gething started - ethereum & using the geth golang client

gething started
geth=
golang + blockchain + ethereum
sathishvj

Talk Set: Utils and Projects in Go
● Identify interesting tools and projects in Go
○ As opposed to focusing only on the language
● Highlight big/awesome projects and inform
dev audience it was written in Go
● Encourage open source contribution in Go
● Promote daily use tools written in Go
● SFO searches Go; BLR searches JSP
○ Courtesy: stackoverflow research data
● For orgs shifting to Go, make available a
wider developer pool

Blockchain
Intro quick highlights of blockchain,
ethereum

Blockchain
A blockchain is a distributed database
that maintains a continuously growing
list of records called blocks secured from
tampering and revision. Each block
contains a timestamp and a link to a
previous block.
4See my more elaborate talk at GDG DevFest: slideshare.net/SathishVJ/blockchain-bitcoin

Bitcoin
A distributed, decentralized,
digital cryptocurrency that relies
on Blockchain technology.
6

Ethereum
A blockchain-based distributed
computing platform, featuring smart
contract functionality. It provides a
decentralized virtual machine that
can execute peer-to-peer contracts
using a cryptocurrency called ether.
7

Blockchain : Bitcoin : Ethereum
Core
Tech
Gen 1: Special
Purpose Apps
Next Gen:
Platform for Apps
8

Ethereum
Clients What all are available?

Ethereum Clients
● Multiple clients based on Ethereum Yellow Paper
● In Go, Rust, C++, Python, JavaScript, etc.
● The Go based Ethereum client is called geth
● Got a dedicated website recently
○ Geth.ethereum.org
● Can also be used a library
○ In Mobiles
○ https://ethereum.karalabe.com/talks/2016-devcon.html

Geth Usage
● Largest ethereum client is the go client,
geth
● Most versions used are up to date, >
1.5.3

Miners in India
● About 100 nodes
● Mostly using geth

Ethereum &
DApps
Architecture Components - Current and Future

Ethereum, Swarm, Whisper
● Contracts: decentralized logic
● Swarm: decentralized storage
● Whisper: decentralized
messaging

Tech Components
● DApp: Distributed Application
● Solidity: a language to write contracts on ethereum
● web3: a library to interact with ethereum blockchain (web3.eth). Contains
other objects like (web3.shh for Whisper)
● Import web3.js in your browser to interact with the blockchain
● General term web3
○ No one definition
○ Multiple meanings in books and magazines
○ Here, it signifies an always “on”, distributed web, capable of massive scale

PoW to PoS, Casper & Tendermint
● Strategies to arrive at consensus in a distributed network
● Proof of Work expends too much energy.
● PoW is skewed towards those who can spend more money.
● Proof of Stake puts a certain number of coins to give one a chance to mine.
○ More egalitarian. Greater security with more participating nodes.
● Casper: scenarios where little to no assumptions should be made on the
altruism of users or validators, e.g. public blockchains.
● Tendermint: scenarios where participants have existing trust or where chance
of attack is less, e.g. consortium or private/hybrid blockchains

Using Geth Demo & Cmds to use the geth client

Project Links
● Github: https://github.com/ethereum/go-ethereum
● Releases: https://github.com/ethereum/go-ethereum/releases
● Downloads: https://geth.ethereum.org/downloads/
● Main site: https://www.ethereum.org
● Install command line tools: https://www.ethereum.org/cli

Installing Geth
● Bundled as a part of GUI tools like Mist/Ethereum-Wallet
● Installable from source
● Install with package manager
○ Homebrew, apt-get
● From standalone pre-built bundle

From Pre-built Bundle
● My Demo Setup: Google Compute Engine, small VM, Ubuntu, attached and
mounted disk of 100GB
● wget
https://gethstore.blob.core.windows.net/builds/geth-alltools-linux-amd64
-1.5.5-ff07d548.tar.gz
○ Check for latest version at https://geth.ethereum.org/downloads/
● tar -xvf geth-alltools-linux-amd64-1.5.5-ff07d548.tar.gz
● cd geth-alltools-linux-amd64-1.5.5-ff07d548
● ./geth
○ This default command will start an ethereum client node
○ Mining is not automatic/default
● Add geth to PATH if you want

Ethereum Account
● Your unique id on the Ethereum platform
○ A number like 0x2f2c...
● Online services can provide you an ethereum account (like email)
○ myetherwallet.com, coinbase.com, jaxx.io, etc.
● You can also setup your own account
● For convenience, use the GUIs Mist/Ethereum-Wallet
○ Electron based, cross platform Dapp browser/Wallet
● Or use cmd line
● geth account list
○ Account #0: {...key...}
/home/ethmine/.ethereum/keystore/UTC--2016-12-16T19-26-20.479741815Z--[key]

New Ethereum Account with Geth
● geth account new
Your new account is locked with a password. Please give a password. Do
not forget this password.
Passphrase:
Repeat Passphrase:
Address: {2fcb....}
● geth account list
● Any number of accounts can be created.

Backup Keystore and Password
● When you run your own node, backup your keystore and password
○ Imagine if you ran your own email server
● There is no way you can get to your account otherwise
● Locations on OSs
○ Windows: C:Usersusername%appdata%RoamingEthereumkeystore
○ Linux: ~/.ethereum/keystore
○ Mac: ~/Library/Ethereum/keystore
● Backup entire keystore folder …
● Or individual files that look like UTC--2016-12-03T18-26-12.919550734Z--key

Starting a Node
● You will need about 50GB of space as of now
● geth --datadir mydatadir --keystore ~/.ethereum
○ Datadir contains the blockchain data
○ I wanted the datadir to be on a different mount point
● A full sync in the beginning takes quite some time (a few days on a 1v-cpu, 1GB
machine) ...
● Speed it up on first sync by using the --fast option
○ This finished in many minutes
○ Cannot mine with just the fast sync

Exporting and Importing Chaindata
● Export & import existing blockchain data from existing sync-d node
● To export to binary format
○ geth export <filename>
● To import from binary format
○ geth export <filename>

Attaching UI to Node
● When UI starts, it checks for a running node
● If it exists, UI attaches to node
● If not, UI starts a node
○ Default is geth
○ Can configure others
● If you want to have a particular client …
○ Start the ethereum client on cmd line
○ Then start Mist or Ethereum-Wallet UI
1
2

Dir Structure
$ find mydatadir -maxdepth 2
mydatadir
mydatadir/geth
mydatadir/geth/chaindata
mydatadir/geth/nodes
mydatadir/geth/LOCK
mydatadir/geth/nodekey
mydatadir/geth.ipc
$ find ~/.ethereum/ -maxdepth 2
.ethereum/
.ethereum/history
.ethereum/keystore
.ethereum/keystore/UTC--2016-12-16T1
9-26-20.479741815Z--[your key]

Mining
● Run your ethereum node as a miner with --mine option
● To be a miner, you need at least one account, the ‘etherbase’ account

Coinbase/Etherbase Account
● If you mine a block, you get a reward of ETHs
● This is added to your ‘etherbase’ account
○ In bitcoin it is ‘coinbase’. Not to be confused with a company of the same name
● By default it is account ‘0’
○ … as listed in geth account list
● But you can specify another one
● --mine option without etherbase set will error out

geth console
● An interactive javascript console where you can do ‘web3’ programming
● Start with
○ geth console
● Exit with Ctrl+D or with >exit
● Attach to another running geth instance with
○ geth attach
● Then you can use console functions on one terminal while, say, sync logs show
on the other
● If running in a specific dir,
○ geth attach mydatadir/geth.ipc

Console commands
● miner.start()
● miner.stop()
● admin.datadir
● net.peerCount
● admin.peers
● web3.fromWei(eth.getBalance(eth.coinbase), "ether")
● personal.newAccount("password")
● personal.listAccounts

References
● Ethereum fundraiser infogram, with ether supply:
http://i.imgur.com/eI2mffD.png
●

Investing in
Ethereum Can we invest in it like Bitcoin or the
Share Market?

Cryptocurrency Investments
● Extremely volatile in general
● Some gigantic wins; many large losses
● Ether is the token/currency (ETH)
○ <1$ -> ~20$ -> 7.5$
○ Was $1B+ Market cap, but lower now
● Very strong technology
● Very good, responsive, knowledgeable, open team
● Very positive sentiment
● Many new, popular projects on Ethereum platform
● Long term investors using current lows to enter

Ether Supply
● http://ethereum.stackexchange.com/questions/443/what-is-the-total-supply-
of-ether
The issuance model is not fixed yet. It is an ongoing discussion whether
or not the costs for the consensus needs to be financed by inflation that
basically taxes every coin holder or if transaction fees are sufficient.
Please note that the costs for secure consensus are much lower
with Casper compared to current proof of work. More details here
For this reason it is guaranteed, that the current issuance amount
will not be increased and might even drop to 0. Another ongoing
discussion is whether or not issues of new coins should be used to fund
ongoing development. A prerequisites for this would be a DAO with a
widely accepted mechanism to control spending of funds effectively. But
also in this case the newly issued coins would not increase.
60 million + 12 million + 18million = ~90million
60 million - is the Pre-sale.
12 million - is the dev fund, 0.2coins per 1 coin sold in
the crowdsale.
~18 million - 1 million coins mined per month for 18
months prior to going from POW to POS.
inflation
After a while, 15,626,576 ether won't represent much of the
total ether available, making the system dis-inflationary (i.e.,
inflation perpetually trending towards 0 but never reaching it).

gething started - ethereum & using the geth golang client

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