v2 Contract SDK
  • Orbs Contract SDK
  • Getting Started
    • About smart contracts
    • Becoming a Go developer
    • Installing Gamma - local blockchain
    • Deploying your first contract
    • The Orbs Starter Kit
    • Downloading the Contract SDK
  • Orbs Contracts
    • Smart contracts
    • Layout of a contract file
    • Data types (Exported Functions)
    • State
    • Address
    • Events
    • Error handling
    • Calling other contracts
    • Calling Ethereum contract
    • API Reference
    • Limitations of Orbs Contracts
    • Creating a new contract
  • Gamma in Depth
    • Starting and stopping the server
    • Test keys and accounts
    • Deploying smart contracts
    • Sending transactions and queries
    • Checking sent transaction status
    • Reading Logs from Contracts
    • Working with multiple environments
    • Upgrading to latest versions
    • Gamma server under the hood
    • Deploying Gamma in the Cloud
      • Amazon Web Services
      • Google Cloud Platform
      • Azure
Powered by GitBook
On this page
  • Package Whitelist
  • Time functions blacklist
  • Blacklisted Features
  1. Orbs Contracts

Limitations of Orbs Contracts

Orbs contracts are written in the Go programming language.

To enhance security and enable multiple virtual chains in the Orbs blockchain, the smart contracts are limited compared to the Go language. Specifically, Orbs limits the features and packages of the language that are allowed to execute inside the Orbs Virtual Machine.

Package Whitelist

All packages in Go are not allowed except for specific packages listed in the whitelist below:

// Orbs Contract SDK
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/address"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/env"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/ethereum"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/events"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/safemath"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/safemath/safeuint32"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/safemath/safeuint64"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/safemath/safeuint256"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/service"
"github.com/orbs-network/orbs-contract-sdk/go/sdk/v1/state"

// Text
"strings"
"strconv"
"text/template"

// Time
"time"

// Binary
"bytes"
"encoding/binary"
"io"

// Encoding
"encoding/json"
"encoding/hex"
"encoding/base32"
"encoding/base64"

// Utils
"sort"

Trying to include any package not in that list results in a failed compilation of the smart contract.

Time functions blacklist

While we enable the use of the time package for time manipulation, it contains several functions which would result in inconsistent and non-deterministic results in contracts, and thus they are blacklisted. These functions are:

"After"
"AfterFunc"
"Sleep"
"Tick"
"NewTimer"
"NewTicker"
"Now"

Using any of these functions results in a failed compilation of the smart contract.

If you want the current time ('Now'), it is possible to use the contract SDK function env.GetBlockTimestamp()

Blacklisted Features

Aside from a whitelist of the allowed packages, Orbs does not allow the usage of the following Go language features:

  • Channels

  • Goroutines (the go statement)

  • The 'arrow' unary expression (<-)

Using any of the above features results in a failed compilation of the smart contract.

PreviousAPI ReferenceNextCreating a new contract

Last updated 5 years ago