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sqlcomment.go
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sqlcomment.go
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// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2016 Datadog, Inc.
package tracer
import (
"strconv"
"strings"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
"gopkg.in/DataDog/dd-trace-go.v1/internal/globalconfig"
"gopkg.in/DataDog/dd-trace-go.v1/internal/log"
"gopkg.in/DataDog/dd-trace-go.v1/internal/samplernames"
)
// SQLCommentInjectionMode represents the mode of SQL comment injection.
//
// Deprecated: Use DBMPropagationMode instead.
type SQLCommentInjectionMode DBMPropagationMode
const (
// SQLInjectionUndefined represents the comment injection mode is not set. This is the same as SQLInjectionDisabled.
SQLInjectionUndefined SQLCommentInjectionMode = SQLCommentInjectionMode(DBMPropagationModeUndefined)
// SQLInjectionDisabled represents the comment injection mode where all injection is disabled.
SQLInjectionDisabled SQLCommentInjectionMode = SQLCommentInjectionMode(DBMPropagationModeDisabled)
// SQLInjectionModeService represents the comment injection mode where only service tags (name, env, version) are injected.
SQLInjectionModeService SQLCommentInjectionMode = SQLCommentInjectionMode(DBMPropagationModeService)
// SQLInjectionModeFull represents the comment injection mode where both service tags and tracing tags. Tracing tags include span id, trace id and sampling priority.
SQLInjectionModeFull SQLCommentInjectionMode = SQLCommentInjectionMode(DBMPropagationModeFull)
)
// DBMPropagationMode represents the mode of dbm propagation.
//
// Note that enabling sql comment propagation results in potentially confidential data (service names)
// being stored in the databases which can then be accessed by other 3rd parties that have been granted
// access to the database.
type DBMPropagationMode string
const (
// DBMPropagationModeUndefined represents the dbm propagation mode not being set. This is the same as DBMPropagationModeDisabled.
DBMPropagationModeUndefined DBMPropagationMode = ""
// DBMPropagationModeDisabled represents the dbm propagation mode where all propagation is disabled.
DBMPropagationModeDisabled DBMPropagationMode = "disabled"
// DBMPropagationModeService represents the dbm propagation mode where only service tags (name, env, version) are propagated to dbm.
DBMPropagationModeService DBMPropagationMode = "service"
// DBMPropagationModeFull represents the dbm propagation mode where both service tags and tracing tags are propagated. Tracing tags include span id, trace id and the sampled flag.
DBMPropagationModeFull DBMPropagationMode = "full"
)
// Key names for SQL comment tags.
const (
sqlCommentTraceParent = "traceparent"
sqlCommentParentService = "ddps"
sqlCommentDBService = "dddbs"
sqlCommentParentVersion = "ddpv"
sqlCommentEnv = "dde"
)
// Current trace context version (see https://www.w3.org/TR/trace-context/#version)
const w3cContextVersion = "00"
// SQLCommentCarrier is a carrier implementation that injects a span context in a SQL query in the form
// of a sqlcommenter formatted comment prepended to the original query text.
// See https://google.github.io/sqlcommenter/spec/ for more details.
type SQLCommentCarrier struct {
Query string
Mode DBMPropagationMode
DBServiceName string
SpanID uint64
}
// Inject injects a span context in the carrier's Query field as a comment.
func (c *SQLCommentCarrier) Inject(spanCtx ddtrace.SpanContext) error {
c.SpanID = generateSpanID(now())
tags := make(map[string]string)
switch c.Mode {
case DBMPropagationModeUndefined:
fallthrough
case DBMPropagationModeDisabled:
return nil
case DBMPropagationModeFull:
var (
sampled int64
traceID uint64
)
if ctx, ok := spanCtx.(*spanContext); ok {
if sp, ok := ctx.samplingPriority(); ok && sp > 0 {
sampled = 1
}
traceID = ctx.TraceID()
}
if traceID == 0 { // check if this is a root span
traceID = c.SpanID
}
tags[sqlCommentTraceParent] = encodeTraceParent(traceID, c.SpanID, sampled)
fallthrough
case DBMPropagationModeService:
if ctx, ok := spanCtx.(*spanContext); ok {
if e, ok := ctx.meta(ext.Environment); ok && e != "" {
tags[sqlCommentEnv] = e
}
if v, ok := ctx.meta(ext.Version); ok && v != "" {
tags[sqlCommentParentVersion] = v
}
}
if globalconfig.ServiceName() != "" {
tags[sqlCommentParentService] = globalconfig.ServiceName()
}
tags[sqlCommentDBService] = c.DBServiceName
}
c.Query = commentQuery(c.Query, tags)
return nil
}
// encodeTraceParent encodes trace parent as per the w3c trace context spec (https://www.w3.org/TR/trace-context/#version).
func encodeTraceParent(traceID uint64, spanID uint64, sampled int64) string {
var b strings.Builder
// traceparent has a fixed length of 55:
// 2 bytes for the version, 32 for the trace id, 16 for the span id, 2 for the sampled flag and 3 for separators
b.Grow(55)
b.WriteString(w3cContextVersion)
b.WriteRune('-')
tid := strconv.FormatUint(traceID, 16)
for i := 0; i < 32-len(tid); i++ {
b.WriteRune('0')
}
b.WriteString(tid)
b.WriteRune('-')
sid := strconv.FormatUint(spanID, 16)
for i := 0; i < 16-len(sid); i++ {
b.WriteRune('0')
}
b.WriteString(sid)
b.WriteRune('-')
b.WriteRune('0')
b.WriteString(strconv.FormatInt(sampled, 16))
return b.String()
}
var (
keyReplacer = strings.NewReplacer(" ", "%20", "!", "%21", "#", "%23", "$", "%24", "%", "%25", "&", "%26", "'", "%27", "(", "%28", ")", "%29", "*", "%2A", "+", "%2B", ",", "%2C", "/", "%2F", ":", "%3A", ";", "%3B", "=", "%3D", "?", "%3F", "@", "%40", "[", "%5B", "]", "%5D")
valueReplacer = strings.NewReplacer(" ", "%20", "!", "%21", "#", "%23", "$", "%24", "%", "%25", "&", "%26", "'", "%27", "(", "%28", ")", "%29", "*", "%2A", "+", "%2B", ",", "%2C", "/", "%2F", ":", "%3A", ";", "%3B", "=", "%3D", "?", "%3F", "@", "%40", "[", "%5B", "]", "%5D", "'", "\\'")
)
// commentQuery returns the given query with the tags from the SQLCommentCarrier applied to it as a
// prepended SQL comment. The format of the comment follows the sqlcommenter spec.
// See https://google.github.io/sqlcommenter/spec/ for more details.
func commentQuery(query string, tags map[string]string) string {
if len(tags) == 0 {
return ""
}
var b strings.Builder
// the sqlcommenter specification dictates that tags should be sorted. Since we know all injected keys,
// we skip a sorting operation by specifying the order of keys statically
orderedKeys := []string{sqlCommentDBService, sqlCommentEnv, sqlCommentParentService, sqlCommentParentVersion, sqlCommentTraceParent}
first := true
for _, k := range orderedKeys {
if v, ok := tags[k]; ok {
// we need to URL-encode both keys and values and escape single quotes in values
// https://google.github.io/sqlcommenter/spec/
key := keyReplacer.Replace(k)
val := valueReplacer.Replace(v)
if first {
b.WriteString("/*")
} else {
b.WriteRune(',')
}
b.WriteString(key)
b.WriteRune('=')
b.WriteRune('\'')
b.WriteString(val)
b.WriteRune('\'')
first = false
}
}
if b.Len() == 0 {
return query
}
b.WriteString("*/")
if query == "" {
return b.String()
}
log.Debug("Injected sql comment: %s", b.String())
b.WriteRune(' ')
b.WriteString(query)
return b.String()
}
// Extract parses for key value attributes in a sql query injected with trace information in order to build a span context
func (c *SQLCommentCarrier) Extract() (ddtrace.SpanContext, error) {
var ctx *spanContext
// There may be multiple comments within the sql query, so we must identify which one contains trace information.
// We look at each comment until we find one that contains a traceparent
if traceComment, found := findTraceComment(c.Query); found {
var err error
if ctx, err = spanContextFromTraceComment(traceComment); err != nil {
return nil, err
}
} else {
return nil, ErrSpanContextNotFound
}
if ctx.traceID.Empty() || ctx.spanID == 0 {
return nil, ErrSpanContextNotFound
}
return ctx, nil
}
// spanContextFromTraceComment looks for specific kv pairs in a comment containing trace information.
// It returns a span context with the appropriate attributes
func spanContextFromTraceComment(c string) (*spanContext, error) {
var ctx spanContext
kvs := strings.Split(c, ",")
for _, unparsedKV := range kvs {
splitKV := strings.Split(unparsedKV, "=")
if len(splitKV) != 2 {
return nil, ErrSpanContextCorrupted
}
key := splitKV[0]
value := strings.Trim(splitKV[1], "'")
switch key {
case sqlCommentTraceParent:
traceIDLower, traceIDUpper, spanID, sampled, err := decodeTraceParent(value)
if err != nil {
return nil, err
}
ctx.traceID.SetLower(traceIDLower)
ctx.traceID.SetUpper(traceIDUpper)
ctx.spanID = spanID
ctx.setSamplingPriority(sampled, samplernames.Unknown)
default:
}
}
return &ctx, nil
}
// decodeTraceParent decodes trace parent as per the w3c trace context spec (https://www.w3.org/TR/trace-context/#version).
// this also supports decoding traceparents from open telemetry sql comments which are 128 bit
func decodeTraceParent(traceParent string) (traceIDLower uint64, traceIDUpper uint64, spanID uint64, sampled int, err error) {
if len(traceParent) < 55 {
return 0, 0, 0, 0, ErrSpanContextCorrupted
}
version := traceParent[0:2]
switch version {
case w3cContextVersion:
if traceIDUpper, err = strconv.ParseUint(traceParent[3:19], 16, 64); err != nil {
return 0, 0, 0, 0, ErrSpanContextCorrupted
}
if traceIDLower, err = strconv.ParseUint(traceParent[19:35], 16, 64); err != nil {
return 0, 0, 0, 0, ErrSpanContextCorrupted
}
if spanID, err = strconv.ParseUint(traceParent[36:52], 16, 64); err != nil {
return 0, 0, 0, 0, ErrSpanContextCorrupted
}
if sampled, err = strconv.Atoi(traceParent[53:55]); err != nil {
return 0, 0, 0, 0, ErrSpanContextCorrupted
}
default:
}
return traceIDLower, traceIDUpper, spanID, sampled, err
}
// findTraceComment looks for a sql comment that contains trace information by looking for the keyword traceparent
func findTraceComment(query string) (traceComment string, found bool) {
startIndex := -1
containsTrace := false
keyLength := len(sqlCommentTraceParent)
qLength := len(query)
for i := 0; i < qLength-1; {
if query[i] == '/' && query[i+1] == '*' {
// look for leading /*
startIndex = i
i += 2
containsTrace = false
} else if query[i] == '*' && query[i+1] == '/' {
// look for closing */
if startIndex == -1 {
// malformed comment, it did not have a leading /*
return "", false
}
if !containsTrace {
// ignore this comment, it was not a trace comment
startIndex = -1
i += 2
} else {
// do not return the query with the leading /* or trailing */
return query[startIndex+2 : i], true
}
} else if !containsTrace && i+keyLength < qLength && query[i:i+keyLength] == sqlCommentTraceParent {
// look for occurrence of keyword in the query if not yet found and make sure we don't go out of range
containsTrace = true
i += keyLength
} else {
i++
}
}
return "", false
}