feat(migrations): Add option migration for inputs.mqtt_consumer

migrations/all/inputs_mqtt_consumer.go

@@ -0,0 +1,5 @@
+//go:build !custom || (migrations && (inputs || inputs.mqtt_consumer))
+
+package all
+
+import _ "github.com/influxdata/telegraf/migrations/inputs_mqtt_consumer" // register migration

migrations/inputs_mqtt_consumer/migration.go

@@ -0,0 +1,43 @@
+package inputs_mqtt_consumer
+
+import (
+	"github.com/influxdata/toml"
+	"github.com/influxdata/toml/ast"
+
+	"github.com/influxdata/telegraf/migrations"
+)
+
+// Migration function
+func migrate(tbl *ast.Table) ([]byte, string, error) {
+	// Decode the old data structure
+	var plugin map[string]interface{}
+	if err := toml.UnmarshalTable(tbl, &plugin); err != nil {
+		return nil, "", err
+	}
+
+	// Check for deprecated option(s) and migrate them
+	var applied bool
+	if _, found := plugin["metric_buffer"]; found {
+		applied = true
+
+		// Remove the ignored setting
+		delete(plugin, "metric_buffer")
+	}
+
+	// No options migrated so we can exit early
+	if !applied {
+		return nil, "", migrations.ErrNotApplicable
+	}
+
+	// Create the corresponding plugin configurations
+	cfg := migrations.CreateTOMLStruct("inputs", "mqtt_consumer")
+	cfg.Add("inputs", "mqtt_consumer", plugin)
+
+	output, err := toml.Marshal(cfg)
+	return output, "", err
+}
+
+// Register the migration function for the plugin type
+func init() {
+	migrations.AddPluginOptionMigration("inputs.mqtt_consumer", migrate)
+}

migrations/inputs_mqtt_consumer/migration_test.go

@@ -0,0 +1,161 @@
+package inputs_mqtt_consumer_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/influxdata/telegraf/config"
+	_ "github.com/influxdata/telegraf/migrations/inputs_mqtt_consumer" // register migration
+	_ "github.com/influxdata/telegraf/plugins/inputs/mqtt_consumer"    // register plugin
+	_ "github.com/influxdata/telegraf/plugins/parsers/all"             // register parsers
+)
+
+func TestNoMigration(t *testing.T) {
+	defaultCfg := []byte(`
+  # Read metrics from MQTT topic(s)
+  [[inputs.mqtt_consumer]]
+  ## Broker URLs for the MQTT server or cluster.  To connect to multiple
+  ## clusters or standalone servers, use a separate plugin instance.
+  ##   example: servers = ["tcp://localhost:1883"]
+  ##            servers = ["ssl://localhost:1883"]
+  ##            servers = ["ws://localhost:1883"]
+  servers = ["tcp://127.0.0.1:1883"]
+
+  ## Topics that will be subscribed to.
+  topics = [
+  "telegraf/host01/cpu",
+  "telegraf/+/mem",
+  "sensors/#",
+  ]
+
+  ## The message topic will be stored in a tag specified by this value.  If set
+  ## to the empty string no topic tag will be created.
+  # topic_tag = "topic"
+
+  ## QoS policy for messages
+  ##   0 = at most once
+  ##   1 = at least once
+  ##   2 = exactly once
+  ##
+  ## When using a QoS of 1 or 2, you should enable persistent_session to allow
+  ## resuming unacknowledged messages.
+  # qos = 0
+
+  ## Connection timeout for initial connection in seconds
+  # connection_timeout = "30s"
+
+  ## Max undelivered messages
+  ## This plugin uses tracking metrics, which ensure messages are read to
+  ## outputs before acknowledging them to the original broker to ensure data
+  ## is not lost. This option sets the maximum messages to read from the
+  ## broker that have not been written by an output.
+  ##
+  ## This value needs to be picked with awareness of the agent's
+  ## metric_batch_size value as well. Setting max undelivered messages too high
+  ## can result in a constant stream of data batches to the output. While
+  ## setting it too low may never flush the broker's messages.
+  # max_undelivered_messages = 1000
+
+  ## Persistent session disables clearing of the client session on connection.
+  ## In order for this option to work you must also set client_id to identify
+  ## the client.  To receive messages that arrived while the client is offline,
+  ## also set the qos option to 1 or 2 and don't forget to also set the QoS when
+  ## publishing.
+  # persistent_session = false
+
+  ## If unset, a random client ID will be generated.
+  # client_id = ""
+
+  ## Username and password to connect MQTT server.
+  # username = "telegraf"
+  # password = "metricsmetricsmetricsmetrics"
+
+  ## Optional TLS Config
+  # tls_ca = "/etc/telegraf/ca.pem"
+  # tls_cert = "/etc/telegraf/cert.pem"
+  # tls_key = "/etc/telegraf/key.pem"
+  ## Use TLS but skip chain & host verification
+  # insecure_skip_verify = false
+
+  ## Client trace messages
+  ## When set to true, and debug mode enabled in the agent settings, the MQTT
+  ## client's messages are included in telegraf logs. These messages are very
+  ## noisey, but essential for debugging issues.
+  # client_trace = false
+
+  ## Data format to consume.
+  ## Each data format has its own unique set of configuration options, read
+  ## more about them here:
+  ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
+  data_format = "influx"
+
+  ## Enable extracting tag values from MQTT topics
+  ## _ denotes an ignored entry in the topic path
+  # [[inputs.mqtt_consumer.topic_parsing]]
+  #   topic = ""
+  #   measurement = ""
+  #   tags = ""
+  #   fields = ""
+  ## Value supported is int, float, unit
+  #   [[inputs.mqtt_consumer.topic.types]]
+  #      key = type
+`)
+
+	// Migrate and check that nothing changed
+	output, n, err := config.ApplyMigrations(defaultCfg)
+	require.NoError(t, err)
+	require.NotEmpty(t, output)
+	require.Zero(t, n)
+	require.Equal(t, string(defaultCfg), string(output))
+}
+
+func TestCases(t *testing.T) {
+	// Get all directories in testdata
+	folders, err := os.ReadDir("testcases")
+	require.NoError(t, err)
+
+	for _, f := range folders {
+		// Only handle folders
+		if !f.IsDir() {
+			continue
+		}
+
+		t.Run(f.Name(), func(t *testing.T) {
+			testcasePath := filepath.Join("testcases", f.Name())
+			inputFile := filepath.Join(testcasePath, "telegraf.conf")
+			expectedFile := filepath.Join(testcasePath, "expected.conf")
+
+			// Read the expected output
+			expected := config.NewConfig()
+			require.NoError(t, expected.LoadConfig(expectedFile))
+			require.NotEmpty(t, expected.Inputs)
+
+			// Read the input data
+			input, remote, err := config.LoadConfigFile(inputFile)
+			require.NoError(t, err)
+			require.False(t, remote)
+			require.NotEmpty(t, input)
+
+			// Migrate
+			output, n, err := config.ApplyMigrations(input)
+			require.NoError(t, err)
+			require.NotEmpty(t, output)
+			require.GreaterOrEqual(t, n, uint64(1))
+			actual := config.NewConfig()
+			require.NoError(t, actual.LoadConfigData(output))
+
+			// Test the output
+			require.Len(t, actual.Inputs, len(expected.Inputs))
+			actualIDs := make([]string, 0, len(expected.Inputs))
+			expectedIDs := make([]string, 0, len(expected.Inputs))
+			for i := range actual.Inputs {
+				actualIDs = append(actualIDs, actual.Inputs[i].ID())
+				expectedIDs = append(expectedIDs, expected.Inputs[i].ID())
+			}
+			require.ElementsMatch(t, expectedIDs, actualIDs, string(output))
+		})
+	}
+}

migrations/inputs_mqtt_consumer/testcases/deprecated_metric_buffer/expected.conf

@@ -0,0 +1,4 @@
+[[inputs.mqtt_consumer]]
+data_format = "influx"
+servers = ["tcp://127.0.0.1:1883"]
+topics = ["telegraf/host01/cpu", "telegraf/+/mem", "sensors/#"]

migrations/inputs_mqtt_consumer/testcases/deprecated_metric_buffer/telegraf.conf

@@ -0,0 +1,10 @@
+# Read metrics from MQTT topic(s)
+[[inputs.mqtt_consumer]]
+  servers = ["tcp://127.0.0.1:1883"]
+  topics = [
+    "telegraf/host01/cpu",
+    "telegraf/+/mem",
+    "sensors/#",
+  ]
+  metric_buffer = 1024
+  data_format = "influx"

migrations/inputs_mqtt_consumer/testcases/deprecated_metric_buffer_parser/expected.conf

@@ -0,0 +1,12 @@
+[[inputs.mqtt_consumer]]
+data_format = "xpath_json"
+servers = ["tcp://127.0.0.1:1883"]
+topics = ["telegraf/host01/cpu", "telegraf/+/mem", "sensors/#"]
+xpath_native_types = true
+
+[[inputs.mqtt_consumer.xpath]]
+field_selection = "/fields/*"
+metric_name = "/name"
+tag_selection = "/tags/*"
+timestamp = "/timestamp"
+timestamp_format = "unix_ms"

migrations/inputs_mqtt_consumer/testcases/deprecated_metric_buffer_parser/telegraf.conf

@@ -0,0 +1,20 @@
+# Read metrics from MQTT topic(s)
+[[inputs.mqtt_consumer]]
+  servers = ["tcp://127.0.0.1:1883"]
+  topics = [
+    "telegraf/host01/cpu",
+    "telegraf/+/mem",
+    "sensors/#",
+  ]
+  metric_buffer = 1024
+
+  data_format = "xpath_json"
+  xpath_native_types = true
+
+  # Configuration matching the first (ENERGY) message
+  [[inputs.mqtt_consumer.xpath]]
+    metric_name = "/name"
+    timestamp = "/timestamp"
+    timestamp_format = "unix_ms"
+    field_selection = "/fields/*"
+    tag_selection = "/tags/*"