frostfs-s3-gw/api/middleware/tracing.go

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package middleware
import (
"context"
"net/http"
"sync"
"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
"go.opentelemetry.io/otel/attribute"
semconv "go.opentelemetry.io/otel/semconv/v1.18.0"
"go.opentelemetry.io/otel/trace"
)
// Tracing adds tracing support for requests.
// Must be placed after prepareRequest middleware.
func Tracing() Func {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
appCtx, span := StartHTTPServerSpan(r, "REQUEST S3")
reqInfo := GetReqInfo(r.Context())
reqInfo.TraceID = span.SpanContext().TraceID().String()
lw := &traceResponseWriter{ResponseWriter: w, ctx: appCtx, span: span}
h.ServeHTTP(lw, r.WithContext(appCtx))
})
}
}
type traceResponseWriter struct {
sync.Once
http.ResponseWriter
ctx context.Context
span trace.Span
}
func (lrw *traceResponseWriter) WriteHeader(code int) {
lrw.Do(func() {
lrw.span.SetAttributes(
semconv.HTTPStatusCode(code),
)
carrier := &httpResponseCarrier{resp: lrw.ResponseWriter}
tracing.Propagator.Inject(lrw.ctx, carrier)
lrw.ResponseWriter.WriteHeader(code)
lrw.span.End()
})
}
func (lrw *traceResponseWriter) Flush() {
if f, ok := lrw.ResponseWriter.(http.Flusher); ok {
f.Flush()
}
}
type httpResponseCarrier struct {
resp http.ResponseWriter
}
func (h httpResponseCarrier) Get(key string) string {
return h.resp.Header().Get(key)
}
func (h httpResponseCarrier) Set(key string, value string) {
h.resp.Header().Set(key, value)
}
func (h httpResponseCarrier) Keys() []string {
result := make([]string, 0, len(h.resp.Header()))
for key := range h.resp.Header() {
result = append(result, key)
}
return result
}
type httpRequestCarrier struct {
req *http.Request
}
func (c *httpRequestCarrier) Get(key string) string {
bytes := c.req.Header.Get(key)
if len(bytes) == 0 {
return ""
}
return bytes
}
func (c *httpRequestCarrier) Set(key string, value string) {
c.req.Response.Header.Set(key, value)
}
func (c *httpRequestCarrier) Keys() []string {
result := make([]string, 0, len(c.req.Header))
for key := range c.req.Header {
result = append(result, key)
}
return result
}
func extractHTTPTraceInfo(ctx context.Context, req *http.Request) context.Context {
if req == nil {
return ctx
}
carrier := &httpRequestCarrier{req: req}
return tracing.Propagator.Extract(ctx, carrier)
}
// StartHTTPServerSpan starts root HTTP server span.
func StartHTTPServerSpan(r *http.Request, operationName string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
ctx := extractHTTPTraceInfo(r.Context(), r)
opts = append(opts, trace.WithAttributes(
attribute.String("s3.client_address", r.RemoteAddr),
attribute.String("s3.path", r.Host),
attribute.String("s3.request_id", GetRequestID(r.Context())),
semconv.HTTPMethod(r.Method),
semconv.RPCService("frostfs-s3-gw"),
attribute.String("s3.query", r.RequestURI),
), trace.WithSpanKind(trace.SpanKindServer))
return tracing.StartSpanFromContext(ctx, operationName, opts...)
}