From 9cdac902bd50df00db6d9deed63ffb1d233b3773 Mon Sep 17 00:00:00 2001
From: Niko Storni <niko@odysee.com>
Date: Tue, 13 May 2025 14:47:19 +0200
Subject: [PATCH] add multiwriter store

---
 store/multiwriter.go | 180 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 180 insertions(+)
 create mode 100644 store/multiwriter.go

diff --git a/store/multiwriter.go b/store/multiwriter.go
new file mode 100644
index 0000000..642f53c
--- /dev/null
+++ b/store/multiwriter.go
@@ -0,0 +1,180 @@
+package store
+
+import (
+	"strings"
+	"sync"
+
+	"github.com/lbryio/lbry.go/v2/extras/errors"
+	"github.com/lbryio/lbry.go/v2/stream"
+	"github.com/lbryio/reflector.go/shared"
+	"github.com/spf13/viper"
+)
+
+// MultiWriterStore writes to multiple destination stores
+type MultiWriterStore struct {
+	name         string
+	destinations []BlobStore
+}
+
+type MultiWriterParams struct {
+	Name         string
+	Destinations []BlobStore
+}
+
+type MultiWriterConfig struct {
+	Name         string   `mapstructure:"name"`
+	Destinations []string `mapstructure:"destinations"`
+}
+
+// NewMultiWriterStore returns a new instance of the MultiWriter store
+func NewMultiWriterStore(params MultiWriterParams) *MultiWriterStore {
+	return &MultiWriterStore{
+		name:         params.Name,
+		destinations: params.Destinations,
+	}
+}
+
+const nameMultiWriter = "multiwriter"
+
+func MultiWriterStoreFactory(config *viper.Viper) (BlobStore, error) {
+	var cfg MultiWriterConfig
+	err := config.Unmarshal(&cfg)
+	if err != nil {
+		return nil, errors.Err(err)
+	}
+
+	var destinations []BlobStore
+	for _, destType := range cfg.Destinations {
+		destConfig := config.Sub(destType)
+		if destConfig == nil {
+			return nil, errors.Err("missing configuration for destination %s", destType)
+		}
+
+		factory, ok := Factories[destType]
+		if !ok {
+			return nil, errors.Err("unknown store type %s", destType)
+		}
+
+		destStore, err := factory(destConfig)
+		if err != nil {
+			return nil, errors.Err(err)
+		}
+		destinations = append(destinations, destStore)
+	}
+
+	return NewMultiWriterStore(MultiWriterParams{
+		Name:         cfg.Name,
+		Destinations: destinations,
+	}), nil
+}
+
+func init() {
+	RegisterStore(nameMultiWriter, MultiWriterStoreFactory)
+}
+
+// Name returns the store name
+func (m *MultiWriterStore) Name() string { return nameMultiWriter + "-" + m.name }
+
+// Has is not supported by MultiWriter
+func (m *MultiWriterStore) Has(hash string) (bool, error) {
+	return false, errors.Err(shared.ErrNotImplemented)
+}
+
+// Get is not supported by MultiWriter
+func (m *MultiWriterStore) Get(hash string) (stream.Blob, shared.BlobTrace, error) {
+	return nil, shared.BlobTrace{}, errors.Err(shared.ErrNotImplemented)
+}
+
+// Put writes the blob to all destination stores
+func (m *MultiWriterStore) Put(hash string, blob stream.Blob) error {
+	var wg sync.WaitGroup
+	errChan := make(chan error, len(m.destinations))
+
+	for _, dest := range m.destinations {
+		wg.Add(1)
+		go func(d BlobStore) {
+			defer wg.Done()
+			if err := d.Put(hash, blob); err != nil {
+				errChan <- errors.Err("failed to write to %s: %v", d.Name(), err)
+			}
+		}(dest)
+	}
+
+	wg.Wait()
+	close(errChan)
+
+	var errs []string
+	for err := range errChan {
+		errs = append(errs, err.Error())
+	}
+
+	if len(errs) > 0 {
+		return errors.Err("failed to write to some destinations: %s", strings.Join(errs, "; "))
+	}
+	return nil
+}
+
+// PutSD writes the SD blob to all destination stores
+func (m *MultiWriterStore) PutSD(hash string, blob stream.Blob) error {
+	var wg sync.WaitGroup
+	errChan := make(chan error, len(m.destinations))
+
+	for _, dest := range m.destinations {
+		wg.Add(1)
+		go func(d BlobStore) {
+			defer wg.Done()
+			if err := d.PutSD(hash, blob); err != nil {
+				errChan <- errors.Err("failed to write SD to %s: %v", d.Name(), err)
+			}
+		}(dest)
+	}
+
+	wg.Wait()
+	close(errChan)
+
+	var errs []string
+	for err := range errChan {
+		errs = append(errs, err.Error())
+	}
+
+	if len(errs) > 0 {
+		return errors.Err("failed to write SD to some destinations: %s", strings.Join(errs, "; "))
+	}
+	return nil
+}
+
+// Delete deletes the blob from all destination stores
+func (m *MultiWriterStore) Delete(hash string) error {
+	var wg sync.WaitGroup
+	errChan := make(chan error, len(m.destinations))
+
+	for _, dest := range m.destinations {
+		wg.Add(1)
+		go func(d BlobStore) {
+			defer wg.Done()
+			if err := d.Delete(hash); err != nil {
+				errChan <- errors.Err("failed to delete from %s: %v", d.Name(), err)
+			}
+		}(dest)
+	}
+
+	wg.Wait()
+	close(errChan)
+
+	var errs []string
+	for err := range errChan {
+		errs = append(errs, err.Error())
+	}
+
+	if len(errs) > 0 {
+		return errors.Err("failed to delete from some destinations: %s", strings.Join(errs, "; "))
+	}
+	return nil
+}
+
+// Shutdown shuts down all destination stores gracefully
+func (m *MultiWriterStore) Shutdown() {
+	for _, dest := range m.destinations {
+		dest.Shutdown()
+	}
+}