forgejo/vendor/go.opentelemetry.io/otel/trace/trace.go
2021-02-28 18:08:33 -05:00

563 lines
18 KiB
Go
Vendored

// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package trace // import "go.opentelemetry.io/otel/trace"
import (
"bytes"
"context"
"encoding/hex"
"encoding/json"
"regexp"
"strings"
"time"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/label"
)
const (
// FlagsSampled is a bitmask with the sampled bit set. A SpanContext
// with the sampling bit set means the span is sampled.
FlagsSampled = byte(0x01)
// FlagsDeferred is a bitmask with the deferred bit set. A SpanContext
// with the deferred bit set means the sampling decision has been
// defered to the receiver.
FlagsDeferred = byte(0x02)
// FlagsDebug is a bitmask with the debug bit set.
FlagsDebug = byte(0x04)
errInvalidHexID errorConst = "trace-id and span-id can only contain [0-9a-f] characters, all lowercase"
errInvalidTraceIDLength errorConst = "hex encoded trace-id must have length equals to 32"
errNilTraceID errorConst = "trace-id can't be all zero"
errInvalidSpanIDLength errorConst = "hex encoded span-id must have length equals to 16"
errNilSpanID errorConst = "span-id can't be all zero"
// based on the W3C Trace Context specification, see https://www.w3.org/TR/trace-context-1/#tracestate-header
traceStateKeyFormat = `[a-z][_0-9a-z\-\*\/]{0,255}`
traceStateKeyFormatWithMultiTenantVendor = `[a-z][_0-9a-z\-\*\/]{0,240}@[a-z][_0-9a-z\-\*\/]{0,13}`
traceStateValueFormat = `[\x20-\x2b\x2d-\x3c\x3e-\x7e]{0,255}[\x21-\x2b\x2d-\x3c\x3e-\x7e]`
traceStateMaxListMembers = 32
errInvalidTraceStateKeyValue errorConst = "provided key or value is not valid according to the" +
" W3C Trace Context specification"
errInvalidTraceStateMembersNumber errorConst = "trace state would exceed the maximum limit of members (32)"
errInvalidTraceStateDuplicate errorConst = "trace state key/value pairs with duplicate keys provided"
)
type errorConst string
func (e errorConst) Error() string {
return string(e)
}
// TraceID is a unique identity of a trace.
// nolint:golint
type TraceID [16]byte
var nilTraceID TraceID
var _ json.Marshaler = nilTraceID
// IsValid checks whether the trace TraceID is valid. A valid trace ID does
// not consist of zeros only.
func (t TraceID) IsValid() bool {
return !bytes.Equal(t[:], nilTraceID[:])
}
// MarshalJSON implements a custom marshal function to encode TraceID
// as a hex string.
func (t TraceID) MarshalJSON() ([]byte, error) {
return json.Marshal(t.String())
}
// String returns the hex string representation form of a TraceID
func (t TraceID) String() string {
return hex.EncodeToString(t[:])
}
// SpanID is a unique identity of a span in a trace.
type SpanID [8]byte
var nilSpanID SpanID
var _ json.Marshaler = nilSpanID
// IsValid checks whether the SpanID is valid. A valid SpanID does not consist
// of zeros only.
func (s SpanID) IsValid() bool {
return !bytes.Equal(s[:], nilSpanID[:])
}
// MarshalJSON implements a custom marshal function to encode SpanID
// as a hex string.
func (s SpanID) MarshalJSON() ([]byte, error) {
return json.Marshal(s.String())
}
// String returns the hex string representation form of a SpanID
func (s SpanID) String() string {
return hex.EncodeToString(s[:])
}
// TraceIDFromHex returns a TraceID from a hex string if it is compliant with
// the W3C trace-context specification. See more at
// https://www.w3.org/TR/trace-context/#trace-id
// nolint:golint
func TraceIDFromHex(h string) (TraceID, error) {
t := TraceID{}
if len(h) != 32 {
return t, errInvalidTraceIDLength
}
if err := decodeHex(h, t[:]); err != nil {
return t, err
}
if !t.IsValid() {
return t, errNilTraceID
}
return t, nil
}
// SpanIDFromHex returns a SpanID from a hex string if it is compliant
// with the w3c trace-context specification.
// See more at https://www.w3.org/TR/trace-context/#parent-id
func SpanIDFromHex(h string) (SpanID, error) {
s := SpanID{}
if len(h) != 16 {
return s, errInvalidSpanIDLength
}
if err := decodeHex(h, s[:]); err != nil {
return s, err
}
if !s.IsValid() {
return s, errNilSpanID
}
return s, nil
}
func decodeHex(h string, b []byte) error {
for _, r := range h {
switch {
case 'a' <= r && r <= 'f':
continue
case '0' <= r && r <= '9':
continue
default:
return errInvalidHexID
}
}
decoded, err := hex.DecodeString(h)
if err != nil {
return err
}
copy(b, decoded)
return nil
}
// TraceState provides additional vendor-specific trace identification information
// across different distributed tracing systems. It represents an immutable list consisting
// of key/value pairs. There can be a maximum of 32 entries in the list.
//
// Key and value of each list member must be valid according to the W3C Trace Context specification
// (see https://www.w3.org/TR/trace-context-1/#key and https://www.w3.org/TR/trace-context-1/#value
// respectively).
//
// Trace state must be valid according to the W3C Trace Context specification at all times. All
// mutating operations validate their input and, in case of valid parameters, return a new TraceState.
type TraceState struct { //nolint:golint
// TODO @matej-g: Consider implementing this as label.Set, see
// comment https://github.com/open-telemetry/opentelemetry-go/pull/1340#discussion_r540599226
kvs []label.KeyValue
}
var _ json.Marshaler = TraceState{}
var keyFormatRegExp = regexp.MustCompile(
`^((` + traceStateKeyFormat + `)|(` + traceStateKeyFormatWithMultiTenantVendor + `))$`,
)
var valueFormatRegExp = regexp.MustCompile(`^(` + traceStateValueFormat + `)$`)
// MarshalJSON implements a custom marshal function to encode trace state.
func (ts TraceState) MarshalJSON() ([]byte, error) {
return json.Marshal(ts.kvs)
}
// String returns trace state as a string valid according to the
// W3C Trace Context specification.
func (ts TraceState) String() string {
var sb strings.Builder
for i, kv := range ts.kvs {
sb.WriteString((string)(kv.Key))
sb.WriteByte('=')
sb.WriteString(kv.Value.Emit())
if i != len(ts.kvs)-1 {
sb.WriteByte(',')
}
}
return sb.String()
}
// Get returns a value for given key from the trace state.
// If no key is found or provided key is invalid, returns an empty value.
func (ts TraceState) Get(key label.Key) label.Value {
if !isTraceStateKeyValid(key) {
return label.Value{}
}
for _, kv := range ts.kvs {
if kv.Key == key {
return kv.Value
}
}
return label.Value{}
}
// Insert adds a new key/value, if one doesn't exists; otherwise updates the existing entry.
// The new or updated entry is always inserted at the beginning of the TraceState, i.e.
// on the left side, as per the W3C Trace Context specification requirement.
func (ts TraceState) Insert(entry label.KeyValue) (TraceState, error) {
if !isTraceStateKeyValueValid(entry) {
return ts, errInvalidTraceStateKeyValue
}
ckvs := ts.copyKVsAndDeleteEntry(entry.Key)
if len(ckvs)+1 > traceStateMaxListMembers {
return ts, errInvalidTraceStateMembersNumber
}
ckvs = append(ckvs, label.KeyValue{})
copy(ckvs[1:], ckvs)
ckvs[0] = entry
return TraceState{ckvs}, nil
}
// Delete removes specified entry from the trace state.
func (ts TraceState) Delete(key label.Key) (TraceState, error) {
if !isTraceStateKeyValid(key) {
return ts, errInvalidTraceStateKeyValue
}
return TraceState{ts.copyKVsAndDeleteEntry(key)}, nil
}
// IsEmpty returns true if the TraceState does not contain any entries
func (ts TraceState) IsEmpty() bool {
return len(ts.kvs) == 0
}
func (ts TraceState) copyKVsAndDeleteEntry(key label.Key) []label.KeyValue {
ckvs := make([]label.KeyValue, len(ts.kvs))
copy(ckvs, ts.kvs)
for i, kv := range ts.kvs {
if kv.Key == key {
ckvs = append(ckvs[:i], ckvs[i+1:]...)
break
}
}
return ckvs
}
// TraceStateFromKeyValues is a convenience method to create a new TraceState from
// provided key/value pairs.
func TraceStateFromKeyValues(kvs ...label.KeyValue) (TraceState, error) { //nolint:golint
if len(kvs) == 0 {
return TraceState{}, nil
}
if len(kvs) > traceStateMaxListMembers {
return TraceState{}, errInvalidTraceStateMembersNumber
}
km := make(map[label.Key]bool)
for _, kv := range kvs {
if !isTraceStateKeyValueValid(kv) {
return TraceState{}, errInvalidTraceStateKeyValue
}
_, ok := km[kv.Key]
if ok {
return TraceState{}, errInvalidTraceStateDuplicate
}
km[kv.Key] = true
}
ckvs := make([]label.KeyValue, len(kvs))
copy(ckvs, kvs)
return TraceState{ckvs}, nil
}
func isTraceStateKeyValid(key label.Key) bool {
return keyFormatRegExp.MatchString(string(key))
}
func isTraceStateKeyValueValid(kv label.KeyValue) bool {
return isTraceStateKeyValid(kv.Key) &&
valueFormatRegExp.MatchString(kv.Value.Emit())
}
// SpanContext contains identifying trace information about a Span.
type SpanContext struct {
TraceID TraceID
SpanID SpanID
TraceFlags byte
TraceState TraceState
}
// IsValid returns if the SpanContext is valid. A valid span context has a
// valid TraceID and SpanID.
func (sc SpanContext) IsValid() bool {
return sc.HasTraceID() && sc.HasSpanID()
}
// HasTraceID checks if the SpanContext has a valid TraceID.
func (sc SpanContext) HasTraceID() bool {
return sc.TraceID.IsValid()
}
// HasSpanID checks if the SpanContext has a valid SpanID.
func (sc SpanContext) HasSpanID() bool {
return sc.SpanID.IsValid()
}
// IsDeferred returns if the deferred bit is set in the trace flags.
func (sc SpanContext) IsDeferred() bool {
return sc.TraceFlags&FlagsDeferred == FlagsDeferred
}
// IsDebug returns if the debug bit is set in the trace flags.
func (sc SpanContext) IsDebug() bool {
return sc.TraceFlags&FlagsDebug == FlagsDebug
}
// IsSampled returns if the sampling bit is set in the trace flags.
func (sc SpanContext) IsSampled() bool {
return sc.TraceFlags&FlagsSampled == FlagsSampled
}
type traceContextKeyType int
const (
currentSpanKey traceContextKeyType = iota
remoteContextKey
)
// ContextWithSpan returns a copy of parent with span set to current.
func ContextWithSpan(parent context.Context, span Span) context.Context {
return context.WithValue(parent, currentSpanKey, span)
}
// SpanFromContext returns the current span from ctx, or noop span if none set.
func SpanFromContext(ctx context.Context) Span {
if span, ok := ctx.Value(currentSpanKey).(Span); ok {
return span
}
return noopSpan{}
}
// SpanContextFromContext returns the current SpanContext from ctx, or an empty SpanContext if none set.
func SpanContextFromContext(ctx context.Context) SpanContext {
if span := SpanFromContext(ctx); span != nil {
return span.SpanContext()
}
return SpanContext{}
}
// ContextWithRemoteSpanContext returns a copy of parent with a remote set as
// the remote span context.
func ContextWithRemoteSpanContext(parent context.Context, remote SpanContext) context.Context {
return context.WithValue(parent, remoteContextKey, remote)
}
// RemoteSpanContextFromContext returns the remote span context from ctx.
func RemoteSpanContextFromContext(ctx context.Context) SpanContext {
if sc, ok := ctx.Value(remoteContextKey).(SpanContext); ok {
return sc
}
return SpanContext{}
}
// Span is the individual component of a trace. It represents a single named
// and timed operation of a workflow that is traced. A Tracer is used to
// create a Span and it is then up to the operation the Span represents to
// properly end the Span when the operation itself ends.
type Span interface {
// Tracer returns the Tracer that created the Span. Tracer MUST NOT be
// nil.
Tracer() Tracer
// End completes the Span. The Span is considered complete and ready to be
// delivered through the rest of the telemetry pipeline after this method
// is called. Therefore, updates to the Span are not allowed after this
// method has been called.
End(options ...SpanOption)
// AddEvent adds an event with the provided name and options.
AddEvent(name string, options ...EventOption)
// IsRecording returns the recording state of the Span. It will return
// true if the Span is active and events can be recorded.
IsRecording() bool
// RecordError records an error as a Span event.
RecordError(err error, options ...EventOption)
// SpanContext returns the SpanContext of the Span. The returned
// SpanContext is usable even after the End has been called for the Span.
SpanContext() SpanContext
// SetStatus sets the status of the Span in the form of a code and a
// message. SetStatus overrides the value of previous calls to SetStatus
// on the Span.
SetStatus(code codes.Code, msg string)
// SetName sets the Span name.
SetName(name string)
// SetAttributes sets kv as attributes of the Span. If a key from kv
// already exists for an attribute of the Span it will be overwritten with
// the value contained in kv.
SetAttributes(kv ...label.KeyValue)
}
// Event is a thing that happened during a Span's lifetime.
type Event struct {
// Name is the name of this event
Name string
// Attributes describe the aspects of the event.
Attributes []label.KeyValue
// Time at which this event was recorded.
Time time.Time
}
// Link is the relationship between two Spans. The relationship can be within
// the same Trace or across different Traces.
//
// For example, a Link is used in the following situations:
//
// 1. Batch Processing: A batch of operations may contain operations
// associated with one or more traces/spans. Since there can only be one
// parent SpanContext, a Link is used to keep reference to the
// SpanContext of all operations in the batch.
// 2. Public Endpoint: A SpanContext for an in incoming client request on a
// public endpoint should be considered untrusted. In such a case, a new
// trace with its own identity and sampling decision needs to be created,
// but this new trace needs to be related to the original trace in some
// form. A Link is used to keep reference to the original SpanContext and
// track the relationship.
type Link struct {
SpanContext
Attributes []label.KeyValue
}
// SpanKind is the role a Span plays in a Trace.
type SpanKind int
// As a convenience, these match the proto definition, see
// https://github.com/open-telemetry/opentelemetry-proto/blob/30d237e1ff3ab7aa50e0922b5bebdd93505090af/opentelemetry/proto/trace/v1/trace.proto#L101-L129
//
// The unspecified value is not a valid `SpanKind`. Use `ValidateSpanKind()`
// to coerce a span kind to a valid value.
const (
// SpanKindUnspecified is an unspecified SpanKind and is not a valid
// SpanKind. SpanKindUnspecified should be replaced with SpanKindInternal
// if it is received.
SpanKindUnspecified SpanKind = 0
// SpanKindInternal is a SpanKind for a Span that represents an internal
// operation within an application.
SpanKindInternal SpanKind = 1
// SpanKindServer is a SpanKind for a Span that represents the operation
// of handling a request from a client.
SpanKindServer SpanKind = 2
// SpanKindClient is a SpanKind for a Span that represents the operation
// of client making a request to a server.
SpanKindClient SpanKind = 3
// SpanKindProducer is a SpanKind for a Span that represents the operation
// of a producer sending a message to a message broker. Unlike
// SpanKindClient and SpanKindServer, there is often no direct
// relationship between this kind of Span and a SpanKindConsumer kind. A
// SpanKindProducer Span will end once the message is accepted by the
// message broker which might not overlap with the processing of that
// message.
SpanKindProducer SpanKind = 4
// SpanKindConsumer is a SpanKind for a Span that represents the operation
// of a consumer receiving a message from a message broker. Like
// SpanKindProducer Spans, there is often no direct relationship between
// this Span and the Span that produced the message.
SpanKindConsumer SpanKind = 5
)
// ValidateSpanKind returns a valid span kind value. This will coerce
// invalid values into the default value, SpanKindInternal.
func ValidateSpanKind(spanKind SpanKind) SpanKind {
switch spanKind {
case SpanKindInternal,
SpanKindServer,
SpanKindClient,
SpanKindProducer,
SpanKindConsumer:
// valid
return spanKind
default:
return SpanKindInternal
}
}
// String returns the specified name of the SpanKind in lower-case.
func (sk SpanKind) String() string {
switch sk {
case SpanKindInternal:
return "internal"
case SpanKindServer:
return "server"
case SpanKindClient:
return "client"
case SpanKindProducer:
return "producer"
case SpanKindConsumer:
return "consumer"
default:
return "unspecified"
}
}
// Tracer is the creator of Spans.
type Tracer interface {
// Start creates a span.
Start(ctx context.Context, spanName string, opts ...SpanOption) (context.Context, Span)
}
// TracerProvider provides access to instrumentation Tracers.
type TracerProvider interface {
// Tracer creates an implementation of the Tracer interface.
// The instrumentationName must be the name of the library providing
// instrumentation. This name may be the same as the instrumented code
// only if that code provides built-in instrumentation. If the
// instrumentationName is empty, then a implementation defined default
// name will be used instead.
Tracer(instrumentationName string, opts ...TracerOption) Tracer
}