Documentation
¶
Overview ¶
Package othttp provides a http.Handler and functions that are intended to be used to add tracing by wrapping existing handlers (with Handler) and routes WithRouteTag.
Index ¶
Examples ¶
Constants ¶
const ( HostKey = core.Key("http.host") // the http host (http.Request.Host) MethodKey = core.Key("http.method") // the http method (http.Request.Method) PathKey = core.Key("http.path") // the http path (http.Request.URL.Path) URLKey = core.Key("http.url") // the http url (http.Request.URL.String()) UserAgentKey = core.Key("http.user_agent") // the http user agent (http.Request.UserAgent()) RouteKey = core.Key("http.route") // the http route (ex: /users/:id) StatusCodeKey = core.Key("http.status_code") // if set, the http status ReadBytesKey = core.Key("http.read_bytes") // if anything was read from the request body, the total number of bytes read ReadErrorKey = core.Key("http.read_error") // If an error occurred while reading a request, the string of the error (io.EOF is not recorded) WroteBytesKey = core.Key("http.wrote_bytes") // if anything was written to the response writer, the total number of bytes written WriteErrorKey = core.Key("http.write_error") // if an error occurred while writing a reply, the string of the error (io.EOF is not recorded) )
Attribute keys that the Handler can add to a span.
const ( ReadEvents event = iota WriteEvents )
Different types of events that can be recorded, see WithMessageEvents
Variables ¶
This section is empty.
Functions ¶
func NewHandler ¶
NewHandler wraps the passed handler, functioning like middleware, in a span named after the operation and with any provided HandlerOptions.
Example ¶
package main
import (
"context"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"strings"
"go.opentelemetry.io/otel/api/core"
"go.opentelemetry.io/otel/api/trace"
"go.opentelemetry.io/otel/exporter/trace/stdout"
"go.opentelemetry.io/otel/global"
"go.opentelemetry.io/otel/plugin/othttp"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
)
func main() {
/* curl -v -d "a painting" http://localhost:7777/hello/bob/ross
...
* upload completely sent off: 10 out of 10 bytes
< HTTP/1.1 200 OK
< Traceparent: 00-76ae040ee5753f38edf1c2bd9bd128bd-dd394138cfd7a3dc-01
< Date: Fri, 04 Oct 2019 02:33:08 GMT
< Content-Length: 45
< Content-Type: text/plain; charset=utf-8
<
Hello, bob/ross!
You sent me this:
a painting
*/
// Write spans to stdout
exporter, err := stdout.NewExporter(stdout.Options{PrettyPrint: true})
if err != nil {
log.Fatal(err)
}
tp, err := sdktrace.NewProvider(sdktrace.WithConfig(sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
sdktrace.WithSyncer(exporter))
if err != nil {
log.Fatal(err)
}
global.SetTraceProvider(tp)
figureOutName := func(ctx context.Context, s string) (string, error) {
pp := strings.SplitN(s, "/", 2)
var err error
switch pp[1] {
case "":
err = fmt.Errorf("expected /hello/:name in %q", s)
default:
trace.CurrentSpan(ctx).SetAttribute(core.Key("name").String(pp[1]))
}
return pp[1], err
}
var mux http.ServeMux
mux.Handle("/hello/",
othttp.WithRouteTag("/hello/:name", http.HandlerFunc(
func(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
var name string
// Wrap another function in it's own span
if err := trace.CurrentSpan(ctx).Tracer().WithSpan(ctx, "figureOutName",
func(ctx context.Context) error {
var err error
name, err = figureOutName(ctx, r.URL.Path[1:])
return err
}); err != nil {
log.Println("error figuring out name: ", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
d, err := ioutil.ReadAll(r.Body)
if err != nil {
log.Println("error reading body: ", err)
w.WriteHeader(http.StatusBadRequest)
return
}
n, err := io.WriteString(w, "Hello, "+name+"!\nYou sent me this:\n"+string(d))
if err != nil {
log.Printf("error writing reply after %d bytes: %s", n, err)
}
}),
),
)
if err := http.ListenAndServe(":7777",
othttp.NewHandler(&mux, "server",
othttp.WithMessageEvents(othttp.ReadEvents, othttp.WriteEvents),
),
); err != nil {
log.Fatal(err)
}
}
Output:
Types ¶
type Handler ¶
type Handler struct {
// contains filtered or unexported fields
}
Handler is http middleware that corresponds to the http.Handler interface and is designed to wrap a http.Mux (or equivalent), while individual routes on the mux are wrapped with WithRouteTag. A Handler will add various attributes to the span using the core.Keys defined in this package.
type Option ¶
type Option func(*Handler)
Option function used for setting *optional* Handler properties
func WithMessageEvents ¶
func WithMessageEvents(events ...event) Option
WithMessageEvents configures the Handler to record the specified events (span.AddEvent) on spans. By default only summary attributes are added at the end of the request.
Valid events are:
- ReadEvents: Record the number of bytes read after every http.Request.Body.Read using the ReadBytesKey
- WriteEvents: Record the number of bytes written after every http.ResponeWriter.Write using the WriteBytesKey
func WithPropagator ¶
func WithPropagator(p propagation.TextFormatPropagator) Option
WithPropagator configures the Handler with a specific propagator. If this option isn't specificed then go.opentelemetry.io/otel/propagation.HTTPTraceContextPropagator is used.
func WithPublicEndpoint ¶
func WithPublicEndpoint() Option
WithPublicEndpoint configures the Handler to link the span with an incoming span context. If this option is not provided, then the association is a child association instead of a link.
func WithSpanOptions ¶
func WithSpanOptions(opts ...trace.SpanOption) Option
WithSpanOptions configures the Handler with an additional set of trace.SpanOptions, which are applied to each new span.
func WithTracer ¶
WithTracer configures the Handler with a specific tracer. If this option isn't specified then the global tracer is used.
Source Files