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Developers' Guide

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Felix Lange edited this page Nov 18, 2016 · 38 revisions

NOTE: These instructions are for people who want to contribute Go source code changes. If you just want to run ethereum, use the normal Installation Instructions

Developers' guide

This document is the entry point for developers of the etherum go implementation. Developers here refer to the hands-on: who are interested in build, develop, debug, submit a bug report or pull request or contribute to go-ethereum with code.

Build and Test

Go environment

We assume that you have go v1.7 installed, and GOPATH is set.

Note:You must have your working copy under $GOPATH/src/github.com/ethereum/go-ethereum.

Since go does not use relative path for import, working in any other directory will have no effect, since the import paths will be appended to $GOPATH/src, and if the lib does not exist, the version at master HEAD will be downloaded.

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 [email protected]:nirname/go-ethereum.git $GOPATH/src/github.com/ethereum/go-ethereum

Updating non-vendored Dependencies

Most go-ethereum dependencies are tracked in the vendor/ directory, with one exception:

The golang.org/x/net/context package needs to be installed using go get. To do that, run

go get

in the repository root after cloning the repository.

Building executables

Switch to the go-ethereum repository root directory.

You can build all code using the go tool, placing the resulting binary in $GOPATH/bin.

go install -v ./...

go-ethereum exectuables can be built individually. To build just geth, use:

go install -v ./cmd/geth

Read about cross compilation of go-ethereum here.

Git flow

To make life easier try git flow it sets this all up and streamlines your work flow.

Testing

Testing one library:

go test -v -cpu 4 ./eth

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, eg.:

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

for more see go test flags

See integration testing information on the Testing wiki page

Metrics and monitoring

geth can do node behaviour monitoring, aggregation and show performance metric charts. Read about metrics and monitoring

Contributing

Only github is used to track issues. (Please include the commit and branch when reporting an issue.)

Pull requests should by default commit on the master branch.

Stacktrace

The code uses pprof on localhost port 6060 by default if geth is started with the --pprof option. So 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.

Note that if you run multiple instances of geth, this port will only work for the first instance that was launched. If you want to generate stacktraces for these other instances, you need to start them up choosing an alternative pprof port. Make sure you are redirecting stderr to a logfile.

geth -port=30300 -loglevel 5 --pprof --pprofport 6060 2>> /tmp/00.glog
geth -port=30301 -loglevel 5 --pprof --pprofport 6061 2>> /tmp/01.glog
geth -port=30302 -loglevel 5 --pprof --pprofport 6062 2>> /tmp/02.glog

Alternatively if you want to kill the clients (in case they hang or stalled synching, etc) but have the stacktrace too, you can use the -QUIT signal with kill:

killall -QUIT geth

This will dump stracktraces for each instance to their respective log file.

Code formatting

Sources are formatted according to the Go Formatting Style.

Dev Tutorials

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