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04de34a2d6
* Update the website getting started docs Add a new example, fib, that contains an application for the computation of Fibonacci numbers. Use this example to update the website getting started documentation. * Revise docs english * Update example/fib/go.mod Co-authored-by: Anthony Mirabella <a9@aneurysm9.com> * Add a What's Next section * Clean up intro * Apply suggestions from code review Co-authored-by: Anthony Mirabella <a9@aneurysm9.com> * Apply feedback * Return from Poll on error * Update website_docs/getting-started.md Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com> * Add root and parent relationship info Co-authored-by: Anthony Mirabella <a9@aneurysm9.com> Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
105 lines
2.5 KiB
Go
105 lines
2.5 KiB
Go
// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"context"
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"fmt"
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"io"
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"log"
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"strconv"
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"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/attribute"
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"go.opentelemetry.io/otel/codes"
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"go.opentelemetry.io/otel/trace"
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)
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// name is the Tracer name used to identify this instrumentation library.
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const name = "fib"
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// App is an Fibonacci computation application.
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type App struct {
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r io.Reader
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l *log.Logger
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}
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// NewApp returns a new App.
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func NewApp(r io.Reader, l *log.Logger) *App {
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return &App{r: r, l: l}
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}
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// Run starts polling users for Fibonacci number requests and writes results.
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func (a *App) Run(ctx context.Context) error {
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for {
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var span trace.Span
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ctx, span = otel.Tracer(name).Start(ctx, "Run")
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n, err := a.Poll(ctx)
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if err != nil {
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span.End()
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return err
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}
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a.Write(ctx, n)
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span.End()
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}
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}
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// Poll asks a user for input and returns the request.
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func (a *App) Poll(ctx context.Context) (uint, error) {
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_, span := otel.Tracer(name).Start(ctx, "Poll")
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defer span.End()
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a.l.Print("What Fibonacci number would you like to know: ")
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var n uint
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_, err := fmt.Fscanf(a.r, "%d", &n)
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if err != nil {
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span.RecordError(err)
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span.SetStatus(codes.Error, err.Error())
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return 0, err
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}
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// Store n as a string to not overflow an int64.
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nStr := strconv.FormatUint(uint64(n), 10)
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span.SetAttributes(attribute.String("request.n", nStr))
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return n, nil
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}
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// Write writes the n-th Fibonacci number back to the user.
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func (a *App) Write(ctx context.Context, n uint) {
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var span trace.Span
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ctx, span = otel.Tracer(name).Start(ctx, "Write")
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defer span.End()
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f, err := func(ctx context.Context) (uint64, error) {
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_, span := otel.Tracer(name).Start(ctx, "Fibonacci")
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defer span.End()
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f, err := Fibonacci(n)
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if err != nil {
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span.RecordError(err)
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span.SetStatus(codes.Error, err.Error())
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}
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return f, err
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}(ctx)
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if err != nil {
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a.l.Printf("Fibonacci(%d): %v\n", n, err)
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} else {
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a.l.Printf("Fibonacci(%d) = %d\n", n, f)
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}
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}
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