ethereum

README

ESWARM

This is enhanced version of swarm 0.3.0, which is used to deliver over 1PB data traffice in about 10K nodes.

Table of Contents

• Building the source
• Running Swarm
• Documentation
• Developers Guide
  • Go Environment
  • Vendored Dependencies
  • Testing
  • Profiling Swarm
  • Metrics and Instrumentation in Swarm
• Public Gateways
• Swarm Dapps
• Contributing
• License

Building the source

Software Installation

add-apt-repository ppa:longsleep/golang-backports -y
apt-get update  
apt install build-essential  govendor autoconf automake libtool  golang-go git -y

Download source code and make swarm

#!/bin/bash
mkdir ~/go/src/github.com/gauss-project -p
cd ~/go/src/github.com/gauss-project
git clone https://github.com/gauss-project/eswarm
cd eswarm
go mod init
mkdir vendor
mv vendor_bak.json vendor.json
govendor migrate
govendor sync -v
cd vendor/github.com/plotozhu/wiredtiger-go
./install-deps.sh
cd ~/go/src/github.com/gauss-project/eswarm
make 
#The swarm file exists in the "/root/go/src/github.com/gauss-project/eswarm/build/bin" directory
make swarm

Running Swarm

Going through all the possible command line flags is out of scope here, but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own Swarm node.

To run Swarm you need an Ethereum account. You can create a new account by running the following command:

geth account new

You will be prompted for a password:

Your new account is locked with a password. Please give a password. Do not forget this password.
Passphrase:
Repeat passphrase:

Once you have specified the password, the output will be the Ethereum address representing that account. For example:

Address: {2f1cd699b0bf461dcfbf0098ad8f5587b038f0f1}

Using this account, connect to Swarm with

swarm --bzzaccount <your-account-here>

# in our example

swarm --bzzaccount 2f1cd699b0bf461dcfbf0098ad8f5587b038f0f1

Verifying that your local Swarm node is running

When running, Swarm is accessible through an HTTP API on port 8500.

Confirm that it is up and running by pointing your browser to http://localhost:8500

Ethereum Name Service resolution

The Ethereum Name Service is the Ethereum equivalent of DNS in the classic web. In order to use ENS to resolve names to Swarm content hashes (e.g. bzz://theswarm.eth), swarm has to connect to a geth instance, which is synced with the Ethereum mainnet. This is done using the --ens-api flag.

swarm --bzzaccount <your-account-here> \
      --ens-api '$HOME/.ethereum/geth.ipc'

# in our example

swarm --bzzaccount 2f1cd699b0bf461dcfbf0098ad8f5587b038f0f1 \
      --ens-api '$HOME/.ethereum/geth.ipc'

For more information on usage, features or command line flags, please consult the Documentation.

Documentation

Swarm documentation can be found at https://swarm-guide.readthedocs.io.

Developers Guide

Go Environment

We assume that you have Go v1.10 installed, and GOPATH is set.

You must have your working copy under $GOPATH/src/github.com/gauss-project/eswarm.

Most likely you will be working from your fork of go-ethereum, let's say from github.com/nirname/go-ethereum. Clone or move your fork into the right place:

git clone git@github.com:nirname/go-ethereum.git $GOPATH/src/github.com/gauss-project/eswarm

Vendored Dependencies

All dependencies are tracked in the vendor directory. We use govendor to manage them.

If you want to add a new dependency, run govendor fetch <import-path>, then commit the result.

If you want to update all dependencies to their latest upstream version, run govendor fetch +v.

Testing

This section explains how to run unit, integration, and end-to-end tests in your development sandbox.

Testing one library:

go test -v -cpu 4 ./swarm/api

Note: Using options -cpu (number of cores allowed) and -v (logging even if no error) is recommended.

Testing only some methods:

go test -v -cpu 4 ./eth -run TestMethod

Note: here all tests with prefix TestMethod will be run, so if you got TestMethod, TestMethod1, then both!

Running benchmarks:

go test -v -cpu 4 -bench . -run BenchmarkJoin

Profiling Swarm

This section explains how to add Go pprof profiler to Swarm

If swarm is started with the --pprof option, a debugging HTTP server is made available on port 6060.

You can bring up http://localhost:6060/debug/pprof to see the heap, running routines etc.

By clicking full goroutine stack dump (clicking http://localhost:6060/debug/pprof/goroutine?debug=2) you can generate trace that is useful for debugging.

Metrics and Instrumentation in Swarm

This section explains how to visualize and use existing Swarm metrics and how to instrument Swarm with a new metric.

Swarm metrics system is based on the go-metrics library.

The most common types of measurements we use in Swarm are counters and resetting timers. Consult the go-metrics documentation for full reference of available types.

# incrementing a counter
metrics.GetOrRegisterCounter("network.stream.received_chunks", nil).Inc(1)

# measuring latency with a resetting timer
start := time.Now()
t := metrics.GetOrRegisterResettingTimer("http.request.GET.time"), nil)
...
t := UpdateSince(start)

Visualizing metrics

Swarm supports an InfluxDB exporter. Consult the help section to learn about the command line arguments used to configure it:

swarm --help | grep metrics

We use Grafana and InfluxDB to visualise metrics reported by Swarm. We keep our Grafana dashboards under version control at ./swarm/grafana_dashboards. You could use them or design your own.

We have built a tool to help with automatic start of Grafana and InfluxDB and provisioning of dashboards at https://github.com/nonsense/stateth , which requires that you have Docker installed.

Once you have stateth installed, and you have Docker running locally, you have to:

1. Run stateth and keep it running in the background

stateth --rm --grafana-dashboards-folder $GOPATH/src/github.com/gauss-project/eswarm/swarm/grafana_dashboards --influxdb-database metrics

1. Run swarm with at least the following params:

--metrics \
--metrics.influxdb.export \
--metrics.influxdb.endpoint "http://localhost:8086" \
--metrics.influxdb.username "admin" \
--metrics.influxdb.password "admin" \
--metrics.influxdb.database "metrics"

1. Open Grafana at http://localhost:3000 and view the dashboards to gain insight into Swarm.

Public Gateways

Swarm offers a local HTTP proxy API that Dapps can use to interact with Swarm. The Ethereum Foundation is hosting a public gateway, which allows free access so that people can try Swarm without running their own node.

The Swarm public gateways are temporary and users should not rely on their existence for production services.

The Swarm public gateway can be found at https://swarm-gateways.net and is always running the latest stable Swarm release.

Swarm Dapps

You can find a few reference Swarm decentralised applications at: https://swarm-gateways.net/bzz:/swarmapps.eth

Their source code can be found at: https://github.com/ethersphere/swarm-dapps

Contributing

Thank you for considering to help out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!

If you'd like to contribute to Swarm, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base. If you wish to submit more complex changes though, please check up with the core devs first on our Swarm gitter channel to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.

Please make sure your contributions adhere to our coding guidelines:

• Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
• Code must be documented adhering to the official Go commentary guidelines.
• Pull requests need to be based on and opened against the master branch.
• Code review guidelines.
• Commit messages should be prefixed with the package(s) they modify.
  • E.g. "swarm/fuse: ignore default manifest entry"

License

The go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The go-ethereum binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.

Documentation

Overview

Package ethereum defines interfaces for interacting with Ethereum.

Index

• Variables
• type CallMsg
• type ChainReader
• type ChainStateReader
• type ChainSyncReader
• type ContractCaller
• type FilterQuery
• type GasEstimator
• type GasPricer
• type LogFilterer
• type PendingContractCaller
• type PendingStateEventer
• type PendingStateReader
• type Subscription
• type SyncProgress
• type TransactionReader
• type TransactionSender

Variables

var NotFound = errors.New("not found")

NotFound is returned by API methods if the requested item does not exist.

Types

type CallMsg

type CallMsg struct {
	From     common.Address  // the sender of the 'transaction'
	To       *common.Address // the destination contract (nil for contract creation)
	Gas      uint64          // if 0, the call executes with near-infinite gas
	GasPrice *big.Int        // wei <-> gas exchange ratio
	Value    *big.Int        // amount of wei sent along with the call
	Data     []byte          // input data, usually an ABI-encoded contract method invocation
}

CallMsg contains parameters for contract calls.

type ChainReader

type ChainReader interface {
	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)

	// This method subscribes to notifications about changes of the head block of
	// the canonical chain.
	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
}

ChainReader provides access to the blockchain. The methods in this interface access raw data from either the canonical chain (when requesting by block number) or any blockchain fork that was previously downloaded and processed by the node. The block number argument can be nil to select the latest canonical block. Reading block headers should be preferred over full blocks whenever possible.

The returned error is NotFound if the requested item does not exist.

type ChainStateReader

type ChainStateReader interface {
	BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
	StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
	NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
}

ChainStateReader wraps access to the state trie of the canonical blockchain. Note that implementations of the interface may be unable to return state values for old blocks. In many cases, using CallContract can be preferable to reading raw contract storage.

type ChainSyncReader

type ChainSyncReader interface {
	SyncProgress(ctx context.Context) (*SyncProgress, error)
}

ChainSyncReader wraps access to the node's current sync status. If there's no sync currently running, it returns nil.

type ContractCaller

type ContractCaller interface {
	CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
}

A ContractCaller provides contract calls, essentially transactions that are executed by the EVM but not mined into the blockchain. ContractCall is a low-level method to execute such calls. For applications which are structured around specific contracts, the abigen tool provides a nicer, properly typed way to perform calls.

type FilterQuery

type FilterQuery struct {
	BlockHash *common.Hash     // used by eth_getLogs, return logs only from block with this hash
	FromBlock *big.Int         // beginning of the queried range, nil means genesis block
	ToBlock   *big.Int         // end of the range, nil means latest block
	Addresses []common.Address // restricts matches to events created by specific contracts

	// The Topic list restricts matches to particular event topics. Each event has a list
	// of topics. Topics matches a prefix of that list. An empty element slice matches any
	// topic. Non-empty elements represent an alternative that matches any of the
	// contained topics.
	//
	// Examples:
	// {} or nil          matches any topic list
	// {{A}}              matches topic A in first position
	// {{}, {B}}          matches any topic in first position AND B in second position
	// {{A}, {B}}         matches topic A in first position AND B in second position
	// {{A, B}, {C, D}}   matches topic (A OR B) in first position AND (C OR D) in second position
	Topics [][]common.Hash
}

FilterQuery contains options for contract log filtering.

type GasEstimator

type GasEstimator interface {
	EstimateGas(ctx context.Context, call CallMsg) (uint64, error)
}

GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a specific transaction based on the pending state. There is no guarantee that this is the true gas limit requirement as other transactions may be added or removed by miners, but it should provide a basis for setting a reasonable default.

type GasPricer

type GasPricer interface {
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
}

GasPricer wraps the gas price oracle, which monitors the blockchain to determine the optimal gas price given current fee market conditions.

type LogFilterer

type LogFilterer interface {
	FilterLogs(ctx context.Context, q FilterQuery) ([]types.Log, error)
	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- types.Log) (Subscription, error)
}

LogFilterer provides access to contract log events using a one-off query or continuous event subscription.

Logs received through a streaming query subscription may have Removed set to true, indicating that the log was reverted due to a chain reorganisation.

type PendingContractCaller

type PendingContractCaller interface {
	PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
}

PendingContractCaller can be used to perform calls against the pending state.

type PendingStateEventer

type PendingStateEventer interface {
	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
}

A PendingStateEventer provides access to real time notifications about changes to the pending state.

type PendingStateReader

type PendingStateReader interface {
	PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
	PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	PendingTransactionCount(ctx context.Context) (uint, error)
}

A PendingStateReader provides access to the pending state, which is the result of all known executable transactions which have not yet been included in the blockchain. It is commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value transfers) initiated by the user. The PendingNonceAt operation is a good way to retrieve the next available transaction nonce for a specific account.

type Subscription

type Subscription interface {
	// Unsubscribe cancels the sending of events to the data channel
	// and closes the error channel.
	Unsubscribe()
	// Err returns the subscription error channel. The error channel receives
	// a value if there is an issue with the subscription (e.g. the network connection
	// delivering the events has been closed). Only one value will ever be sent.
	// The error channel is closed by Unsubscribe.
	Err() <-chan error
}

Subscription represents an event subscription where events are delivered on a data channel.

type SyncProgress

type SyncProgress struct {
	StartingBlock uint64 // Block number where sync began
	CurrentBlock  uint64 // Current block number where sync is at
	HighestBlock  uint64 // Highest alleged block number in the chain
	PulledStates  uint64 // Number of state trie entries already downloaded
	KnownStates   uint64 // Total number of state trie entries known about
}

SyncProgress gives progress indications when the node is synchronising with the Ethereum network.

type TransactionReader

type TransactionReader interface {
	// TransactionByHash checks the pool of pending transactions in addition to the
	// blockchain. The isPending return value indicates whether the transaction has been
	// mined yet. Note that the transaction may not be part of the canonical chain even if
	// it's not pending.
	TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
	// TransactionReceipt returns the receipt of a mined transaction. Note that the
	// transaction may not be included in the current canonical chain even if a receipt
	// exists.
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}

TransactionReader provides access to past transactions and their receipts. Implementations may impose arbitrary restrictions on the transactions and receipts that can be retrieved. Historic transactions may not be available.

Avoid relying on this interface if possible. Contract logs (through the LogFilterer interface) are more reliable and usually safer in the presence of chain reorganisations.

The returned error is NotFound if the requested item does not exist.

type TransactionSender

type TransactionSender interface {
	SendTransaction(ctx context.Context, tx *types.Transaction) error
}

TransactionSender wraps transaction sending. The SendTransaction method injects a signed transaction into the pending transaction pool for execution. If the transaction was a contract creation, the TransactionReceipt method can be used to retrieve the contract address after the transaction has been mined.

The transaction must be signed and have a valid nonce to be included. Consumers of the API can use package accounts to maintain local private keys and need can retrieve the next available nonce using PendingNonceAt.