ref impl: driver agent: respond to head events and stay in sync

go.mod

@@ -28,6 +28,7 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/tsdb v0.7.1 // indirect
 	github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible // indirect
+	github.com/stretchr/objx v0.1.1 // indirect
 	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 // indirect
 	github.com/tklauser/go-sysconf v0.3.5 // indirect
 	github.com/tklauser/numcpus v0.2.2 // indirect

go.sum

@@ -336,6 +336,7 @@ github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/status-im/keycard-go v0.0.0-20190316090335-8537d3370df4/go.mod h1:RZLeN1LMWmRsyYjvAu+I6Dm9QmlDaIIt+Y+4Kd7Tp+Q=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.0/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=

opnode/internal/testlog/LICENSE

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+  The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+  2. Conveying Modified Versions.
+
+  If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
+that uses the facility (other than as an argument passed when the
+facility is invoked), then you may convey a copy of the modified
+version:
+
+   a) under this License, provided that you make a good faith effort to
+   ensure that, in the event an Application does not supply the
+   function or data, the facility still operates, and performs
+   whatever part of its purpose remains meaningful, or
+
+   b) under the GNU GPL, with none of the additional permissions of
+   this License applicable to that copy.
+
+  3. Object Code Incorporating Material from Library Header Files.
+
+  The object code form of an Application may incorporate material from
+a header file that is part of the Library.  You may convey such object
+code under terms of your choice, provided that, if the incorporated
+material is not limited to numerical parameters, data structure
+layouts and accessors, or small macros, inline functions and templates
+(ten or fewer lines in length), you do both of the following:
+
+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the object code with a copy of the GNU GPL and this license
+   document.
+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
+taken together, effectively do not restrict modification of the
+portions of the Library contained in the Combined Work and reverse
+engineering for debugging such modifications, if you also do each of
+the following:
+
+   a) Give prominent notice with each copy of the Combined Work that
+   the Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the Combined Work with a copy of the GNU GPL and this license
+   document.
+
+   c) For a Combined Work that displays copyright notices during
+   execution, include the copyright notice for the Library among
+   these notices, as well as a reference directing the user to the
+   copies of the GNU GPL and this license document.
+
+   d) Do one of the following:
+
+       0) Convey the Minimal Corresponding Source under the terms of this
+       License, and the Corresponding Application Code in a form
+       suitable for, and under terms that permit, the user to
+       recombine or relink the Application with a modified version of
+       the Linked Version to produce a modified Combined Work, in the
+       manner specified by section 6 of the GNU GPL for conveying
+       Corresponding Source.
+
+       1) Use a suitable shared library mechanism for linking with the
+       Library.  A suitable mechanism is one that (a) uses at run time
+       a copy of the Library already present on the user's computer
+       system, and (b) will operate properly with a modified version
+       of the Library that is interface-compatible with the Linked
+       Version.
+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
+   GNU GPL, and only to the extent that such information is
+   necessary to install and execute a modified version of the
+   Combined Work produced by recombining or relinking the
+   Application with a modified version of the Linked Version. (If
+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
+   Code. If you use option 4d1, you must provide the Installation
+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
+   conveyed under the terms of this License.
+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.

opnode/internal/testlog/README.md

@@ -0,0 +1,6 @@
+# testlog
+
+`github.com/ethereum/go-ethereum/internal/testlog`: a Go-ethereum util for logging in tests.
+
+Since we use the same logging, but as an external package, we have to move the test utility to our own internal package.
+

opnode/internal/testlog/testlog.go

@@ -0,0 +1,142 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package testlog provides a log handler for unit tests.
+package testlog
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// Handler returns a log handler which logs to the unit test log of t.
+func Handler(t *testing.T, level log.Lvl) log.Handler {
+	return log.LvlFilterHandler(level, &handler{t, log.TerminalFormat(false)})
+}
+
+type handler struct {
+	t   *testing.T
+	fmt log.Format
+}
+
+func (h *handler) Log(r *log.Record) error {
+	h.t.Logf("%s", h.fmt.Format(r))
+	return nil
+}
+
+// logger implements log.Logger such that all output goes to the unit test log via
+// t.Logf(). All methods in between logger.Trace, logger.Debug, etc. are marked as test
+// helpers, so the file and line number in unit test output correspond to the call site
+// which emitted the log message.
+type logger struct {
+	t  *testing.T
+	l  log.Logger
+	mu *sync.Mutex
+	h  *bufHandler
+}
+
+type bufHandler struct {
+	buf []*log.Record
+	fmt log.Format
+}
+
+func (h *bufHandler) Log(r *log.Record) error {
+	h.buf = append(h.buf, r)
+	return nil
+}
+
+// Logger returns a logger which logs to the unit test log of t.
+func Logger(t *testing.T, level log.Lvl) log.Logger {
+	l := &logger{
+		t:  t,
+		l:  log.New(),
+		mu: new(sync.Mutex),
+		h:  &bufHandler{fmt: log.TerminalFormat(false)},
+	}
+	l.l.SetHandler(log.LvlFilterHandler(level, l.h))
+	return l
+}
+
+func (l *logger) Trace(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Trace(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) Debug(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Debug(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) Info(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Info(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) Warn(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Warn(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) Error(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Error(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) Crit(msg string, ctx ...interface{}) {
+	l.t.Helper()
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.l.Crit(msg, ctx...)
+	l.flush()
+}
+
+func (l *logger) New(ctx ...interface{}) log.Logger {
+	return &logger{l.t, l.l.New(ctx...), l.mu, l.h}
+}
+
+func (l *logger) GetHandler() log.Handler {
+	return l.l.GetHandler()
+}
+
+func (l *logger) SetHandler(h log.Handler) {
+	l.l.SetHandler(h)
+}
+
+// flush writes all buffered messages and clears the buffer.
+func (l *logger) flush() {
+	l.t.Helper()
+	for _, r := range l.h.buf {
+		l.t.Logf("%s", l.h.fmt.Format(r))
+	}
+	l.h.buf = nil
+}

opnode/l2/driver.go

@@ -0,0 +1,62 @@
+package l2
+
+import (
+	"context"
+	"sync"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/event"
+
+	"github.com/ethereum-optimism/optimistic-specs/opnode/eth"
+
+	"github.com/ethereum/go-ethereum/log"
+)
+
+type Driver interface {
+	requestEngineHead(ctx context.Context) (refL1 eth.BlockID, refL2 eth.BlockID, err error)
+	findSyncStart(ctx context.Context) (nextRefL1 eth.BlockID, refL2 eth.BlockID, err error)
+	driverStep(ctx context.Context, nextRefL1 eth.BlockID, refL2 eth.BlockID, finalized eth.BlockID) (l2ID eth.BlockID, err error)
+}
+
+type EngineDriver struct {
+	Log log.Logger
+	// API bindings to execution engine
+	RPC     DriverAPI
+	DL      Downloader
+	SyncRef SyncReference
+
+	// The current driving force, to shutdown before closing the engine.
+	driveSub ethereum.Subscription
+	// There may only be 1 driver at a time
+	driveLock sync.Mutex
+
+	EngineDriverState
+}
+
+func (e *EngineDriver) Drive(ctx context.Context, l1Heads <-chan eth.HeadSignal) ethereum.Subscription {
+	e.driveLock.Lock()
+	defer e.driveLock.Unlock()
+	if e.driveSub != nil {
+		return e.driveSub
+	}
+
+	e.driveSub = event.NewSubscription(NewDriverLoop(ctx, &e.EngineDriverState, e.Log, l1Heads, e))
+	return e.driveSub
+}
+
+func (e *EngineDriver) requestEngineHead(ctx context.Context) (refL1 eth.BlockID, refL2 eth.BlockID, err error) {
+	refL1, refL2, _, err = e.SyncRef.RefByL2Num(ctx, nil, &e.Genesis)
+	return
+}
+
+func (e *EngineDriver) findSyncStart(ctx context.Context) (nextRefL1 eth.BlockID, refL2 eth.BlockID, err error) {
+	return FindSyncStart(ctx, e.SyncRef, &e.Genesis)
+}
+
+func (e *EngineDriver) driverStep(ctx context.Context, nextRefL1 eth.BlockID, refL2 eth.BlockID, finalized eth.BlockID) (l2ID eth.BlockID, err error) {
+	return DriverStep(ctx, e.Log, e.RPC, e.DL, nextRefL1, refL2, finalized.Hash)
+}
+
+func (e *EngineDriver) Close() {
+	e.driveSub.Unsubscribe()
+}