Kingwel2020-优快云博客

原创 Substrate - Execute Extrinsic

How runtime runs for a block or extrinsicImportBlockOriginated from Consensus and invoked by NetworkWorkerClient as BlockImport::ImportBlock -> prepare_block_storage_changes -> runtime_api.execute_block_with_context--------------- Enter Runtime -

2021-11-03 09:15:41 240

原创 Substrate - ImportQueue or BlockImport Pipeline

Trait/// Blocks import queue API.////// The `import_*` methods can be called in order to send elements for the import queue to verify./// Afterwards, call `poll_actions` to determine how to respond to these elements.pub trait ImportQueue<B: BlockT

2021-11-03 09:14:04 249

原创 Substrate - Babe consensus

Babe is another slote based consensus, but unlike Aura, Babe is using VRF PRNG to randomly select a validator to produce block.Babe startupCode can be found in node_cli::service.block_import: grandpaconsensus: babeimport_queue: base BasicQueue let

2021-11-03 09:12:49 349

原创 Substrate - Aura consensus

AuraAura (Authority-round) is one of the consensus in substrate.//! Aura works by having a list of authorities A who are expected to roughly//! agree on the current time. Time is divided up into discrete slots of t//! seconds each. For each slot s, the

2021-11-03 09:12:00 297

原创 Substrate - Client DB

@TOC(Client) Database in substrateClientClient -> Backend -> DatabaseBackend/// Disk backend.////// Disk backend keeps data in a key-value store. In archive mode, trie nodes are kept from all/// blocks. Otherwise, trie nodes are kept only fro

2021-10-26 17:21:42 146

原创 Substrate - node-template startup

substrate node-template initializationentry: main()cli commandslite nodefull nodeClientClient EventClient Servicesrpcnetworkentry: main()-> cli::runcli commandscli commands can be found in substrate/client/cli::sc_cli#[derive(Debug, StructOpt)]pub

2021-10-26 17:17:10 213

原创 Rust 学习心得＜6＞：再谈 Send 与 Sync

Rust 学习心得＜6＞：再谈 Send 与 Sync基本场景异步代码：跨越 await 问题总结Send 与 Sync 可能是Rust多线程以及异步代码种最常见到的约束。在前面一篇讨论多线程的文章中介绍过这两个约束的由来。但是，真正书写比较复杂的代码时，还是会经常遇到编译器的各种不配合。这里借用我的同事遇到的一个问题再次举例谈一谈 Send 与 Sync 的故事。基本场景C/C++中不存在Send/Sync的概念，数据对象可以任意在多线程中访问，只不过需要程序员保证线程安全，也就是所谓“加锁”。而在

2020-10-14 16:31:07 1131

原创 Rust 学习心得＜5＞：异步代码的几种写法

Rust 学习心得＜5＞：异步代码的几种写法

2020-08-16 00:25:35 1152

原创 Rust 学习心得＜4＞：async/await 如何工作

Rust 学习心得＜4＞：async/await 如何工作async现在我们来看一看async/await的实现原理。async简单滴说，async语法生成一个实现 Future trait object 的对象。如下：async fn foo() -> { ...}async 关键字，将函数的原型修改为返回一个Future trait object。然后将执行的结果包装在一个新的future中返回。大致相当于：fn foo() -> impl Future<Output

2020-08-13 22:47:34 1592

原创 Rust 学习心得＜3＞：无栈协程

RUST 学习心得之一：无栈协程有栈协程 vs. 无栈协程GO 有栈协程RUST 协程绿色线程 GreenThread无栈协程协程解决的问题RUST作为一门新兴语言，主打系统编程。提供了多种编写代码的模式。2019年底正式推出了 async/await语法，标志着RUST也进入了协程时代。下面让我们来看一看。RUST协程和GO协程究竟有什么不同。有栈协程 vs. 无栈协程协程的需求来自于C10K问题，这里不做更多探讨。早期解决此类问题的办法是依赖于操作系统提供的I/O复用操作，也就是 epoll/IO

2020-08-12 22:26:46 1804

原创 Rust 学习心得＜2＞：多线程

Rust 学习心得＜2＞：多线程其他语言的做法Rust 做法Send，Sync 究竟是什么异步代码，协程完美了么？死锁问题现代的CPU基本都是多核结构，为了充分利用多核的能力，多线程都是绕不开的话题。无论是同步或是异步编程，与多线程相关的问题一直都是困难并且容易出错的，本质上是因为多线程程序的复杂性，特别是竞争条件的错误，使得错误发生具备一定的随机性，而随着程序的规模越来越大，解决问题的难度也随之越来越高。其他语言的做法C/C++将同步互斥，以及线程通信的问题全部交给了程序员。关键的共享资源一般需要通

2020-08-11 21:05:34 1006

原创 Rust 学习心得＜1＞：开篇

近段时间在学习研究RUST。都说RUST学习曲线陡峭。本人的感觉也是如此。之前学习GO，基本上没有专门去看语法，只是在需要的时候上网查一查，再花点时间看看大型的开源软件项目，差不多自己就会写生产级别的代码了。而RUST则不然，至少我花了差不多两周的时间专门学习语法，然而去看开源的项目依然觉得很吃力，又花了一些时间才搞明白了rust的几种编码模式，特别是异步模式，又分为poll循环的方式和await协程的方式，各种坑比较多，填坑的过程还是比较吃力的。整个大约两个多月学习过程中，曾经碰到过很多的问题，在网上阅

2020-08-10 22:23:38 998

原创 rust, blocking 0.4

Blocking 可以把阻塞异步代码的执行直至完成，或者阻塞的代码转为异步的模式。本身实际上是一个简单的future的 executor，大致的原理是启用一个线程池，将阻塞的代码放到线程池中执行，通过一个channel返回执行的结果。之所以要学习这个库的原因是这里提供了异步框架 executor 实现思路。库作者在 smol 这个轻量级的异步运行库实现了完整的execute功能，而 smol 实际上就是 async-std 的基础。To convert async to blocking, block

2020-07-08 19:46:21 314

原创 rust, libp2p, preliminary

rust, libp2p, preliminaryMultiaddrProtocolMultiaddrmaddr ==> "/ip4/127.0.0.1/tcp/10000"multiaddr 本质上是一个 ’Vec<u8>，因此可以支持 PartialEq, Eq, Clone, Hash。/// Representation of a Multiaddr.#[derive(PartialEq, Eq, Clone, Hash)]pub struct Multiaddr {

2020-07-08 10:19:33 355

原创 rust, smol Async I/O

rust, smol Async I/O`Aync`read_withwrite_withdropAsyncRead/AsyncWriteAsyncReadExt/AsyncWriteExtread 实现`Async` `Async` 以及其他...smol 实现同步 I/O 包装为异步操作，从而可以与 epoll 之类的操作系统异步模型集成。值得注意的是，Async IO 仅支持网络类型的操作，也就是 TCP/UDP/Unix socket。不支持普通文件类的操作。事实上，文件操作在 smol 中是通

2020-07-07 21:44:58 503

原创 rust, smol

rust, smolDependenciesCross-platform, I/O multiplexingExecutorsWork-stealing Executorsmol::runparker.park()Wake upSmol is a lightweight async I/O runtime library, which is currently support async-std as the Executor and Reactor.Dependenciesasync-task,

2020-07-07 20:08:54 708

原创 rust, future & executor

rust, future & executor一个简单的 Executor同时执行多个future的 ExecutorFuture提供Paul的方法。每次execute来轮询future，Poll方法会返回一个 Poll<> Enum，包含两种可能：Ready 或者 Pending。一个简单的 Executor一个最简单的只能执行单一future 的 executor 代码如下所示。注意这里一般创建一对 Parker和 Waker。从性能方面考虑。这样一对数据结构可以放在线程本地存

2020-07-04 11:21:09 324

原创 rust, future & generator

rust, future, how to create a futurefuture traitfn() -> impl Futureasync fn() 以及闭包async {}await探讨future的不同写法。以及其中的差异。future trait自定义实现一个 trait 特征。需要实现 poll 方法。该方法返回一个枚举值: Poll<T>, Ready 代表完成包裹了真正的返回数据；Pending 意味着任务还未完成。pub trait Future { /

2020-07-02 19:36:51 473

原创 rust, async programming

rust, async programmingThis is a collection of rust async programming resourcesThis is a collection of rust async programming resourcesThe Future With Futuresexplains the concept of async io, and shows code examples from futures to tokiowritten in 20

2020-06-23 11:18:24 316 1

原创 rust, smart pointer

rust, smart pointerBox<>Box::newRc<>Rc.newWeak<>Cell<>Cell.newCell get/setRefCell<>RefCell borrow/borrow_mutArc<>Arc::newBox<>Like unique_ptr in C++.Internally, it contains a Unqiue<> which holds the raw p

2020-06-10 22:01:09 268

原创 rust, mem alloc/free

rust, mem alloc/freeStringVec<>vec!Box<>Rc<>StringIn rust, &str is a reference to a static string which can not be altered. Instead, it could be converted to a String by to_string(), which will eventaully allocate memory from heap:

2020-06-10 15:37:32 466

原创 CosmosSDK, BaseApp and Modules

CosmosSDK, BaseApp and ModulesBaseAppABCIbeginBlocker/endBlocker/initChainerrouterrunTxAppModuleManagerABCI Call StackBeginBlockEndBlockCommitCheckTxDeliverTxThis article is about to explain how CosmosSDK works together with ABCI. Or in other words, how t

2020-05-24 17:28:49 381

原创 CosmosSDK, first application with scaffold

CosmosSDK, first application with scaffoldscaffoldGenerated CodeAppData StructureInterfacesBaseAppAppd & AppcliInit and StartStart as a remote serverStart as a in-process serverscaffoldThis tool is used to generate skeleton code for an Application bl

2020-05-23 15:22:52 839

原创 tendermint, local & remote client

tendermint, local & remote clientclientCreatorcreateAndStartProxyAppConnsmultiAppConnLocal ClientRemote ClientTendermint supports both local and remote clients. Local client means using tendermint as a library, thus we will only hvae a single os proce

2020-05-21 17:19:47 294

原创 tendermint, consensus reactor

tendermint, consensus reactorChannelMessagesOnStartPeerStateAddPeerReceiveSwitchToConsensusThe consensus reactor is the service for consensus p2p messages.Channel StateChannel = byte(0x20) DataChannel = byte(0x21) VoteChannel = byt

2020-05-21 16:50:13 218

原创 tendermint, consensus state

tendermint, consensus stateStateEventSwitchRoundStateRoundStepTypeupdateToStateStartreceiveRoutinehandleTxsAvailableenterProposehandleMsghandleTimeoutHow it works on Single NodeStateIt is the core state machine of consensus algorithm, handling votes and

2020-05-20 21:42:45 268

原创 tendermint, PEX

tendermint, PEXReactorConfigChannels & MessagesStartcrawlPeersRoutine()ensurePeersRoutine()AddPeer & RemovePeerReceivepexRequestMessagepexAddrsMessagedialPeerAddrBookInitializationStartPEX handles peer exchange, finding more peers and building the

2020-05-20 08:47:03 318

原创 tendermint, evidence

tendermint, evidenceInitializationevidenceDB and storeevPoolevPool.PendingEvidenceevPool.UpdateevPool.AddEvidenceevidence ReactorbroadcastEvidenceRoutineReceiveInitializationIn NewNode(),evidenceReactor, evidencePool, err := createEvidenceReactor(config

2020-05-19 18:23:22 213

原创 tendermint, blockchain reactor

tendermint, blockchain reactorData StructureChannelMessagesAddPeer/RemovePeerpoolRoutineBlockPoolJudgement of CaughtUpPool.requestersPool.maxPeerHeightpool.makeRequestersRoutine()bpRequesterbpRequester.requestRoutineBlockchain reactor is used to sync up t

2020-05-18 20:48:13 285

原创 tendermint, MultiplexTransport

tendermint, MultiplexTransportInterfaceImplementationUpgradeSecretConnectionIt is a TCP based multiplexed connection manager.InterfaceAbstract of making inbound/outbound connection with peer.// Transport emits and connects to Peers. The implementation

2020-05-18 09:38:05 254

libp2p-multistream.pcap

高性能网关类产品设计原则 （数据面应该如何实现）

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高性能网关类产品设计原则（数据面应该如何实现）