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opentelemetry-go/example/dice/rolldice.go
Robert Pająk 0425c09c31
Add dice example (#4539)
* Add dice example

* Add manual instrumentation

* Update changelog

* Add comments

* Use naked return consistently

* Move handleFunc to main

* refactor: Extract newHTTPHandler

* Fix comment

* Improve comments

* Update example/dice/otel.go

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

* Simplify BaseContext

* Update doc.go

* Update example/dice/main.go

Co-authored-by: Phillip Carter <pcarter@fastmail.com>

* Rename span and metric names

---------

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Phillip Carter <pcarter@fastmail.com>
2023-09-26 07:10:58 -07:00

60 lines
1.5 KiB
Go

// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"io"
"log"
"math/rand"
"net/http"
"strconv"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/metric"
)
var (
tracer = otel.Tracer("rolldice")
meter = otel.Meter("rolldice")
rollCnt metric.Int64Counter
)
func init() {
var err error
rollCnt, err = meter.Int64Counter("dice.rolls",
metric.WithDescription("The number of rolls by roll value"),
metric.WithUnit("{roll}"))
if err != nil {
panic(err)
}
}
func rolldice(w http.ResponseWriter, r *http.Request) {
ctx, span := tracer.Start(r.Context(), "roll")
defer span.End()
roll := 1 + rand.Intn(6)
rollValueAttr := attribute.Int("roll.value", roll)
span.SetAttributes(rollValueAttr)
rollCnt.Add(ctx, 1, metric.WithAttributes(rollValueAttr))
resp := strconv.Itoa(roll) + "\n"
if _, err := io.WriteString(w, resp); err != nil {
log.Printf("Write failed: %v\n", err)
}
}