Add B3 trace IDs to cf cli commands

Author: Samze

api/cloudcontroller/wrapper/b3_trace_request.go

@@ -0,0 +1,54 @@
+package wrapper
+
+import (
+	"code.cloudfoundry.org/cli/api/cloudcontroller"
+)
+
+// TODO
+// 1. tests
+// 2. do not overwrite headers if explicitly set (cf curl)
+// 3. headers should go on other clients (uaa/routing) as well (with same value)
+// 4. environment variable override
+
+const (
+	// B3TraceIDHeader is the header key for the b3 trace id.
+	B3TraceIDHeader = "X-B3-Traceid"
+
+	// B3SpanIDHeader is the header key for the b3 span id.
+	B3SpanIDHeader = "X-B3-Spanid"
+)
+
+// TraceHeaderRequest is a wrapper that adds b3 trace headers to requests.
+type TraceHeaderRequest struct {
+	b3trace    string
+	b3span     string
+	connection cloudcontroller.Connection
+}
+
+// NewTraceHeaderRequest returns a pointer to a TraceHeaderRequest wrapper.
+func NewTraceHeaderRequest(trace, span string) *TraceHeaderRequest {
+	return &TraceHeaderRequest{
+		b3trace: trace,
+		b3span:  span,
+	}
+}
+
+// Add tracing headers if they are not already set.
+func (t *TraceHeaderRequest) Make(request *cloudcontroller.Request, passedResponse *cloudcontroller.Response) error {
+
+	// todo
+	// only override the trace headers if they are not already set (e.g. already explicitly set by cf curl)
+	if request.Header.Get(B3TraceIDHeader) != "" {
+		request.Header.Add(B3TraceIDHeader, t.b3trace)
+	}
+	if request.Header.Get(B3SpanIDHeader) != "" {
+		request.Header.Add(B3SpanIDHeader, t.b3span)
+	}
+	return t.connection.Make(request, passedResponse)
+}
+
+// Wrap sets the connection in the TraceHeaderRequest and returns itself.
+func (t *TraceHeaderRequest) Wrap(innerconnection cloudcontroller.Connection) cloudcontroller.Connection {
+	t.connection = innerconnection
+	return t
+}

command/commandfakes/fake_config.go

@@ -15,6 +15,8 @@ type Config interface {
 	AddPluginRepository(name string, url string)
 	AuthorizationEndpoint() string
 	APIVersion() string
+	B3TraceID() string
+	B3SpanID() string
 	BinaryName() string
 	BinaryVersion() string
 	CFPassword() string

command/config.go

@@ -46,6 +46,7 @@ func NewWrappedCloudControllerClient(config command.Config, ui command.UI, extra
 		ccWrappers = append(ccWrappers, ccWrapper.NewRequestLogger(ui.RequestLoggerFileWriter(location)))
 	}
 
+	ccWrappers = append(ccWrappers, ccWrapper.NewTraceHeaderRequest(config.B3TraceID(), config.B3SpanID()))
 	ccWrappers = append(ccWrappers, extraWrappers...)
 	ccWrappers = append(ccWrappers, ccWrapper.NewRetryRequest(config.RequestRetryCount()))
 

command/v7/shared/new_clients.go

@@ -5,6 +5,8 @@ import (
 	"strconv"
 	"strings"
 	"time"
+
+	"code.cloudfoundry.org/cli/util/random"
 )
 
 // EnvOverride represents all the environment variables read by the CF CLI
@@ -20,6 +22,8 @@ type EnvOverride struct {
 	CFStartupTimeout string
 	CFTrace          string
 	CFUsername       string
+	CFB3TraceID      string
+	CFB3SpanID       string
 	DockerPassword   string
 	CNBCredentials   string
 	Experimental     string
@@ -160,3 +164,17 @@ func (config *Config) StartupTimeout() time.Duration {
 
 	return DefaultStartupTimeout
 }
+
+func (config *Config) B3TraceID() string {
+	if config.ENV.CFB3TraceID == "" {
+		return random.GenerateHex(32)
+	}
+	return config.ENV.CFB3TraceID
+}
+
+func (config *Config) B3SpanID() string {
+	if config.ENV.CFB3SpanID == "" {
+		return random.GenerateHex(16)
+	}
+	return config.ENV.CFB3SpanID
+}

util/configv3/env.go

@@ -127,6 +127,8 @@ func LoadConfig(flags ...FlagOverride) (*Config, error) {
 		CFStartupTimeout: os.Getenv("CF_STARTUP_TIMEOUT"),
 		CFTrace:          os.Getenv("CF_TRACE"),
 		CFUsername:       os.Getenv("CF_USERNAME"),
+		CFB3TraceID:      os.Getenv("CF_B3_TRACE_ID"),
+		CFB3SpanID:       os.Getenv("CF_B3_SPAN_ID"),
 		DockerPassword:   os.Getenv("CF_DOCKER_PASSWORD"),
 		CNBCredentials:   os.Getenv("CNB_REGISTRY_CREDS"),
 		Experimental:     os.Getenv("CF_CLI_EXPERIMENTAL"),

util/configv3/load_config.go

@@ -0,0 +1,15 @@
+package random
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+)
+
+func GenerateHex(length int) string {
+	b := make([]byte, length/2)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+
+	return hex.EncodeToString(b)
+}