feat(storeutil): construct loader & storer from store

Utility functions to construct loaders/storers from a go-blockstore

go.mod

@@ -4,13 +4,17 @@ go 1.12
 
 require (
 	github.com/btcsuite/btcd v0.0.0-20190629003639-c26ffa870fd8 // indirect
+	github.com/dgraph-io/badger v2.0.0-rc.2+incompatible // indirect
 	github.com/gogo/protobuf v1.2.1
 	github.com/golang/protobuf v1.3.2 // indirect
 	github.com/ipfs/go-block-format v0.0.2
 	github.com/ipfs/go-cid v0.0.3
+	github.com/ipfs/go-datastore v0.0.5
+	github.com/ipfs/go-ipfs v0.4.21 // indirect
+	github.com/ipfs/go-ipfs-blockstore v0.0.1
 	github.com/ipfs/go-ipfs-blocksutil v0.0.1
 	github.com/ipfs/go-log v0.0.1
-	github.com/ipfs/go-peertaskqueue v0.0.1
+	github.com/ipfs/go-peertaskqueue v0.0.4
 	github.com/ipld/go-ipld-prime v0.0.0-20190730002952-369bb56ad071
 	github.com/jbenet/go-random v0.0.0-20190219211222-123a90aedc0c
 	github.com/libp2p/go-eventbus v0.0.3 // indirect
@@ -18,12 +22,12 @@ require (
 	github.com/libp2p/go-libp2p-core v0.0.9
 	github.com/libp2p/go-libp2p-net v0.1.0 // indirect
 	github.com/libp2p/go-libp2p-secio v0.1.1 // indirect
+	github.com/libp2p/go-libp2p-transport v0.0.5 // indirect
 	github.com/libp2p/go-msgio v0.0.4 // indirect
 	github.com/mattn/go-colorable v0.1.2 // indirect
 	github.com/multiformats/go-multiaddr v0.0.4
 	github.com/multiformats/go-multiaddr-dns v0.0.3 // indirect
 	github.com/multiformats/go-multihash v0.0.6
-	github.com/opentracing/opentracing-go v1.1.0 // indirect
 	github.com/smartystreets/goconvey v0.0.0-20190710185942-9d28bd7c0945 // indirect
 	go.opencensus.io v0.22.0 // indirect
 	golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4 // indirect

storeutil/storeutil.go

+package storeutil
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	blocks "github.com/ipfs/go-block-format"
+	bstore "github.com/ipfs/go-ipfs-blockstore"
+	ipld "github.com/ipld/go-ipld-prime"
+	cidlink "github.com/ipld/go-ipld-prime/linking/cid"
+)
+
+// LoaderForBlockstore returns an IPLD Loader function compatible with graphsync
+// from an IPFS blockstore
+func LoaderForBlockstore(bs bstore.Blockstore) ipld.Loader {
+	return func(lnk ipld.Link, lnkCtx ipld.LinkContext) (io.Reader, error) {
+		asCidLink, ok := lnk.(cidlink.Link)
+		if !ok {
+			return nil, fmt.Errorf("Unsupported Link Type")
+		}
+		block, err := bs.Get(asCidLink.Cid)
+		if err != nil {
+			return nil, err
+		}
+		return bytes.NewReader(block.RawData()), nil
+	}
+}
+
+// StorerForBlockstore returns an IPLD Storer function compatible with graphsync
+// from an IPFS blockstore
+func StorerForBlockstore(bs bstore.Blockstore) ipld.Storer {
+	return func(lnkCtx ipld.LinkContext) (io.Writer, ipld.StoreCommitter, error) {
+		var buffer bytes.Buffer
+		committer := func(lnk ipld.Link) error {
+			asCidLink, ok := lnk.(cidlink.Link)
+			if !ok {
+				return fmt.Errorf("Unsupported Link Type")
+			}
+			block, err := blocks.NewBlockWithCid(buffer.Bytes(), asCidLink.Cid)
+			if err != nil {
+				return err
+			}
+			return bs.Put(block)
+		}
+		return &buffer, committer, nil
+	}
+}

storeutil/storeutil_test.go

+package storeutil
+
+import (
+	"io/ioutil"
+	"testing"
+
+	blocks "github.com/ipfs/go-block-format"
+	"github.com/ipfs/go-datastore"
+	dss "github.com/ipfs/go-datastore/sync"
+	bstore "github.com/ipfs/go-ipfs-blockstore"
+	ipld "github.com/ipld/go-ipld-prime"
+	cidlink "github.com/ipld/go-ipld-prime/linking/cid"
+
+	"github.com/ipfs/go-graphsync/testutil"
+)
+
+func TestLoader(t *testing.T) {
+	store := bstore.NewBlockstore(dss.MutexWrap(datastore.NewMapDatastore()))
+	blk := testutil.GenerateBlocksOfSize(1, 1000)[0]
+	err := store.Put(blk)
+	if err != nil {
+		t.Fatal("Unable to put block to store")
+	}
+	loader := LoaderForBlockstore(store)
+	data, err := loader(cidlink.Link{Cid: blk.Cid()}, ipld.LinkContext{})
+	if err != nil {
+		t.Fatal("Unable to load block with loader")
+	}
+	bytes, err := ioutil.ReadAll(data)
+	if err != nil {
+		t.Fatal("Unable to read bytes from reader returned by loader")
+	}
+	returnedBlock := blocks.NewBlock(bytes)
+	if returnedBlock.Cid() != blk.Cid() {
+		t.Fatal("Did not return correct block with loader")
+	}
+}
+
+func TestStorer(t *testing.T) {
+	store := bstore.NewBlockstore(dss.MutexWrap(datastore.NewMapDatastore()))
+	blk := testutil.GenerateBlocksOfSize(1, 1000)[0]
+	storer := StorerForBlockstore(store)
+	buffer, commit, err := storer(ipld.LinkContext{})
+	if err != nil {
+		t.Fatal("Unable to setup buffer")
+	}
+	_, err = buffer.Write(blk.RawData())
+	if err != nil {
+		t.Fatal("Unable to write data to buffer")
+	}
+	err = commit(cidlink.Link{Cid: blk.Cid()})
+	if err != nil {
+		t.Fatal("Unable to commit with storer function")
+	}
+	_, err = store.Get(blk.Cid())
+	if err != nil {
+		t.Fatal("Block not written to store")
+	}
+}