feat(parsers.avro): Get metric name from the message field (#13914)

plugins/parsers/avro/README.md

@@ -10,6 +10,20 @@ The message is supposed to be encoded as follows:
 | 1-4   | Schema ID  | 4-byte schema ID as returned by Schema Registry. |
 | 5-    | Data       | Serialized data.                                 |
 
+The metric name will be set according the following priority:
+
+  1. Try to get metric name from the message field if it is set in the
+     `avro_measurement_field` option.
+  2. If the name is not determined, then try to get it from
+     `avro_measurement` option as the static value.
+  3. If the name is still not determined, then try to get it from the
+     schema definition in the following format `[schema_namespace.]schema_name`,
+     where schema namespace is optional and will be added only if it is specified
+     in the schema definition.
+
+In case if the metric name could not be determined according to these steps
+the error will be rised and the message will not be parsed.
+
 ## Configuration
 
 ```toml
@@ -63,6 +77,11 @@ The message is supposed to be encoded as follows:
   #      }
   #'''
 
+  ## Measurement field name; The meauserment name will be taken 
+  ## from this field. If not set, determine measurement name
+  ## from the following 'avro_measurement' option
+  # avro_measurement_field = "field_name"
+
   ## Measurement string; if not set, determine measurement name from
   ## schema (as "<namespace>.<name>")
   # avro_measurement = "ratings"

plugins/parsers/avro/parser.go

@@ -24,18 +24,19 @@ import (
 // an attached schema or schema fingerprint
 
 type Parser struct {
-	MetricName      string            `toml:"metric_name"`
+	MetricName       string            `toml:"metric_name"`
-	SchemaRegistry  string            `toml:"avro_schema_registry"`
+	SchemaRegistry   string            `toml:"avro_schema_registry"`
-	CaCertPath      string            `toml:"avro_schema_registry_cert"`
+	CaCertPath       string            `toml:"avro_schema_registry_cert"`
-	Schema          string            `toml:"avro_schema"`
+	Schema           string            `toml:"avro_schema"`
-	Format          string            `toml:"avro_format"`
+	Format           string            `toml:"avro_format"`
-	Measurement     string            `toml:"avro_measurement"`
+	Measurement      string            `toml:"avro_measurement"`
-	Tags            []string          `toml:"avro_tags"`
+	MeasurementField string            `toml:"avro_measurement_field"`
-	Fields          []string          `toml:"avro_fields"`
+	Tags             []string          `toml:"avro_tags"`
-	Timestamp       string            `toml:"avro_timestamp"`
+	Fields           []string          `toml:"avro_fields"`
-	TimestampFormat string            `toml:"avro_timestamp_format"`
+	Timestamp        string            `toml:"avro_timestamp"`
-	FieldSeparator  string            `toml:"avro_field_separator"`
+	TimestampFormat  string            `toml:"avro_timestamp_format"`
-	DefaultTags     map[string]string `toml:"tags"`
+	FieldSeparator   string            `toml:"avro_field_separator"`
+	DefaultTags      map[string]string `toml:"tags"`
 
 	Log         telegraf.Logger `toml:"-"`
 	registryObj *schemaRegistry
@@ -212,9 +213,26 @@ func (p *Parser) createMetric(data map[string]interface{}, schema string) (teleg
 		// A telegraf metric needs at least one field.
 		return nil, errors.New("number of fields is 0; unable to create metric")
 	}
+
+	// If measurement field name is specified in the configuration
+	// take value from that field and do not include it into fields or tags
+	name := ""
+	if p.MeasurementField != "" {
+		sField := p.MeasurementField
+		sMetric, err := internal.ToString(data[sField])
+		if err != nil {
+			p.Log.Warnf("Could not convert %v to string for metric name %q: %w", data[sField], sField, err)
+		} else {
+			name = sMetric
+		}
+	}
 	// Now some fancy stuff to extract the measurement.
 	// If it's set in the configuration, use that.
-	name := p.Measurement
+	if name == "" {
+		// If field name is not specified or field does not exist and
+		// metric name set in the configuration, use that.
+		name = p.Measurement
+	}
 	separator := "."
 	if name == "" {
 		// Try using the namespace defined in the schema. In case there

plugins/parsers/avro/testdata/measurement_name_from_message/expected.out

@@ -0,0 +1 @@
+cpu_load,Server=test_server Value=18.7 1694526986671

plugins/parsers/avro/testdata/measurement_name_from_message/message.avro

@@ -0,0 +1 @@
+ÞæîšÑbtest_server33333³2@cpu_load

plugins/parsers/avro/testdata/measurement_name_from_message/telegraf.conf

@@ -0,0 +1,30 @@
+[[ inputs.file ]]
+  files = ["./testdata/measurement_name_from_message/message.avro"]
+  data_format = "avro"
+  avro_measurement_field = "Measurement"
+  avro_tags = [ "Server" ]
+  avro_fields = [ "Value" ]
+  avro_schema = '''
+{
+  "type": "record",
+  "name": "TestRecord",
+  "fields": [
+    {
+      "name": "ServerTs",
+      "type": "long"
+    },
+    {
+      "name": "Server",
+      "type": "string"
+    },
+    {
+      "name": "Value",
+      "type": "double"
+    },
+    {
+      "name": "Measurement",
+      "type": "string"
+    }
+  ]
+}
+'''