1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250package httplog
import (
"log/slog"
"strings"
"time"
)
const (
ECSResponseDuration = "event.duration"
OTELResponseDuration = "http.server.request.duration"
GCPResponseDuration = "httpRequest:latency"
)
// Schema defines the mapping of semantic log fields to their corresponding
// field names in different logging systems and standards.
//
// This enables log output in different formats compatible with various logging
// platforms and standards (ECS, OTEL, GCP, etc.) by providing the schema.
type Schema struct {
// Base attributes for core logging information.
Timestamp string // Timestamp of the log entry
Level string // Log level (e.g. INFO, WARNING, ERROR)
Message string // Primary log message
ErrorMessage string // Error message when an error occurs
ErrorType string // Low-cardinality error type (e.g. "ClientAborted", "ValidationError")
ErrorStackTrace string // Stack trace for panic or error
// Source code location attributes for tracking origin of log statements.
SourceFile string // Source file name where the log originated
SourceLine string // Line number in the source file
SourceFunction string // Function name where the log originated
// Request attributes for the incoming HTTP request.
// NOTE: RequestQuery is intentionally not supported as it would likely leak sensitive data.
RequestURL string // Full request URL
RequestMethod string // HTTP method (e.g. GET, POST)
RequestPath string // URL path component
RequestRemoteIP string // Client IP address
RequestHost string // Host header value
RequestScheme string // URL scheme (http, https)
RequestProto string // HTTP protocol version (e.g. HTTP/1.1, HTTP/2)
RequestHeaders string // Selected request headers
RequestBody string // Request body content, if logged.
RequestBytes string // Size of request body in bytes
RequestBytesUnread string // Unread bytes in request body
RequestUserAgent string // User-Agent header value
RequestReferer string // Referer header value
// Response attributes for the HTTP response.
ResponseHeaders string // Selected response headers
ResponseBody string // Response body content, if logged.
ResponseStatus string // HTTP status code
ResponseDuration string // Request processing duration
ResponseBytes string // Size of response body in bytes
// GroupDelimiter is an optional delimiter for nested objects in some formats.
// For example, GCP uses nested JSON objects like "httpRequest": {}.
GroupDelimiter string
}
var (
// SchemaECS represents the Elastic Common Schema (ECS) version 9.0.0.
// This schema is widely used with Elasticsearch and the Elastic Stack.
//
// Reference: https://www.elastic.co/guide/en/ecs/current/ecs-http.html
SchemaECS = &Schema{
Timestamp: "@timestamp",
Level: "log.level",
Message: "message",
ErrorMessage: "error.message",
ErrorType: "error.type",
ErrorStackTrace: "error.stack_trace",
SourceFile: "log.origin.file.name",
SourceLine: "log.origin.file.line",
SourceFunction: "log.origin.function",
RequestURL: "url.full",
RequestMethod: "http.request.method",
RequestPath: "url.path",
RequestRemoteIP: "client.ip",
RequestHost: "url.domain",
RequestScheme: "url.scheme",
RequestProto: "http.version",
RequestHeaders: "http.request.headers",
RequestBody: "http.request.body.content",
RequestBytes: "http.request.body.bytes",
RequestBytesUnread: "http.request.body.unread.bytes",
RequestUserAgent: "user_agent.original",
RequestReferer: "http.request.referrer",
ResponseHeaders: "http.response.headers",
ResponseBody: "http.response.body.content",
ResponseStatus: "http.response.status_code",
ResponseDuration: ECSResponseDuration,
ResponseBytes: "http.response.body.bytes",
}
// SchemaOTEL represents OpenTelemetry (OTEL) semantic conventions version 1.34.0.
// This schema follows OpenTelemetry standards for observability data.
//
// Reference: https://opentelemetry.io/docs/specs/semconv/http/http-metrics
SchemaOTEL = &Schema{
Timestamp: "timestamp",
Level: "severity_text",
Message: "body",
ErrorMessage: "error.message",
ErrorType: "error.type",
ErrorStackTrace: "exception.stacktrace",
SourceFile: "code.filepath",
SourceLine: "code.lineno",
SourceFunction: "code.function",
RequestURL: "url.full",
RequestMethod: "http.request.method",
RequestPath: "url.path",
RequestRemoteIP: "client.address",
RequestHost: "server.address",
RequestScheme: "url.scheme",
RequestProto: "network.protocol.version",
RequestHeaders: "http.request.header",
RequestBody: "http.request.body.content",
RequestBytes: "http.request.body.size",
RequestBytesUnread: "http.request.body.unread.size",
RequestUserAgent: "user_agent.original",
RequestReferer: "http.request.header.referer",
ResponseHeaders: "http.response.header",
ResponseBody: "http.response.body.content",
ResponseStatus: "http.response.status_code",
ResponseDuration: OTELResponseDuration,
ResponseBytes: "http.response.body.size",
}
// SchemaGCP represents Google Cloud Platform's structured logging format.
// This schema is optimized for Google Cloud Logging service.
//
// References:
// - https://cloud.google.com/logging/docs/structured-logging
// - https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry#HttpRequest
SchemaGCP = &Schema{
Timestamp: "timestamp",
Level: "severity",
Message: "message",
ErrorMessage: "error",
ErrorType: "error_type",
ErrorStackTrace: "stack_trace",
SourceFile: "logging.googleapis.com/sourceLocation:file",
SourceLine: "logging.googleapis.com/sourceLocation:line",
SourceFunction: "logging.googleapis.com/sourceLocation:function",
RequestURL: "httpRequest:requestUrl",
RequestMethod: "httpRequest:requestMethod",
RequestPath: "httpRequest:requestPath",
RequestRemoteIP: "httpRequest:remoteIp",
RequestHost: "httpRequest:host",
RequestScheme: "httpRequest:scheme",
RequestProto: "httpRequest:protocol",
RequestHeaders: "httpRequest:requestHeaders",
RequestBody: "httpRequest:requestBody",
RequestBytes: "httpRequest:requestSize",
RequestBytesUnread: "httpRequest:requestUnreadSize",
RequestUserAgent: "httpRequest:userAgent",
RequestReferer: "httpRequest:referer",
ResponseHeaders: "httpRequest:responseHeaders",
ResponseBody: "httpRequest:responseBody",
ResponseStatus: "httpRequest:status",
ResponseDuration: GCPResponseDuration,
ResponseBytes: "httpRequest:responseSize",
GroupDelimiter: ":",
}
)
// ReplaceAttr returns transforms standard slog attribute names to the schema format.
func (s *Schema) ReplaceAttr(groups []string, a slog.Attr) slog.Attr {
if len(groups) > 0 {
return a
}
switch a.Key {
case slog.TimeKey:
if s.Timestamp == "" {
return a
}
return slog.String(s.Timestamp, a.Value.Time().Format(time.RFC3339))
case slog.LevelKey:
if s.Level == "" {
return a
}
return slog.String(s.Level, a.Value.String())
case slog.MessageKey:
if s.Message == "" {
return a
}
return slog.String(s.Message, a.Value.String())
case slog.SourceKey:
source, ok := a.Value.Any().(*slog.Source)
if !ok {
return a
}
if s.SourceFile == "" {
// Ignore httplog.RequestLogger middleware source.
if strings.Contains(source.File, "/go-chi/httplog/") {
return slog.Attr{}
}
return a
}
if s.GroupDelimiter == "" {
return slog.Group("", slog.String(s.SourceFile, source.File), slog.Int(s.SourceLine, source.Line), slog.String(s.SourceFunction, source.Function))
}
grp, file, _ := strings.Cut(s.SourceFile, s.GroupDelimiter)
_, line, _ := strings.Cut(s.SourceLine, s.GroupDelimiter)
_, fn, _ := strings.Cut(s.SourceFunction, s.GroupDelimiter)
return slog.Group(grp, slog.String(file, source.File), slog.Int(line, source.Line), slog.String(fn, source.Function))
case ErrorKey:
if s.GroupDelimiter == "" {
return slog.Attr{Key: s.ErrorMessage, Value: a.Value}
}
grp, errMsg, found := strings.Cut(s.ErrorMessage, s.GroupDelimiter)
if !found {
return slog.Attr{Key: s.ErrorMessage, Value: a.Value}
}
return slog.Group(grp, slog.Attr{Key: errMsg, Value: a.Value})
}
return a
}
// Concise returns a simplified schema with essential fields only.
// If concise is true, it reduces log verbosity.
//
// This is useful for localhost development to reduce log verbosity.
func (s *Schema) Concise(concise bool) *Schema {
if !concise {
return s
}
return &Schema{
ErrorMessage: s.ErrorMessage,
ErrorStackTrace: s.ErrorStackTrace,
RequestHeaders: s.RequestHeaders,
RequestBody: s.RequestBody,
RequestBytesUnread: s.RequestBytesUnread,
ResponseHeaders: s.ResponseHeaders,
ResponseBody: s.ResponseBody,
GroupDelimiter: s.GroupDelimiter,
}
}