Syslog drain app error messages in app log stream

src/cmd/syslog-agent/app/syslog_agent.go

@@ -56,19 +56,8 @@ func NewSyslogAgent(
 	cfg Config,
 	m Metrics,
 	l *log.Logger,
+	factory syslog.AppLogEmitterFactory,
 ) *SyslogAgent {
-	internalTlsConfig, externalTlsConfig := drainTLSConfig(cfg)
-	writerFactory := syslog.NewWriterFactory(
-		internalTlsConfig,
-		externalTlsConfig,
-		syslog.NetworkTimeoutConfig{
-			Keepalive:    10 * time.Second,
-			DialTimeout:  10 * time.Second,
-			WriteTimeout: 10 * time.Second,
-		},
-		m,
-	)
-
 	ingressTLSConfig, err := loggregator.NewIngressTLSConfig(
 		cfg.GRPC.CAFile,
 		cfg.GRPC.CertFile,
@@ -81,17 +70,25 @@ func NewSyslogAgent(
 	logClient, err := loggregator.NewIngressClient(
 		ingressTLSConfig,
 		loggregator.WithLogger(log.New(os.Stderr, "", log.LstdFlags)),
+		loggregator.WithAddr(fmt.Sprintf("127.0.0.1:%d", cfg.GRPC.Port)),
 	)
 	if err != nil {
 		l.Panicf("failed to create log client for syslog connector: %q", err)
 	}
 
+	internalTlsConfig, externalTlsConfig := drainTLSConfig(cfg)
+	writerFactory := syslog.NewWriterFactory(internalTlsConfig, externalTlsConfig, syslog.NetworkTimeoutConfig{
+		Keepalive:    10 * time.Second,
+		DialTimeout:  10 * time.Second,
+		WriteTimeout: 10 * time.Second,
+	}, m)
+
 	connector := syslog.NewSyslogConnector(
 		cfg.DrainSkipCertVerify,
 		timeoutwaitgroup.New(time.Minute),
 		writerFactory,
 		m,
-		syslog.WithLogClient(logClient, "syslog_agent"),
+		syslog.WithAppLogEmitter(factory.NewAppLogEmitter(logClient, "syslog_agent")),
 	)
 
 	var cacheClient *cache.CacheClient
@@ -112,6 +109,7 @@ func NewSyslogAgent(
 			m,
 			cfg.WarnOnInvalidDrains,
 			l,
+			factory.NewAppLogEmitter(logClient, "syslog_agent"),
 		)
 		cupsFetcher = bindings.NewDrainParamParser(cupsFetcher, cfg.DefaultDrainMetadata)
 	}

src/cmd/syslog-agent/app/syslog_agent_mtls_test.go

@@ -1,6 +1,7 @@
 package app_test
 
 import (
+	"code.cloudfoundry.org/loggregator-agent-release/src/pkg/egress/syslog"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -41,6 +42,8 @@ var _ = Describe("SyslogAgent with mTLS", func() {
 		agentMetrics *metricsHelpers.SpyMetricsRegistry
 		agentLogr    *log.Logger
 		agent        *app.SyslogAgent
+
+		factory syslog.AppLogEmitterFactory
 	)
 
 	BeforeEach(func() {
@@ -141,6 +144,9 @@ var _ = Describe("SyslogAgent with mTLS", func() {
 		}
 		agentMetrics = metricsHelpers.NewMetricsRegistry()
 		agentLogr = log.New(GinkgoWriter, "", log.LstdFlags)
+
+		defaultFactory := syslog.NewDefaultAppLogEmitterFactory()
+		factory = &defaultFactory
 	})
 
 	JustBeforeEach(func() {
@@ -154,7 +160,7 @@ var _ = Describe("SyslogAgent with mTLS", func() {
 			agentCfg.Cache.PollingInterval = 10 * time.Millisecond
 		}
 
-		agent = app.NewSyslogAgent(agentCfg, agentMetrics, agentLogr)
+		agent = app.NewSyslogAgent(agentCfg, agentMetrics, agentLogr, factory)
 		go agent.Run()
 	})
 
@@ -216,6 +222,7 @@ var _ = Describe("SyslogAgent with mTLS", func() {
 		})
 
 		It("will not be able to connect with those drains", func() {
+			//todo check if pr check runs
 			ctx, cancel := context.WithCancel(context.Background())
 			emitLogs(ctx, appIDs, grpcPort, agentCerts)
 			defer cancel()

src/cmd/syslog-agent/app/syslog_agent_test.go

@@ -1,6 +1,7 @@
 package app_test
 
 import (
+	"code.cloudfoundry.org/loggregator-agent-release/src/pkg/egress/syslog"
 	"context"
 	"crypto/tls"
 	"fmt"
@@ -48,6 +49,8 @@ var _ = Describe("SyslogAgent", func() {
 		agentMetrics *metricsHelpers.SpyMetricsRegistry
 		agentLogr    *log.Logger
 		agent        *app.SyslogAgent
+
+		factory syslog.AppLogEmitterFactory
 	)
 
 	BeforeEach(func() {
@@ -121,6 +124,9 @@ var _ = Describe("SyslogAgent", func() {
 		}
 		agentMetrics = metricsHelpers.NewMetricsRegistry()
 		agentLogr = log.New(GinkgoWriter, "", log.LstdFlags)
+
+		defaultFactory := syslog.NewDefaultAppLogEmitterFactory()
+		factory = &defaultFactory
 	})
 
 	JustBeforeEach(func() {
@@ -134,7 +140,7 @@ var _ = Describe("SyslogAgent", func() {
 			agentCfg.Cache.PollingInterval = 10 * time.Millisecond
 		}
 
-		agent = app.NewSyslogAgent(agentCfg, agentMetrics, agentLogr)
+		agent = app.NewSyslogAgent(agentCfg, agentMetrics, agentLogr, factory)
 		go agent.Run()
 	})
 
@@ -238,6 +244,14 @@ var _ = Describe("SyslogAgent", func() {
 		Eventually(agentMetrics.GetDebugMetricsEnabled).Should(BeFalse())
 	})
 
+	It("configures appLogEmitter", func() {
+		spyFactory := testhelper.SpyAppLogEmitterFactory{}
+		app.NewSyslogAgent(agentCfg, agentMetrics, agentLogr, &spyFactory)
+
+		Expect(spyFactory.SourceIndex()).Should(Equal("syslog_agent"))
+		Expect(spyFactory.LogClient()).ShouldNot(BeNil())
+	})
+
 	Context("when debug configuration is enabled", func() {
 		BeforeEach(func() {
 			agentCfg.MetricsServer.DebugMetrics = true
@@ -423,7 +437,7 @@ var _ = Describe("SyslogAgent", func() {
 			cfgCopy.GRPC.KeyFile = "invalid"
 
 			msg := `failed to configure client TLS: "failed to load keypair: open invalid: no such file or directory"`
-			Expect(func() { app.NewSyslogAgent(cfgCopy, agentMetrics, agentLogr) }).To(PanicWith(msg))
+			Expect(func() { app.NewSyslogAgent(cfgCopy, agentMetrics, agentLogr, factory) }).To(PanicWith(msg))
 		})
 	})
 })

src/cmd/syslog-agent/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"code.cloudfoundry.org/loggregator-agent-release/src/pkg/egress/syslog"
 	"log"
 	_ "net/http/pprof" //nolint:gosec
 	"os"
@@ -33,5 +34,7 @@ func main() {
 		),
 	)
 
-	app.NewSyslogAgent(cfg, m, logger).Run()
+	factory := syslog.NewDefaultAppLogEmitterFactory()
+
+	app.NewSyslogAgent(cfg, m, logger, &factory).Run()
 }

src/internal/testhelper/spy_app_log_emitter.go

@@ -0,0 +1,34 @@
+package testhelper
+
+import "code.cloudfoundry.org/loggregator-agent-release/src/pkg/egress/syslog"
+
+type SpyAppLogEmitter struct {
+}
+
+func (emitter *SpyAppLogEmitter) EmitLog(appID string, message string) {
+
+}
+
+func NewSpyAppEmitter() SpyAppLogEmitter {
+	return SpyAppLogEmitter{}
+}
+
+type SpyAppLogEmitterFactory struct {
+	logClient   syslog.LogClient
+	sourceIndex string
+}
+
+func (factory *SpyAppLogEmitterFactory) LogClient() syslog.LogClient {
+	return factory.logClient
+}
+
+func (factory *SpyAppLogEmitterFactory) SourceIndex() string {
+	return factory.sourceIndex
+}
+
+func (factory *SpyAppLogEmitterFactory) NewAppLogEmitter(logClient syslog.LogClient, sourceIndex string) syslog.AppLogEmitter {
+	factory.logClient = logClient
+	factory.sourceIndex = sourceIndex
+	emitter := NewSpyAppEmitter()
+	return &emitter
+}

src/internal/testhelper/spy_log_client.go

@@ -0,0 +1,82 @@
+package testhelper
+
+import (
+	"code.cloudfoundry.org/go-loggregator/v10"
+	v2 "code.cloudfoundry.org/go-loggregator/v10/rpc/loggregator_v2"
+	"sync"
+)
+
+type spyLogClient struct {
+	mu       sync.Mutex
+	_message []string
+	_appID   []string
+
+	// We use maps to ensure that we can query the keys
+	_sourceType     map[string]struct{}
+	_sourceInstance map[string]struct{}
+}
+
+func NewSpyLogClient() *spyLogClient {
+	return &spyLogClient{
+		_sourceType:     make(map[string]struct{}),
+		_sourceInstance: make(map[string]struct{}),
+	}
+}
+
+func (s *spyLogClient) EmitLog(message string, opts ...loggregator.EmitLogOption) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	env := &v2.Envelope{
+		Tags: make(map[string]string),
+	}
+
+	for _, o := range opts {
+		o(env)
+	}
+
+	s._message = append(s._message, message)
+	s._appID = append(s._appID, env.SourceId)
+	s._sourceType[env.GetTags()["source_type"]] = struct{}{}
+	s._sourceInstance[env.GetInstanceId()] = struct{}{}
+}
+
+func (s *spyLogClient) Message() []string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	return s._message
+}
+
+func (s *spyLogClient) AppID() []string {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	return s._appID
+}
+
+func (s *spyLogClient) SourceType() map[string]struct{} {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// Copy map so the orig does not escape the mutex and induce a race.
+	m := make(map[string]struct{})
+	for k := range s._sourceType {
+		m[k] = struct{}{}
+	}
+
+	return m
+}
+
+func (s *spyLogClient) SourceInstance() map[string]struct{} {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// Copy map so the orig does not escape the mutex and induce a race.
+	m := make(map[string]struct{})
+	for k := range s._sourceInstance {
+		m[k] = struct{}{}
+	}
+
+	return m
+}

src/pkg/egress/syslog/app_log_emitter.go

@@ -0,0 +1,59 @@
+package syslog
+
+import (
+	"code.cloudfoundry.org/go-loggregator/v10"
+)
+
+// LogClient is used to emit logs.
+type LogClient interface {
+	EmitLog(message string, opts ...loggregator.EmitLogOption)
+}
+
+// AppLogEmitter abstracts the sending of a log to the application log stream.
+type AppLogEmitter interface {
+	EmitLog(appID string, message string)
+}
+
+// DefaultAppLogEmitter is an implementation of AppLogEmitter which sends logs to an instance of a LogClient
+type DefaultAppLogEmitter struct {
+	logClient   LogClient
+	sourceIndex string
+}
+
+// EmitLog writes a message in the application log stream using a LogClient.
+func (appLogEmitter *DefaultAppLogEmitter) EmitLog(appID string, message string) {
+	if appLogEmitter.logClient == nil || appID == "" {
+		return
+	}
+
+	option := loggregator.WithAppInfo(appID, "LGR", "")
+	appLogEmitter.logClient.EmitLog(message, option)
+
+	option = loggregator.WithAppInfo(
+		appID,
+		"SYS",
+		appLogEmitter.sourceIndex,
+	)
+	appLogEmitter.logClient.EmitLog(message, option)
+}
+
+// AppLogEmitterFactory is used to create new instances of AppLogEmitter
+type AppLogEmitterFactory interface {
+	NewAppLogEmitter(logClient LogClient, sourceIndex string) AppLogEmitter
+}
+
+// DefaultAppLogEmitterFactory implementation of AppLogEmitterFactory to produce DefaultAppLogEmitter.
+type DefaultAppLogEmitterFactory struct {
+}
+
+// NewAppLogEmitter creates a new DefaultAppLogEmitter.
+func (factory *DefaultAppLogEmitterFactory) NewAppLogEmitter(logClient LogClient, sourceIndex string) AppLogEmitter {
+	return &DefaultAppLogEmitter{
+		logClient:   logClient,
+		sourceIndex: sourceIndex,
+	}
+}
+
+func NewDefaultAppLogEmitterFactory() DefaultAppLogEmitterFactory {
+	return DefaultAppLogEmitterFactory{}
+}