Created dry run flag for collector

.chloggen/add-dry-run-flag-validate-all-fields.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note:  Added dry run flag to validate config file without running collector.
+
+# One or more tracking issues or pull requests related to the change
+issues: [6445]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

config/moved_config.go

@@ -153,6 +153,97 @@ func (cfg *Config) validateService() error {
 	}
 	return nil
 }
+func (cfg *Config) DryRunValidate() {
+	// Currently, there is no default receiver enabled.
+	// The configuration must specify at least one receiver to be valid.
+	if len(cfg.Receivers) == 0 {
+		fmt.Printf("**..%v\n", errMissingReceivers)
+	} else {
+		for recvID, recvCfg := range cfg.Receivers {
+			if err := recvCfg.Validate(); err != nil {
+				fmt.Printf("**..receiver %q has invalid configuration: %v\n", recvID, err)
+			}
+		}
+	}
+
+	// Currently, there is no default exporter enabled.
+	// The configuration must specify at least one exporter to be valid.
+	if len(cfg.Exporters) == 0 {
+		fmt.Printf("**..%v\n", errMissingExporters)
+	} else {
+		for expID, expCfg := range cfg.Exporters {
+			if err := expCfg.Validate(); err != nil {
+				fmt.Printf("**..exporter %q has invalid configuration: %v\n", expID, err)
+			}
+		}
+	}
+
+	// Validate the processor configuration.
+	for procID, procCfg := range cfg.Processors {
+		if err := procCfg.Validate(); err != nil {
+			fmt.Printf("**..processor %q has invalid configuration: %v\n", procID, err)
+		}
+	}
+
+	// Validate the extension configuration.
+	for extID, extCfg := range cfg.Extensions {
+		if err := extCfg.Validate(); err != nil {
+			fmt.Printf("**..extension %q has invalid configuration: %v\n", extID, err)
+		}
+	}
+	cfg.dryRunValidateService()
+}
+
+func (cfg *Config) dryRunValidateService() {
+
+	for _, ref := range cfg.Service.Extensions {
+		// Check that the name referenced in the Service extensions exists in the top-level extensions.
+		if cfg.Extensions[ref] == nil {
+			fmt.Printf("**..service references extension %q which does not exist\n", ref)
+		}
+	}
+
+	// Must have at least one pipeline.
+	if len(cfg.Service.Pipelines) == 0 {
+		fmt.Printf("**..%v\n", errMissingServicePipelines)
+	} else {
+		for pipelineID, pipeline := range cfg.Service.Pipelines {
+			if pipelineID.Type() != TracesDataType && pipelineID.Type() != MetricsDataType && pipelineID.Type() != LogsDataType {
+				fmt.Printf("**..unknown pipeline datatype %q for %v\n", pipelineID.Type(), pipelineID)
+			}
+
+			// Validate pipeline has at least one receiver.
+			if len(pipeline.Receivers) == 0 {
+				fmt.Printf("**..pipeline %q must have at least one receiver\n", pipelineID)
+			} else {
+				for _, ref := range pipeline.Receivers {
+					// Check that the name referenced in the pipeline's receivers exists in the top-level receivers.
+					if cfg.Receivers[ref] == nil {
+						fmt.Printf("**..pipeline %q references receiver %q which does not exist\n", pipelineID, ref)
+					}
+				}
+			}
+			for _, ref := range pipeline.Processors {
+				// Check that the name referenced in the pipeline's processors exists in the top-level processors.
+				if cfg.Processors[ref] == nil {
+					fmt.Printf("**..pipeline %q references processor %q which does not exist\n", pipelineID, ref)
+				}
+			}
+
+			// Validate pipeline has at least one exporter.
+			if len(pipeline.Exporters) == 0 {
+				fmt.Printf("**..pipeline %q must have at least one exporter\n", pipelineID)
+			} else {
+				for _, ref := range pipeline.Exporters {
+					// Check that the name referenced in the pipeline's Exporters exists in the top-level Exporters.
+					if cfg.Exporters[ref] == nil {
+						fmt.Printf("**..pipeline %q references exporter %q which does not exist\n", pipelineID, ref)
+					}
+				}
+			}
+		}
+	}
+}
 
 // Service defines the configurable components of the service.
 // Deprecated: [v0.52.0] Use service.ConfigService

service/README.md

@@ -94,4 +94,10 @@ key:
 
 1. Does not support setting a key that contains a dot `.`.
 2. Does not support setting a key that contains a equal sign `=`.
-3. The configuration key separator inside the value part of the property is "::". For example `--set "name={a::b: c}"` is equivalent with `--set name.a.b=c`.
+3. The configuration key separator inside the value part of the property is "::". For example `--set "name={a::b: c}"` is equivalent with `--set name.a.b=c`.
+
+## How to validate configuration file and return all errors without running collector
+
+```bash
+   ./otelcorecol --config=file:examples/local/otel-config.yaml  --dry-run
+```

service/collector.go

@@ -24,6 +24,8 @@ import (
 	"os/signal"
 	"syscall"
 
+	"go.opentelemetry.io/collector/service/internal/configunmarshaler"
+
 	"go.uber.org/atomic"
 	"go.uber.org/multierr"
 	"go.uber.org/zap"
@@ -157,6 +159,21 @@ func (col *Collector) setupConfigurationComponents(ctx context.Context) error {
 
 // Run starts the collector according to the given configuration, and waits for it to complete.
 // Consecutive calls to Run are not allowed, Run shouldn't be called once a collector is shut down.
+
+func (col *Collector) DryRun(ctx context.Context) error {
+	_, err, errorcheck := col.set.ConfigProvider.DryRunGet(ctx, col.set.Factories)
+	if err != nil {
+		return fmt.Errorf("failed to get config: %w", err)
+	}
+
+	if errorcheck {
+		ExtensionValidateErrors, ExportersValidateErrors, ReceiversValidateErrors, ProcessorsValidateErrors := configunmarshaler.ReturnValidateErrors()
+		printMarshalErrors(ExtensionValidateErrors, ExportersValidateErrors, ReceiversValidateErrors, ProcessorsValidateErrors)
+		return nil
+	}
+	return nil
+}
+
 func (col *Collector) Run(ctx context.Context) error {
 	if err := col.setupConfigurationComponents(ctx); err != nil {
 		col.setCollectorState(Closed)

service/command.go

@@ -50,6 +50,9 @@ func NewCommand(set CollectorSettings) *cobra.Command {
 			if err != nil {
 				return err
 			}
+			if dryRun {
+				return col.DryRun(cmd.Context())
+			}
 			return col.Run(cmd.Context())
 		},
 	}

service/config_provider.go

@@ -60,6 +60,8 @@ type ConfigProvider interface {
 	//
 	// Should never be called concurrently with itself or Get.
 	Shutdown(ctx context.Context) error
+	// DryRunGet validates the configuration, prints out all related errors without running the collector
+	DryRunGet(ctx context.Context, factories component.Factories) (*Config, error, bool)
 }
 
 type configProvider struct {
@@ -116,6 +118,24 @@ func (cm *configProvider) Get(ctx context.Context, factories component.Factories
 
 	return cfg, nil
 }
+func (cm *configProvider) DryRunGet(ctx context.Context, factories component.Factories) (*Config, error, bool) {
+	retMap, err := cm.mapResolver.Resolve(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("cannot resolve the configuration: %w", err), false
+	}
+
+	var cfg *Config
+	cfg, err, errorcheck := configunmarshaler.New().DryRunUnmarshal(retMap, factories)
+	if err != nil {
+		return nil, fmt.Errorf("cannot unmarshal the configuration: %w", err), false
+	}
+	if errorcheck {
+		return nil, nil, errorcheck
+	}
+
+	cfg.DryRunValidate()
+	return nil, nil, false
+}
 
 func (cm *configProvider) Watch() <-chan error {
 	return cm.mapResolver.Watch()

service/dry_run.go

@@ -0,0 +1,36 @@
+package service
+
+import (
+	"fmt"
+
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/service/internal/configunmarshaler"
+)
+
+func printMarshalErrors(exterrs []configunmarshaler.ExtensionValidateError, experrs []configunmarshaler.ExporterValidateError, recerrs []configunmarshaler.ReceiverValidateError, procerrs []configunmarshaler.ProcessorValidateError) {
+	count := 1
+	for _, exterr := range exterrs {
+		validateErrorText(count, exterr.Component, exterr.Id, exterr.Err)
+		count++
+	}
+	for _, experr := range experrs {
+		validateErrorText(count, experr.Component, experr.Id, experr.Err)
+		count++
+	}
+	for _, recerr := range recerrs {
+		validateErrorText(count, recerr.Component, recerr.Id, recerr.Err)
+		count++
+	}
+	for _, procerr := range procerrs {
+		validateErrorText(count, procerr.Component, procerr.Id, procerr.Err)
+		count++
+	}
+}
+
+func validateErrorText(count int, idType string, id config.ComponentID, err string) {
+	fmt.Printf("Error %d\n", count)
+	fmt.Printf("=============\n")
+	fmt.Printf("%s:\n", idType)
+	fmt.Printf("	%s\n", id)
+	fmt.Printf("	^---^--- %s\n", err)
+}

service/flags.go

@@ -25,8 +25,11 @@ import (
 const (
 	configFlag       = "config"
 	featureGatesFlag = "feature-gates"
+	dryRunFlag       = "dry-run"
 )
 
+var dryRun bool
+
 type configFlagValue struct {
 	values []string
 	sets   []string
@@ -64,6 +67,7 @@ func flags() *flag.FlagSet {
 	flagSet.Var(featuregate.FlagValue{}, featureGatesFlag,
 		"Comma-delimited list of feature gate identifiers. Prefix with '-' to disable the feature. '+' or no prefix will enable the feature.")
 
+	flagSet.BoolVar(&dryRun, dryRunFlag, false, "Validate configuration without running the calculator, must be used with the config flag!")
 	return flagSet
 }
 

service/internal/configunmarshaler/defaultunmarshaler.go

@@ -81,31 +81,32 @@ func New() ConfigUnmarshaler {
 	return ConfigUnmarshaler{}
 }
 
+var rawCfg = configSettings{
+	// TODO: Add a component.ServiceFactory to allow this to be defined by the Service.
+	Service: config.Service{
+		Telemetry: telemetry.Config{
+			Logs: telemetry.LogsConfig{
+				Level:             zapcore.InfoLevel,
+				Development:       false,
+				Encoding:          "console",
+				OutputPaths:       []string{"stderr"},
+				ErrorOutputPaths:  []string{"stderr"},
+				DisableCaller:     false,
+				DisableStacktrace: false,
+				InitialFields:     map[string]interface{}(nil),
+			},
+			Metrics: telemetry.MetricsConfig{
+				Level:   configtelemetry.LevelBasic,
+				Address: ":8888",
+			},
+		},
+	},
+}
+
 // Unmarshal the config.Config from a confmap.Conf.
 // After the config is unmarshalled, `Validate()` must be called to validate.
 func (ConfigUnmarshaler) Unmarshal(v *confmap.Conf, factories component.Factories) (*config.Config, error) {
 	// Unmarshal top level sections and validate.
-	rawCfg := configSettings{
-		// TODO: Add a component.ServiceFactory to allow this to be defined by the Service.
-		Service: config.Service{
-			Telemetry: telemetry.Config{
-				Logs: telemetry.LogsConfig{
-					Level:             zapcore.InfoLevel,
-					Development:       false,
-					Encoding:          "console",
-					OutputPaths:       []string{"stderr"},
-					ErrorOutputPaths:  []string{"stderr"},
-					DisableCaller:     false,
-					DisableStacktrace: false,
-					InitialFields:     map[string]interface{}(nil),
-				},
-				Metrics: telemetry.MetricsConfig{
-					Level:   configtelemetry.LevelBasic,
-					Address: ":8888",
-				},
-			},
-		},
-	}
 	if err := v.Unmarshal(&rawCfg, confmap.WithErrorUnused()); err != nil {
 		return nil, configError{
 			error: fmt.Errorf("error reading top level configuration sections: %w", err),