[extension/jaegerremotesampling] Tie in the strategy storages (#8818)

* Tie in the strategy storages

This change adds support for the strategy stores, previously referenced as client config managers.

This implements both the local file strategy store and the remote (gRPC) store.

Fixes #6695

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

* Add changelog

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

* Improved readme

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

CHANGELOG.md

@@ -9,6 +9,7 @@
   generated code (#5270) 
 - Add `make crosslink` target to ensure replace statements are included in `go.mod` for all transitive dependencies within repository (#8822)
 - `filestorageextension`: Change bbolt DB settings for better performance (#9004)
+- `jaegerremotesamplingextension`: Add local and remote sampling stores (#8818)
 
 ### 🛑 Breaking changes 🛑
 

extension/jaegerremotesampling/README.md

@@ -10,21 +10,26 @@ Note that the port `14250` will clash with the Jaeger Receiver. When both are us
 
 Although this extension is derived from Jaeger, it can be used by any clients who can consume this standard, such as the [OpenTelemetry Java SDK](https://github.com/open-telemetry/opentelemetry-java/tree/v1.9.1/sdk-extensions/jaeger-remote-sampler).
 
+At this moment, the `reload_interval` option is only effective for the `file` source. In the future, this property will be used to control a local cache for a `remote` source.
+
+The `file` source can be used to load files from the local file system or from remote HTTP/S sources. The `remote` source must be used with a gRPC server that provides a Jaeger remote sampling service.
+
 ## Configuration
 
 ```yaml
 extensions:
   jaegerremotesampling:
-    grpc:
-      endpoint: :15251
     source:
       remote:
         endpoint: jaeger-collector:14250
   jaegerremotesampling/1:
-    http:
-      endpoint: :5878
     source:
-      file: /etc/otel/sampling_strategies.json
+      reload_interval: 1s
+      file: /etc/otelcol/sampling_strategies.json
+  jaegerremotesampling/2:
+    source:
+      reload_interval: 1s
+      file: http://jaeger.example.com/sampling_strategies.json
 ```
 
 A sampling strategy file could look like:

extension/jaegerremotesampling/config_test.go

@@ -17,6 +17,7 @@ package jaegerremotesampling
 import (
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -60,7 +61,8 @@ func TestLoadConfig(t *testing.T) {
 			HTTPServerSettings: &confighttp.HTTPServerSettings{Endpoint: ":5778"},
 			GRPCServerSettings: &configgrpc.GRPCServerSettings{NetAddr: confignet.NetAddr{Endpoint: ":14250"}},
 			Source: Source{
-				File: "/etc/otel/sampling_strategies.json",
+				ReloadInterval: time.Second,
+				File:           "/etc/otelcol/sampling_strategies.json",
 			},
 		},
 		ext1)

extension/jaegerremotesampling/extension.go

@@ -16,48 +16,102 @@ package jaegerremotesampling // import "github.com/open-telemetry/opentelemetry-
 
 import (
 	"context"
+	"fmt"
 
+	grpcStore "github.com/jaegertracing/jaeger/cmd/agent/app/configmanager/grpc"
+	"github.com/jaegertracing/jaeger/cmd/collector/app/sampling/strategystore"
+	"github.com/jaegertracing/jaeger/plugin/sampling/strategystore/static"
 	"go.opentelemetry.io/collector/component"
+	"go.uber.org/zap"
+	"google.golang.org/grpc"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/jaegerremotesampling/internal"
 )
 
 var _ component.Extension = (*jrsExtension)(nil)
 
 type jrsExtension struct {
-	httpServer component.Component
+	cfg       *Config
+	telemetry component.TelemetrySettings
+
+	httpServer    component.Component
+	samplingStore strategystore.StrategyStore
+
+	closers []func() error
 }
 
-func newExtension(cfg *Config, telemetry component.TelemetrySettings) (*jrsExtension, error) {
-	// TODO(jpkroehling): get a proper instance
-	cfgMgr := internal.NewClientConfigManager()
-	ext := &jrsExtension{}
+func newExtension(cfg *Config, telemetry component.TelemetrySettings) *jrsExtension {
+	jrse := &jrsExtension{
+		cfg:       cfg,
+		telemetry: telemetry,
+	}
+	return jrse
+}
 
-	if cfg.HTTPServerSettings != nil {
-		httpServer, err := internal.NewHTTP(telemetry, *cfg.HTTPServerSettings, cfgMgr)
+func (jrse *jrsExtension) Start(ctx context.Context, host component.Host) error {
+	// the config validation will take care of ensuring we have one and only one of the following about the
+	// source of the sampling config:
+	// - remote (gRPC)
+	// - local file
+	// we can then use a simplified logic here to assign the appropriate store
+	if jrse.cfg.Source.File != "" {
+		opts := static.Options{
+			StrategiesFile: jrse.cfg.Source.File,
+			ReloadInterval: jrse.cfg.Source.ReloadInterval,
+		}
+		ss, err := static.NewStrategyStore(opts, jrse.telemetry.Logger)
 		if err != nil {
-			return nil, err
+			return fmt.Errorf("failed to create the local file strategy store: %v", err)
 		}
-		ext.httpServer = httpServer
+
+		// there's a Close function on the concrete type, which is not visible to us...
+		// how can we close it then?
+		jrse.samplingStore = ss
 	}
 
-	return ext, nil
-}
+	if jrse.cfg.Source.Remote != nil {
+		opts, err := jrse.cfg.Source.Remote.ToDialOptions(host, jrse.telemetry)
+		if err != nil {
+			return fmt.Errorf("error while setting up the remote sampling source: %v", err)
+		}
+		conn, err := grpc.Dial(jrse.cfg.Source.Remote.Endpoint, opts...)
+		if err != nil {
+			return fmt.Errorf("error while connecting to the remote sampling source: %v", err)
+		}
+
+		jrse.samplingStore = grpcStore.NewConfigManager(conn)
+		jrse.closers = append(jrse.closers, func() error {
+			return conn.Close()
+		})
+	}
+
+	if jrse.cfg.HTTPServerSettings != nil {
+		httpServer, err := internal.NewHTTP(jrse.telemetry, *jrse.cfg.HTTPServerSettings, jrse.samplingStore)
+		if err != nil {
+			return fmt.Errorf("error while creating the HTTP server: %v", err)
+		}
+		jrse.httpServer = httpServer
+	}
 
-func (jrse *jrsExtension) Start(ctx context.Context, host component.Host) error {
 	// then we start our own server interfaces, starting with the HTTP one
 	err := jrse.httpServer.Start(ctx, host)
 	if err != nil {
-		return err
+		return fmt.Errorf("error while starting the HTTP server: %v", err)
 	}
 
 	return nil
 }
 
 func (jrse *jrsExtension) Shutdown(ctx context.Context) error {
-	err := jrse.httpServer.Shutdown(ctx)
-	if err != nil {
-		return err
+	// we probably don't want to break whenever an error occurs, we want to continue and close the other resources
+	if err := jrse.httpServer.Shutdown(ctx); err != nil {
+		jrse.telemetry.Logger.Error("error while shutting down the HTTP server", zap.Error(err))
+	}
+
+	for _, closer := range jrse.closers {
+		if err := closer(); err != nil {
+			jrse.telemetry.Logger.Error("error while shutting down the sampling store", zap.Error(err))
+		}
 	}
 
 	return nil

extension/jaegerremotesampling/extension_test.go

@@ -16,89 +16,79 @@ package jaegerremotesampling
 
 import (
 	"context"
-	"errors"
+	"fmt"
+	"net"
+	"path/filepath"
 	"testing"
 
+	"github.com/jaegertracing/jaeger/proto-gen/api_v2"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config/configgrpc"
+	"google.golang.org/grpc"
 )
 
 func TestNewExtension(t *testing.T) {
 	// test
-	e, err := newExtension(createDefaultConfig().(*Config), componenttest.NewNopTelemetrySettings())
-	require.NoError(t, err)
+	cfg := createDefaultConfig().(*Config)
+	cfg.Source.File = filepath.Join("testdata", "strategy.json")
+	e := newExtension(cfg, componenttest.NewNopTelemetrySettings())
 
 	// verify
 	assert.NotNil(t, e)
 }
 
-func TestStartAndShutdown(t *testing.T) {
+func TestStartAndShutdownLocalFile(t *testing.T) {
 	// prepare
-	e, err := newExtension(createDefaultConfig().(*Config), componenttest.NewNopTelemetrySettings())
+	cfg := createDefaultConfig().(*Config)
+	cfg.Source.File = filepath.Join("testdata", "strategy.json")
+
+	e := newExtension(cfg, componenttest.NewNopTelemetrySettings())
 	require.NotNil(t, e)
-	require.NoError(t, err)
 	require.NoError(t, e.Start(context.Background(), componenttest.NewNopHost()))
 
 	// test and verify
 	assert.NoError(t, e.Shutdown(context.Background()))
 }
 
-func TestFailedToStartHTTPServer(t *testing.T) {
-	// prepare
-	errBooBoo := errors.New("the server made a boo boo")
-
-	e, err := newExtension(createDefaultConfig().(*Config), componenttest.NewNopTelemetrySettings())
-	require.NotNil(t, e)
+func TestStartAndShutdownRemote(t *testing.T) {
+	// prepare the socket the mock server will listen at
+	lis, err := net.Listen("tcp", "localhost:0")
 	require.NoError(t, err)
 
-	e.httpServer = &mockComponent{
-		StartFunc: func(_ context.Context, _ component.Host) error {
-			return errBooBoo
-		},
+	// create the mock server
+	server := grpc.NewServer()
+	go func() {
+		err = server.Serve(lis)
+		require.NoError(t, err)
+	}()
+
+	// register the service
+	api_v2.RegisterSamplingManagerServer(server, &samplingServer{})
+
+	// create the config, pointing to the mock server
+	cfg := createDefaultConfig().(*Config)
+	cfg.Source.Remote = &configgrpc.GRPCClientSettings{
+		Endpoint:     fmt.Sprintf("localhost:%d", lis.Addr().(*net.TCPAddr).Port),
+		WaitForReady: true,
 	}
 
-	// test and verify
-	assert.Equal(t, errBooBoo, e.Start(context.Background(), componenttest.NewNopHost()))
-}
-
-func TestFailedToShutdownHTTPServer(t *testing.T) {
-	// prepare
-	errBooBoo := errors.New("the server made a boo boo")
-
-	e, err := newExtension(createDefaultConfig().(*Config), componenttest.NewNopTelemetrySettings())
+	// create the extension
+	e := newExtension(cfg, componenttest.NewNopTelemetrySettings())
 	require.NotNil(t, e)
-	require.NoError(t, err)
 
-	e.httpServer = &mockComponent{
-		ShutdownFunc: func(_ context.Context) error {
-			return errBooBoo
-		},
-	}
-	require.NoError(t, e.Start(context.Background(), componenttest.NewNopHost()))
-
-	// test and verify
-	assert.Equal(t, errBooBoo, e.Shutdown(context.Background()))
-}
-
-type mockComponent struct {
-	StartFunc    func(_ context.Context, _ component.Host) error
-	ShutdownFunc func(_ context.Context) error
+	// test
+	assert.NoError(t, e.Start(context.Background(), componenttest.NewNopHost()))
+	assert.NoError(t, e.Shutdown(context.Background()))
 }
 
-func (s *mockComponent) Start(ctx context.Context, host component.Host) error {
-	if s.StartFunc == nil {
-		return nil
-	}
-
-	return s.StartFunc(ctx, host)
+type samplingServer struct {
+	api_v2.UnimplementedSamplingManagerServer
 }
 
-func (s *mockComponent) Shutdown(ctx context.Context) error {
-	if s.ShutdownFunc == nil {
-		return nil
-	}
-
-	return s.ShutdownFunc(ctx)
+func (s samplingServer) GetSamplingStrategy(ctx context.Context, param *api_v2.SamplingStrategyParameters) (*api_v2.SamplingStrategyResponse, error) {
+	return &api_v2.SamplingStrategyResponse{
+		StrategyType: api_v2.SamplingStrategyType_PROBABILISTIC,
+	}, nil
 }

extension/jaegerremotesampling/factory.go

@@ -48,9 +48,10 @@ func createDefaultConfig() config.Extension {
 				Endpoint: ":14250",
 			},
 		},
+		Source: Source{},
 	}
 }
 
 func createExtension(_ context.Context, set component.ExtensionCreateSettings, cfg config.Extension) (component.Extension, error) {
-	return newExtension(cfg.(*Config), set.TelemetrySettings)
+	return newExtension(cfg.(*Config), set.TelemetrySettings), nil
 }