Derek interprets Bytom Source-start and stop

Derek

Brief introduction

GitHub Address: Github.com/bytom/bytom

Gitee Address: Gitee.com/bytomblockchain/bytom

This chapter describes the process of Bytom code Initiation, node initialization, and stopping

The author uses the MacOS operating system, and the other platforms are similar
Golang version:1.8

Preparatory work compiling the installation

For detailed steps See official Bytom Install

Set Debug Log Output

Open debug output file, function, line number and other details

export BYTOM_DEBUG=debug

Initialize and start BYTOMD

Initialization

./bytomd init --chain_id testnet

BYTOMD currently supports two types of networks, where we use the test network
Mainnet: Main network
Testnet: Test Network

Start BYTOMD

./bytomd node --mining --prof_laddr=":8011"

--prof_laddr= ": 8080"//Turn on PPROF output performance indicator
Visit: http://127.0.0.1:8080/debug/pprof/

BYTOMD Init initialization

Entry function
* * CMD/BYTOMD/MAIN.GO * *

func init() {    log.SetFormatter(&log.TextFormatter{FullTimestamp: true, DisableColors: true})    // If environment variable BYTOM_DEBUG is not empty,    // then add the hook to logrus and set the log level to DEBUG    if os.Getenv("BYTOM_DEBUG") != "" {        log.AddHook(ContextHook{})        log.SetLevel(log.DebugLevel)    }}func main() {    cmd := cli.PrepareBaseCmd(commands.RootCmd, "TM", os.ExpandEnv(config.DefaultDataDir()))    cmd.Execute()}

The INIT function will initialize before main executes, and you can see the BYTOMD load bytom_debug variable in init to set the debug log output

Command CLI parameter initialization
BYTOMD CLI parsing using the Cobra Library

* * Cmd/bytomd/commands * *

• Cmd/bytomd/commands/root.go
  Initializes the--root pass parameter. BYTOMD storage configuration, KeyStore, the root directory of the data. Under MacOS, the default path is ~/library/bytom/
• Cmd/bytomd/commands/init.go
  Initializes the--chain_id pass parameter. Select the network type, when we start BYTOMD we select Testnet, which is the test network
• Cmd/bytomd/commands/version.go
  Initializing version parameters
• Cmd/bytomd/commands/run_node.go
  Initialize the parameters required to run node nodes

Initialize default configuration
The user passes only a subset of parameters, and the other parameters required by the node need to be loaded from the default configuration.
* * CMD/BYTOMD/COMMANDS/ROOT.GO * *

var (    config = cfg.DefaultConfig())

In Root.go, there is a config global variable that loads all the default parameters required by node

// Default configurable parameters.func DefaultConfig() *Config {    return &Config{        BaseConfig: DefaultBaseConfig(),  // node基础相关配置        P2P:        DefaultP2PConfig(),   // p2p网络相关配置        Wallet:     DefaultWalletConfig(),   // 钱包相关配置        Auth:       DefaultRPCAuthConfig(),  // 验证相关配置        Web:        DefaultWebConfig(),   // web相关配置    }}

Each of the following articles will describe the role of each configuration

BYTOMD Daemon Start and exit

* * CMD/BYTOMD/COMMANDS/RUN_NODE.GO * *

func runNode(cmd *cobra.Command, args []string) error {    // Create & start node    n := node.NewNode(config)    if _, err := n.Start(); err != nil {        return fmt.Errorf("Failed to start node: %v", err)    } else {        log.WithField("nodeInfo", n.SyncManager().Switch().NodeInfo()).Info("Started node")    }    // Trap signal, run forever.    n.RunForever()    return nil}

The Runnode function has three steps:
Node. NewNode: Initializing node Runtime environment
N.start: Start node
N.runforever: Listen for exit signal, receive CTRL + C operation to exit node. Keep the process in Linux listen to the sigterm signal (CTRL + C) as a signal to exit the daemon

Initializing the Node runtime environment

In BYTOMD, there are five DB databases stored in the data directory under the--root parameter

• Accesstoken.db//Store Token-related information (Wallet access control rights)
• TRUSTHISTORY.DB//Storage-to-peer network synchronization related information
• TXDB.DB//Store Transaction related information
• Txfeeds.db//
• WALLET.DB//Storage wallet related information

* * Node/node.go * *

Func NewNode (config *cfg. Config) *node {ctx: = context. Background () initactivenetparams (config)//Get Store initializes the TXDB database txdb: = dbm. Newdb ("txdb", config. Dbbackend, CONFIG. Dbdir ()) Store: = Leveldb. Newstore (TXDB)//Initialize Accesstoken database tokendb: = dbm. Newdb ("Accesstoken", config. Dbbackend, CONFIG. Dbdir ()) Accesstokens: = Accesstoken. Newstore (TOKENDB)//Initialize event Scheduler, also known as Task Scheduler. A task can be called multiple times//make event switch Eventswitch: = types. Neweventswitch () _, Err: = Eventswitch.start () if err! = Nil {cmn. Exit (CMN. FMT ("Failed to start switch:%v", err)}//Initialize the trading pool Txpool: = protocol. Newtxpool () chain, err: = protocol. Newchain (store, txpool) if err! = Nil {cmn. Exit (CMN. FMT ("Failed to create chain structure:%v", err)} var accounts *account. Manager = nil var assets *asset. Registry = nil var wallet *w.wallet = nil var txfeed *txfeed. Tracker = nil//Initialize Txfeeds database txfeeddb: = dbm. Newdb ("txfeeds", config. Dbbackend, config. Dbdir ()) Txfeed = Txfeed. Newtracker (TXFEEDDB, chain) If Err = Txfeed.prepare (CTX); Err! = Nil {log. Withfield ("error", err). Error ("Start Txfeed") return nil}//Initialize KeyStore HSM, err: = Pseudohsm. New (config. Keysdir ()) if err! = Nil {cmn. Exit (CMN. FMT ("Initialize HSM failed:%v", err)}//Initialize wallet, default wallet is on if!config. wallet.disable {walletdb: = dbm. NEWDB ("wallet", config. Dbbackend, CONFIG. Dbdir ()) accounts = account. Newmanager (WALLETDB, chain) assets = asset.  Newregistry (WALLETDB, chain) wallet, err = W.newwallet (walletdb, accounts, assets, HSM, chain) if err! = Nil {log. Withfield ("error", err).        Error ("Init Newwallet")}//Clean up expired UTXO reservations periodically. Go accounts. Expirereservations (CTX, Expirereservationsperiod)} Newblockch: = Make (chan *bc. Hash, Maxnewblockchsize)//Initialize Network node synchronization management SyncManager, _: = Netsync. Newsyncmanager (config, chain, txpool, NEWBLOCKCH)//Initialize PPROF,PPROF for output performance indicators, need to set--PROF_LADDR parameters to open, at the beginning of the article we have opened the function//run the profile server Profilehost : = config. proflistenaddress if Profilehost! = "" {//Profiling BYTOMD Programs.see (blog.golang.org/profiling-go-programs )//GO tool pprof Http://profileHose/debug/pprof/heap go func () {http. Listenandserve (Profilehost, Nil)} ()}//Initialize node, populate all parameters required for node: = &node{Config:config       , Syncmanager:syncmanager, Evsw:eventswitch, Accesstokens:accesstokens, wallet: Wallet, Chain:chain, Txfeed:txfeed, Miningenable:config. Mining,}//Initialize mining Node.cpuminer = Cpuminer. Newcpuminer (chain, accounts, Txpool, newblockch) Node.miningpool = Miningpool. Newminingpool (chain, accounts, Txpool, newblockch) node. Baseservice = *cmn. Newbaseservice (Nil, "node", node) return node}

Currently BYTOMD only supports CPU mining, so only cpuminer initialization information in the code

Start node

* * NODE/NODE.GO * *

// Lanch web broser or notfunc lanchWebBroser() {    log.Info("Launching System Browser with :", webAddress)    if err := browser.Open(webAddress); err != nil {        log.Error(err.Error())        return    }}func (n *Node) initAndstartApiServer() {    n.api = api.NewAPI(n.syncManager, n.wallet, n.txfeed, n.cpuMiner, n.miningPool, n.chain, n.config, n.accessTokens)    listenAddr := env.String("LISTEN", n.config.ApiAddress)    env.Parse()    n.api.StartServer(*listenAddr)}func (n *Node) OnStart() error {    if n.miningEnable {        n.cpuMiner.Start()    }    n.syncManager.Start()    n.initAndstartApiServer()    if !n.config.Web.Closed {        lanchWebBroser()    }    return nil}

OnStart () starts the node process as follows:

• Start Mining function
• Start Peer-Network synchronization
• Apiserver service to start the HTTP protocol
• Open a browser to access Bytond's trading page

Stop node

The BYTOMD executes n at boot time. The Runforever () function, which is the function of the Tendermint framework to initiate a listening signal:
* * VENDOR/GITHUB.COM/TENDERMINT/TMLIBS/COMMON/OS.GO * *

func TrapSignal(cb func()) {    c := make(chan os.Signal, 1)    signal.Notify(c, os.Interrupt, syscall.SIGTERM)    go func() {        for sig := range c {            fmt.Printf("captured %v, exiting...\n", sig)            if cb != nil {                cb()            }            os.Exit(1)        }    }()    select {}}

trapsignal function listens to the sigterm signal, BYTOMD can become a daemon that does not quit. The BYTOMD process exits only if CTRL + C or kill bytomd_pid is triggered. When exiting BYTOMD do the following:
* * NODE/NODE.GO * *

func (n *Node) OnStop() {    n.BaseService.OnStop()    if n.miningEnable {        n.cpuMiner.Stop()    }    n.syncManager.Stop()    log.Info("Stopping Node")    // TODO: gracefully disconnect from peers.}

The BYTOMD will stop the mining function, and the peer network stops.