multi: add force tick endpoint behind debug server

To itest our autolooper, we need to be able to trigger dispatch on
demand. This functionality is included in a separate rpc server behind
a dev flag. Since it is unlikely that we need to split loop into
multiple rpc servers, this commit simply adds an additional debug server
rather than opting for a full subserver setup.

Author: carlaKC

.travis.yml

@@ -24,6 +24,7 @@ sudo: required
 script:
   - export GO111MODULE=on
   - make lint unit build mod-check
+  - make tags=dev
 
 after_script:
   - echo "Uploading to termbin.com..." && find *.log | xargs -I{} sh -c "cat {} | nc termbin.com 9999 | xargs -r0 printf '{} uploaded to %s'"

Makefile

@@ -11,6 +11,7 @@ GOMOD := GO111MODULE=on go mod
 
 COMMIT := $(shell git describe --abbrev=40 --dirty)
 LDFLAGS := -ldflags "-X $(PKG)/build.Commit=$(COMMIT)"
+DEV_TAGS = dev
 
 GOFILES_NOVENDOR = $(shell find . -type f -name '*.go' -not -path "./vendor/*")
 GOLIST := go list $(PKG)/... | grep -v '/vendor/'
@@ -64,10 +65,10 @@ mod-check:
 
 build:
 	@$(call print, "Building debug loop and loopd.")
-	$(GOBUILD) -o loop-debug $(LDFLAGS) $(PKG)/cmd/loop
-	$(GOBUILD) -o loopd-debug $(LDFLAGS) $(PKG)/cmd/loopd
+	$(GOBUILD) -tags="$(DEV_TAGS)" -o loop-debug $(LDFLAGS) $(PKG)/cmd/loop
+	$(GOBUILD) -tags="$(DEV_TAGS)" -o loopd-debug $(LDFLAGS) $(PKG)/cmd/loopd
 
 install:
 	@$(call print, "Installing loop and loopd.")
-	$(GOINSTALL) $(LDFLAGS) $(PKG)/cmd/loop
-	$(GOINSTALL) $(LDFLAGS) $(PKG)/cmd/loopd
+	$(GOINSTALL) -tags="${tags}" $(LDFLAGS) $(PKG)/cmd/loop
+	$(GOINSTALL) -tags="${tags}" $(LDFLAGS) $(PKG)/cmd/loopd

liquidity/liquidity.go

@@ -453,6 +453,17 @@ func (m *Manager) autoloop(ctx context.Context) error {
 	return nil
 }
 
+// ForceAutoLoop force-ticks our auto-out ticker.
+func (m *Manager) ForceAutoLoop(ctx context.Context) error {
+	select {
+	case m.cfg.AutoOutTicker.Force <- m.cfg.Clock.Now():
+		return nil
+
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
 // SuggestSwaps returns a set of swap suggestions based on our current liquidity
 // balance for the set of rules configured for the manager, failing if there are
 // no rules set. It takes an autoOut boolean that indicates whether the

loopd/daemon.go

@@ -197,6 +197,9 @@ func (d *Daemon) startWebServers() error {
 	d.grpcServer = grpc.NewServer(serverOpts...)
 	looprpc.RegisterSwapClientServer(d.grpcServer, d)
 
+	// Register our debug server if it is compiled in.
+	d.registerDebugServer()
+
 	// Next, start the gRPC server listening for HTTP/2 connections.
 	log.Infof("Starting gRPC listener")
 	serverTLSCfg, restClientCreds, err := getTLSConfig(d.cfg)
@@ -355,6 +358,7 @@ func (d *Daemon) initialize() error {
 
 	// Now finally fully initialize the swap client RPC server instance.
 	d.swapClientServer = swapClientServer{
+		network:      lndclient.Network(d.cfg.Network),
 		impl:         swapclient,
 		liquidityMgr: getLiquidityManager(swapclient),
 		lnd:          &d.lnd.LndServices,

loopd/macaroons.go

@@ -164,7 +164,8 @@ func (d *Daemon) startMacaroonService() error {
 		// We only generate one default macaroon that contains all
 		// existing permissions (equivalent to the admin.macaroon in
 		// lnd). Custom macaroons can be created through the bakery
-		// RPC.
+		// RPC. Add our debug permissions if required.
+		allPermissions = append(allPermissions, debugPermissions...)
 		loopMac, err := d.macaroonService.Oven.NewMacaroon(
 			ctx, bakery.LatestVersion, nil, allPermissions...,
 		)
@@ -196,6 +197,12 @@ func (d *Daemon) stopMacaroonService() error {
 // macaroonInterceptor creates gRPC server options with the macaroon security
 // interceptors.
 func (d *Daemon) macaroonInterceptor() []grpc.ServerOption {
+	// Add our debug permissions to our main set of required permissions
+	// if compiled in.
+	for endpoint, perm := range debugRequiredPermissions {
+		RequiredPermissions[endpoint] = perm
+	}
+
 	unaryInterceptor := d.macaroonService.UnaryServerInterceptor(
 		RequiredPermissions,
 	)

loopd/register_default.go

@@ -0,0 +1,14 @@
+// +build !dev
+
+package loopd
+
+import "gopkg.in/macaroon-bakery.v2/bakery"
+
+var (
+	debugRequiredPermissions = map[string][]bakery.Op{}
+	debugPermissions         []bakery.Op
+)
+
+// registerDebugServer is our default debug server registration function, which
+// excludes debug functionality.
+func (d *Daemon) registerDebugServer() {}

loopd/swapclient_server.go

@@ -34,6 +34,7 @@ const (
 
 // swapClientServer implements the grpc service exposed by loopd.
 type swapClientServer struct {
+	network          lndclient.Network
 	impl             *loop.Client
 	liquidityMgr     *liquidity.Manager
 	lnd              *lndclient.LndServices

loopd/swapclient_server_debug.go

@@ -0,0 +1,48 @@
+// +build dev
+
+package loopd
+
+import (
+	"context"
+	"fmt"
+
+	"gopkg.in/macaroon-bakery.v2/bakery"
+
+	"github.com/lightninglabs/lndclient"
+	"github.com/lightninglabs/loop/looprpc"
+)
+
+var (
+	debugRequiredPermissions = map[string][]bakery.Op{
+		"/looprpc.Debug/ForceAutoLoop": {{
+			Entity: "debug",
+			Action: "write",
+		}},
+	}
+
+	debugPermissions = []bakery.Op{
+		{
+			Entity: "debug",
+			Action: "write",
+		},
+	}
+)
+
+// registerDebugServer registers the debug server.
+func (d *Daemon) registerDebugServer() {
+	looprpc.RegisterDebugServer(d.grpcServer, d)
+}
+
+// ForceAutoLoop triggers our liquidity manager to dispatch an automated swap,
+// if one is suggested. This endpoint is only for testing purposes and cannot be
+// used on mainnet.
+func (s *swapClientServer) ForceAutoLoop(ctx context.Context,
+	_ *looprpc.ForceAutoLoopRequest) (*looprpc.ForceAutoLoopResponse, error) {
+
+	if s.network == lndclient.NetworkMainnet {
+		return nil, fmt.Errorf("force autoloop not allowed on mainnet")
+	}
+
+	err := s.liquidityMgr.ForceAutoLoop(ctx)
+	return &looprpc.ForceAutoLoopResponse{}, err
+}

looprpc/debug.pb.go

@@ -0,0 +1,23 @@
+syntax = "proto3";
+
+package looprpc;
+
+/*
+Debug is a service that exposes endpoints intended for testing purposes. These
+endpoints should not operate on mainnet, and should only be included if loop is
+built with the dev build tag.
+*/
+service Debug {
+    /*
+    ForceAutoLoop is intended for *testing purposes only* and will not work on
+    mainnet. This endpoint ticks our autoloop timer, triggering automated
+    dispatch of a swap if one is suggested.
+    */
+    rpc ForceAutoLoop(ForceAutoLoopRequest) returns (ForceAutoLoopResponse){}
+}
+
+message ForceAutoLoopRequest {
+}
+
+message ForceAutoLoopResponse {
+}