otlploghttp: Generate internal/retry (#5165)

exporters/otlp/otlplog/otlploghttp/config.go

@@ -8,6 +8,8 @@ import (
 	"net/http"
 	"net/url"
 	"time"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp/internal/retry"
 )
 
 // Option applies an option to the Exporter.
@@ -165,9 +167,7 @@ func WithTimeout(duration time.Duration) Option {
 
 // RetryConfig defines configuration for retrying the export of log data that
 // failed.
-type RetryConfig struct {
-	// TODO: implement.
-}
+type RetryConfig retry.Config
 
 // WithRetry sets the retry policy for transient retryable errors that are
 // returned by the target endpoint.

exporters/otlp/otlplog/otlploghttp/go.mod

@@ -3,6 +3,7 @@ module go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp
 go 1.21
 
 require (
+	github.com/cenkalti/backoff/v4 v4.3.0
 	github.com/stretchr/testify v1.9.0
 	go.opentelemetry.io/otel/sdk/log v0.0.0-20240403115316-6c6e1e7416e9
 )

exporters/otlp/otlplog/otlploghttp/go.sum

@@ -1,3 +1,5 @@
+github.com/cenkalti/backoff/v4 v4.3.0 h1:MyRJ/UdXutAwSAT+s3wNd7MfTIcy71VQueUuFK343L8=
+github.com/cenkalti/backoff/v4 v4.3.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=

exporters/otlp/otlplog/otlploghttp/internal/gen.go

@@ -0,0 +1,7 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package internal // import "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp/internal"
+
+//go:generate gotmpl --body=../../../../../internal/shared/otlp/retry/retry.go.tmpl "--data={}" --out=retry/retry.go
+//go:generate gotmpl --body=../../../../../internal/shared/otlp/retry/retry_test.go.tmpl "--data={}" --out=retry/retry_test.go

exporters/otlp/otlplog/otlploghttp/internal/retry/retry.go

@@ -0,0 +1,145 @@
+// Code created by gotmpl. DO NOT MODIFY.
+// source: internal/shared/otlp/retry/retry.go.tmpl
+
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package retry provides request retry functionality that can perform
+// configurable exponential backoff for transient errors and honor any
+// explicit throttle responses received.
+package retry // import "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp/internal/retry"
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+)
+
+// DefaultConfig are the recommended defaults to use.
+var DefaultConfig = Config{
+	Enabled:         true,
+	InitialInterval: 5 * time.Second,
+	MaxInterval:     30 * time.Second,
+	MaxElapsedTime:  time.Minute,
+}
+
+// Config defines configuration for retrying batches in case of export failure
+// using an exponential backoff.
+type Config struct {
+	// Enabled indicates whether to not retry sending batches in case of
+	// export failure.
+	Enabled bool
+	// InitialInterval the time to wait after the first failure before
+	// retrying.
+	InitialInterval time.Duration
+	// MaxInterval is the upper bound on backoff interval. Once this value is
+	// reached the delay between consecutive retries will always be
+	// `MaxInterval`.
+	MaxInterval time.Duration
+	// MaxElapsedTime is the maximum amount of time (including retries) spent
+	// trying to send a request/batch.  Once this value is reached, the data
+	// is discarded.
+	MaxElapsedTime time.Duration
+}
+
+// RequestFunc wraps a request with retry logic.
+type RequestFunc func(context.Context, func(context.Context) error) error
+
+// EvaluateFunc returns if an error is retry-able and if an explicit throttle
+// duration should be honored that was included in the error.
+//
+// The function must return true if the error argument is retry-able,
+// otherwise it must return false for the first return parameter.
+//
+// The function must return a non-zero time.Duration if the error contains
+// explicit throttle duration that should be honored, otherwise it must return
+// a zero valued time.Duration.
+type EvaluateFunc func(error) (bool, time.Duration)
+
+// RequestFunc returns a RequestFunc using the evaluate function to determine
+// if requests can be retried and based on the exponential backoff
+// configuration of c.
+func (c Config) RequestFunc(evaluate EvaluateFunc) RequestFunc {
+	if !c.Enabled {
+		return func(ctx context.Context, fn func(context.Context) error) error {
+			return fn(ctx)
+		}
+	}
+
+	return func(ctx context.Context, fn func(context.Context) error) error {
+		// Do not use NewExponentialBackOff since it calls Reset and the code here
+		// must call Reset after changing the InitialInterval (this saves an
+		// unnecessary call to Now).
+		b := &backoff.ExponentialBackOff{
+			InitialInterval:     c.InitialInterval,
+			RandomizationFactor: backoff.DefaultRandomizationFactor,
+			Multiplier:          backoff.DefaultMultiplier,
+			MaxInterval:         c.MaxInterval,
+			MaxElapsedTime:      c.MaxElapsedTime,
+			Stop:                backoff.Stop,
+			Clock:               backoff.SystemClock,
+		}
+		b.Reset()
+
+		for {
+			err := fn(ctx)
+			if err == nil {
+				return nil
+			}
+
+			retryable, throttle := evaluate(err)
+			if !retryable {
+				return err
+			}
+
+			bOff := b.NextBackOff()
+			if bOff == backoff.Stop {
+				return fmt.Errorf("max retry time elapsed: %w", err)
+			}
+
+			// Wait for the greater of the backoff or throttle delay.
+			var delay time.Duration
+			if bOff > throttle {
+				delay = bOff
+			} else {
+				elapsed := b.GetElapsedTime()
+				if b.MaxElapsedTime != 0 && elapsed+throttle > b.MaxElapsedTime {
+					return fmt.Errorf("max retry time would elapse: %w", err)
+				}
+				delay = throttle
+			}
+
+			if ctxErr := waitFunc(ctx, delay); ctxErr != nil {
+				return fmt.Errorf("%w: %s", ctxErr, err)
+			}
+		}
+	}
+}
+
+// Allow override for testing.
+var waitFunc = wait
+
+// wait takes the caller's context, and the amount of time to wait.  It will
+// return nil if the timer fires before or at the same time as the context's
+// deadline.  This indicates that the call can be retried.
+func wait(ctx context.Context, delay time.Duration) error {
+	timer := time.NewTimer(delay)
+	defer timer.Stop()
+
+	select {
+	case <-ctx.Done():
+		// Handle the case where the timer and context deadline end
+		// simultaneously by prioritizing the timer expiration nil value
+		// response.
+		select {
+		case <-timer.C:
+		default:
+			return ctx.Err()
+		}
+	case <-timer.C:
+	}
+
+	return nil
+}