/
distributed_tracing.go
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/
distributed_tracing.go
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// Copyright 2020 New Relic Corporation. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
package newrelic
import (
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"net/http"
"regexp"
"strconv"
"strings"
"time"
"github.com/newrelic/go-agent/v3/internal"
)
type distTraceVersion [2]int
func (v distTraceVersion) major() int { return v[0] }
func (v distTraceVersion) minor() int { return v[1] }
const (
// callerTypeApp is the Type field's value for outbound payloads.
callerTypeApp = "App"
// callerTypeBrowser is the Type field's value for browser payloads
callerTypeBrowser = "Browser"
// callerTypeMobile is the Type field's value for mobile payloads
callerTypeMobile = "Mobile"
)
var (
currentDistTraceVersion = distTraceVersion([2]int{0 /* Major */, 1 /* Minor */})
callerUnknown = payloadCaller{Type: "Unknown", App: "Unknown", Account: "Unknown", TransportType: "Unknown"}
traceParentRegex = regexp.MustCompile(`^([a-f0-9]{2})-` + // version
`([a-f0-9]{32})-` + // traceId
`([a-f0-9]{16})-` + // parentId
`([a-f0-9]{2})(-.*)?$`) // flags
)
// timestampMillis allows raw payloads to use exact times, and marshalled
// payloads to use times in millis.
type timestampMillis time.Time
func (tm *timestampMillis) UnmarshalJSON(data []byte) error {
var millis uint64
if err := json.Unmarshal(data, &millis); nil != err {
return err
}
*tm = timestampMillis(timeFromUnixMilliseconds(millis))
return nil
}
func (tm timestampMillis) MarshalJSON() ([]byte, error) {
return json.Marshal(timeToUnixMilliseconds(tm.Time()))
}
func (tm timestampMillis) Time() time.Time { return time.Time(tm) }
func (tm *timestampMillis) Set(t time.Time) { *tm = timestampMillis(t) }
func (tm timestampMillis) unixMillisecondsString() string {
ms := timeToUnixMilliseconds(tm.Time())
return strconv.FormatUint(ms, 10)
}
// payload is the distributed tracing payload.
type payload struct {
Type string `json:"ty"`
App string `json:"ap"`
Account string `json:"ac"`
TransactionID string `json:"tx,omitempty"`
ID string `json:"id,omitempty"`
TracedID string `json:"tr"`
Priority priority `json:"pr"`
// This is a *bool instead of a normal bool so we can tell the different between unset and false.
Sampled *bool `json:"sa"`
Timestamp timestampMillis `json:"ti"`
TransportDuration time.Duration `json:"-"`
TrustedParentID string `json:"-"`
TracingVendors string `json:"-"`
HasNewRelicTraceInfo bool `json:"-"`
TrustedAccountKey string `json:"tk,omitempty"`
NonTrustedTraceState string `json:"-"`
OriginalTraceState string `json:"-"`
}
type payloadCaller struct {
TransportType string
Type string
App string
Account string
}
var (
errPayloadMissingGUIDTxnID = errors.New("payload is missing both guid/id and TransactionId/tx")
errPayloadMissingType = errors.New("payload is missing Type/ty")
errPayloadMissingAccount = errors.New("payload is missing Account/ac")
errPayloadMissingApp = errors.New("payload is missing App/ap")
errPayloadMissingTraceID = errors.New("payload is missing TracedID/tr")
errPayloadMissingTimestamp = errors.New("payload is missing Timestamp/ti")
errPayloadMissingVersion = errors.New("payload is missing Version/v")
)
// IsValid IsValidNewRelicData the payload data by looking for missing fields.
// Returns an error if there's a problem, nil if everything's fine
func (p payload) validateNewRelicData() error {
// If a payload is missing both `guid` and `transactionId` is received,
// a ParseException supportability metric should be generated.
if "" == p.TransactionID && "" == p.ID {
return errPayloadMissingGUIDTxnID
}
if "" == p.Type {
return errPayloadMissingType
}
if "" == p.Account {
return errPayloadMissingAccount
}
if "" == p.App {
return errPayloadMissingApp
}
if "" == p.TracedID {
return errPayloadMissingTraceID
}
if p.Timestamp.Time().IsZero() || 0 == p.Timestamp.Time().Unix() {
return errPayloadMissingTimestamp
}
return nil
}
func (p payload) text(v distTraceVersion) []byte {
// TrustedAccountKey should only be attached to the outbound payload if its value differs
// from the Account field.
if p.TrustedAccountKey == p.Account {
p.TrustedAccountKey = ""
}
js, _ := json.Marshal(struct {
Version distTraceVersion `json:"v"`
Data payload `json:"d"`
}{
Version: v,
Data: p,
})
return js
}
// NRText implements newrelic.DistributedTracePayload.
func (p payload) NRText() string {
t := p.text(currentDistTraceVersion)
return string(t)
}
// NRHTTPSafe implements newrelic.DistributedTracePayload.
func (p payload) NRHTTPSafe() string {
t := p.text(currentDistTraceVersion)
return base64.StdEncoding.EncodeToString(t)
}
var (
typeMap = map[string]string{
callerTypeApp: "0",
callerTypeBrowser: "1",
callerTypeMobile: "2",
}
typeMapReverse = func() map[string]string {
reversed := make(map[string]string)
for k, v := range typeMap {
reversed[v] = k
}
return reversed
}()
)
const (
w3cVersion = "00"
traceStateVersion = "0"
)
// W3CTraceParent returns the W3C TraceParent header for this payload
func (p payload) W3CTraceParent() string {
var flags string
if p.isSampled() {
flags = "01"
} else {
flags = "00"
}
traceID := strings.ToLower(p.TracedID)
if idLen := len(traceID); idLen < internal.TraceIDHexStringLen {
traceID = strings.Repeat("0", internal.TraceIDHexStringLen-idLen) + traceID
} else if idLen > internal.TraceIDHexStringLen {
traceID = traceID[idLen-internal.TraceIDHexStringLen:]
}
return w3cVersion + "-" + traceID + "-" + p.ID + "-" + flags
}
// W3CTraceState returns the W3C TraceState header for this payload
func (p payload) W3CTraceState() string {
var flags string
if p.isSampled() {
flags = "1"
} else {
flags = "0"
}
state := p.TrustedAccountKey + "@nr=" +
traceStateVersion + "-" +
typeMap[p.Type] + "-" +
p.Account + "-" +
p.App + "-" +
p.ID + "-" +
p.TransactionID + "-" +
flags + "-" +
p.Priority.traceStateFormat() + "-" +
p.Timestamp.unixMillisecondsString()
if p.NonTrustedTraceState != "" {
state += "," + p.NonTrustedTraceState
}
return state
}
var (
trueVal = true
falseVal = false
boolPtrs = map[bool]*bool{
true: &trueVal,
false: &falseVal,
}
)
// SetSampled lets us set a value for our *bool,
// which we can't do directly since a pointer
// needs something to point at.
func (p *payload) SetSampled(sampled bool) {
p.Sampled = boolPtrs[sampled]
}
func (p payload) isSampled() bool {
return p.Sampled != nil && *p.Sampled
}
// acceptPayload parses the inbound distributed tracing payload.
func acceptPayload(hdrs http.Header, trustedAccountKey string, support *distributedTracingSupport) (*payload, error) {
if hdrs.Get(DistributedTraceW3CTraceParentHeader) != "" {
return processW3CHeaders(hdrs, trustedAccountKey, support)
}
return processNRDTString(hdrs.Get(DistributedTraceNewRelicHeader), support)
}
func processNRDTString(str string, support *distributedTracingSupport) (*payload, error) {
if str == "" {
return nil, nil
}
var decoded []byte
if '{' == str[0] {
decoded = []byte(str)
} else {
var err error
decoded, err = base64.StdEncoding.DecodeString(str)
if nil != err {
support.AcceptPayloadParseException = true
return nil, fmt.Errorf("unable to decode payload: %v", err)
}
}
envelope := struct {
Version distTraceVersion `json:"v"`
Data json.RawMessage `json:"d"`
}{}
if err := json.Unmarshal(decoded, &envelope); nil != err {
support.AcceptPayloadParseException = true
return nil, fmt.Errorf("unable to unmarshal payload: %v", err)
}
if 0 == envelope.Version.major() && 0 == envelope.Version.minor() {
support.AcceptPayloadParseException = true
return nil, errPayloadMissingVersion
}
if envelope.Version.major() > currentDistTraceVersion.major() {
support.AcceptPayloadIgnoredVersion = true
return nil, fmt.Errorf("unsupported major version number %v",
envelope.Version.major())
}
payload := new(payload)
if err := json.Unmarshal(envelope.Data, payload); nil != err {
support.AcceptPayloadParseException = true
return nil, fmt.Errorf("unable to unmarshal payload data: %v", err)
}
payload.HasNewRelicTraceInfo = true
if err := payload.validateNewRelicData(); err != nil {
support.AcceptPayloadParseException = true
return nil, err
}
support.AcceptPayloadSuccess = true
return payload, nil
}
func processW3CHeaders(hdrs http.Header, trustedAccountKey string, support *distributedTracingSupport) (*payload, error) {
p, err := processTraceParent(hdrs)
if nil != err {
support.TraceContextParentParseException = true
return nil, err
}
err = processTraceState(hdrs, trustedAccountKey, p)
if nil != err {
if err == errInvalidNRTraceState {
support.TraceContextStateInvalidNrEntry = true
} else {
support.TraceContextStateNoNrEntry = true
}
}
support.TraceContextAcceptSuccess = true
return p, nil
}
var (
errTooManyHdrs = errors.New("too many TraceParent headers")
errNumEntries = errors.New("invalid number of TraceParent entries")
errInvalidTraceID = errors.New("invalid TraceParent trace ID")
errInvalidParentID = errors.New("invalid TraceParent parent ID")
errInvalidFlags = errors.New("invalid TraceParent flags for this version")
errInvalidNRTraceState = errors.New("invalid NR entry in trace state")
errMissingTrustedNR = errors.New("no trusted NR entry found in trace state")
)
func processTraceParent(hdrs http.Header) (*payload, error) {
traceParents := hdrs[DistributedTraceW3CTraceParentHeader]
if len(traceParents) > 1 {
return nil, errTooManyHdrs
}
subMatches := traceParentRegex.FindStringSubmatch(traceParents[0])
if subMatches == nil || len(subMatches) != 6 {
return nil, errNumEntries
}
if !validateVersionAndFlags(subMatches) {
return nil, errInvalidFlags
}
p := new(payload)
p.TracedID = subMatches[2]
if p.TracedID == "00000000000000000000000000000000" {
return nil, errInvalidTraceID
}
p.ID = subMatches[3]
if p.ID == "0000000000000000" {
return nil, errInvalidParentID
}
return p, nil
}
func validateVersionAndFlags(subMatches []string) bool {
if subMatches[1] == w3cVersion {
if subMatches[5] != "" {
return false
}
}
// Invalid version: https://w3c.github.io/trace-context/#version
if subMatches[1] == "ff" {
return false
}
return true
}
func processTraceState(hdrs http.Header, trustedAccountKey string, p *payload) error {
traceStates := hdrs[DistributedTraceW3CTraceStateHeader]
fullTraceState := strings.Join(traceStates, ",")
p.OriginalTraceState = fullTraceState
var trustedVal string
p.TracingVendors, p.NonTrustedTraceState, trustedVal = parseTraceState(fullTraceState, trustedAccountKey)
if trustedVal == "" {
return errMissingTrustedNR
}
matches := strings.Split(trustedVal, "-")
if len(matches) < 9 {
return errInvalidNRTraceState
}
// Required Fields:
version := matches[0]
parentType := typeMapReverse[matches[1]]
account := matches[2]
app := matches[3]
timestamp, err := strconv.ParseUint(matches[8], 10, 64)
if nil != err || "" == version || "" == parentType || "" == account || "" == app {
return errInvalidNRTraceState
}
p.TrustedAccountKey = trustedAccountKey
p.Type = parentType
p.Account = account
p.App = app
p.TrustedParentID = matches[4]
p.TransactionID = matches[5]
// If sampled isn't "1" or "0", leave it unset
if matches[6] == "1" {
p.SetSampled(true)
} else if matches[6] == "0" {
p.SetSampled(false)
}
pty, err := strconv.ParseFloat(matches[7], 32)
if nil == err {
p.Priority = priority(pty)
}
p.Timestamp = timestampMillis(timeFromUnixMilliseconds(timestamp))
p.HasNewRelicTraceInfo = true
return nil
}
func parseTraceState(fullState, trustedAccountKey string) (nonTrustedVendors string, nonTrustedState string, trustedEntryValue string) {
trustedKey := trustedAccountKey + "@nr"
pairs := strings.Split(fullState, ",")
vendors := make([]string, 0, len(pairs))
states := make([]string, 0, len(pairs))
for _, entry := range pairs {
entry = strings.TrimSpace(entry)
m := strings.Split(entry, "=")
if len(m) != 2 {
continue
}
if key, val := m[0], m[1]; key == trustedKey {
trustedEntryValue = val
} else {
vendors = append(vendors, key)
states = append(states, entry)
}
}
nonTrustedVendors = strings.Join(vendors, ",")
nonTrustedState = strings.Join(states, ",")
return
}