Crossdock sampling redirection to collector (#6115)

## Which problem is this PR solving?
- Resolve #6083 
## Description of the changes
- 

## How was this change tested?
- make test 

## Checklist
- [ ] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [ ] I have signed all commits
- [ ] I have added unit tests for the new functionality
- [ ] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `yarn lint` and `yarn test`

---------

Signed-off-by: chahatsagarmain <chahatsagar2003@gmail.com>

crossdock/docker-compose.yml

@@ -55,6 +55,7 @@ services:
             - "8080"
         environment:
             - JAEGER_COLLECTOR_HC_HOST_PORT=jaeger-collector:${JAEGER_COLLECTOR_HC_PORT}
+            - JAEGER_COLLECTOR_HOST_PORT=jaeger-collector:${JAEGER_COLLECTOR_HOST_PORT}
         depends_on:
             - jaeger-query
             - jaeger-collector

crossdock/main.go

@@ -19,19 +19,17 @@ import (
 const (
 	behaviorEndToEnd = "endtoend"
 
-	envAgentHostPort = "JAEGER_AGENT_HOST_PORT"
-	envQueryHostPort = "JAEGER_QUERY_HOST_PORT"
-
+	envCollectorSamplingHostPort    = "JAEGER_COLLECTOR_HOST_PORT"
+	envQueryHostPort                = "JAEGER_QUERY_HOST_PORT"
 	envQueryHealthcheckHostPort     = "JAEGER_QUERY_HC_HOST_PORT"
 	envCollectorHealthcheckHostPort = "JAEGER_COLLECTOR_HC_HOST_PORT"
 )
 
 var (
 	logger, _ = zap.NewDevelopment()
 
-	agentHostPort string
-	queryHostPort string
-
+	collectorSamplingHostPort    string
+	queryHostPort                string
 	queryHealthcheckHostPort     string
 	collectorHealthcheckHostPort string
 )
@@ -44,7 +42,7 @@ type clientHandler struct {
 }
 
 func main() {
-	agentHostPort = getEnv(envAgentHostPort, "jaeger-agent:5778")
+	collectorSamplingHostPort = getEnv(envCollectorSamplingHostPort, "jaeger-collector:14268")
 	queryHostPort = getEnv(envQueryHostPort, "jaeger-query:16686")
 	queryHealthcheckHostPort = getEnv(envQueryHealthcheckHostPort, "jaeger-query:16687")
 	collectorHealthcheckHostPort = getEnv(envCollectorHealthcheckHostPort, "jaeger-collector:14269")
@@ -78,9 +76,9 @@ func (h *clientHandler) initialize() {
 	httpHealthCheck(logger, "jaeger-collector", "http://"+collectorHealthcheckHostPort)
 
 	queryService := services.NewQueryService("http://"+queryHostPort, logger)
-	agentService := services.NewAgentService("http://"+agentHostPort, logger)
+	collectorService := services.NewCollectorService("http://"+collectorSamplingHostPort, logger)
 
-	traceHandler := services.NewTraceHandler(queryService, agentService, logger)
+	traceHandler := services.NewTraceHandler(queryService, collectorService, logger)
 	behaviors := crossdock.Behaviors{
 		behaviorEndToEnd: traceHandler.EndToEndTest,
 	}

crossdock/services/agent.go

@@ -18,30 +18,36 @@ import (
 
 var errSamplingRateMissing = errors.New("sampling rate is missing")
 
-// AgentService is the service used to report traces to the collector.
-type AgentService interface {
+// CollectorService is the service used to report traces to the collector.
+type CollectorService interface {
 	GetSamplingRate(service, operation string) (float64, error)
 }
 
-type agentService struct {
+type collectorService struct {
 	url    string
 	logger *zap.Logger
 }
 
-// NewAgentService returns an instance of AgentService.
-func NewAgentService(url string, logger *zap.Logger) AgentService {
-	return &agentService{
+// NewCollectorService returns an instance of CollectorService.
+func NewCollectorService(url string, logger *zap.Logger) CollectorService {
+	logger.Info("Initializing Collector Service",
+		zap.String("url", url))
+	return &collectorService{
 		url:    url,
 		logger: logger,
 	}
 }
 
 func getSamplingURL(url string) string {
-	return url + "/sampling?service=%s"
+	return url + "/api/sampling?service=%s"
 }
 
 // GetSamplingRate returns the sampling rate for the service-operation from the agent service.
-func (s *agentService) GetSamplingRate(service, operation string) (float64, error) {
+func (s *collectorService) GetSamplingRate(service, operation string) (float64, error) {
+	s.logger.Info("Getting sampling rate",
+		zap.String("url", s.url),
+		zap.String("service", service),
+		zap.String("operation", operation))
 	url := fmt.Sprintf(getSamplingURL(s.url), getTracerServiceName(service))
 	resp, err := http.Get(url)
 	if err != nil {
@@ -52,7 +58,7 @@ func (s *agentService) GetSamplingRate(service, operation string) (float64, erro
 	if err != nil {
 		return 0, err
 	}
-	s.logger.Info("Retrieved sampling rates from agent", zap.String("body", string(body)))
+	s.logger.Info("Retrieved sampling rates from collector", zap.String("body", string(body)))
 
 	response, err := p2json.SamplingStrategyResponseFromJSON(body)
 	if err != nil {

crossdock/services/agent_test.go

@@ -52,10 +52,14 @@ func TestGetSamplingRateInternal(t *testing.T) {
 	}
 }
 
-type testAgentHandler struct{}
+type testAgentHandler struct {
+	logger *zap.Logger
+}
 
-func (*testAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+func (h *testAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	svc := r.FormValue("service")
+	h.logger.Info("Handling sampling request",
+		zap.String("service", svc))
 	body := []byte("bad json")
 	if svc == "crossdock-svc" {
 		response := api_v2.SamplingStrategyResponse{
@@ -77,16 +81,19 @@ func (*testAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 func TestGetSamplingRate(t *testing.T) {
-	handler := &testAgentHandler{}
+	logger := zap.NewExample()
+	handler := &testAgentHandler{logger: logger}
 	server := httptest.NewServer(handler)
 	defer server.Close()
 
 	// Test with no http server
-	agent := NewAgentService("", zap.NewNop())
+	agent := NewCollectorService("", zap.NewNop())
 	_, err := agent.GetSamplingRate("svc", "op")
 	require.Error(t, err)
 
-	agent = NewAgentService(server.URL, zap.NewNop())
+	agent = NewCollectorService(server.URL, zap.NewNop())
+	logger.Info("Testing with mock server",
+		zap.String("url", server.URL))
 	rate, err := agent.GetSamplingRate("svc", "op")
 	require.NoError(t, err)
 	assert.InDelta(t, 1.0, rate, 0.01)
@@ -100,7 +107,7 @@ func TestGetSamplingRateReadAllErr(t *testing.T) {
 		w.Header().Set("Content-Length", "1")
 	}))
 	defer server.Close()
-	agent := NewAgentService(server.URL, zap.NewNop())
+	agent := NewCollectorService(server.URL, zap.NewNop())
 	_, err := agent.GetSamplingRate("svc", "op")
 	require.EqualError(t, err, "unexpected EOF")
 }

crossdock/services/tracehandler.go

@@ -46,7 +46,7 @@ type testFunc func(service string, request *traceRequest) ([]*ui.Trace, error)
 // TraceHandler handles creating traces and verifying them
 type TraceHandler struct {
 	query                                 QueryService
-	agent                                 AgentService
+	agent                                 CollectorService
 	logger                                *zap.Logger
 	getClientURL                          func(service string) string
 	getTags                               func() map[string]string
@@ -57,7 +57,7 @@ type TraceHandler struct {
 }
 
 // NewTraceHandler returns a TraceHandler that can create traces and verify them
-func NewTraceHandler(query QueryService, agent AgentService, logger *zap.Logger) *TraceHandler {
+func NewTraceHandler(query QueryService, agent CollectorService, logger *zap.Logger) *TraceHandler {
 	return &TraceHandler{
 		query:  query,
 		agent:  agent,