in the response.
+type Label struct {
+	Key   string `yaml:"key,omitempty"`
+	Value string `yaml:"value,omitempty"`
+}