Wait for handler to register

cmd/server/main.go

@@ -28,6 +28,7 @@ import (
 
 	"github.com/livekit/egress/pkg/config"
 	"github.com/livekit/egress/pkg/errors"
+	"github.com/livekit/egress/pkg/handler"
 	"github.com/livekit/egress/pkg/service"
 	"github.com/livekit/egress/version"
 	"github.com/livekit/protocol/logger"
@@ -202,7 +203,7 @@ func runHandler(c *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	handler, err := service.NewHandler(conf, bus, ioClient)
+	h, err := handler.NewHandler(conf, bus, ioClient)
 	if err != nil {
 		if errors.IsFatal(err) {
 			// service will send info update and shut down
@@ -217,8 +218,8 @@ func runHandler(c *cli.Context) error {
 	go func() {
 		sig := <-killChan
 		logger.Infow("exit requested, stopping recording and shutting down", "signal", sig)
-		handler.Kill()
+		h.Kill()
 	}()
 
-	return handler.Run()
+	return h.Run()
 }

go.mod

@@ -19,7 +19,7 @@ require (
 	github.com/gorilla/websocket v1.5.0
 	github.com/livekit/livekit-server v1.5.1-0.20231026153736-8b16db227070
 	github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1
-	github.com/livekit/protocol v1.9.4-0.20231205184613-4bd1ed6a0258
+	github.com/livekit/protocol v1.9.4-0.20231206174612-7bba17ea7876
 	github.com/livekit/psrpc v0.5.2
 	github.com/livekit/server-sdk-go v1.1.1
 	github.com/pion/rtp v1.8.3
@@ -32,7 +32,7 @@ require (
 	github.com/urfave/cli/v2 v2.25.7
 	go.uber.org/atomic v1.11.0
 	go.uber.org/zap v1.26.0
-	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa
+	golang.org/x/exp v0.0.0-20231127185646-65229373498e
 	google.golang.org/api v0.130.0
 	google.golang.org/grpc v1.59.0
 	google.golang.org/protobuf v1.31.0
@@ -79,7 +79,6 @@ require (
 	github.com/mattn/go-ieproxy v0.0.1 // indirect
 	github.com/mattn/go-pointer v0.0.1 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
-	github.com/mitchellh/go-ps v1.0.0 // indirect
 	github.com/nats-io/nats.go v1.31.0 // indirect
 	github.com/nats-io/nkeys v0.4.6 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
@@ -98,7 +97,7 @@ require (
 	github.com/pion/transport/v2 v2.2.4 // indirect
 	github.com/pion/turn/v2 v2.1.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/prometheus/procfs v0.11.1 // indirect
+	github.com/prometheus/procfs v0.12.0 // indirect
 	github.com/redis/go-redis/v9 v9.3.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/thoas/go-funk v0.9.3 // indirect
@@ -107,12 +106,12 @@ require (
 	github.com/zeebo/xxh3 v1.0.2 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
-	golang.org/x/crypto v0.15.0 // indirect
+	golang.org/x/crypto v0.16.0 // indirect
 	golang.org/x/mod v0.14.0 // indirect
-	golang.org/x/net v0.18.0 // indirect
+	golang.org/x/net v0.19.0 // indirect
 	golang.org/x/oauth2 v0.11.0 // indirect
 	golang.org/x/sync v0.5.0 // indirect
-	golang.org/x/sys v0.14.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect

go.sum

@@ -180,8 +180,8 @@ github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1 h1:jm09419p0lqTkD
 github.com/livekit/mageutil v0.0.0-20230125210925-54e8a70427c1/go.mod h1:Rs3MhFwutWhGwmY1VQsygw28z5bWcnEYmS1OG9OxjOQ=
 github.com/livekit/mediatransportutil v0.0.0-20231017082622-43f077b4e60e h1:yNeIo7MSMUWgoLu7LkNKnBYnJBFPFH9Wq4S6h1kS44M=
 github.com/livekit/mediatransportutil v0.0.0-20231017082622-43f077b4e60e/go.mod h1:+WIOYwiBMive5T81V8B2wdAc2zQNRjNQiJIcPxMTILY=
-github.com/livekit/protocol v1.9.4-0.20231205184613-4bd1ed6a0258 h1:LiuPyPbV1WVBn7RBhrwSicPgDgkts/xjL06JR2ELriM=
-github.com/livekit/protocol v1.9.4-0.20231205184613-4bd1ed6a0258/go.mod h1:Lzra2vdFeXkKy5oFb7oXRKVqCZ+uT8w9hbZO4mEy0+Q=
+github.com/livekit/protocol v1.9.4-0.20231206174612-7bba17ea7876 h1:NnbpPgxDHOcSdgW0JzBkc4QzzLVAe4sOaiYqUUH0/K4=
+github.com/livekit/protocol v1.9.4-0.20231206174612-7bba17ea7876/go.mod h1:SzrmeWw8sbf99laJJNMwp+5izlvh/ynlMbVOX0JUoes=
 github.com/livekit/psrpc v0.5.2 h1:+MvG8Otm/J6MTg2MP/uuMbrkxOWsrj2hDhu/I1VIU1U=
 github.com/livekit/psrpc v0.5.2/go.mod h1:cQjxg1oCxYHhxxv6KJH1gSvdtCHQoRZCHgPdm5N8v2g=
 github.com/livekit/server-sdk-go v1.1.1 h1:TkDD/Ecyh7XNuxgxhpsDQ1uzbTlDWwwJrbkyUjQmcbY=
@@ -198,8 +198,6 @@ github.com/mattn/go-pointer v0.0.1 h1:n+XhsuGeVO6MEAp7xyEukFINEa+Quek5psIR/ylA6o
 github.com/mattn/go-pointer v0.0.1/go.mod h1:2zXcozF6qYGgmsG+SeTZz3oAbFLdD3OWqnUbNvJZAlc=
 github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
-github.com/mitchellh/go-ps v1.0.0 h1:i6ampVEEF4wQFF+bkYfwYgY+F/uYJDktmvLPf7qIgjc=
-github.com/mitchellh/go-ps v1.0.0/go.mod h1:J4lOc8z8yJs6vUwklHw2XEIiT4z4C40KtWVN3nvg8Pg=
 github.com/nats-io/nats.go v1.31.0 h1:/WFBHEc/dOKBF6qf1TZhrdEfTmOZ5JzdJ+Y3m6Y/p7E=
 github.com/nats-io/nats.go v1.31.0/go.mod h1:di3Bm5MLsoB4Bx61CBTsxuarI36WbhAwOm8QrW39+i8=
 github.com/nats-io/nkeys v0.4.6 h1:IzVe95ru2CT6ta874rt9saQRkWfe2nFj1NtvYSLqMzY=
@@ -272,8 +270,8 @@ github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16 h1:v7DLq
 github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
 github.com/prometheus/common v0.44.0 h1:+5BrQJwiBB9xsMygAB3TNvpQKOwlkc25LbISbrdOOfY=
 github.com/prometheus/common v0.44.0/go.mod h1:ofAIvZbQ1e/nugmZGz4/qCb9Ap1VoSTIO7x0VV9VvuY=
-github.com/prometheus/procfs v0.11.1 h1:xRC8Iq1yyca5ypa9n1EZnWZkt7dwcoRPQwX/5gwaUuI=
-github.com/prometheus/procfs v0.11.1/go.mod h1:eesXgaPo1q7lBpVMoMy0ZOFTth9hBn4W/y0/p/ScXhY=
+github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=
+github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
 github.com/redis/go-redis/v9 v9.3.0 h1:RiVDjmig62jIWp7Kk4XVLs0hzV6pI3PyTnnL0cnn0u0=
 github.com/redis/go-redis/v9 v9.3.0/go.mod h1:hdY0cQFCN4fnSYT6TkisLufl/4W5UIXyv0b/CLO2V2M=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
@@ -332,11 +330,11 @@ golang.org/x/crypto v0.8.0/go.mod h1:mRqEX+O9/h5TFCrQhkgjo2yKi0yYA+9ecGkdQoHrywE
 golang.org/x/crypto v0.10.0/go.mod h1:o4eNf7Ede1fv+hwOwZsTHl9EsPFO6q6ZvYR8vYfY45I=
 golang.org/x/crypto v0.11.0/go.mod h1:xgJhtzW8F9jGdVFWZESrid1U1bjeNy4zgy5cRr/CIio=
 golang.org/x/crypto v0.12.0/go.mod h1:NF0Gs7EO5K4qLn+Ylc+fih8BSTeIjAP05siRnAh98yw=
-golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
-golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
+golang.org/x/crypto v0.16.0 h1:mMMrFzRSCF0GvB7Ne27XVtVAaXLrPmgPC7/v0tkwHaY=
+golang.org/x/crypto v0.16.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
-golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa h1:FRnLl4eNAQl8hwxVVC17teOw8kdjVDVAiFMtgUdTSRQ=
-golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa/go.mod h1:zk2irFbV9DP96SEBUUAy67IdHUaZuSnrz1n472HUCLE=
+golang.org/x/exp v0.0.0-20231127185646-65229373498e h1:Gvh4YaCaXNs6dKTlfgismwWZKyjVZXwOPfIyUaqU3No=
+golang.org/x/exp v0.0.0-20231127185646-65229373498e/go.mod h1:iRJReGqOEeBhDZGkGbynYwcHlctCvnjTYIamk7uXpHI=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
@@ -371,8 +369,8 @@ golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
 golang.org/x/net v0.11.0/go.mod h1:2L/ixqYpgIVXmeoSA/4Lu7BzTG4KIyPIryS4IsOd1oQ=
 golang.org/x/net v0.13.0/go.mod h1:zEVYFnQC7m/vmpQFELhcD1EWkZlX69l4oqgmer6hfKA=
 golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
-golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
-golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
+golang.org/x/net v0.19.0 h1:zTwKpTd2XuCqf8huc7Fo2iSy+4RHPd10s4KzeTnVr1c=
+golang.org/x/net v0.19.0/go.mod h1:CfAk/cbD4CthTvqiEl8NpboMuiuOYsAr/7NOjZJtv1U=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.11.0 h1:vPL4xzxBM4niKCW6g9whtaWVXTJf1U5e4aZxxFx/gbU=
@@ -412,8 +410,8 @@ golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.9.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
-golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
+golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.1.0/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=

pkg/handler/handler.go

@@ -0,0 +1,132 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// 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 handler
+
+import (
+	"context"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/frostbyte73/core"
+	"google.golang.org/grpc"
+
+	"github.com/livekit/egress/pkg/config"
+	"github.com/livekit/egress/pkg/errors"
+	"github.com/livekit/egress/pkg/ipc"
+	"github.com/livekit/egress/pkg/pipeline"
+	"github.com/livekit/protocol/livekit"
+	"github.com/livekit/protocol/logger"
+	"github.com/livekit/protocol/rpc"
+	"github.com/livekit/protocol/tracer"
+	"github.com/livekit/psrpc"
+)
+
+type Handler struct {
+	ipc.UnimplementedEgressHandlerServer
+
+	conf             *config.PipelineConfig
+	pipeline         *pipeline.Controller
+	rpcServer        rpc.EgressHandlerServer
+	ipcHandlerServer *grpc.Server
+	ipcServiceClient ipc.EgressServiceClient
+	ioClient         rpc.IOInfoClient
+	kill             core.Fuse
+}
+
+func NewHandler(conf *config.PipelineConfig, bus psrpc.MessageBus, ioClient rpc.IOInfoClient) (*Handler, error) {
+	ipcClient, err := ipc.NewServiceClient(path.Join(conf.TmpDir[:strings.LastIndex(conf.TmpDir, "/")], conf.NodeID))
+	if err != nil {
+		return nil, err
+	}
+
+	h := &Handler{
+		conf:             conf,
+		ioClient:         ioClient,
+		ipcHandlerServer: grpc.NewServer(),
+		ipcServiceClient: ipcClient,
+		kill:             core.NewFuse(),
+	}
+
+	ipc.RegisterEgressHandlerServer(h.ipcHandlerServer, h)
+	if err = ipc.StartHandlerListener(h.ipcHandlerServer, conf.TmpDir); err != nil {
+		return nil, err
+	}
+
+	rpcServer, err := rpc.NewEgressHandlerServer(h, bus)
+	if err != nil {
+		return nil, errors.Fatal(err)
+	}
+	if err = rpcServer.RegisterUpdateStreamTopic(conf.Info.EgressId); err != nil {
+		return nil, errors.Fatal(err)
+	}
+	if err = rpcServer.RegisterStopEgressTopic(conf.Info.EgressId); err != nil {
+		return nil, errors.Fatal(err)
+	}
+	h.rpcServer = rpcServer
+
+	_, err = h.ipcServiceClient.HandlerReady(context.Background(), &ipc.HandlerReadyRequest{EgressId: conf.Info.EgressId})
+	if err != nil {
+		logger.Errorw("failed to notify service", err)
+		return nil, err
+	}
+
+	h.pipeline, err = pipeline.New(context.Background(), conf, h.ioClient)
+	if err != nil {
+		if !errors.IsFatal(err) {
+			// user error, send update
+			now := time.Now().UnixNano()
+			conf.Info.UpdatedAt = now
+			conf.Info.EndedAt = now
+			conf.Info.Status = livekit.EgressStatus_EGRESS_FAILED
+			conf.Info.Error = err.Error()
+			_, _ = h.ioClient.UpdateEgress(context.Background(), conf.Info)
+		}
+		return nil, err
+	}
+
+	return h, nil
+}
+
+func (h *Handler) Run() error {
+	ctx, span := tracer.Start(context.Background(), "Handler.Run")
+	defer span.End()
+
+	// start egress
+	result := make(chan *livekit.EgressInfo, 1)
+	go func() {
+		result <- h.pipeline.Run(ctx)
+	}()
+
+	kill := h.kill.Watch()
+	for {
+		select {
+		case <-kill:
+			// kill signal received
+			h.pipeline.SendEOS(ctx)
+
+		case res := <-result:
+			// recording finished
+			_, _ = h.ioClient.UpdateEgress(ctx, res)
+			h.rpcServer.Shutdown()
+			h.ipcHandlerServer.Stop()
+			return nil
+		}
+	}
+}
+
+func (h *Handler) Kill() {
+	h.kill.Break()
+}

pkg/handler/handler_ipc.go

@@ -0,0 +1,113 @@
+// Copyright 2023 LiveKit, Inc.
+//
+// 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 handler
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"github.com/livekit/egress/pkg/errors"
+	"github.com/livekit/egress/pkg/ipc"
+	"github.com/livekit/protocol/logger"
+	"github.com/livekit/protocol/pprof"
+	"github.com/livekit/protocol/tracer"
+)
+
+func (h *Handler) GetPipelineDot(ctx context.Context, _ *ipc.GstPipelineDebugDotRequest) (*ipc.GstPipelineDebugDotResponse, error) {
+	ctx, span := tracer.Start(ctx, "Handler.GetPipelineDot")
+	defer span.End()
+
+	if h.pipeline == nil {
+		return nil, errors.ErrEgressNotFound
+	}
+
+	res := make(chan string, 1)
+	go func() {
+		res <- h.pipeline.GetGstPipelineDebugDot()
+	}()
+
+	select {
+	case r := <-res:
+		return &ipc.GstPipelineDebugDotResponse{
+			DotFile: r,
+		}, nil
+
+	case <-time.After(2 * time.Second):
+		return nil, status.New(codes.DeadlineExceeded, "timed out requesting pipeline debug info").Err()
+	}
+}
+
+func (h *Handler) GetPProf(ctx context.Context, req *ipc.PProfRequest) (*ipc.PProfResponse, error) {
+	ctx, span := tracer.Start(ctx, "Handler.GetPProf")
+	defer span.End()
+
+	if h.pipeline == nil {
+		return nil, errors.ErrEgressNotFound
+	}
+
+	b, err := pprof.GetProfileData(ctx, req.ProfileName, int(req.Timeout), int(req.Debug))
+	if err != nil {
+		return nil, err
+	}
+
+	return &ipc.PProfResponse{
+		PprofFile: b,
+	}, nil
+}
+
+// GetMetrics implement the handler-side gathering of metrics to return over IPC
+func (h *Handler) GetMetrics(ctx context.Context, req *ipc.MetricsRequest) (*ipc.MetricsResponse, error) {
+	ctx, span := tracer.Start(ctx, "Handler.GetMetrics")
+	defer span.End()
+
+	metrics, err := prometheus.DefaultGatherer.Gather()
+	if err != nil {
+		return nil, err
+	}
+
+	metricsAsString, err := renderMetrics(metrics)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ipc.MetricsResponse{
+		Metrics: metricsAsString,
+	}, nil
+}
+
+func renderMetrics(metrics []*dto.MetricFamily) (string, error) {
+	// Create a StringWriter to render the metrics into text format
+	writer := &strings.Builder{}
+	totalCnt := 0
+	for _, metric := range metrics {
+		// Write each metric family to text
+		cnt, err := expfmt.MetricFamilyToText(writer, metric)
+		if err != nil {
+			logger.Errorw("error writing metric family", err)
+			return "", err
+		}
+		totalCnt += cnt
+	}
+
+	// Get the rendered metrics as a string from the StringWriter
+	return writer.String(), nil
+}