Fuel Client

Fuel client implementation.

Contributing

If you are interested in contributing to Fuel, see our CONTRIBUTING.md guidelines for coding standards and review process.

Before pushing any changes or creating pull request please run source ci_checks.sh.

Building

System Requirements

There are several system requirements including clang.

MacOS

brew update
brew install cmake
brew install protobuf

Debian

apt update
apt install -y cmake pkg-config build-essential git clang libclang-dev protobuf-compiler

Arch

pacman -Syu --needed --noconfirm cmake gcc pkgconf git clang protobuf-compiler

Building

We recommend using xtask to build fuel-core:

cargo xtask build

This will run cargo build as well as any other custom build processes we have such as re-generating a GraphQL schema for the client.

Running

The service can be launched by executing fuel-core run. The list of options for running can be accessed via the help option:

$ ./target/debug/fuel-core run --help

USAGE:
    fuel-core run [OPTIONS]

OPTIONS:
        --chain <CHAIN_CONFIG>
            Specify either an alias to a built-in configuration or filepath to a JSON file [default:
            local_testnet]
        ...

For many development puposes it is useful to have a state that won't persist and the db-type option can be set to in-memory as in the following example.

Example

$ ./target/debug/fuel-core run --db-type in-memory
Jul 12 23:28:47.238  INFO fuel_core: Binding GraphQL provider to 127.0.0.1:4000

Troubleshooting

Outdated database

If you encounter an error such as

thread 'main' panicked at 'unable to open database: DatabaseError(Error { message: "Invalid argument: Column families not opened: column-11, column-10, column-9, column-8, column-7, column-6, column-5, column-4, column-3, column-2, column-1, column-0" })', fuel-core/src/main.rs:23:66

Clear your local database using: rm -rf ~/.fuel/db

File descriptor limits

On some macOS versions the default file descriptor limit is quite low, which can lead to IO errors with messages like Too many open files or even fatal runtime error: Rust cannot catch foreign exceptions when RocksDB encounters these issues. Use the following command to increase the open file limit. Note that this only affects the current shell session, so consider adding it to ~/.zshrc.

ulimit -n 10240

Log level

The service relies on the environment variable RUST_LOG. For more information, check the EnvFilter examples crate.

Human logging can be disabled with the environment variable HUMAN_LOGGING=false

Docker & Kubernetes

# Create Docker Image
docker build -t fuel-core . -f deployment/Dockerfile

# Delete Docker Image
docker image rm fuel-core

# Create Kubernetes Volume, Deployment & Service
kubectl create -f deployment/fuel-core.yml

# Delete Kubernetes Volume, Deployment & Service
kubectl delete -f deployment/fuel-core.yml

GraphQL service

The client functionality is available through a service endpoint that expect GraphQL queries.

Transaction executor

The transaction executor currently performs instant block production. Changes are persisted to RocksDB by default.

• Service endpoint: /graphql
• Schema (available after building): fuel-client/assets/schema.sdl

The service expects a mutation defined as submit that receives a Transaction in hex encoded binary format, as specified here.

cURL example

This example will execute a script that represents the following sequence of ASM:

ADDI(0x10, REG_ZERO, 0xca),
ADDI(0x11, REG_ZERO, 0xba),
LOG(0x10, 0x11, REG_ZERO, REG_ZERO),
RET(REG_ONE),

$ cargo run --bin fuel-gql-cli -- transaction submit \
"{\"Script\":{\"gas_price\":0,\"gas_limit\":1000000,\"maturity\":0,\"script\":[80,64,0,202,80,68,0,186,51,65,16,0,36,4,0,0],\"script_data\":[],\"inputs\":[],\"outputs\":[],\"witnesses\":[],\"receipts_root\":\"0x6114142d12e0f58cfb8c72c270cd0535944fb1ba763dce83c17e882c482224a2\"}}"