fix: allow skipping publish of existing advert (#117)

If one or multiple users upload the same blob multiple times the
`assert/index` invocation will create an advert that already exists.
This will cause `ipni-publisher` to return `ErrAlreadyAdvertised` and
the invocation fails. This PR ignores `ErrAlreadyAdvertised` because,
that's fine, whatever.

It also adds a mutex around publish per
storacha/ipni-publisher#3

---------

Co-authored-by: Vicente Olmedo <[email protected]>

pkg/service/providerindex/providerindex.go

@@ -3,9 +3,11 @@ package providerindex
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"iter"
 	"slices"
+	"sync"
 
 	logging "github.com/ipfs/go-log/v2"
 	ipnifind "github.com/ipni/go-libipni/find/client"
@@ -36,6 +38,7 @@ type ProviderIndexService struct {
 	findClient    ipnifind.Finder
 	publisher     publisher.Publisher
 	legacyClaims  LegacyClaimsFinder
+	mutex         sync.Mutex
 }
 
 var _ ProviderIndex = (*ProviderIndexService)(nil)
@@ -254,9 +257,18 @@ func (pi *ProviderIndexService) Publish(ctx context.Context, provider peer.AddrI
 		return fmt.Errorf("caching provider results: %w", err)
 	}
 
+	pi.mutex.Lock()
+	defer pi.mutex.Unlock()
+
 	id, err := pi.publisher.Publish(ctx, provider, contextID, digests, meta)
 	if err != nil {
-		return err
+		if errors.Is(err, publisher.ErrAlreadyAdvertised) {
+			// skipping is ok in this case
+			log.Warnf("Skipping previously published advert")
+			return nil
+		}
+
+		return fmt.Errorf("publishing advert: %w", err)
 	}
 	log.Infof("published IPNI advert: %s", id)
 	return nil

pkg/service/providerindex/providerindex_test.go

@@ -3,14 +3,19 @@ package providerindex
 import (
 	"context"
 	"errors"
+	"iter"
+	"slices"
 	"testing"
 
 	"github.com/ipni/go-libipni/find/model"
 	"github.com/multiformats/go-multicodec"
+	"github.com/multiformats/go-multihash"
 	"github.com/storacha/go-metadata"
 	"github.com/storacha/indexing-service/pkg/internal/testutil"
 	"github.com/storacha/indexing-service/pkg/internal/testutil/extmocks"
 	"github.com/storacha/indexing-service/pkg/types"
+	"github.com/storacha/ipni-publisher/pkg/publisher"
+	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -221,3 +226,32 @@ func TestGetProviderResults(t *testing.T) {
 		require.Error(t, err)
 	})
 }
+
+func TestPublish(t *testing.T) {
+	t.Run("allow skip publish existing advert", func(t *testing.T) {
+		mockStore := types.NewMockProviderStore(t)
+		mockIpniFinder := extmocks.NewMockIpniFinder(t)
+		mockIpniPublisher := extmocks.NewMockIpniPublisher(t)
+		mockLegacyClaims := NewMockLegacyClaimsFinder(t)
+
+		providerIndex := New(mockStore, mockIpniFinder, mockIpniPublisher, mockLegacyClaims)
+
+		result := testutil.RandomLocationCommitmentProviderResult()
+		provider := *result.Provider
+		contextID := string(result.ContextID)
+		digest := testutil.RandomMultihash()
+		anyDigestSeq := mock.MatchedBy(func(digests iter.Seq[multihash.Multihash]) bool {
+			return true
+		})
+		meta := metadata.MetadataContext.New()
+		err := meta.UnmarshalBinary(result.Metadata)
+		require.NoError(t, err)
+
+		mockStore.EXPECT().Add(testutil.AnyContext, digest, result).Return(1, nil)
+		mockStore.EXPECT().SetExpirable(testutil.AnyContext, digest, false).Return(nil)
+		mockIpniPublisher.EXPECT().Publish(testutil.AnyContext, provider, contextID, anyDigestSeq, meta).Return(testutil.RandomCID(), publisher.ErrAlreadyAdvertised)
+
+		err = providerIndex.Publish(context.Background(), provider, contextID, slices.Values([]multihash.Multihash{digest}), meta)
+		require.NoError(t, err)
+	})
+}