Geth - GoLang client

(based on 1.6.1)

> geth [options] command [command options] [args....]

Options

• Configuration (paths, etc.)
• API & Console (port for console, etc.)
• Misc. (help...)
• Account
• Gas price (don't mess with)
• Miner
• Performance tuning
• VM (Ethereum VM)
• Networking
• Logging, debugging (a lot geared towards developers)
• Expermental
• --help
• --netrestrict : restrict communication to given IP networks
• --verbosity : 0=silent 1=error. 6 max
• --identity "MyCustomIDName"
• --datadir : chain data & other house keeping files
• --keystore :
• --networkid : 1=live (default), 3=testnet (ropsten), private = user assigned
• --testnet (equals --networkid 3)
• --syncmode
  • "fast"(download without verify?) "full" "light" (no download, depend on other full node)
• --dev : developer mode, private network, multiple debug flags
• --unlock "comma separated list of address/index" (otherwise all locked by default)
• --password "password file" (start from #0, one password a line)
• mining options
  • --mine : enable mining
  • -- minerthreads : default=8
  • --etherbase : address of reward account, default = #0
  • --gasprice "value" : minimal gas accepted (default 2E10)
  • --extradata "somedata" : block extra data by miner, default = client miner
  • --targetgaslimit "value" : (later...)

Command

• File management (export/import)
• Database (remove, update...)
• Console interface (interact with running geth instance)
• Version, help, license
• Init - a new private chain
• Account - creating/managing aeccounts

List of some commands:

• version
• help
• license
• console (start JavaScript console)
  • options
    • --preload "files,.,."
    • --jspath
    • --exec "JS statement" ex: geth --exec "personal.listAccounts" console
  • console commands
    • admin : information, datadir
• attach
  • IPC-RPC : attach "pipe address"
  • JSON-RPC : attach "http://....:8545"
  • WS-RPC: attach "ws://....:8546"
• account
  • account new
    • key file generated under key file dir
    • UTC--datetime--address
    • ok to copy keystore file (like import)
  • account list
  • account update (password)
  • account import (or just copy key files)
• exit

RPC

• IPC-RPC
  • enabled by default
  • Used by local Dapp (not over network)
  • API include: admin, web3, miner..... (many more)
  • --ipcdisable
  • --ipcvalue : enable/disable api (all enabled by default)
  • --ipcpath : "geth.ipc"
• JSON-RPC / WS-RPC
  • disabled by default
  • API: exposed by default (only 3 for security reason) eth, web3, net
  • JSON
    • default: http, port 8545
    • --rpc : enable JSON-RPC (maybe not good practice, user admin object instead)
    • --rpcapi :default = eth,web3,net
    • --rpcaddr, --rpcport
    • --rpccorsdomain "domains,.," or "*" (any)
  • WS-RPC (maybe not good practice, user admin object instead)
    • default: tcp port 8546
    • --ws : enable
    • --wsapi
    • --wsaddr, --wsport

Javascript Runtime

• Can execute javascript code
• Invoke management API
• Support interactive / non-interactive mode

Web3 API Overview

• for building Dapp
• function groups
  • .eth : Ethereum blockchain related methods (shorthand: eth)
    • web3.eth.accounts
  • .net : Node's network status (shorthand: net)
    • net.listening (return true/false)
  • .db : get/put for local LevelDB
  • .shh : P2P messaging using Whisper

Transaction pools (txpool) and Account Nonce

• every transaction under an account has a unique nonce (nonce to prevent replay attack)
  • normally not specified and start from 0 and counting
  • personal.sendTransaction() can specify a nonce
  • transaction goes to
    • in sequence (=last_nonce+1) : go pending pool
    • not in sequence: go Queued pool
  • pending pool :
    • transactions ready to be mined (but not yet have been),
    • come from any account across the Ethereum network,
    • once mined will be removed from the queue
  • queued pool :
    • transaction from local node
    • held locally, not persisted (restart geth will lose it)
    • been initiated but are not ready to be mined
    • with a nonce larger than next sequence (say, 210 instead of 200)
    • once some transactions have been sent so next nonce is the one in queued pool, it's moved to pending pool

Management API Overview

• https://github.com/ethereum/go-ethereum/wiki/Management-APIs
• admin (object)
  • node management, such as setting RPC parameters
  • node information
  • commands
    • .nodeInfo (version, name, enode url: for add this as peer to other node)
    • .datadir
    • .peers
      • addPeers(url) (may configure topology of a private peers network)
    • .exportChain(file), .importChain(file) - avoid synchronizing a new node
    • .startRPC("localhost",8545,"web3") - host, port, APIs
    • .stopRPC
    • .startWS(...) .stopWS()
    • .setSolc('path to compiler')
• personal (object)
  • account management
  • commands
    • .newAccount("pass")
    • .listAccount
    • (to delete account just remove key file)
    • .importRawKey(keydata, password) - import raw private key
    • .unlockAccount() / .lockAccount()
    • .sendTransaction(txt_object{from:"xxx",to:"xxxx", value: wei_value, nonce : optional) : note NOT in ETH!!! in WEI!!! we3.toWei() converts from ETH to wei
      • returns transaction hash
• transaction object
  • from : from account address
  • to : to account address
  • amount : amount
  • nonce : optional, nonce
  • data : optional data
• miner (object)
  • .start(num_threads) .stop() = --mine, --minethreads
  • .setEtherbase(addr) = --etherbase
    • miner.setEtherbase(personal.listAccounts[1])
  • .setGasPrice(num) = --gasprice "value"
  • .setExtra() = --extradata
• txpool (object)
  • transaction pool (list pending tx, etc.)
  • .status - show counts in pending & queued pools
  • .inspect - summaries of transactions - including (from) addresses of transactions
  • .content - details of transactions
• debug (object) (non-stadard)
  • information
    • .verbosity(level) - set verbosity of the node (dump to node console)
    • .dumpBlock(number) - not typical on console, output a lot of data
    • .traceBlockByNumber(number) .traceBlockByHash(hash) : replay the block (validate)
    • .traceTransaction(txHash...) " a lot of dump of opcode executed & storage state
  • performance
    • .gcStats() : garbage collection
    • .memStats() : memory usage
    • cpu profile methods, etc.
  • go code level debug methods (not for typical dapp developers but for geth client developers)