feat: Implement deprecation infrastructure

.markdownlint.yml

@@ -1,3 +1,6 @@
 {
-    "MD013": false
+    "MD013": false,
+    "MD033": {
+      "allowed_elements": ["br"]
+    }
 }

Makefile

@@ -44,6 +44,8 @@ HOSTGO := env -u GOOS -u GOARCH -u GOARM -- go
 LDFLAGS := $(LDFLAGS) -X main.commit=$(commit) -X main.branch=$(branch) -X main.goos=$(GOOS) -X main.goarch=$(GOARCH)
 ifneq ($(tag),)
 	LDFLAGS += -X main.version=$(version)
+else
+	LDFLAGS += -X main.version=$(version)-$(commit)
 endif
 
 # Go built-in race detector works only for 64 bits architectures.
@@ -160,6 +162,10 @@ lint:
 		exit 1
 	endif
 
+	ifeq (, $(shell which markdownlint-cli))
+		$(info markdownlint-cli can't be found, please run: make lint-install)
+		exit 1
+	endif
 	markdownlint-cli
 
 .PHONY: lint-branch

cmd/telegraf/telegraf.go

@@ -60,6 +60,8 @@ var fVersion = flag.Bool("version", false, "display the version and exit")
 var fSampleConfig = flag.Bool("sample-config", false,
 	"print out full sample configuration")
 var fPidfile = flag.String("pidfile", "", "file to write our pid to")
+var fDeprecationList = flag.Bool("deprecation-list", false,
+	"print all deprecated plugins or plugin options.")
 var fSectionFilters = flag.String("section-filter", "",
 	"filter the sections to print, separator is ':'. Valid values are 'agent', 'global_tags', 'outputs', 'processors', 'aggregators' and 'inputs'")
 var fInputFilters = flag.String("input-filter", "",
@@ -270,6 +272,19 @@ func runAgent(ctx context.Context,
 	log.Printf("I! Loaded outputs: %s", strings.Join(c.OutputNames(), " "))
 	log.Printf("I! Tags enabled: %s", c.ListTags())
 
+	if count, found := c.Deprecations["inputs"]; found && (count[0] > 0 || count[1] > 0) {
+		log.Printf("W! Deprecated inputs: %d and %d options", count[0], count[1])
+	}
+	if count, found := c.Deprecations["aggregators"]; found && (count[0] > 0 || count[1] > 0) {
+		log.Printf("W! Deprecated aggregators: %d and %d options", count[0], count[1])
+	}
+	if count, found := c.Deprecations["processors"]; found && (count[0] > 0 || count[1] > 0) {
+		log.Printf("W! Deprecated processors: %d and %d options", count[0], count[1])
+	}
+	if count, found := c.Deprecations["outputs"]; found && (count[0] > 0 || count[1] > 0) {
+		log.Printf("W! Deprecated outputs: %d and %d options", count[0], count[1])
+	}
+
 	if *fPidfile != "" {
 		f, err := os.OpenFile(*fPidfile, os.O_CREATE|os.O_WRONLY, 0644)
 		if err != nil {
@@ -348,6 +363,11 @@ func main() {
 
 	logger.SetupLogging(logger.LogConfig{})
 
+	// Configure version
+	if err := internal.SetVersion(version); err != nil {
+		log.Println("Telegraf version already configured to: " + internal.Version())
+	}
+
 	// Load external plugins, if requested.
 	if *fPlugins != "" {
 		log.Printf("I! Loading external plugins from: %s", *fPlugins)
@@ -392,6 +412,27 @@ func main() {
 
 	// switch for flags which just do something and exit immediately
 	switch {
+	case *fDeprecationList:
+		c := config.NewConfig()
+		infos := c.CollectDeprecationInfos(
+			inputFilters,
+			outputFilters,
+			aggregatorFilters,
+			processorFilters,
+		)
+		//nolint:revive // We will notice if Println fails
+		fmt.Println("Deprecated Input Plugins: ")
+		c.PrintDeprecationList(infos["inputs"])
+		//nolint:revive // We will notice if Println fails
+		fmt.Println("Deprecated Output Plugins: ")
+		c.PrintDeprecationList(infos["outputs"])
+		//nolint:revive // We will notice if Println fails
+		fmt.Println("Deprecated Processor Plugins: ")
+		c.PrintDeprecationList(infos["processors"])
+		//nolint:revive // We will notice if Println fails
+		fmt.Println("Deprecated Aggregator Plugins: ")
+		c.PrintDeprecationList(infos["aggregators"])
+		return
 	case *fOutputList:
 		fmt.Println("Available Output Plugins: ")
 		names := make([]string, 0, len(outputs.Outputs))
@@ -435,16 +476,6 @@ func main() {
 		return
 	}
 
-	shortVersion := version
-	if shortVersion == "" {
-		shortVersion = "unknown"
-	}
-
-	// Configure version
-	if err := internal.SetVersion(shortVersion); err != nil {
-		log.Println("Telegraf version already configured to: " + internal.Version())
-	}
-
 	run(
 		inputFilters,
 		outputFilters,

config/config.go

@@ -17,6 +17,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/coreos/go-semver/semver"
+
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/internal/choice"
@@ -77,6 +79,9 @@ type Config struct {
 	// Processors have a slice wrapper type because they need to be sorted
 	Processors    models.RunningProcessors
 	AggProcessors models.RunningProcessors
+
+	Deprecations map[string][]int64
+	version      *semver.Version
 }
 
 // NewConfig creates a new struct to hold the Telegraf config.
@@ -102,7 +107,15 @@ func NewConfig() *Config {
 		AggProcessors: make([]*models.RunningProcessor, 0),
 		InputFilters:  make([]string, 0),
 		OutputFilters: make([]string, 0),
+		Deprecations:  make(map[string][]int64),
+	}
+
+	// Handle unknown version
+	version := internal.Version()
+	if version == "" || version == "unknown" {
+		version = "0.0.0-unknown"
 	}
+	c.version = semver.New(version)
 
 	tomlCfg := &toml.Config{
 		NormFieldName: toml.DefaultConfig.NormFieldName,
@@ -1008,6 +1021,11 @@ func parseConfig(contents []byte) (*ast.Table, error) {
 func (c *Config) addAggregator(name string, table *ast.Table) error {
 	creator, ok := aggregators.Aggregators[name]
 	if !ok {
+		// Handle removed, deprecated plugins
+		if di, deprecated := aggregators.Deprecations[name]; deprecated {
+			printHistoricPluginDeprecationNotice("aggregators", name, di)
+			return fmt.Errorf("plugin deprecated")
+		}
 		return fmt.Errorf("Undefined but requested aggregator: %s", name)
 	}
 	aggregator := creator()
@@ -1021,13 +1039,22 @@ func (c *Config) addAggregator(name string, table *ast.Table) error {
 		return err
 	}
 
+	if err := c.printUserDeprecation("aggregators", name, aggregator); err != nil {
+		return err
+	}
+
 	c.Aggregators = append(c.Aggregators, models.NewRunningAggregator(aggregator, conf))
 	return nil
 }
 
 func (c *Config) addProcessor(name string, table *ast.Table) error {
 	creator, ok := processors.Processors[name]
 	if !ok {
+		// Handle removed, deprecated plugins
+		if di, deprecated := processors.Deprecations[name]; deprecated {
+			printHistoricPluginDeprecationNotice("processors", name, di)
+			return fmt.Errorf("plugin deprecated")
+		}
 		return fmt.Errorf("Undefined but requested processor: %s", name)
 	}
 
@@ -1069,6 +1096,10 @@ func (c *Config) newRunningProcessor(
 		}
 	}
 
+	if err := c.printUserDeprecation("processors", processorConfig.Name, processor); err != nil {
+		return nil, err
+	}
+
 	rf := models.NewRunningProcessor(processor, processorConfig)
 	return rf, nil
 }
@@ -1079,6 +1110,11 @@ func (c *Config) addOutput(name string, table *ast.Table) error {
 	}
 	creator, ok := outputs.Outputs[name]
 	if !ok {
+		// Handle removed, deprecated plugins
+		if di, deprecated := outputs.Deprecations[name]; deprecated {
+			printHistoricPluginDeprecationNotice("outputs", name, di)
+			return fmt.Errorf("plugin deprecated")
+		}
 		return fmt.Errorf("Undefined but requested output: %s", name)
 	}
 	output := creator()
@@ -1103,6 +1139,10 @@ func (c *Config) addOutput(name string, table *ast.Table) error {
 		return err
 	}
 
+	if err := c.printUserDeprecation("outputs", name, output); err != nil {
+		return err
+	}
+
 	ro := models.NewRunningOutput(output, outputConfig, c.Agent.MetricBatchSize, c.Agent.MetricBufferLimit)
 	c.Outputs = append(c.Outputs, ro)
 	return nil
@@ -1112,13 +1152,23 @@ func (c *Config) addInput(name string, table *ast.Table) error {
 	if len(c.InputFilters) > 0 && !sliceContains(name, c.InputFilters) {
 		return nil
 	}
+
 	// Legacy support renaming io input to diskio
 	if name == "io" {
+		if err := c.printUserDeprecation("inputs", name, nil); err != nil {
+			return err
+		}
 		name = "diskio"
 	}
 
 	creator, ok := inputs.Inputs[name]
 	if !ok {
+		// Handle removed, deprecated plugins
+		if di, deprecated := inputs.Deprecations[name]; deprecated {
+			printHistoricPluginDeprecationNotice("inputs", name, di)
+			return fmt.Errorf("plugin deprecated")
+		}
+
 		return fmt.Errorf("Undefined but requested input: %s", name)
 	}
 	input := creator()
@@ -1152,6 +1202,10 @@ func (c *Config) addInput(name string, table *ast.Table) error {
 		return err
 	}
 
+	if err := c.printUserDeprecation("inputs", name, input); err != nil {
+		return err
+	}
+
 	rp := models.NewRunningInput(input, pluginConfig)
 	rp.SetDefaultTags(c.Tags)
 	c.Inputs = append(c.Inputs, rp)