hyperledger-labs/scorex

Scorex 2.0 Core

Scorex 2 - The modular blockchain framework

Scorex and Scorex 2

Scorex 2 is modular blockchain framework is Scala language which allows for free and limitless experimentation with a wide variety of designs.

It is a complete rewrite of Scorex framework, which can be found at https://github.com/input-output-hk/Scorex.

Motivation

If you have a new design for a blockchain system, there are few options available in regards with an implementation:

• you can fork codebase of a Bitcoin or Ethereum client. However, such clients are optimized towards concrete protocol, thus implementing something different would be a cumbersome task.
• there are some modular frameworks, such as Scorex, where you can change consensus layer, or transactional layer, or both. Still, these modules have concrete interfaces, so for many designs more low-level and abstract approach was needed.

We have read a lot of research papers to make Scorex 2 supporting their implementations. Its abstract core allows for implementing a broad range of systems, including ones with multiple types of blocks and non-linear history.

Features

• Compact, functional code
• Modular design with fine granularity
• Scala language
• Asynchronous networking layer on top of TCP
• JSON API
• Cryptographic primitives externalized into separate scrypto framework
• Some examples provided, including one working in production

Documentation and Communication.

Please join maillist at https://groups.io/g/scorex-dev. There is tutorial in progress, available at https://github.com/ScorexFoundation/ScorexTutorial.

Examples

There are two examples of blockchain systems built with Scorex:

• implementation of TwinsCoin, a hybrid (Proof-of-Work + Proof-of-Stake) cryptocurrency is provided in this repository, please check dedicated readme.
• TreasuryCoin is an experimental implementation of the perspective treasury system described in A Treasury System for Cryptocurrencies: Enabling Better Collaborative Intelligence.
• Ergo Platform, a Proof-of-Work cryptocurrency and financial contracts platform, with support for stateless nodes, different operating regimes with up to 4 possible sections in a block etc.

Development Plans

Final 1.0 release of Scorex 2 is not done but near. Currently we're polishing and auditing the codebase towards the release. Then we will consider further plans, possibly including:

• Improved networking layer
• Support for Scala 3
• More examples, possibly including non-linear systems (such as DAGs)

Contributions

Contributions are welcome! Please take a look into issues. Testing codebase is still not perfect at the moment, so writing a test is not just good for start, but useful for the product as well.

New examples would be very helpful as well!

Release

To publish release version to Sonatype:

• make a tag with version number vX.Y.Z (used by sbt-dynver to set version in build.sbt);
• use the new tag to make a Github release, which triggers release.yml workflow and publishes release version to Sonatype;

scorex's Issues

Extract "self-exclusion" logic from PeerDatabase

Make PeerManager responsible for not letting "self" get into the PeerDatabase. See discussion in #156 .

Eliminate VL type parameter in NodeViewHolderTests?

Is it possible to eliminate VL type parameter in NodeViewHolderTests class?

Implement DefaultWallet25519.scan() and bulkScan()

Make Access Control Allowed Origin tunable

Currently, all the settings.json files have a field called rpcAllowed, but it is not used anywhere. I would assume that this was designed to take in some origins for which CORS would be allowed.

At the same time, when you set cors to be true. Access-Control-Allow-Origin will be set to * in ApiRoute.scala.

Wouldn't it make more sense to control the Access-Control-Allow-Origin with the origins specified in rpcAllowed?

Hello World sample

It will really help a newcomer to get started if there is a "Hello World" level app with Scorex (something similar to slide 20 from https://www.slideshare.net/AlexChepurnoy/scorex-the-modular-blockchain-framework or https://github.com/input-output-hk/Scorex/wiki/Getting-started#running-scorex).

I tried to port https://github.com/input-output-hk/Scorex/wiki/Getting-started#running-scorex, but there are quite a few changes between the input-output-hk version and the ScorexFoundation version, so I got lost). I am looking at examples in https://github.com/ScorexFoundation/Scorex/tree/master/examples, but there is a lot going on there, so for someone that is just starting out, it can be a bit intimidating.

Warning and error messages in Twinscoin logs to fix

Found some strange behaviour between two running nodes.
It looks like for each sync request we get 2 answers from 1 node.
That is the reason for warnings like
[2-Hop-akka.actor.default-dispatcher-2] >> [WARN ] examples.hybrid.HybridNodeViewHolder >> 16:21:48.003 Received modifier 99aQPCZfUYc68nrvQtEH7PJ5RVv28abBWECaMce2bttL that is already in history

Full log

[2-Hop-akka.actor.default-dispatcher-10] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.985 Send message MessageSpec(22: RequestModifier) to localhost/127.0.0.1:54378
[2-Hop-akka.actor.default-dispatcher-12] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.986 Send message MessageSpec(22: RequestModifier) to localhost/127.0.0.1:9084
[2-Hop-akka.actor.default-dispatcher-4] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.987 Received message MessageSpec(33: Modifier) from localhost/127.0.0.1:9084
[2-Hop-akka.actor.default-dispatcher-4] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.988 Got modifiers of type 3 with ids Pojoe34B1cxMSXR2GZNAURNv3csphAQ2DY6ddnHQ3zm
[2-Hop-akka.actor.default-dispatcher-4] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.988 From remote connected peer: ConnectedPeer(localhost/127.0.0.1:9084)
[2-Hop-akka.actor.default-dispatcher-12] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.987 Received message MessageSpec(33: Modifier) from localhost/127.0.0.1:54378
[2-Hop-akka.actor.default-dispatcher-6] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.992 Got modifiers of type 3 with ids Pojoe34B1cxMSXR2GZNAURNv3csphAQ2DY6ddnHQ3zm
[2-Hop-akka.actor.default-dispatcher-6] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.992 From remote connected peer: ConnectedPeer(localhost/127.0.0.1:54378)
[2-Hop-akka.actor.default-dispatcher-13] >> [WARN ] examples.hybrid.HybridNodeViewHolder >> 16:21:47.992 Received modifier Pojoe34B1cxMSXR2GZNAURNv3csphAQ2DY6ddnHQ3zm that is already in history
[2-Hop-akka.actor.default-dispatcher-13] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.996 Received message MessageSpec(55: Inv) from localhost/127.0.0.1:54378
[2-Hop-akka.actor.default-dispatcher-6] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.996 Received message MessageSpec(55: Inv) from localhost/127.0.0.1:9084
[2-Hop-akka.actor.default-dispatcher-12] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.996 Send message MessageSpec(22: RequestModifier) to localhost/127.0.0.1:54378
[2-Hop-akka.actor.default-dispatcher-2] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.997 Send message MessageSpec(22: RequestModifier) to localhost/127.0.0.1:9084
[2-Hop-akka.actor.default-dispatcher-12] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.999 Received message MessageSpec(33: Modifier) from localhost/127.0.0.1:54378
[2-Hop-akka.actor.default-dispatcher-8] >> [INFO ] s.core.network.PeerConnectionHandler >> 16:21:47.999 Received message MessageSpec(33: Modifier) from localhost/127.0.0.1:9084
[2-Hop-akka.actor.default-dispatcher-2] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.999 Got modifiers of type 4 with ids 99aQPCZfUYc68nrvQtEH7PJ5RVv28abBWECaMce2bttL
[2-Hop-akka.actor.default-dispatcher-2] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:47.999 From remote connected peer: ConnectedPeer(localhost/127.0.0.1:54378)
[2-Hop-akka.actor.default-dispatcher-2] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:48.000 Got modifiers of type 4 with ids 99aQPCZfUYc68nrvQtEH7PJ5RVv28abBWECaMce2bttL
[2-Hop-akka.actor.default-dispatcher-2] >> [INFO ] s.core.network.NodeViewSynchronizer >> 16:21:48.000 From remote connected peer: ConnectedPeer(localhost/127.0.0.1:9084)
[2-Hop-akka.actor.default-dispatcher-2] >> [WARN ] examples.hybrid.HybridNodeViewHolder >> 16:21:48.003 Received modifier 99aQPCZfUYc68nrvQtEH7PJ5RVv28abBWECaMce2bttL that is already in history

Opened connections

Looks like 2 nodes opens a lot of connections to each other, should be only 1.

versionID is already used during restart of a HybridApp node

Hello there,

I am encountering an issue of nodes not being able to restore its state after restart. I was able to replicate this issue by doing the following:

1. Clear the /tmp/scorex/ directory
2. Start a node with HybridApp and wait for generation of several blocks
3. Ctrl+C in the terminal
4. Restart the node
   and the error I am getting is following:

[ERROR] [03/16/2017 16:50:03.284] [2-Hop-akka.actor.default-dispatcher-4] [akka://2-Hop/user/$b] versionID is already used
akka.actor.ActorInitializationException: akka://2-Hop/user/$b: exception during creation
	at akka.actor.ActorInitializationException$.apply(Actor.scala:175)
	at akka.actor.ActorCell.create(ActorCell.scala:607)
	at akka.actor.ActorCell.invokeAll$1(ActorCell.scala:461)
	at akka.actor.ActorCell.systemInvoke(ActorCell.scala:483)
	at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:282)
	at akka.dispatch.Mailbox.run(Mailbox.scala:223)
	at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at akka.util.Reflect$.instantiate(Reflect.scala:65)
	at akka.actor.ArgsReflectConstructor.produce(IndirectActorProducer.scala:96)
	at akka.actor.Props.newActor(Props.scala:213)
	at akka.actor.ActorCell.newActor(ActorCell.scala:562)
	at akka.actor.ActorCell.create(ActorCell.scala:588)
	... 9 more
Caused by: java.lang.IllegalArgumentException: versionID is already used
	at io.iohk.iodb.LSMStore.update(LSMStore.scala:370)
	at examples.hybrid.history.HistoryStorage.update(HistoryStorage.scala:91)
	at examples.hybrid.history.HybridHistory.$anonfun$append$1(HybridHistory.scala:110)
	at scala.util.Try$.apply(Try.scala:209)
	at examples.hybrid.history.HybridHistory.append(HybridHistory.scala:99)
	at examples.hybrid.HybridNodeViewHolder.genesisState(HybridNodeViewHolder.scala:69)
	at scorex.core.NodeViewHolder.$anonfun$nodeView$1(NodeViewHolder.scala:55)
	at scala.Option.getOrElse(Option.scala:121)
	at scorex.core.NodeViewHolder.$init$(NodeViewHolder.scala:55)
	at examples.hybrid.HybridNodeViewHolder.<init>(HybridNodeViewHolder.scala:18)
	... 18 more

5. Further requests to Swagger UI respond with There was an internal server error. and no blocks will be generated

Write PeersApiSpecs and UtilsApiSpecs.

Write tests for this endpoint to make sure that description is accurate.

Add rollback to History

At the moment History basic trait doesn't have a rollback functionality, but it is probably needed if block is failed to be applied to a current state. Reconsider interface & application logic.

Parsing of JSON settings could be simplified

I would suggest using play.api.libs.json.Json and making Settings a case class. Similar to what is done in Agora for parsing parameters (see https://gitlab.com/aossie/Agora/blob/master/src/main/scala/agora/parser/ParameterParser.scala and lines 39--65 in https://gitlab.com/aossie/Agora/blob/master/src/main/scala/agora/model/Parameters.scala).

Combine corsAllowed and corsAllowedOrigin into one setting

Also move ActorHelper to utils package.

NodeViewHolder modifiersCache

If some invalid modifiers appear in modifiersCache, they'll live there forever.

• Clear old modifier by some condition
• Limit modifiersCache size
• Do not show all ids list in logs (which is huge if cache size ~40000)

Fix findbugs warnings

Findbugs tool (running via "sbt findbugs") is finding a couple of high-priority warnings and a lot of medium-priority warnings. We need to fix them (most of claims are definitely reasonable). Good task for an external contributor!

Split maximum number of ingoing/outgoing connections in settings

For now, we have the single constant for maximum number of connections. Split it to set incoming / outgoing connections max number in settings (like in Bitcoin core ref. impl.)

Connection to Peer in TwinsCoin Testnet Fails

I followed the instructions in the README for the examples, and then I keep getting the following message:

> [INFO ] s.core.network.NetworkController >> 18:27:53.805 Failed to connect to : /34.210.250.171:9084

And then:

$ ping 34.210.250.171
PING 34.210.250.171 (34.210.250.171): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
Request timeout for icmp_seq 3
Request timeout for icmp_seq 4
Request timeout for icmp_seq 5

Is there any active TwinsCode node besides 34.210.250.171?

Node view synchronizer refactoring

NodeViewSynchronizer is caching ids of modifiers (blocks/transactions etc) asked from network (so only objects requested are expected to be delivered):
private val asked = mutable.MapModifierTypeId, mutable.Set[ModifierId]

However, this structure is not storing a peer being asked.

Also, we need to have another structure which contains objects delivered, in order to extract a peer when, during processing, a node is realizing that object sent is e.g. invalid (so the peer is to be banned or de-prioritized)

private val delivered = mutable.MapModifierId, ConnectedPeer

Hybrid - difficulty recalculation

Difficulty recalculation algorithm is broken

HybridApp example error while finding commong block

Description

On HybridAppHistory, finding suffixes after a common block between branches it's not working.

Cause

@tailrec
  private def suffixesAfterCommonBlock(winnerChain: Seq[BlockId], loserChain: Seq[BlockId]): (Seq[BlockId], Seq[BlockId]) = {
    val c1h = winnerChain.head
    val c2h = loserChain.head

    if (loserChain.contains(c1h)) {
      (winnerChain, loserChain.dropWhile(id => !(id sameElements c2h)))
    } else if (winnerChain.contains(c2h)) {
      (winnerChain.dropWhile(id => !(id sameElements c2h)), loserChain)
    } else suffixesAfterCommonBlock(blockById(c1h).get.parentId +: winnerChain, blockById(c2h).get.parentId +: loserChain)
  }

On the first if branch (when loserChain.contains(c1h) == true) it should be comparing by c1h while dropping. If not, the condition is matched at the first dropWhile iteration (because c2h is the head of loserChain sequence)

How to fix

Change the first dropWhile condition. The function may look like:

@tailrec
  private def suffixesAfterCommonBlock(winnerChain: Seq[BlockId], loserChain: Seq[BlockId]): (Seq[BlockId], Seq[BlockId]) = {
    val c1h = winnerChain.head
    val c2h = loserChain.head

    if (loserChain.contains(c1h)) {
      (winnerChain, loserChain.dropWhile(id => !(id sameElements c1h)))
    } else if (winnerChain.contains(c2h)) {
      (winnerChain.dropWhile(id => !(id sameElements c2h)), loserChain)
    } else suffixesAfterCommonBlock(blockById(c1h).get.parentId +: winnerChain, blockById(c2h).get.parentId +: loserChain)
  }

Properties Tests for InvSpec / RequestModifierSpec

Write properties tests about messages round-trip for InvSpec / RequestModifierSpec. Check the case when invs set size exceeding MaxObjects.

Investigate whether we could/should make more use of "ask" instead of "tell"

See #162 (comment) .

PeerSynchronizer has a hard-coded timeout

Maybe it would be more elegant to obtain this timeout from a config file?

Include instructions explaining how to perform a transaction in the Examples's readme

https://github.com/ScorexFoundation/Scorex/tree/master/examples

We have user demand for this information. Here is what a user asked in the gitter channel:

Hi. I'd like to know if there are instructions about how to perform a transaction through wallet/transfer?

Json serializers

Extract Json serializers and remove json field from JsonSerializable

Rework NodeViewHolder to retrieve data from it asynchronously.

Now only 1 thread is processing messages in queue which leads to 500 errors in API, sync message storm etc.

Generic Boxes

Currently, boxes are parameterized only by proposition, with a value type of Long. It seems that a lot of the code is intertwined with this assumption, but there's no particular reason why box values should be limited to Long.

One example is using String as the value type for a box in order to define access restrictions to a blockchain resource.

Display connection type in Peer API

Show connection type ( incoming / outgoing ) in peer-related API calls

Curvepos example throws an ActorInitializationException

I'm trying to run the Curvepos example with

sbt runMain examples.curvepos.SimpleApp

but I keep getting the exception thrown some time after the application starts. Here's the stack trace for it:

[info] Running (fork) examples.curvepos.SimpleApp [info] [main] >> [WARN ] scorex.core.settings.ScorexSettings$ >> 00:49:28.880 NO CONFIGURATION FILE WAS PROVIDED. STARTING WITH DEFAULT SETTINGS FOR TESTNET! [info] [scorex-akka.actor.default-dispatcher-2] >> [INFO ] scorex.core.network.UPnP >> 00:49:29.589 Looking for UPnP gateway device... [info] [ERROR] [11/17/2017 00:49:30.023] [scorex-akka.actor.default-dispatcher-3] [akka://scorex/user/$e] assertion failed [info] akka.actor.ActorInitializationException: akka://scorex/user/$e: exception during creation [info] at akka.actor.ActorInitializationException$.apply(Actor.scala:180) [info] at akka.actor.ActorCell.create(ActorCell.scala:607) [info] at akka.actor.ActorCell.invokeAll$1(ActorCell.scala:461) [info] at akka.actor.ActorCell.systemInvoke(ActorCell.scala:483) [info] at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:282) [info] at akka.dispatch.Mailbox.run(Mailbox.scala:223) [info] at akka.dispatch.Mailbox.exec(Mailbox.scala:234) [info] at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) [info] at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) [info] at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) [info] at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157) [info] Caused by: java.lang.AssertionError: assertion failed [info] at scala.Predef$.assert(Predef.scala:204) [info] at scala.Predef$Ensuring$.ensuring$extension2(Predef.scala:316) [info] at examples.curvepos.transaction.SimpleState.$anonfun$validate$3(SimpleState.scala:115) [info] at scala.collection.immutable.List.foreach(List.scala:389) [info] at examples.curvepos.transaction.SimpleState.$anonfun$validate$2(SimpleState.scala:115) [info] at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12) [info] at scala.util.Try$.apply(Try.scala:209) [info] at examples.curvepos.transaction.SimpleState.validate(SimpleState.scala:115) [info] at examples.curvepos.transaction.SimpleState.validate(SimpleState.scala:19) [info] at scorex.mid.state.BoxMinimalState.applyModifier(BoxMinimalState.scala:29) [info] at scorex.mid.state.BoxMinimalState.applyModifier$(BoxMinimalState.scala:28) [info] at examples.curvepos.transaction.SimpleState.applyModifier(SimpleState.scala:19) [info] at examples.curvepos.SimpleNodeViewHolder.genesisState(SimpleNodeViewHolder.scala:55) [info] at scorex.core.NodeViewHolder.$anonfun$nodeView$1(NodeViewHolder.scala:52) [info] at scala.Option.getOrElse(Option.scala:121) [info] at scorex.core.NodeViewHolder.$init$(NodeViewHolder.scala:52) [info] at examples.curvepos.SimpleNodeViewHolder.<init>(SimpleNodeViewHolder.scala:15) [info] at examples.curvepos.SimpleApp.$anonfun$nodeViewHolderRef$1(SimpleApp.scala:32) [info] at akka.actor.TypedCreatorFunctionConsumer.produce(IndirectActorProducer.scala:87) [info] at akka.actor.Props.newActor(Props.scala:213) [info] at akka.actor.ActorCell.newActor(ActorCell.scala:562) [info] at akka.actor.ActorCell.create(ActorCell.scala:588) [info] ... 9 more

After the exception is thrown, the app continues to run, but the only thing it does is repeatedly write this message to the console:

[info] [INFO] [11/17/2017 00:49:30.029] [scorex-akka.actor.default-dispatcher-8] [akka://scorex/user/$e] Message [scorex.core.NodeViewHolder$Subscribe] from Actor[akka://scorex/user/$c#-1848096250] to Actor[akka://scorex/user/$e#-362370127] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.

Examples' README.md needs to be updated

The Examples's README.md needs to be updated to Scorex 2.0. At the end of the README, the user is told to use cli.sh, but Scorex 2.0 doesn't have a cli.sh anymore.

Reorganize and document where messages come from

Scorex's code organization and documentation would be greatly improved if we were more systematic about where we define messages and how we import them to be used elsewhere and about documenting from/to where they go.

I propose that we follow the style used in these actors: https://gitlab.com/AxiomFlow/OuroborosPraos/tree/master/src/main/scala/ouroboros/actor (GitLab Login Required)

Integrate Scoverage to measure test coverage

I have added the Scoverage plugin to Scorex in #76. It can be used manually within the SBT shell for now. But a better integration could still be done:

• Make Scoverage work within the Examples module.
• Add Scoverage to Scorex's CI pipeline, so that a coverage report is generated automatically.
• Add a coverage percentage badge on Scorex's README.md .

Code duplication between generators in testkit and in core's test

The following two files contain repeated code:

• https://github.com/ScorexFoundation/Scorex/blob/master/testkit/src/main/scala/scorex/testkit/generators/CoreGenerators.scala

• https://github.com/ScorexFoundation/Scorex/blob/master/src/test/scala/scorex/ObjectGenerators.scala

Remove FastCryptographicHash

Make the types of settings as specific as possible

Warning in PeerDatabaseImpl

[warn] Scorex/src/main/scala/scorex/core/network/peer/PeerDatabaseImpl.scala:39:70: AnyVal and Option[Long] are unrelated: they will most likely always compare unequal
[warn]       case true => knownPeers(false).filter(_._2.nonce.getOrElse(-1) != ownNonce)
[warn]                                                                      ^
[warn] there was one unchecked warning; re-run with -unchecked for details
[warn] three warnings found

Make a test suite for properties tests

Fow now only following tests are to be launched by "sbt test"

[info] SigningFunctionsSpecification:
[info] - PrivateKey25519Companion generates valid keypair (379 milliseconds)
[info] - PrivateKey25519Companion serialization (187 milliseconds)
[info] HandshakeSpecification:
[info] - handshake should remain the same after serialization/deserialization (147 milliseconds)

Implement PrivateKey25519Companion.owns()

Just a test. Ignore.

Smart contracts support

Do you plan support for smart contracts in Scorex framework ?

Plug NodeViewHolderTests / NodeViewSynchronizerTests into BlockchainSanity

Intermittent NullPointerException

Travis CI initially failed in PR 110, because a NullPointerException was thrown during the execution of the test "NodeViewHolder: forking - switching" in NodeViewHolderTests.

[info] - NodeViewHolder: forking - switching *** FAILED ***
[info]   java.lang.NullPointerException:
[info]   at scorex.testkit.properties.NodeViewHolderTests.$anonfun$$init$$39(NodeViewHolderTests.scala:239)
[info]   at scorex.testkit.properties.NodeViewHolderTests.$anonfun$$init$$39$adapted(NodeViewHolderTests.scala:211)
[info]   at scorex.testkit.properties.NodeViewHolderTests.withFixture(NodeViewHolderTests.scala:47)
[info]   at scorex.testkit.properties.NodeViewHolderTests.$anonfun$$init$$38(NodeViewHolderTests.scala:211)
[info]   at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
[info]   at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
[info]   at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
[info]   at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
[info]   at org.scalatest.Transformer.apply(Transformer.scala:22)
[info]   at org.scalatest.Transformer.apply(Transformer.scala:20)
[info]   ...

However, when I asked Travis to re-run this build, the test passed. So, whatever is causing this problem doesn't happen all the time.

Hybrid - offlineGeneration

offlineGeneration=false don't work, node still generates blocks alone

Props factory methods for all actors

Rework the way how we obtaining actors. According to official documentation Props factory is the best way to do it.

Connection authentication using Noise

Noise Protocol Framework https://noiseprotocol.org/

"Noise is a framework for building crypto protocols. Noise protocols support mutual and optional authentication, identity hiding, forward secrecy, zero round-trip encryption, and other advanced features. "

Let's use Noise for optional auth. handshake.

Fix "last seen date" for connected peers api route.

Currently api route /peers/connected returns list of objects with lastSeen field. This field is being filled with now() timestamp instead of correct last seen date. However class Handshake has its own time field. Maybe we should consider use this field instead of now()?

Alternative to keeping an actor's state in mutable collections

I noticed that NodeViewSynchronizer has a few global mutable collections to keep state information.

An alternative to that could be to use the become approach and pass state information as arguments to the Receive methods.

Forks comparison

Currently, a node in the TwinsCoin example is getting Nonsense status initially (other peer if getting Younger status). Naturally, a peer should obtain correct status (Older). We also should ban for Nonsense status probably.

Double notification from NVHT

In case if semantically valid modifier is being applied to NVH we gonna get 2 notification about semantic validity of this modifier.

ApiClient Json parsing error

Description

After downloading and running one of the example projects when trying to query REST api using the provided ApiClient we are receiving an error while parsing Json response.

Error Output

[info] Welcome to the Scorex command-line client...
GET utils/seed
[info] [GET utils/seed RESULT] Problem occurred java.lang.RuntimeException: com.fasterxml.jackson.core.JsonParseException: Unexpected end-of-input: expected close marker for OBJECT (from [Source: {; line: 1, column: 0])
[info]  at [Source: {; line: 1, column: 3]! 

How to reproduce

1. Startup any of the examplel projects included in this repo, for example, SimpleApp.scala
2. Run ApiClient
3. Execute the command GET utils/seed

Cause

It seems that scorex.core.api.http.ApiRoute#jsonRoute calls Json.toString which uses by default spaces2 formatting and returns a multi line string but ApiClient is expecting a single one

scala> foo.asJson.noSpaces
res0: String = {"Qux":{"i":13,"d":14.0}}

scala> foo.asJson.spaces2
res1: String =
{
  "Qux" : {
    "i" : 13,
    "d" : 14.0
  }
}

scala> foo.asJson.toString
res3: String =
{
  "Qux" : {
    "i" : 13,
    "d" : 14.0
  }
}

How to Fix

There are two options:

1. Change ApiRoute in order to return Json encoded with noSpaces (this might be the best alternative because formatting is not needed before sending to the wire)
2. Change ApiClient to receive multiline Strings, val result = Source.fromInputStream(stream) mkString ""

We can create a PR if you want to.

Remove non-public peer from database

For now, we're adding peer to the peer database if its public (declared address is the same as the socket address). It is also needed to remove peer from database the peer is not public.