Migrate remote-storage to YAML configuration with shared storageconfig package (#7704)

## Migrated remote-storage to YAML configuration with shared
storageconfig package

Addressed all feedback from @yurishkuro to eliminate duplication and
maintain test coverage.

### Changes Made:

1. **Shared Storage Configuration with Comprehensive Tests**
(`cmd/internal/storageconfig/`)
- Created shared package with `Config`, `TraceBackend`, and
`MetricBackend` types
- **PrometheusConfiguration now in storageconfig** with
`promcfg.Configuration` type
- **MetricBackend.Unmarshal in storageconfig** initializes prometheus
defaults
   - Implemented `CreateTraceStorageFactory` with optional auth support
- Both jaeger and remote-storage now use shared factory creation logic
- **Added comprehensive unit tests** (`config_test.go`,
`factory_test.go`)
   - **Config validation and unmarshaling: 100% test coverage**
- **Factory creation tested for all backend types** (Memory, Badger,
Cassandra, ClickHouse, Elasticsearch, OpenSearch)
- **Total package coverage: 98.3%** (config.go: 100%, factory.go: 96.2%)
   - ES/OS backends tested with mock HTTP servers
   - ClickHouse tested with clickhousetest server
   - GRPC tested via jaegerstorage extension (requires component.Host)

2. **Refactored jaegerstorage Extension**
(`cmd/jaeger/internal/extension/jaegerstorage/`)
   - **Config now embeds storageconfig.Config** with mapstructure squash
   - Extension uses shared `storageconfig.CreateTraceStorageFactory`
- Eliminated ~80 lines of duplicate code (config types + factory
creation)
   - Maintained 99.1% test coverage (previously 99.4%)
   - No duplicate PrometheusConfiguration or MetricBackend definitions

3. **Updated All Test Files**
   - Migrated all test references to use embedded Config initialization
- Fixed references in extension, exporter, processor, and remote
sampling tests
   - All tests passing with high coverage

4. **Enhanced remote-storage Configuration**
   - Uses viper's built-in `--config-file` flag
   - Removed all CLI flag support and v1 factory dependencies
   - Added validation to enforce single backend constraint
   - Added default configuration support (memory storage on :17271)
   - Maintains backward compatibility with integration tests

### Testing Results:
- ✅ **storageconfig package: 98.3% coverage** (config.go: 100%,
factory.go: 96.2%)
- ✅ jaegerstorage extension: 99.1% coverage
- ✅ All exporters, processors: 100% coverage
- ✅ remote-storage: 94% coverage
- ✅ All test suites passing
- ✅ Lint clean
- ✅ remote-storage starts successfully without config file

### Benefits:
- ✅ No duplication - all config types in shared storageconfig
- ✅ **Comprehensive test coverage for shared code** (98.3%)
- ✅ Single source of truth for storage configuration
- ✅ High test coverage maintained across all packages
- ✅ Clean architecture with embedded config
- ✅ Backward compatible with existing deployments

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<details>

<summary>Original prompt</summary>

> Can you solve this issue
#7703 ?


</details>



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---------

Signed-off-by: Yuri Shkuro <[email protected]>
Signed-off-by: Yuri Shkuro <[email protected]>
Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: yurishkuro <[email protected]>
Co-authored-by: Yuri Shkuro <[email protected]>
Co-authored-by: Yuri Shkuro <[email protected]>

Author: Copilot

Makefile

@@ -40,6 +40,7 @@ ALL_SRC = $(shell find . -name '*.go' \
 # All .sh or .py or Makefile or .mk files that should be auto-formatted and linted.
 SCRIPTS_SRC = $(shell find . \( -name '*.sh' -o -name '*.py' -o -name '*.mk' -o -name 'Makefile*' -o -name 'Dockerfile*' \) \
 						-not -path './.git/*' \
+						-not -path './vendor/*' \
 						-not -path './idl/*' \
 						-not -path './jaeger-ui/*' \
 						-type f | \

cmd/internal/flags/flags.go

@@ -16,10 +16,9 @@ import (
 )
 
 const (
-	spanStorageType = "span-storage.type" // deprecated
-	logLevel        = "log-level"
-	logEncoding     = "log-encoding" // json or console
-	configFile      = "config-file"
+	logLevel    = "log-level"
+	logEncoding = "log-encoding" // json or console
+	configFile  = "config-file"
 )
 
 // AddConfigFileFlag adds flags for ExternalConfFlags
@@ -92,12 +91,6 @@ type logging struct {
 	Encoding string
 }
 
-// AddFlags adds flags for SharedFlags
-func AddFlags(flagSet *flag.FlagSet) {
-	flagSet.String(spanStorageType, "", "(deprecated) please use SPAN_STORAGE_TYPE environment variable. Run this binary with the 'env' command for help.")
-	AddLoggingFlags(flagSet)
-}
-
 // AddLoggingFlag adds logging flag for SharedFlags
 func AddLoggingFlags(flagSet *flag.FlagSet) {
 	flagSet.String(logLevel, "info", "Minimal allowed log Level. For more levels see https://github.com/uber-go/zap")

cmd/internal/flags/service.go

@@ -28,9 +28,6 @@ type Service struct {
 	// AdminPort is the HTTP port number for admin server.
 	AdminPort int
 
-	// NoStorage indicates that storage-type CLI flag is not applicable
-	NoStorage bool
-
 	// Admin is the admin server that hosts the health check and metrics endpoints.
 	Admin *AdminServer
 
@@ -80,11 +77,7 @@ func NewService(adminPort int) *Service {
 // AddFlags registers CLI flags.
 func (s *Service) AddFlags(flagSet *flag.FlagSet) {
 	AddConfigFileFlag(flagSet)
-	if s.NoStorage {
-		AddLoggingFlags(flagSet)
-	} else {
-		AddFlags(flagSet)
-	}
+	AddLoggingFlags(flagSet)
 	metricsbuilder.AddFlags(flagSet)
 	s.Admin.AddFlags(flagSet)
 	featuregate.GlobalRegistry().RegisterFlags(flagSet)

cmd/internal/flags/service_test.go

@@ -21,9 +21,6 @@ import (
 func TestAddFlags(*testing.T) {
 	s := NewService(0)
 	s.AddFlags(new(flag.FlagSet))
-
-	s.NoStorage = true
-	s.AddFlags(new(flag.FlagSet))
 }
 
 func TestStartErrors(t *testing.T) {

cmd/internal/storageconfig/config.go

@@ -0,0 +1,134 @@
+// Copyright (c) 2025 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package storageconfig
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"time"
+
+	"go.opentelemetry.io/collector/confmap"
+
+	"github.com/jaegertracing/jaeger/internal/config/promcfg"
+	cascfg "github.com/jaegertracing/jaeger/internal/storage/cassandra/config"
+	escfg "github.com/jaegertracing/jaeger/internal/storage/elasticsearch/config"
+	"github.com/jaegertracing/jaeger/internal/storage/metricstore/prometheus"
+	"github.com/jaegertracing/jaeger/internal/storage/v1/badger"
+	"github.com/jaegertracing/jaeger/internal/storage/v1/cassandra"
+	es "github.com/jaegertracing/jaeger/internal/storage/v1/elasticsearch"
+	"github.com/jaegertracing/jaeger/internal/storage/v1/memory"
+	"github.com/jaegertracing/jaeger/internal/storage/v2/clickhouse"
+	"github.com/jaegertracing/jaeger/internal/storage/v2/grpc"
+)
+
+var (
+	_ confmap.Unmarshaler = (*TraceBackend)(nil)
+	_ confmap.Unmarshaler = (*MetricBackend)(nil)
+)
+
+// Config contains configuration(s) for Jaeger trace storage.
+type Config struct {
+	TraceBackends  map[string]TraceBackend  `mapstructure:"backends"`
+	MetricBackends map[string]MetricBackend `mapstructure:"metric_backends"`
+}
+
+// TraceBackend contains configuration for a single trace storage backend.
+type TraceBackend struct {
+	Memory        *memory.Configuration     `mapstructure:"memory"`
+	Badger        *badger.Config            `mapstructure:"badger"`
+	GRPC          *grpc.Config              `mapstructure:"grpc"`
+	Cassandra     *cassandra.Options        `mapstructure:"cassandra"`
+	Elasticsearch *escfg.Configuration      `mapstructure:"elasticsearch"`
+	Opensearch    *escfg.Configuration      `mapstructure:"opensearch"`
+	ClickHouse    *clickhouse.Configuration `mapstructure:"clickhouse"`
+}
+
+// MetricBackend contains configuration for a single metric storage backend.
+type MetricBackend struct {
+	Prometheus    *PrometheusConfiguration `mapstructure:"prometheus"`
+	Elasticsearch *escfg.Configuration     `mapstructure:"elasticsearch"`
+	Opensearch    *escfg.Configuration     `mapstructure:"opensearch"`
+}
+
+type PrometheusConfiguration struct {
+	Configuration  promcfg.Configuration `mapstructure:",squash"`
+	Authentication escfg.Authentication  `mapstructure:"auth"`
+}
+
+// Unmarshal implements confmap.Unmarshaler. This allows us to provide
+// defaults for different configs.
+func (cfg *TraceBackend) Unmarshal(conf *confmap.Conf) error {
+	// apply defaults
+	if conf.IsSet("memory") {
+		cfg.Memory = &memory.Configuration{
+			MaxTraces: 1_000_000,
+		}
+	}
+	if conf.IsSet("badger") {
+		v := badger.DefaultConfig()
+		cfg.Badger = v
+	}
+	if conf.IsSet("grpc") {
+		v := grpc.DefaultConfig()
+		cfg.GRPC = &v
+	}
+	if conf.IsSet("cassandra") {
+		cfg.Cassandra = &cassandra.Options{
+			NamespaceConfig: cassandra.NamespaceConfig{
+				Configuration: cascfg.DefaultConfiguration(),
+				Enabled:       true,
+			},
+			SpanStoreWriteCacheTTL: 12 * time.Hour,
+			Index: cassandra.IndexConfig{
+				Tags:        true,
+				ProcessTags: true,
+				Logs:        true,
+			},
+		}
+	}
+	if conf.IsSet("elasticsearch") {
+		v := es.DefaultConfig()
+		cfg.Elasticsearch = &v
+	}
+	if conf.IsSet("opensearch") {
+		v := es.DefaultConfig()
+		cfg.Opensearch = &v
+	}
+	return conf.Unmarshal(cfg)
+}
+
+// Unmarshal implements confmap.Unmarshaler for MetricBackend.
+func (cfg *MetricBackend) Unmarshal(conf *confmap.Conf) error {
+	// apply defaults
+	if conf.IsSet("prometheus") {
+		v := prometheus.DefaultConfig()
+		cfg.Prometheus = &PrometheusConfiguration{
+			Configuration: v,
+		}
+	}
+	if conf.IsSet("elasticsearch") {
+		v := es.DefaultConfig()
+		cfg.Elasticsearch = &v
+	}
+	if conf.IsSet("opensearch") {
+		v := es.DefaultConfig()
+		cfg.Opensearch = &v
+	}
+	return conf.Unmarshal(cfg)
+}
+
+// Validate validates the storage configuration.
+func (c *Config) Validate() error {
+	if len(c.TraceBackends) == 0 {
+		return errors.New("at least one storage backend is required")
+	}
+	for name, b := range c.TraceBackends {
+		empty := TraceBackend{}
+		if reflect.DeepEqual(b, empty) {
+			return fmt.Errorf("empty backend configuration for storage '%s'", name)
+		}
+	}
+	return nil
+}