Overflow

Tooling to help develop application on the the Flow Blockchain

Set of go scripts to make it easer to run a story consisting of creating accounts, deploying contracts, executing transactions and running scripts on the Flow Blockchain. These go scripts also make writing integration tests of your smart contracts much easier.

Information

Main features

• Create a single go file that will start emulator, deploy contracts, create accounts and run scripts and transactions. see examples/demo/main.go
• Fetch events, store progress in a file and send results to Discord. see examples/event/main.go
• Support inline scripts if you do not want to store everything in a file when testing
• Supports writing tests against transactions and scripts with some limitations on how to implement them.
• Asserts to make it easier to use the library in writing tests see examples/transaction_test.go for examples

Gotchas

• When specifying extra accounts that are created on emulator they are created in alphabetical order, the addresses the emulator assign is always fixed.
• tldr; Name your stakeholder accounts in alphabetical order
• When writing integration tests, tests must be in the same folder as flow.json with contracts and transactions/scripts in subdirectories in order for the path resolver to work correctly

Resources

• Check other codebases that use this project
• Feel free to ask questions to @bjartek in the Flow Discord.

Usage

First create a project directory, initialize the go module and install overflow:

mkdir test-overflow && cd test-overflow
flow init
go mod init example.com/test-overflow
go get github.com/bjartek/overflow/overflow

Then create a task file:

touch tasks/main.go

In that task file, you can then import overflow and use it to your convenience, for example:

package main

import (
    "fmt"

    "github.com/bjartek/overflow/overflow"
)

func main() {
    o := overflow.NewOverflow().Start()
    fmt.Printf("%v", o.State.Accounts())
}

Then you can run

go run ./tasks/main.go

This is a minimal example that only prints accounts, but from there you can branch out.

The following env vars are supported

• OVERFLOW_ENV : set the environment to run against "emulator|embedded|testnet|mainnet" (embedded is standard)
• OVEFFLOW_CONTINUE: if you do not want overflow to deploy contracts and accounts on emulator you can set this to true
• OVERFLOW_LOGGING: Set this to 0-4 to get increasing log

Credits

This project is the successor of https://github.com/bjartek/go-with-the-flow