[chore][pkg/stanza] Cleanup udp input operator files (#32078)

Contributes to #32058

pkg/stanza/operator/input/udp/config.go

@@ -0,0 +1,144 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package udp // import "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/input/udp"
+
+import (
+	"fmt"
+	"net"
+	"sync"
+
+	"go.uber.org/zap"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/decode"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/operator/helper"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/split"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/trim"
+)
+
+const (
+	operatorType = "udp_input"
+
+	// Maximum UDP packet size
+	MaxUDPSize = 64 * 1024
+
+	defaultReaders        = 1
+	defaultProcessors     = 1
+	defaultMaxQueueLength = 100
+)
+
+func init() {
+	operator.Register(operatorType, func() operator.Builder { return NewConfig() })
+}
+
+// NewConfig creates a new UDP input config with default values
+func NewConfig() *Config {
+	return NewConfigWithID(operatorType)
+}
+
+// NewConfigWithID creates a new UDP input config with default values
+func NewConfigWithID(operatorID string) *Config {
+	return &Config{
+		InputConfig: helper.NewInputConfig(operatorID, operatorType),
+		BaseConfig: BaseConfig{
+			Encoding:        "utf-8",
+			OneLogPerPacket: false,
+			SplitConfig: split.Config{
+				LineEndPattern: ".^", // Use never matching regex to not split data by default
+			},
+		},
+	}
+}
+
+// Config is the configuration of a udp input operator.
+type Config struct {
+	helper.InputConfig `mapstructure:",squash"`
+	BaseConfig         `mapstructure:",squash"`
+}
+
+type AsyncConfig struct {
+	Readers        int `mapstructure:"readers,omitempty"`
+	Processors     int `mapstructure:"processors,omitempty"`
+	MaxQueueLength int `mapstructure:"max_queue_length,omitempty"`
+}
+
+// BaseConfig is the details configuration of a udp input operator.
+type BaseConfig struct {
+	ListenAddress   string       `mapstructure:"listen_address,omitempty"`
+	OneLogPerPacket bool         `mapstructure:"one_log_per_packet,omitempty"`
+	AddAttributes   bool         `mapstructure:"add_attributes,omitempty"`
+	Encoding        string       `mapstructure:"encoding,omitempty"`
+	SplitConfig     split.Config `mapstructure:"multiline,omitempty"`
+	TrimConfig      trim.Config  `mapstructure:",squash"`
+	AsyncConfig     *AsyncConfig `mapstructure:"async,omitempty"`
+}
+
+// Build will build a udp input operator.
+func (c Config) Build(logger *zap.SugaredLogger) (operator.Operator, error) {
+	inputOperator, err := c.InputConfig.Build(logger)
+	if err != nil {
+		return nil, err
+	}
+
+	if c.ListenAddress == "" {
+		return nil, fmt.Errorf("missing required parameter 'listen_address'")
+	}
+
+	address, err := net.ResolveUDPAddr("udp", c.ListenAddress)
+	if err != nil {
+		return nil, fmt.Errorf("failed to resolve listen_address: %w", err)
+	}
+
+	enc, err := decode.LookupEncoding(c.Encoding)
+	if err != nil {
+		return nil, err
+	}
+
+	// Build split func
+	splitFunc, err := c.SplitConfig.Func(enc, true, MaxUDPSize)
+	if err != nil {
+		return nil, err
+	}
+	splitFunc = trim.WithFunc(splitFunc, c.TrimConfig.Func())
+
+	var resolver *helper.IPResolver
+	if c.AddAttributes {
+		resolver = helper.NewIPResolver()
+	}
+
+	if c.AsyncConfig != nil {
+		if c.AsyncConfig.Readers <= 0 {
+			c.AsyncConfig.Readers = defaultReaders
+		}
+		if c.AsyncConfig.Processors <= 0 {
+			c.AsyncConfig.Processors = defaultProcessors
+		}
+		if c.AsyncConfig.MaxQueueLength <= 0 {
+			c.AsyncConfig.MaxQueueLength = defaultMaxQueueLength
+		}
+	}
+
+	udpInput := &Input{
+		InputOperator:   inputOperator,
+		address:         address,
+		buffer:          make([]byte, MaxUDPSize),
+		addAttributes:   c.AddAttributes,
+		encoding:        enc,
+		splitFunc:       splitFunc,
+		resolver:        resolver,
+		OneLogPerPacket: c.OneLogPerPacket,
+		AsyncConfig:     c.AsyncConfig,
+	}
+
+	if c.AsyncConfig != nil {
+		udpInput.messageQueue = make(chan messageAndAddress, c.AsyncConfig.MaxQueueLength)
+		udpInput.readBufferPool = sync.Pool{
+			New: func() any {
+				buffer := make([]byte, MaxUDPSize)
+				return &buffer
+			},
+		}
+	}
+	return udpInput, nil
+}