Merge pull request #404 from cosmos/feature/multi-query

Add Proper query to BaseApp and rootMultiStore

baseapp/baseapp.go

@@ -199,9 +199,14 @@ func (app *BaseApp) InitChain(req abci.RequestInitChain) (res abci.ResponseInitC
 }
 
 // Implements ABCI.
+// Delegates to CommitMultiStore if it implements Queryable
 func (app *BaseApp) Query(req abci.RequestQuery) (res abci.ResponseQuery) {
-	// TODO: See app/query.go
-	return
+	queryable, ok := app.cms.(sdk.Queryable)
+	if !ok {
+		msg := "application doesn't support queries"
+		return sdk.ErrUnknownRequest(msg).Result().ToQuery()
+	}
+	return queryable.Query(req)
 }
 
 // Implements ABCI.

store/cachemultistore.go

@@ -10,14 +10,18 @@ import (
 // cacheMultiStore holds many cache-wrapped stores.
 // Implements MultiStore.
 type cacheMultiStore struct {
-	db     CacheKVStore
-	stores map[StoreKey]CacheWrap
+	db         CacheKVStore
+	stores     map[StoreKey]CacheWrap
+	keysByName map[string]StoreKey
 }
 
+var _ CacheMultiStore = cacheMultiStore{}
+
 func newCacheMultiStoreFromRMS(rms *rootMultiStore) cacheMultiStore {
 	cms := cacheMultiStore{
-		db:     NewCacheKVStore(dbStoreAdapter{rms.db}),
-		stores: make(map[StoreKey]CacheWrap, len(rms.stores)),
+		db:         NewCacheKVStore(dbStoreAdapter{rms.db}),
+		stores:     make(map[StoreKey]CacheWrap, len(rms.stores)),
+		keysByName: rms.keysByName,
 	}
 	for key, store := range rms.stores {
 		cms.stores[key] = store.CacheWrap()

store/iavlstore.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"sync"
 
+	abci "github.com/tendermint/abci/types"
 	"github.com/tendermint/iavl"
 	cmn "github.com/tendermint/tmlibs/common"
 	dbm "github.com/tendermint/tmlibs/db"
@@ -31,6 +32,7 @@ func LoadIAVLStore(db dbm.DB, id CommitID) (CommitStore, error) {
 
 var _ KVStore = (*iavlStore)(nil)
 var _ CommitStore = (*iavlStore)(nil)
+var _ Queryable = (*iavlStore)(nil)
 
 // iavlStore Implements KVStore and CommitStore.
 type iavlStore struct {
@@ -123,6 +125,55 @@ func (st *iavlStore) ReverseIterator(start, end []byte) Iterator {
 	return newIAVLIterator(st.tree.Tree(), start, end, false)
 }
 
+// Query implements ABCI interface, allows queries
+//
+// by default we will return from (latest height -1),
+// as we will have merkle proofs immediately (header height = data height + 1)
+// If latest-1 is not present, use latest (which must be present)
+// if you care to have the latest data to see a tx results, you must
+// explicitly set the height you want to see
+func (st *iavlStore) Query(req abci.RequestQuery) (res abci.ResponseQuery) {
+	if len(req.Data) == 0 {
+		msg := "Query cannot be zero length"
+		return sdk.ErrTxParse(msg).Result().ToQuery()
+	}
+
+	tree := st.tree
+	height := req.Height
+	if height == 0 {
+		latest := tree.Version64()
+		if tree.VersionExists(latest - 1) {
+			height = latest - 1
+		} else {
+			height = latest
+		}
+	}
+	// store the height we chose in the response
+	res.Height = height
+
+	switch req.Path {
+	case "/store", "/key": // Get by key
+		key := req.Data // Data holds the key bytes
+		res.Key = key
+		if req.Prove {
+			value, proof, err := tree.GetVersionedWithProof(key, height)
+			if err != nil {
+				res.Log = err.Error()
+				break
+			}
+			res.Value = value
+			res.Proof = proof.Bytes()
+		} else {
+			_, res.Value = tree.GetVersioned(key, height)
+		}
+
+	default:
+		msg := fmt.Sprintf("Unexpected Query path: %v", req.Path)
+		return sdk.ErrUnknownRequest(msg).Result().ToQuery()
+	}
+	return
+}
+
 //----------------------------------------
 
 // Implements Iterator.

store/iavlstore_test.go

@@ -5,10 +5,12 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	abci "github.com/tendermint/abci/types"
+	"github.com/tendermint/iavl"
 	cmn "github.com/tendermint/tmlibs/common"
 	dbm "github.com/tendermint/tmlibs/db"
 
-	"github.com/tendermint/iavl"
+	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 var (
@@ -79,3 +81,63 @@ func TestIAVLIterator(t *testing.T) {
 		i += 1
 	}
 }
+
+func TestIAVLStoreQuery(t *testing.T) {
+	db := dbm.NewMemDB()
+	tree := iavl.NewVersionedTree(db, cacheSize)
+	iavlStore := newIAVLStore(tree, numHistory)
+
+	k, v := []byte("wind"), []byte("blows")
+	k2, v2 := []byte("water"), []byte("flows")
+	v3 := []byte("is cold")
+	// k3, v3 := []byte("earth"), []byte("soes")
+	// k4, v4 := []byte("fire"), []byte("woes")
+
+	cid := iavlStore.Commit()
+	ver := cid.Version
+	query := abci.RequestQuery{Path: "/key", Data: k, Height: ver}
+
+	// set data without commit, doesn't show up
+	iavlStore.Set(k, v)
+	qres := iavlStore.Query(query)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Nil(t, qres.Value)
+
+	// commit it, but still don't see on old version
+	cid = iavlStore.Commit()
+	qres = iavlStore.Query(query)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Nil(t, qres.Value)
+
+	// but yes on the new version
+	query.Height = cid.Version
+	qres = iavlStore.Query(query)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Equal(t, v, qres.Value)
+
+	// modify
+	iavlStore.Set(k2, v2)
+	iavlStore.Set(k, v3)
+	cid = iavlStore.Commit()
+
+	// query will return old values, as height is fixed
+	qres = iavlStore.Query(query)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Equal(t, v, qres.Value)
+
+	// update to latest in the query and we are happy
+	query.Height = cid.Version
+	qres = iavlStore.Query(query)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Equal(t, v3, qres.Value)
+	query2 := abci.RequestQuery{Path: "/key", Data: k2, Height: cid.Version}
+	qres = iavlStore.Query(query2)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Equal(t, v2, qres.Value)
+
+	// default (height 0) will show latest -1
+	query0 := abci.RequestQuery{Path: "/store", Data: k}
+	qres = iavlStore.Query(query0)
+	assert.Equal(t, uint32(sdk.CodeOK), qres.Code)
+	assert.Equal(t, v, qres.Value)
+}

store/rootmultistore.go

@@ -2,10 +2,13 @@ package store
 
 import (
 	"fmt"
+	"strings"
 
+	"golang.org/x/crypto/ripemd160"
+
+	abci "github.com/tendermint/abci/types"
 	dbm "github.com/tendermint/tmlibs/db"
 	"github.com/tendermint/tmlibs/merkle"
-	"golang.org/x/crypto/ripemd160"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
@@ -24,15 +27,18 @@ type rootMultiStore struct {
 	lastCommitID CommitID
 	storesParams map[StoreKey]storeParams
 	stores       map[StoreKey]CommitStore
+	keysByName   map[string]StoreKey
 }
 
 var _ CommitMultiStore = (*rootMultiStore)(nil)
+var _ Queryable = (*rootMultiStore)(nil)
 
 func NewCommitMultiStore(db dbm.DB) *rootMultiStore {
 	return &rootMultiStore{
 		db:           db,
 		storesParams: make(map[StoreKey]storeParams),
 		stores:       make(map[StoreKey]CommitStore),
+		keysByName:   make(map[string]StoreKey),
 	}
 }
 
@@ -53,6 +59,7 @@ func (rs *rootMultiStore) MountStoreWithDB(key StoreKey, typ StoreType, db dbm.D
 		db:  db,
 		typ: typ,
 	}
+	rs.keysByName[key.Name()] = key
 }
 
 // Implements CommitMultiStore.
@@ -169,6 +176,66 @@ func (rs *rootMultiStore) GetKVStore(key StoreKey) KVStore {
 	return rs.stores[key].(KVStore)
 }
 
+// getStoreByName will first convert the original name to
+// a special key, before looking up the CommitStore.
+// This is not exposed to the extensions (which will need the
+// StoreKey), but is useful in main, and particularly app.Query,
+// in order to convert human strings into CommitStores.
+func (rs *rootMultiStore) getStoreByName(name string) Store {
+	key := rs.keysByName[name]
+	if key == nil {
+		return nil
+	}
+	return rs.stores[key]
+}
+
+//---------------------- Query ------------------
+
+// Query calls substore.Query with the same `req` where `req.Path` is
+// modified to remove the substore prefix.
+// Ie. `req.Path` here is `/<substore>/<path>`, and trimmed to `/<path>` for the substore.
+// TODO: add proof for `multistore -> substore`.
+func (rs *rootMultiStore) Query(req abci.RequestQuery) abci.ResponseQuery {
+	// Query just routes this to a substore.
+	path := req.Path
+	storeName, subpath, err := parsePath(path)
+	if err != nil {
+		return err.Result().ToQuery()
+	}
+
+	store := rs.getStoreByName(storeName)
+	if store == nil {
+		msg := fmt.Sprintf("no such store: %s", storeName)
+		return sdk.ErrUnknownRequest(msg).Result().ToQuery()
+	}
+	queryable, ok := store.(Queryable)
+	if !ok {
+		msg := fmt.Sprintf("store %s doesn't support queries", storeName)
+		return sdk.ErrUnknownRequest(msg).Result().ToQuery()
+	}
+
+	// trim the path and make the query
+	req.Path = subpath
+	res := queryable.Query(req)
+	return res
+}
+
+// parsePath expects a format like /<storeName>[/<subpath>]
+// Must start with /, subpath may be empty
+// Returns error if it doesn't start with /
+func parsePath(path string) (storeName string, subpath string, err sdk.Error) {
+	if !strings.HasPrefix(path, "/") {
+		err = sdk.ErrUnknownRequest(fmt.Sprintf("invalid path: %s", path))
+		return
+	}
+	paths := strings.SplitN(path[1:], "/", 2)
+	storeName = paths[0]
+	if len(paths) == 2 {
+		subpath = "/" + paths[1]
+	}
+	return
+}
+
 //----------------------------------------
 
 func (rs *rootMultiStore) loadCommitStoreFromParams(id CommitID, params storeParams) (store CommitStore, err error) {