/
gin.go
137 lines (113 loc) · 2.97 KB
/
gin.go
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package gin
import (
"github.com/gin-gonic/gin"
"github.com/google/uuid"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/metric"
"go.opentelemetry.io/otel/trace"
"log/slog"
"time"
)
const (
RequestIdHeader = "request-id"
)
var (
engine *gin.Engine
requestsInstrument metric.Int64Counter
errorsInstrument metric.Int64Counter
latencyInstrument metric.Int64Histogram
responseSizeInstrument metric.Int64Histogram
)
func GetRouter(relativePath string) gin.IRouter {
return engine.Group(relativePath)
}
func Start() error {
return engine.Run()
}
type writeFunc func([]byte) (int, error)
func (fn writeFunc) Write(data []byte) (int, error) {
return fn(data)
}
func ConfigureGin() error {
gin.DefaultWriter = writeFunc(func(data []byte) (int, error) {
slog.Debug(string(data))
return 0, nil
})
engine = gin.Default()
engine.Use(gin.Recovery())
return nil
}
func ConfigureTelemetry() error {
// TODO: Fix path
meter := otel.GetMeterProvider().Meter("github.com/Untanky/modern-auth/http")
var err error
requestsInstrument, err = meter.Int64Counter("requestsInstrument")
if err != nil {
return err
}
errorsInstrument, err = meter.Int64Counter("errorsInstrument")
if err != nil {
return err
}
latencyInstrument, err = meter.Int64Histogram("latencyInstrument", metric.WithUnit("µs"))
if err != nil {
return err
}
responseSizeInstrument, err = meter.Int64Histogram("response_size", metric.WithUnit("byte"))
if err != nil {
return err
}
engine.Use(handleRequestId, handleRequestTelemetry, handleError)
return nil
}
func handleRequestId(c *gin.Context) {
requestId := c.GetHeader(RequestIdHeader)
if requestId == "" {
requestId = uuid.New().String()
}
c.Set("requestId", requestId)
c.Header(RequestIdHeader, requestId)
c.Next()
}
func handleRequestTelemetry(c *gin.Context) {
start := time.Now()
path := c.Request.URL.Path
c.Next()
status := c.Writer.Status()
size := c.Writer.Size()
isError := status >= 500
latency := time.Since(start)
// METRICS
// increase counters for observable metrics
requestsInstrument.Add(c.Request.Context(), 1)
if isError {
errorsInstrument.Add(c.Request.Context(), 1)
}
latencyInstrument.Record(c.Request.Context(), latency.Microseconds())
responseSizeInstrument.Record(c.Request.Context(), int64(size))
// LOGGING
// create meta data fields for logging
msg := ""
fields := []any{
slog.String("method", c.Request.Method),
slog.String("path", path),
slog.String("ip", c.ClientIP()),
slog.Int("status", status),
slog.String("user-agent", c.Request.UserAgent()),
slog.Duration("latencyInstrument", latency),
slog.Int("body-size", size),
slog.String("request-id", c.GetString("requestId")),
}
if isError {
slog.Error(msg, fields...)
} else {
slog.Debug(msg, fields...)
}
}
func handleError(ctx *gin.Context) {
ctx.Next()
for _, err := range ctx.Errors {
trace.SpanFromContext(ctx).RecordError(err)
slog.ErrorContext(ctx, "Encountered error", "err", err)
}
}