Adding upstream version 1.34.4.

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

plugins/outputs/mqtt/topic_name_generator.go

@@ -0,0 +1,88 @@
+package mqtt
+
+import (
+	"fmt"
+	"strings"
+	"text/template"
+	"time"
+
+	"github.com/Masterminds/sprig/v3"
+
+	"github.com/influxdata/telegraf"
+)
+
+type TopicNameGenerator struct {
+	TopicPrefix string
+	metric      telegraf.TemplateMetric
+	template    *template.Template
+}
+
+func NewTopicNameGenerator(topicPrefix, topic string) (*TopicNameGenerator, error) {
+	topic = hostnameRe.ReplaceAllString(topic, `$1.Tag "host"$2`)
+	topic = pluginNameRe.ReplaceAllString(topic, `$1.Name$2`)
+
+	tt, err := template.New("topic_name").Funcs(sprig.TxtFuncMap()).Parse(topic)
+	if err != nil {
+		return nil, err
+	}
+	for _, p := range strings.Split(topic, "/") {
+		if strings.ContainsAny(p, "#+") {
+			return nil, fmt.Errorf("found forbidden character %s in the topic name %s", p, topic)
+		}
+	}
+	return &TopicNameGenerator{TopicPrefix: topicPrefix, template: tt}, nil
+}
+
+func (t *TopicNameGenerator) Name() string {
+	return t.metric.Name()
+}
+
+func (t *TopicNameGenerator) Tag(key string) string {
+	return t.metric.Tag(key)
+}
+
+func (t *TopicNameGenerator) Field(key string) interface{} {
+	return t.metric.Field(key)
+}
+
+func (t *TopicNameGenerator) Time() time.Time {
+	return t.metric.Time()
+}
+
+func (t *TopicNameGenerator) Tags() map[string]string {
+	return t.metric.Tags()
+}
+
+func (t *TopicNameGenerator) Fields() map[string]interface{} {
+	return t.metric.Fields()
+}
+
+func (t *TopicNameGenerator) String() string {
+	return t.metric.String()
+}
+
+func (m *MQTT) generateTopic(metric telegraf.Metric) (string, error) {
+	m.generator.metric = metric.(telegraf.TemplateMetric)
+
+	// Cannot directly pass TemplateMetric since TopicNameGenerator still contains TopicPrefix (until v1.35.0)
+	var b strings.Builder
+	err := m.generator.template.Execute(&b, m.generator)
+	if err != nil {
+		return "", err
+	}
+	var ts []string
+	for _, p := range strings.Split(b.String(), "/") {
+		if p != "" {
+			ts = append(ts, p)
+		}
+	}
+	topic := strings.Join(ts, "/")
+	// This is to keep backward compatibility with previous behaviour where the plugin name was always present
+	if topic == "" {
+		return metric.Name(), nil
+	}
+	if strings.HasPrefix(b.String(), "/") {
+		topic = "/" + topic
+	}
+	return topic, nil
+}