Official golang implementation of the Celo blockchain, based off of the official golang implementation of the Ethereum protocol.
Documentation for Celo more generally can be found at docs.celo.org
Most functionality of this client is similar to
go-ethereum, also known as
geth, from which it was forked. If you do not find your question answered by Celo-specific documentation, try searching the geth wiki.
Building the source
geth requires both a Go (version 1.16) and a C compiler.
You can install them using your favourite package manager. Once the dependencies are installed, run
or, to build the full suite of utilities:
There are two different commands in the
Makefile to build the
ios and the
android command it applies a git patch (
patches/mobileLibsForBuild.patch) required to swap some libs from the
go.mod for the client to work, installs those libs, builds the client, and then reverts the patch.
The Celo blockchain client comes with several wrappers/executables found in the
||The main Celo Blockchain client. It is the entry point into the Celo network, capable of running as a full node (default), archive node (retaining all historical state), light node (retrieving data live), or lightest node (retrieving minimum number of block headers to verify existing validator set). It can be used by other processes as a gateway into the Celo network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports.
||Source code generator to convert Celo contract definitions into easy to use, compile-time type-safe Go packages. It operates on plain Ethereum contract ABIs with expanded functionality if the contract bytecode is also available. However it also accepts Solidity source files, making development much more streamlined. Please see Ethereum's Native DApps wiki page for details.|
||Stripped down version of the Celo client implementation that only takes part in the network node discovery protocol, but does not run any of the higher level application protocols. It can be used as a lightweight bootstrap node to aid in finding peers in private networks.|
||Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g.
||Developer utility tool to support the ethereum/rpc-test test suite which validates baseline conformity to the Ethereum JSON RPC specs. Please see the ethereum test suite's readme for details.|
||Developer utility tool to convert binary RLP (Recursive Length Prefix) dumps (data encoding used by the Celo protocol both network as well as consensus wise) to user friendlier hierarchical representation (e.g.
Prior to running tests you will need to run
This will checkout the celo-monorepo and compile the system contracts for use
in full network tests. The rule will copy the compiled contracts from
compiled-system-contracts. If you subsequently edit the
system contracts source, running the make rule again will re-compile them and
copy them into place.
This make rule will shallow checkout
../.celo-blockchain-monorepo-checkout relative to this project's root, and it
will checkout the commit defined in the variable MONOREPO_COMMIT in the
These values can be overridden if required, by setting those variables in the make command, for example:
make prepare-system-contracts MONOREPO_COMMIT=master MONOREPO_PATH=../alt-monorepo
Without first running this make rule, certain tests will fail with errors such as:
panic: Can't read bytecode for monorepo/packages/protocol/build/contracts/FixidityLib.json: open
Please see the docs.celo.org/getting-started for instructions on how to run a node connected the Celo network using the prebuilt Docker image.
Going through all the possible command line flags is out of scope here, please consult
geth --help for more complete information.
We've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own Celo blockchain client instance.
Full node on the main Celo network
By default, the Celo client will connect to the Mainnet. Running the following command will create a full node that will sync with the Celo network and allow access to all of its functionality.
$ geth console
This command will:
gethin full sync mode which will download and execute all historical block information.
- Start up
consolesubcommand) through which you can invoke all official
web3methods as well as
geth's own management APIs. This tool is optional and if you leave it out you can always attach to an already running
A Full node on the Alfajores test network
Smart contract developers will be most interested in the Alfajores testnet. On Alfajores, you can receive testnet Celo through the Alfajores faucet and deploy smart contracts in an environment very similar to Mainnet. More information about the Alfajores testnet can be found on docs.celo.org.
$ geth --alfajores console
Note: Although there are some internal protective measures to prevent transactions from
crossing over between the main network and test network, you should make sure to always
use separate accounts for testnet-tokens and real-tokens. Unless you manually move
geth will by default correctly separate the two networks and will not make any
accounts available between them.
Full node on the Baklava test network
Validators and full node operators will be most interested in the Baklava testnet. On Baklava, you can receive a distribution of testnet Celo Gold to become a validator on the network and test out running a validator for the first time, or try out new infrastructure. More information about the Baklava testnet can be found on docs.celo.org. A full guide to getting started as a validator on Baklava can be found in the Getting Started guides
$ geth --baklava console
As an alternative to passing the numerous flags to the
Celo binary, you can also pass a configuration file via:
$ geth --config /path/to/your_config.toml
To get an idea how the file should look like you can use the
dumpconfig subcommand to
export your existing configuration:
$ geth --your-favourite-flags dumpconfig
As a developer, sooner rather than later you'll want to start interacting with
geth and the
Celo network via your own programs and not manually through the console. To aid
geth has built-in support for a JSON-RPC based APIs (standard APIs
geth specific APIs).
These can be exposed via HTTP, WebSockets and IPC (UNIX sockets on UNIX based
platforms, and named pipes on Windows).
The IPC interface is enabled by default and exposes all the APIs supported by
whereas the HTTP and WS interfaces need to manually be enabled and only expose a
subset of APIs due to security reasons. These can be turned on/off and configured as
HTTP based JSON-RPC API options:
--httpEnable the HTTP-RPC server
--http.addrHTTP-RPC server listening interface (default:
--http.portHTTP-RPC server listening port (default:
--http.apiAPI's offered over the HTTP-RPC interface (default:
--http.corsdomainComma separated list of domains from which to accept cross origin requests (browser enforced)
--wsEnable the WS-RPC server
--ws.addrWS-RPC server listening interface (default:
--ws.portWS-RPC server listening port (default:
--ws.apiAPI's offered over the WS-RPC interface (default:
--ws.origins valueOrigins from which to accept websockets requests
--graphqlEnable GraphQL on the HTTP-RPC server. Note that GraphQL can only be started if an HTTP server is started as well.
--graphql.corsdomain valueComma separated list of domains from which to accept cross origin requests (browser enforced)
--graphql.vhosts valueComma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard. (default: "localhost")
--ipcdisableDisable the IPC-RPC server
--ipcapiAPI's offered over the IPC-RPC interface (default:
--ipcpathFilename for IPC socket/pipe within the datadir (explicit paths escape it)
You'll need to use your own programming environments' capabilities (libraries, tools, etc) to
connect via HTTP, WS or IPC to a
geth node configured with the above flags and you'll
need to speak JSON-RPC on all transports. You
can reuse the same connection for multiple requests!
Note: Please understand the security implications of opening up an HTTP/WS based transport before doing so! Hackers on the internet are actively trying to subvert Celo nodes with exposed APIs! Further, all browser tabs can access locally running web servers, so malicious web pages could try to subvert locally available APIs!
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 celo-blockchain, 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 the official Celo forum 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
- Commit messages should be prefixed with the package(s) they modify.
- E.g. "eth, rpc: make trace configs optional"
Submitting an issue
If you come across a bug, pleas open a GitHub issue with information about your build and what happened.
CI Testing and automerge
We run a circle CI test suite on each PR. The following tests are required to merge a PR.
- Unit tests:
./build/env.sh go run build/ci.go test
make lint(Fix go format errors with
- End to end sync and transfer tests
- Check imports:
celo-blockchain is based on
go-ethereum, but the import path has been renamed from
Developers are encouraged to run
./scripts/setup_git_hooks.sh to enable checking that import path has been changed to
git merge and
Imports can automatically be renamed with
Individual package tests can be run with
./build/env.sh go test github.com/celo-org/celo-blockchain/$(PATH_TO_GO_PACKAGE)
if you don't have
Once a PR is approved, adding on the
automerge label will keep it up to date
and do a squash merge once all the required tests have passed.
Golang has built in support for running benchmarks with go tool
go test -run=ThisIsNotATestName -bench=. ./$PACKAGE_NAME will run all benchmarks in a package.
One note around running benchmarks is that
BenchmarkHandlePreprepare is quite takes a while to run, particularly when testing with a larger number of validators.
-bench=. will specify which tests to run. Adding
-cpuprofile=cpu.out which can be visualized with
go tool pprof -html:8080 cpu.out if
graphviz is installed.
The celo-blockchain 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
The celo-blockchain 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