gotosocial/vendor/go.opentelemetry.io/otel/baggage/baggage.go
2023-05-09 18:19:48 +01:00

571 lines
15 KiB
Go

// 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 baggage // import "go.opentelemetry.io/otel/baggage"
import (
"errors"
"fmt"
"net/url"
"regexp"
"strings"
"go.opentelemetry.io/otel/internal/baggage"
)
const (
maxMembers = 180
maxBytesPerMembers = 4096
maxBytesPerBaggageString = 8192
listDelimiter = ","
keyValueDelimiter = "="
propertyDelimiter = ";"
keyDef = `([\x21\x23-\x27\x2A\x2B\x2D\x2E\x30-\x39\x41-\x5a\x5e-\x7a\x7c\x7e]+)`
valueDef = `([\x21\x23-\x2b\x2d-\x3a\x3c-\x5B\x5D-\x7e]*)`
keyValueDef = `\s*` + keyDef + `\s*` + keyValueDelimiter + `\s*` + valueDef + `\s*`
)
var (
keyRe = regexp.MustCompile(`^` + keyDef + `$`)
valueRe = regexp.MustCompile(`^` + valueDef + `$`)
propertyRe = regexp.MustCompile(`^(?:\s*` + keyDef + `\s*|` + keyValueDef + `)$`)
)
var (
errInvalidKey = errors.New("invalid key")
errInvalidValue = errors.New("invalid value")
errInvalidProperty = errors.New("invalid baggage list-member property")
errInvalidMember = errors.New("invalid baggage list-member")
errMemberNumber = errors.New("too many list-members in baggage-string")
errMemberBytes = errors.New("list-member too large")
errBaggageBytes = errors.New("baggage-string too large")
)
// Property is an additional metadata entry for a baggage list-member.
type Property struct {
key, value string
// hasValue indicates if a zero-value value means the property does not
// have a value or if it was the zero-value.
hasValue bool
// hasData indicates whether the created property contains data or not.
// Properties that do not contain data are invalid with no other check
// required.
hasData bool
}
// NewKeyProperty returns a new Property for key.
//
// If key is invalid, an error will be returned.
func NewKeyProperty(key string) (Property, error) {
if !keyRe.MatchString(key) {
return newInvalidProperty(), fmt.Errorf("%w: %q", errInvalidKey, key)
}
p := Property{key: key, hasData: true}
return p, nil
}
// NewKeyValueProperty returns a new Property for key with value.
//
// If key or value are invalid, an error will be returned.
func NewKeyValueProperty(key, value string) (Property, error) {
if !keyRe.MatchString(key) {
return newInvalidProperty(), fmt.Errorf("%w: %q", errInvalidKey, key)
}
if !valueRe.MatchString(value) {
return newInvalidProperty(), fmt.Errorf("%w: %q", errInvalidValue, value)
}
p := Property{
key: key,
value: value,
hasValue: true,
hasData: true,
}
return p, nil
}
func newInvalidProperty() Property {
return Property{}
}
// parseProperty attempts to decode a Property from the passed string. It
// returns an error if the input is invalid according to the W3C Baggage
// specification.
func parseProperty(property string) (Property, error) {
if property == "" {
return newInvalidProperty(), nil
}
match := propertyRe.FindStringSubmatch(property)
if len(match) != 4 {
return newInvalidProperty(), fmt.Errorf("%w: %q", errInvalidProperty, property)
}
p := Property{hasData: true}
if match[1] != "" {
p.key = match[1]
} else {
p.key = match[2]
p.value = match[3]
p.hasValue = true
}
return p, nil
}
// validate ensures p conforms to the W3C Baggage specification, returning an
// error otherwise.
func (p Property) validate() error {
errFunc := func(err error) error {
return fmt.Errorf("invalid property: %w", err)
}
if !p.hasData {
return errFunc(fmt.Errorf("%w: %q", errInvalidProperty, p))
}
if !keyRe.MatchString(p.key) {
return errFunc(fmt.Errorf("%w: %q", errInvalidKey, p.key))
}
if p.hasValue && !valueRe.MatchString(p.value) {
return errFunc(fmt.Errorf("%w: %q", errInvalidValue, p.value))
}
if !p.hasValue && p.value != "" {
return errFunc(errors.New("inconsistent value"))
}
return nil
}
// Key returns the Property key.
func (p Property) Key() string {
return p.key
}
// Value returns the Property value. Additionally, a boolean value is returned
// indicating if the returned value is the empty if the Property has a value
// that is empty or if the value is not set.
func (p Property) Value() (string, bool) {
return p.value, p.hasValue
}
// String encodes Property into a string compliant with the W3C Baggage
// specification.
func (p Property) String() string {
if p.hasValue {
return fmt.Sprintf("%s%s%v", p.key, keyValueDelimiter, p.value)
}
return p.key
}
type properties []Property
func fromInternalProperties(iProps []baggage.Property) properties {
if len(iProps) == 0 {
return nil
}
props := make(properties, len(iProps))
for i, p := range iProps {
props[i] = Property{
key: p.Key,
value: p.Value,
hasValue: p.HasValue,
}
}
return props
}
func (p properties) asInternal() []baggage.Property {
if len(p) == 0 {
return nil
}
iProps := make([]baggage.Property, len(p))
for i, prop := range p {
iProps[i] = baggage.Property{
Key: prop.key,
Value: prop.value,
HasValue: prop.hasValue,
}
}
return iProps
}
func (p properties) Copy() properties {
if len(p) == 0 {
return nil
}
props := make(properties, len(p))
copy(props, p)
return props
}
// validate ensures each Property in p conforms to the W3C Baggage
// specification, returning an error otherwise.
func (p properties) validate() error {
for _, prop := range p {
if err := prop.validate(); err != nil {
return err
}
}
return nil
}
// String encodes properties into a string compliant with the W3C Baggage
// specification.
func (p properties) String() string {
props := make([]string, len(p))
for i, prop := range p {
props[i] = prop.String()
}
return strings.Join(props, propertyDelimiter)
}
// Member is a list-member of a baggage-string as defined by the W3C Baggage
// specification.
type Member struct {
key, value string
properties properties
// hasData indicates whether the created property contains data or not.
// Properties that do not contain data are invalid with no other check
// required.
hasData bool
}
// NewMember returns a new Member from the passed arguments. The key will be
// used directly while the value will be url decoded after validation. An error
// is returned if the created Member would be invalid according to the W3C
// Baggage specification.
func NewMember(key, value string, props ...Property) (Member, error) {
m := Member{
key: key,
value: value,
properties: properties(props).Copy(),
hasData: true,
}
if err := m.validate(); err != nil {
return newInvalidMember(), err
}
decodedValue, err := url.QueryUnescape(value)
if err != nil {
return newInvalidMember(), fmt.Errorf("%w: %q", errInvalidValue, value)
}
m.value = decodedValue
return m, nil
}
func newInvalidMember() Member {
return Member{}
}
// parseMember attempts to decode a Member from the passed string. It returns
// an error if the input is invalid according to the W3C Baggage
// specification.
func parseMember(member string) (Member, error) {
if n := len(member); n > maxBytesPerMembers {
return newInvalidMember(), fmt.Errorf("%w: %d", errMemberBytes, n)
}
var (
key, value string
props properties
)
parts := strings.SplitN(member, propertyDelimiter, 2)
switch len(parts) {
case 2:
// Parse the member properties.
for _, pStr := range strings.Split(parts[1], propertyDelimiter) {
p, err := parseProperty(pStr)
if err != nil {
return newInvalidMember(), err
}
props = append(props, p)
}
fallthrough
case 1:
// Parse the member key/value pair.
// Take into account a value can contain equal signs (=).
kv := strings.SplitN(parts[0], keyValueDelimiter, 2)
if len(kv) != 2 {
return newInvalidMember(), fmt.Errorf("%w: %q", errInvalidMember, member)
}
// "Leading and trailing whitespaces are allowed but MUST be trimmed
// when converting the header into a data structure."
key = strings.TrimSpace(kv[0])
var err error
value, err = url.QueryUnescape(strings.TrimSpace(kv[1]))
if err != nil {
return newInvalidMember(), fmt.Errorf("%w: %q", err, value)
}
if !keyRe.MatchString(key) {
return newInvalidMember(), fmt.Errorf("%w: %q", errInvalidKey, key)
}
if !valueRe.MatchString(value) {
return newInvalidMember(), fmt.Errorf("%w: %q", errInvalidValue, value)
}
default:
// This should never happen unless a developer has changed the string
// splitting somehow. Panic instead of failing silently and allowing
// the bug to slip past the CI checks.
panic("failed to parse baggage member")
}
return Member{key: key, value: value, properties: props, hasData: true}, nil
}
// validate ensures m conforms to the W3C Baggage specification.
// A key is just an ASCII string, but a value must be URL encoded UTF-8,
// returning an error otherwise.
func (m Member) validate() error {
if !m.hasData {
return fmt.Errorf("%w: %q", errInvalidMember, m)
}
if !keyRe.MatchString(m.key) {
return fmt.Errorf("%w: %q", errInvalidKey, m.key)
}
if !valueRe.MatchString(m.value) {
return fmt.Errorf("%w: %q", errInvalidValue, m.value)
}
return m.properties.validate()
}
// Key returns the Member key.
func (m Member) Key() string { return m.key }
// Value returns the Member value.
func (m Member) Value() string { return m.value }
// Properties returns a copy of the Member properties.
func (m Member) Properties() []Property { return m.properties.Copy() }
// String encodes Member into a string compliant with the W3C Baggage
// specification.
func (m Member) String() string {
// A key is just an ASCII string, but a value is URL encoded UTF-8.
s := fmt.Sprintf("%s%s%s", m.key, keyValueDelimiter, url.QueryEscape(m.value))
if len(m.properties) > 0 {
s = fmt.Sprintf("%s%s%s", s, propertyDelimiter, m.properties.String())
}
return s
}
// Baggage is a list of baggage members representing the baggage-string as
// defined by the W3C Baggage specification.
type Baggage struct { //nolint:golint
list baggage.List
}
// New returns a new valid Baggage. It returns an error if it results in a
// Baggage exceeding limits set in that specification.
//
// It expects all the provided members to have already been validated.
func New(members ...Member) (Baggage, error) {
if len(members) == 0 {
return Baggage{}, nil
}
b := make(baggage.List)
for _, m := range members {
if !m.hasData {
return Baggage{}, errInvalidMember
}
// OpenTelemetry resolves duplicates by last-one-wins.
b[m.key] = baggage.Item{
Value: m.value,
Properties: m.properties.asInternal(),
}
}
// Check member numbers after deduplication.
if len(b) > maxMembers {
return Baggage{}, errMemberNumber
}
bag := Baggage{b}
if n := len(bag.String()); n > maxBytesPerBaggageString {
return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
}
return bag, nil
}
// Parse attempts to decode a baggage-string from the passed string. It
// returns an error if the input is invalid according to the W3C Baggage
// specification.
//
// If there are duplicate list-members contained in baggage, the last one
// defined (reading left-to-right) will be the only one kept. This diverges
// from the W3C Baggage specification which allows duplicate list-members, but
// conforms to the OpenTelemetry Baggage specification.
func Parse(bStr string) (Baggage, error) {
if bStr == "" {
return Baggage{}, nil
}
if n := len(bStr); n > maxBytesPerBaggageString {
return Baggage{}, fmt.Errorf("%w: %d", errBaggageBytes, n)
}
b := make(baggage.List)
for _, memberStr := range strings.Split(bStr, listDelimiter) {
m, err := parseMember(memberStr)
if err != nil {
return Baggage{}, err
}
// OpenTelemetry resolves duplicates by last-one-wins.
b[m.key] = baggage.Item{
Value: m.value,
Properties: m.properties.asInternal(),
}
}
// OpenTelemetry does not allow for duplicate list-members, but the W3C
// specification does. Now that we have deduplicated, ensure the baggage
// does not exceed list-member limits.
if len(b) > maxMembers {
return Baggage{}, errMemberNumber
}
return Baggage{b}, nil
}
// Member returns the baggage list-member identified by key.
//
// If there is no list-member matching the passed key the returned Member will
// be a zero-value Member.
// The returned member is not validated, as we assume the validation happened
// when it was added to the Baggage.
func (b Baggage) Member(key string) Member {
v, ok := b.list[key]
if !ok {
// We do not need to worry about distinguishing between the situation
// where a zero-valued Member is included in the Baggage because a
// zero-valued Member is invalid according to the W3C Baggage
// specification (it has an empty key).
return newInvalidMember()
}
return Member{
key: key,
value: v.Value,
properties: fromInternalProperties(v.Properties),
hasData: true,
}
}
// Members returns all the baggage list-members.
// The order of the returned list-members does not have significance.
//
// The returned members are not validated, as we assume the validation happened
// when they were added to the Baggage.
func (b Baggage) Members() []Member {
if len(b.list) == 0 {
return nil
}
members := make([]Member, 0, len(b.list))
for k, v := range b.list {
members = append(members, Member{
key: k,
value: v.Value,
properties: fromInternalProperties(v.Properties),
hasData: true,
})
}
return members
}
// SetMember returns a copy the Baggage with the member included. If the
// baggage contains a Member with the same key the existing Member is
// replaced.
//
// If member is invalid according to the W3C Baggage specification, an error
// is returned with the original Baggage.
func (b Baggage) SetMember(member Member) (Baggage, error) {
if !member.hasData {
return b, errInvalidMember
}
n := len(b.list)
if _, ok := b.list[member.key]; !ok {
n++
}
list := make(baggage.List, n)
for k, v := range b.list {
// Do not copy if we are just going to overwrite.
if k == member.key {
continue
}
list[k] = v
}
list[member.key] = baggage.Item{
Value: member.value,
Properties: member.properties.asInternal(),
}
return Baggage{list: list}, nil
}
// DeleteMember returns a copy of the Baggage with the list-member identified
// by key removed.
func (b Baggage) DeleteMember(key string) Baggage {
n := len(b.list)
if _, ok := b.list[key]; ok {
n--
}
list := make(baggage.List, n)
for k, v := range b.list {
if k == key {
continue
}
list[k] = v
}
return Baggage{list: list}
}
// Len returns the number of list-members in the Baggage.
func (b Baggage) Len() int {
return len(b.list)
}
// String encodes Baggage into a string compliant with the W3C Baggage
// specification. The returned string will be invalid if the Baggage contains
// any invalid list-members.
func (b Baggage) String() string {
members := make([]string, 0, len(b.list))
for k, v := range b.list {
members = append(members, Member{
key: k,
value: v.Value,
properties: fromInternalProperties(v.Properties),
}.String())
}
return strings.Join(members, listDelimiter)
}