improve docs, logging and errors

share/shwap/p2p/bitswap/block_fetch.go

@@ -50,7 +50,6 @@ const maxPerFetch = 1024
 // See [Fetch] for detailed description.
 func fetch(ctx context.Context, exchg exchange.Interface, root *share.Root, blks ...Block) error {
 	fetcher := getFetcher(ctx, exchg)
-
 	cids := make([]cid.Cid, 0, len(blks))
 	duplicates := make(map[cid.Cid]Block)
 	for _, blk := range blks {
@@ -122,14 +121,14 @@ func unmarshal(unmarshalFn UnmarshalFn, data []byte) ([]byte, error) {
 	if err != nil {
 		return nil, fmt.Errorf("casting cid: %w", err)
 	}
-	// get ID out of CID validating it
+	// getBlock ID out of CID validating it
 	id, err := extractCID(cid)
 	if err != nil {
 		return nil, fmt.Errorf("validating cid: %w", err)
 	}
 
 	if unmarshalFn == nil {
-		// get registered UnmarshalFn and use it to check data validity and
+		// getBlock registered UnmarshalFn and use it to check data validity and
 		// pass it to Fetch caller
 		val, ok := unmarshalFns.Load(cid)
 		if !ok {

share/shwap/p2p/bitswap/block_registry.go

@@ -1,6 +1,7 @@
 package bitswap
 
 import (
+	"fmt"
 	"hash"
 
 	"github.com/ipfs/go-cid"
@@ -26,4 +27,8 @@ type blockSpec struct {
 	builder func(cid.Cid) (Block, error)
 }
 
+func (spec *blockSpec) String() string {
+	return fmt.Sprintf("BlockSpec{size: %d, codec: %d}", spec.size, spec.codec)
+}
+
 var specRegistry = make(map[uint64]blockSpec)

share/shwap/p2p/bitswap/block_store.go

@@ -11,32 +11,36 @@ import (
 	bitswappb "github.com/celestiaorg/celestia-node/share/shwap/p2p/bitswap/pb"
 )
 
+// Accessors abstracts storage system that indexes and manages multiple eds.Accessors by network height.
 type Accessors interface {
+	// Get returns an Accessor by its height.
 	Get(ctx context.Context, height uint64) (eds.Accessor, error)
 }
 
+// Blockstore implements generalized Bitswap compatible storage over Shwap containers
+// that operates with Block and accesses data through Accessors.
 type Blockstore struct {
 	Accessors
 }
 
-func (b *Blockstore) Get(ctx context.Context, cid cid.Cid) (blocks.Block, error) {
+func (b *Blockstore) getBlock(ctx context.Context, cid cid.Cid) (blocks.Block, error) {
 	spec, ok := specRegistry[cid.Prefix().MhType]
 	if !ok {
-		return nil, fmt.Errorf("unsupported codec")
+		return nil, fmt.Errorf("unsupported Block type: %v", cid.Prefix().MhType)
 	}
 
 	blk, err := spec.builder(cid)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to build a Block for %s: %w", spec.String(), err)
 	}
 
 	eds, err := b.Accessors.Get(ctx, blk.Height())
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("getting EDS Accessor for height %v: %w", blk.Height(), err)
 	}
 
 	if err = blk.Populate(ctx, eds); err != nil {
-		return nil, fmt.Errorf("failed to unmarshal Shwap Block: %w", err)
+		return nil, fmt.Errorf("failed to populate Shwap Block on height %v for %s: %w", blk.Height(), spec.String(), err)
 	}
 
 	containerData, err := blk.Marshal()
@@ -62,6 +66,16 @@ func (b *Blockstore) Get(ctx context.Context, cid cid.Cid) (blocks.Block, error)
 	return bitswapBlk, nil
 }
 
+func (b *Blockstore) Get(ctx context.Context, cid cid.Cid) (blocks.Block, error) {
+	blk, err := b.getBlock(ctx, cid)
+	if err != nil {
+		log.Errorf("blockstore: getting local block(%s): %s", cid, err)
+		return nil, err
+	}
+
+	return blk, nil
+}
+
 func (b *Blockstore) GetSize(ctx context.Context, cid cid.Cid) (int, error) {
 	// TODO(@Wondertan): There must be a way to derive size without reading, proving, serializing and
 	//  allocating Sample's block.Block or we could do hashing