feat(lens): Optimize StateGetActor calls.

go.sum

@@ -1346,6 +1346,7 @@ github.com/onsi/gomega v1.9.0/go.mod h1:Ho0h+IUsWyvy1OpqCwxlQ/21gkhVunqlU8fDGcoT
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 github.com/onsi/gomega v1.10.2 h1:aY/nuoWlKJud2J6U0E3NWsjlg+0GtwXxgEqthRdzlcs=
 github.com/onsi/gomega v1.10.2/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
+github.com/op/go-logging v0.0.0-20160315200505-970db520ece7 h1:lDH9UUVJtmYCjyT0CI4q8xvlXPxeZ0gYCVvWbmPlp88=
 github.com/op/go-logging v0.0.0-20160315200505-970db520ece7/go.mod h1:HzydrMdWErDVzsI23lYNej1Htcns9BCg93Dk0bBINWk=
 github.com/opentracing-contrib/go-grpc v0.0.0-20180928155321-4b5a12d3ff02/go.mod h1:JNdpVEzCpXBgIiv4ds+TzhN1hrtxq6ClLrTlT9OQRSc=
 github.com/opentracing-contrib/go-grpc v0.0.0-20191001143057-db30781987df h1:vdYtBU6zvL7v+Tr+0xFM/qhahw/EvY8DMMunZHKH6eE=

lens/carrepo/carrepo.go

@@ -32,5 +32,6 @@ func NewAPIOpener(c *cli.Context) (lens.APIOpener, lens.APICloser, error) {
 		tsk := types.NewTipSetKey(c...)
 		return &tsk, nil
 	}
+
 	return util.NewAPIOpener(c, cacheDB, h)
 }

lens/lotus/api.go

@@ -132,7 +132,10 @@ func (aw *APIWrapper) StateGetActor(ctx context.Context, actor address.Address,
 	ctx, _ = tag.New(ctx, tag.Upsert(metrics.API, "StateGetActor"))
 	stop := metrics.Timer(ctx, metrics.LensRequestDuration)
 	defer stop()
-	return aw.FullNode.StateGetActor(ctx, actor, tsk)
+
+	//return aw.FullNode.StateGetActor(ctx, actor, tsk)
+	// TODO idk how to get a store.ChainStore here
+	return lens.OptimizedStateGetActorWithFallback(ctx, aw.Store(), aw.FullNode, aw.FullNode, actor, tsk)
 }
 
 func (aw *APIWrapper) StateListActors(ctx context.Context, tsk types.TipSetKey) ([]address.Address, error) {

lens/lotusrepo/repo.go

@@ -126,6 +126,11 @@ func (ra *RepoAPI) Store() adt.Store {
 	return adtStore
 }
 
+// TODO: Remove. See https://github.com/filecoin-project/sentinel-visor/issues/196
+func (ra *RepoAPI) StateGetActor(ctx context.Context, actor address.Address, tsk types.TipSetKey) (*types.Actor, error) {
+	return lens.OptimizedStateGetActorWithFallback(ctx, ra.ChainAPI.Chain.Store(ctx), ra.ChainAPI, ra.StateAPI, actor, tsk)
+}
+
 func (ra *RepoAPI) ClientStartDeal(ctx context.Context, params *api.StartDealParams) (*cid.Cid, error) {
 	return nil, fmt.Errorf("unsupported")
 }

lens/util.go

@@ -0,0 +1,58 @@
+package lens
+
+import (
+	"context"
+	"errors"
+
+	"github.com/filecoin-project/go-address"
+	"github.com/filecoin-project/lotus/chain/state"
+	"github.com/filecoin-project/lotus/chain/types"
+	"github.com/filecoin-project/lotus/node/impl/full"
+	cbor "github.com/ipfs/go-ipld-cbor"
+	logging "github.com/ipfs/go-log/v2"
+	"golang.org/x/xerrors"
+)
+
+var logger = logging.Logger("visor/lens/lotus")
+
+// OptimizedStateGetActorWithFallback is a helper to obtain an actor in the
+// state of the current tipset without recomputing the full tipset. It does
+// this by obtaining the child tipset (current height+1) and using the
+// pre-computed ParentState().
+//
+// TODO: Remove. See:  https://github.com/filecoin-project/sentinel-visor/issues/196
+func OptimizedStateGetActorWithFallback(ctx context.Context, store cbor.IpldStore, chainAPI full.ChainModuleAPI, fallback full.StateModuleAPI, actor address.Address, tsk types.TipSetKey) (*types.Actor, error) {
+	act, err := efficientStateGetActorFromChainStore(ctx, store, chainAPI, actor, tsk)
+	if err != nil {
+		logger.Warnf("Optimized StateGetActorError: %s. Falling back to default StateGetActor().", err)
+		return fallback.StateGetActor(ctx, actor, tsk)
+	}
+	return act, nil
+}
+
+func efficientStateGetActorFromChainStore(ctx context.Context, store cbor.IpldStore, chainAPI full.ChainModuleAPI, actor address.Address, tsk types.TipSetKey) (*types.Actor, error) {
+	ts, err := chainAPI.ChainGetTipSet(ctx, tsk)
+	if err != nil {
+		return nil, xerrors.Errorf("Failed to load tipset: %w", err)
+	}
+
+	// heaviest tipset means look on the main chain and false means return tipset following null round.
+	head, err := chainAPI.ChainHead(ctx)
+	if err != nil {
+		return nil, xerrors.Errorf("Failed to get chain head: %w", err)
+	}
+	child, err := chainAPI.ChainGetTipSetByHeight(ctx, ts.Height()+1, head.Key())
+	if err != nil {
+		return nil, xerrors.Errorf("load child tipset: %w", err)
+	}
+
+	if !types.CidArrsEqual(child.Parents().Cids(), ts.Cids()) {
+		return nil, errors.New("child is not on the same chain")
+	}
+
+	st, err := state.LoadStateTree(store, child.ParentState())
+	if err != nil {
+		return nil, xerrors.Errorf("load state tree: %w", err)
+	}
+	return st.GetActor(actor)
+}

lens/util/repo.go

@@ -104,6 +104,11 @@ type LensAPI struct {
 	cs        *store.ChainStore
 }
 
+// TODO: Remove. See https://github.com/filecoin-project/sentinel-visor/issues/196
+func (ra *LensAPI) StateGetActor(ctx context.Context, actor address.Address, tsk types.TipSetKey) (*types.Actor, error) {
+	return lens.OptimizedStateGetActorWithFallback(ctx, ra.cs.Store(ctx), ra.FullNodeAPI.ChainAPI, ra.FullNodeAPI.StateAPI, actor, tsk)
+}
+
 func (ra *LensAPI) ComputeGasOutputs(gasUsed, gasLimit int64, baseFee, feeCap, gasPremium abi.TokenAmount) vm.GasOutputs {
 	return vm.ComputeGasOutputs(gasUsed, gasLimit, baseFee, feeCap, gasPremium)
 }