Refactor zipkin to add ability to get trace from traceId (#348)

test/spoof/spoof.go

@@ -19,8 +19,6 @@ limitations under the License.
 package spoof
 
 import (
-	"bytes"
-	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -229,33 +227,15 @@ func (sc *SpoofingClient) logZipkinTrace(spoofResp *Response) {
 	}
 
 	traceID := spoofResp.Header.Get(zipkin.ZipkinTraceIDHeader)
-	if err := zipkin.CheckZipkinPortAvailability(); err == nil {
-		sc.logf("port-forwarding for Zipkin is not-setup. Failing Zipkin Trace retrieval")
-		return
-	}
+	sc.logf("Logging Zipkin Trace for: %s", traceID)
 
-	sc.logf("Logging Zipkin Trace: %s", traceID)
-
-	zipkinTraceEndpoint := zipkin.ZipkinTraceEndpoint + traceID
 	// Sleep to ensure all traces are correctly pushed on the backend.
 	time.Sleep(5 * time.Second)
-	resp, err := http.Get(zipkinTraceEndpoint)
-	if err != nil {
-		sc.logf("Error retrieving Zipkin trace: %v", err)
-		return
-	}
-	defer resp.Body.Close()
 
-	trace, err := ioutil.ReadAll(resp.Body)
+	json, err := zipkin.JSONTrace(traceID)
 	if err != nil {
-		sc.logf("Error reading Zipkin trace response: %v", err)
-		return
+		sc.logf("Error getting zipkin trace: %v", err)
 	}
 
-	var prettyJSON bytes.Buffer
-	if error := json.Indent(&prettyJSON, trace, "", "\t"); error != nil {
-		sc.logf("JSON Parser Error while trying for Pretty-Format: %v, Original Response: %s", error, string(trace))
-		return
-	}
-	sc.logf("%s", prettyJSON.String())
+	sc.logf("%s", json)
 }

test/zipkin/util.go

@@ -19,6 +19,10 @@ limitations under the License.
 package zipkin
 
 import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
 	"sync"
 
 	"github.com/knative/pkg/test/logging"
@@ -112,3 +116,30 @@ func CleanupZipkinTracingSetup(logf logging.FormatLogger) {
 func CheckZipkinPortAvailability() error {
 	return monitoring.CheckPortAvailability(ZipkinPort)
 }
+
+// JSONTrace returns a trace for the given traceId in JSON format
+func JSONTrace(traceID string) (string, error) {
+	// Check if zipkin port forwarding is setup correctly
+	if err := CheckZipkinPortAvailability(); err == nil {
+		return "", err
+	}
+
+	resp, err := http.Get(ZipkinTraceEndpoint + traceID)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	trace, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	var prettyJSON bytes.Buffer
+	err = json.Indent(&prettyJSON, trace, "", "\t")
+	if err != nil {
+		return "", err
+	}
+
+	return prettyJSON.String(), nil
+}