exp(jaeger-v2): Simplify all-in-one configuration (#4875)

## Which problem is this PR solving?
- Part of #4843 
- Improvement on #4842, where all-in-one configuration was created via
createDefaultConfig methods of extensions called by OTel automatically.
This resulted in the memstore always being present in the config and
always instantiated, which is not the desired behavior.

## Description of the changes
- The cmd.RunE interceptor is changed to provide an internal value to
the `--config` flag if no flag was present on cmd line
- This avoids creating the collector manually, once we set the flag we
always delegate back to official OTel code
- The value for the config is embedded in the binary and passed using
`yaml:...`, which is one of the official config providers in OTel

## How was this change tested?
- Ran all-in-one manually

Signed-off-by: Yuri Shkuro <[email protected]>

cmd/jaeger-v2/internal/all-in-one.yaml

@@ -0,0 +1,38 @@
+service:
+  extensions: [jaeger_storage, jaeger_query]
+  pipelines:
+    traces:
+      receivers: [otlp, jaeger, zipkin]
+      processors: [batch]
+      exporters: [jaeger_storage_exporter]
+
+extensions:
+  jaeger_query:
+    trace_storage: memstore
+
+  jaeger_storage:
+    memory:
+      memstore:
+        max_traces: 100000
+
+receivers:
+  otlp:
+    protocols:
+      grpc:
+      http:
+
+  jaeger:
+    protocols:
+      grpc:
+      thrift_binary:
+      thrift_compact:
+      thrift_http:
+
+  zipkin:
+
+processors:
+  batch:
+
+exporters:
+  jaeger_storage_exporter:
+    trace_storage: memstore

cmd/jaeger-v2/internal/command.go

@@ -4,16 +4,20 @@
 package internal
 
 import (
+	"embed"
+	"fmt"
 	"log"
 
 	"github.com/spf13/cobra"
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/otelcol"
 
-	allinone "github.com/jaegertracing/jaeger/cmd/jaeger-v2/internal/all-in-one"
 	"github.com/jaegertracing/jaeger/pkg/version"
 )
 
+//go:embed all-in-one.yaml
+var yamlAllInOne embed.FS
+
 const description = "Jaeger backend v2"
 
 func Command() *cobra.Command {
@@ -38,25 +42,20 @@ func Command() *cobra.Command {
 	// We want to support running the binary in all-in-one mode without a config file.
 	// Since there are no explicit hooks in OTel Collector for that today (as of v0.87),
 	// we intercept the official RunE implementation and check if any `--config` flags
-	// are present in the args. If not, we pass a custom ConfigProvider, and create the
-	// collector manually. Unfortunately, `set`(tings) is passed to NewCommand above
-	// by value, otherwise we could've overwritten it in the interceptor and then delegated
-	// back to the official RunE.
+	// are present in the args. If not, we create one with all-in-one configuration.
 	otelRunE := cmd.RunE
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
-		// a bit of a hack to check if '--config' flag was present
-		configFlag := cmd.Flag("config").Value.String()
-		if configFlag != "" && configFlag != "[]" {
-			return otelRunE(cmd, args)
-		}
-		log.Print("No '--config' flags detected, using default All-in-One configuration with memory storage.")
-		log.Print("To customize All-in-One behavior, pass a proper configuration.")
-		settings.ConfigProvider = allinone.NewConfigProvider()
-		col, err := otelcol.NewCollector(settings)
-		if err != nil {
-			return err
+		configFlag := cmd.Flag("config")
+		if !configFlag.Changed {
+			log.Print("No '--config' flags detected, using default All-in-One configuration with memory storage.")
+			log.Print("To customize All-in-One behavior, pass a proper configuration.")
+			data, err := yamlAllInOne.ReadFile("all-in-one.yaml")
+			if err != nil {
+				return fmt.Errorf("cannot read embedded all-in-one configuration: %w", err)
+			}
+			configFlag.Value.Set("yaml:" + string(data))
 		}
-		return col.Run(cmd.Context())
+		return otelRunE(cmd, args)
 	}
 
 	cmd.Short = description

cmd/jaeger-v2/internal/exporters/storageexporter/factory.go

@@ -10,8 +10,6 @@ import (
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/exporter"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
-
-	"github.com/jaegertracing/jaeger/cmd/jaeger-v2/internal/extension/jaegerstorage"
 )
 
 // componentType is the name of this extension in configuration.
@@ -30,9 +28,7 @@ func NewFactory() exporter.Factory {
 }
 
 func createDefaultConfig() component.Config {
-	return &Config{
-		TraceStorage: jaegerstorage.DefaultMemoryStore,
-	}
+	return &Config{}
 }
 
 func createTracesExporter(ctx context.Context, set exporter.CreateSettings, config component.Config) (exporter.Traces, error) {

cmd/jaeger-v2/internal/extension/jaegerquery/factory.go

@@ -10,7 +10,6 @@ import (
 	"go.opentelemetry.io/collector/config/confighttp"
 	"go.opentelemetry.io/collector/extension"
 
-	"github.com/jaegertracing/jaeger/cmd/jaeger-v2/internal/extension/jaegerstorage"
 	"github.com/jaegertracing/jaeger/ports"
 )
 
@@ -26,7 +25,6 @@ func NewFactory() extension.Factory {
 
 func createDefaultConfig() component.Config {
 	return &Config{
-		TraceStoragePrimary: jaegerstorage.DefaultMemoryStore,
 		HTTPServerSettings: confighttp.HTTPServerSettings{
 			Endpoint: ports.PortToHostPort(ports.QueryHTTP),
 		},

cmd/jaeger-v2/internal/extension/jaegerstorage/factory.go

@@ -8,17 +8,10 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/extension"
-
-	memoryCfg "github.com/jaegertracing/jaeger/pkg/memory/config"
 )
 
-const (
-	// componentType is the name of this extension in configuration.
-	componentType = component.Type("jaeger_storage")
-
-	// DefaultMemoryStore is the name of the memory storage included in the default configuration.
-	DefaultMemoryStore = "memstore"
-)
+// componentType is the name of this extension in configuration.
+const componentType = component.Type("jaeger_storage")
 
 // ID is the identifier of this extension.
 var ID = component.NewID(componentType)
@@ -33,13 +26,7 @@ func NewFactory() extension.Factory {
 }
 
 func createDefaultConfig() component.Config {
-	return &Config{
-		Memory: map[string]memoryCfg.Configuration{
-			DefaultMemoryStore: {
-				MaxTraces: 100_000,
-			},
-		},
-	}
+	return &Config{}
 }
 
 // createExtension creates the extension based on this config.