feat(*): hijack application metrics

api/mesh/v1alpha1/metrics.proto

@@ -48,4 +48,23 @@ message PrometheusMetricsBackendConfig {
   // If true then endpoints for scraping metrics won't require mTLS even if mTLS
   // is enabled in Mesh. If nil, then it is treated as false.
   google.protobuf.BoolValue skipMTLS = 4;
+
+  // Map with the configuration of applications which metrics are going to be
+  // scrapped by kuma-dp.
+  map<string, PrometheusAggregateMetricsConfig> aggregate = 5;
+}
+
+// PrometheusAggregateMetricsConfig defines endpoints that should be scrapped
+// by kuma-dp for prometheus metrics.
+// Any configuration change require sidecar restart.
+message PrometheusAggregateMetricsConfig {
+  // Port on which a service expose HTTP endpoint with Prometheus metrics.
+  uint32 port = 1;
+
+  // Path on which a service expose HTTP endpoint with Prometheus metrics.
+  string path = 2;
+
+  // If false then the application won't be scrapped. If nil, then it is treated
+  // as true and kuma-dp scrapes metrics from the service.
+  google.protobuf.BoolValue enabled = 3;
 }

app/kuma-dp/cmd/run.go

@@ -24,7 +24,9 @@ import (
 	"github.com/kumahq/kuma/pkg/core/runtime/component"
 	core_xds "github.com/kumahq/kuma/pkg/core/xds"
 	util_net "github.com/kumahq/kuma/pkg/util/net"
+	"github.com/kumahq/kuma/pkg/util/proto"
 	kuma_version "github.com/kumahq/kuma/pkg/version"
+	"github.com/kumahq/kuma/pkg/xds/bootstrap/types"
 )
 
 var runLog = dataplaneLog.WithName("run")
@@ -209,7 +211,7 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 			runLog.Info("fetched Envoy version", "version", envoyVersion)
 
 			runLog.Info("generating bootstrap configuration")
-			bootstrap, bootstrapBytes, err := rootCtx.BootstrapGenerator(gracefulCtx, opts.Config.ControlPlane.URL, opts.Config, envoy.BootstrapParams{
+			bootstrap, kumaSidecarConfiguration, err := rootCtx.BootstrapGenerator(gracefulCtx, opts.Config.ControlPlane.URL, opts.Config, envoy.BootstrapParams{
 				Dataplane:       opts.Dataplane,
 				DNSPort:         cfg.DNS.EnvoyDNSPort,
 				EmptyDNSPort:    cfg.DNS.CoreDNSEmptyPort,
@@ -221,7 +223,10 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 			}
 			runLog.Info("received bootstrap configuration", "adminPort", bootstrap.GetAdmin().GetAddress().GetSocketAddress().GetPortValue())
 
-			opts.BootstrapConfig = bootstrapBytes
+			opts.BootstrapConfig, err = proto.ToYAML(bootstrap)
+			if err != nil {
+				return errors.Errorf("could not convert to yaml. %v", err)
+			}
 			opts.AdminPort = bootstrap.GetAdmin().GetAddress().GetSocketAddress().GetPortValue()
 
 			dataplane, err := envoy.New(opts)
@@ -230,8 +235,7 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 			}
 
 			components = append(components, dataplane)
-
-			metricsServer := metrics.New(cfg.Dataplane, bootstrap.GetAdmin().GetAddress().GetSocketAddress().GetPortValue())
+			metricsServer := metrics.New(cfg.Dataplane, getApplicationsToScrape(kumaSidecarConfiguration, bootstrap.GetAdmin().GetAddress().GetSocketAddress().GetPortValue()))
 			components = append(components, metricsServer)
 
 			if err := rootCtx.ComponentManager.Add(components...); err != nil {
@@ -296,6 +300,27 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 	return cmd
 }
 
+func getApplicationsToScrape(kumaSidecarConfiguration *types.KumaSidecarConfiguration, envoyAdminPort uint32) []*metrics.ApplicationToScrape {
+	applicationsToScrape := []*metrics.ApplicationToScrape{}
+	if kumaSidecarConfiguration != nil && len(kumaSidecarConfiguration.Metrics.Aggregate) > 0 {
+		for _, item := range kumaSidecarConfiguration.Metrics.Aggregate {
+			applicationsToScrape = append(applicationsToScrape, &metrics.ApplicationToScrape{
+				Name: item.Name,
+				Path: item.Path,
+				Port: item.Port,
+			})
+		}
+	}
+	// by default add envoy configuration
+	applicationsToScrape = append(applicationsToScrape, &metrics.ApplicationToScrape{
+		Name:    "envoy",
+		Path:    "/stats/prometheus",
+		Port:    envoyAdminPort,
+		Mutator: metrics.MergeClusters,
+	})
+	return applicationsToScrape
+}
+
 func writeFile(filename string, data []byte, perm os.FileMode) error {
 	if err := os.MkdirAll(filepath.Dir(filename), perm); err != nil {
 		return err

app/kuma-dp/cmd/run_test.go

@@ -23,6 +23,7 @@ import (
 	kumadp "github.com/kumahq/kuma/pkg/config/app/kuma-dp"
 	"github.com/kumahq/kuma/pkg/test"
 	util_proto "github.com/kumahq/kuma/pkg/util/proto"
+	"github.com/kumahq/kuma/pkg/xds/bootstrap/types"
 )
 
 var _ = Describe("run", func() {
@@ -95,14 +96,14 @@ var _ = Describe("run", func() {
 
 			// given
 			rootCtx := DefaultRootContext()
-			rootCtx.BootstrapGenerator = func(_ context.Context, _ string, cfg kumadp.Config, _ envoy.BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, []byte, error) {
+			rootCtx.BootstrapGenerator = func(_ context.Context, _ string, cfg kumadp.Config, _ envoy.BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, *types.KumaSidecarConfiguration, error) {
 				respBytes, err := os.ReadFile(filepath.Join("testdata", "bootstrap-config.golden.yaml"))
 				Expect(err).ToNot(HaveOccurred())
 				bootstrap := &envoy_bootstrap_v3.Bootstrap{}
 				if err := util_proto.FromYAML(respBytes, bootstrap); err != nil {
 					return nil, nil, err
 				}
-				return bootstrap, respBytes, nil
+				return bootstrap, &types.KumaSidecarConfiguration{}, nil
 			}
 
 			reader, writer := io.Pipe()

app/kuma-dp/pkg/dataplane/envoy/envoy.go

@@ -23,6 +23,7 @@ import (
 	"github.com/kumahq/kuma/pkg/core/runtime/component"
 	pkg_log "github.com/kumahq/kuma/pkg/log"
 	"github.com/kumahq/kuma/pkg/util/files"
+	"github.com/kumahq/kuma/pkg/xds/bootstrap/types"
 )
 
 var (
@@ -37,7 +38,7 @@ type BootstrapParams struct {
 	DynamicMetadata map[string]string
 }
 
-type BootstrapConfigFactoryFunc func(ctx context.Context, url string, cfg kuma_dp.Config, params BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, []byte, error)
+type BootstrapConfigFactoryFunc func(ctx context.Context, url string, cfg kuma_dp.Config, params BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, *types.KumaSidecarConfiguration, error)
 
 type Opts struct {
 	Config          kuma_dp.Config

app/kuma-dp/pkg/dataplane/envoy/remote_bootstrap.go

@@ -45,7 +45,7 @@ func IsInvalidRequestErr(err error) bool {
 	return strings.HasPrefix(err.Error(), "Invalid request: ")
 }
 
-func (b *remoteBootstrap) Generate(ctx context.Context, url string, cfg kuma_dp.Config, params BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, []byte, error) {
+func (b *remoteBootstrap) Generate(ctx context.Context, url string, cfg kuma_dp.Config, params BootstrapParams) (*envoy_bootstrap_v3.Bootstrap, *types.KumaSidecarConfiguration, error) {
 	bootstrapUrl, err := net_url.Parse(url)
 	if err != nil {
 		return nil, nil, err
@@ -91,11 +91,16 @@ func (b *remoteBootstrap) Generate(ctx context.Context, url string, cfg kuma_dp.
 		return nil, nil, err
 	}
 
-	bootstrap := &envoy_bootstrap_v3.Bootstrap{}
-	if err := util_proto.FromYAML(respBytes, bootstrap); err != nil {
+	bootstrap := &types.BootstrapResponse{}
+	if err := json.Unmarshal(respBytes, bootstrap); err != nil {
 		return nil, nil, err
 	}
-	return bootstrap, respBytes, nil
+
+	envoyBootstrap := &envoy_bootstrap_v3.Bootstrap{}
+	if err := util_proto.FromYAML(bootstrap.Bootstrap, envoyBootstrap); err != nil {
+		return nil, nil, err
+	}
+	return envoyBootstrap, &bootstrap.KumaSidecarConfiguration, nil
 }
 
 func (b *remoteBootstrap) requestForBootstrap(ctx context.Context, url *net_url.URL, cfg kuma_dp.Config, params BootstrapParams) ([]byte, error) {
@@ -154,6 +159,7 @@ func (b *remoteBootstrap) requestForBootstrap(ctx context.Context, url *net_url.
 	if err != nil {
 		return nil, err
 	}
+	req.Header.Set("accept", "application/json")
 	req.Header.Set("content-type", "application/json")
 	resp, err := b.client.Do(req)
 	if err != nil {