Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/inputs/example/example.go

@@ -0,0 +1,139 @@
+//go:generate ../../../tools/readme_config_includer/generator
+package example
+
+import (
+	"crypto/rand"
+	_ "embed"
+	"errors"
+	"fmt"
+	"math"
+	"math/big"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+//go:embed sample.conf
+var sampleConfig string
+
+// Example struct should be named the same as the Plugin
+type Example struct {
+	// Example for a mandatory option to set a tag
+	DeviceName string `toml:"device_name"`
+
+	// Config options are converted to the correct type automatically
+	NumberFields int64 `toml:"number_fields"`
+
+	// We can also use booleans and have diverging names between user-configuration options and struct members
+	EnableRandomVariable bool `toml:"enable_random"`
+
+	// Example of passing a duration option allowing the format of e.g. "100ms", "5m" or "1h"
+	Timeout config.Duration `toml:"timeout"`
+
+	// Example of passing a password/token/username or other sensitive data with the secret-store
+	UserName config.Secret `toml:"username"`
+	Password config.Secret `toml:"password"`
+
+	// Telegraf logging facility
+	// The exact name is important to allow automatic initialization by telegraf.
+	Log telegraf.Logger `toml:"-"`
+
+	// This is a non-exported internal state.
+	count int64
+}
+
+func (*Example) SampleConfig() string {
+	return sampleConfig
+}
+
+// Init can be implemented to do one-time processing stuff like initializing variables
+func (m *Example) Init() error {
+	// Check your options according to your requirements
+	if m.DeviceName == "" {
+		return errors.New("device name cannot be empty")
+	}
+
+	// Set your defaults.
+	// Please note: In golang all fields are initialized to their nil value, so you should not
+	// set these fields if the nil value is what you want (e.g. for booleans).
+	if m.NumberFields < 1 {
+		m.Log.Debugf("Setting number of fields to default from invalid value %d", m.NumberFields)
+		m.NumberFields = 2
+	}
+
+	// Check using the secret-store
+	if m.UserName.Empty() {
+		// For example, use a default value
+		m.Log.Debug("using default username")
+	}
+
+	// Retrieve credentials using the secret-store
+	password, err := m.Password.Get()
+	if err != nil {
+		return fmt.Errorf("getting password failed: %w", err)
+	}
+	defer password.Destroy()
+
+	// Initialize your internal states
+	m.count = 1
+
+	return nil
+}
+
+// Gather defines what data the plugin will gather.
+func (m *Example) Gather(acc telegraf.Accumulator) error {
+	// Imagine some completely arbitrary error occurring here
+	if m.NumberFields > 10 {
+		return errors.New("too many fields")
+	}
+
+	// For illustration, we gather three metrics in one go
+	for run := 0; run < 3; run++ {
+		// Imagine an error occurs here, but you want to keep the other
+		// metrics, then you cannot simply return, as this would drop
+		// all later metrics. Simply accumulate errors in this case
+		// and ignore the metric.
+		if m.EnableRandomVariable && m.DeviceName == "flappy" && run > 1 {
+			acc.AddError(errors.New("too many runs for random values"))
+			continue
+		}
+
+		// Construct the fields
+		fields := map[string]interface{}{"count": m.count}
+		for i := int64(1); i < m.NumberFields; i++ {
+			name := fmt.Sprintf("field%d", i)
+			var err error
+			value := big.NewInt(0)
+			if m.EnableRandomVariable {
+				value, err = rand.Int(rand.Reader, big.NewInt(math.MaxUint32))
+				if err != nil {
+					acc.AddError(err)
+					continue
+				}
+			}
+			fields[name] = float64(value.Int64())
+		}
+
+		// Construct the tags
+		tags := map[string]string{"device": m.DeviceName}
+
+		// Add the metric with the current timestamp
+		acc.AddFields("example", fields, tags)
+
+		m.count++
+	}
+
+	return nil
+}
+
+// Register the plugin
+func init() {
+	inputs.Add("example", func() telegraf.Input {
+		return &Example{
+			// Set the default timeout here to distinguish it from the user setting it to zero
+			Timeout: config.Duration(100 * time.Millisecond),
+		}
+	})
+}