Go

hivekit-go modules are compiled with TinyGo (-target=wasm-unknown) and packaged as Hive Bytecode (.hbc); the compiled code inside implements the hive-wasm-v1 ABI.

Writing a module

package main

import (
  "errors"

  hivekit "github.com/necter-network/hivekit-go"
)

type pair struct {
  A float64 `json:"a"`
  B float64 `json:"b"`
}

func init() {
  // Typed: input decoded from JSON, output encoded as JSON, error fails the call.
  hivekit.DefineJSON("divide", func(p pair) (map[string]float64, error) {
    if p.B == 0 {
      return nil, errors.New("division by zero")
    }
    return map[string]float64{"result": p.A / p.B}, nil
  })

  // Untyped JSON object in, JSON object out.
  hivekit.Define("greet", func(in map[string]any) map[string]any {
    name, _ := in["name"].(string)
    return map[string]any{"message": "Hello, " + name}
  })

  // Raw bytes in, raw UTF-8 bytes out.
  hivekit.DefineRaw("echo", func(in []byte) ([]byte, error) { return in, nil })
}

func main() {} // required by Go, never called by NDSR

Register functions from init() (or package-level initializers). Names must match [A-Za-z_][A-Za-z0-9_]{0,63}; registering a name twice panics. NDSR never calls _start: the SDK initializes TinyGo’s runtime lazily on the first call, which costs roughly 35–40k gas per call.

Host API

Go	Host import	Notes
StorageGet(key) ([]byte, bool), StorageGetString, StorageGetJSON	storage.get	absent → false
StorageSet(key, val), StorageSetString, StorageSetJSON	storage.set	empty value deletes
StorageDel(key)	storage.del
Emit(name, data), EmitRaw(name, json)	hive.emit	canonical-JSON compatible data
Call(addr, fn, input) ([]byte, error), CallJSON(addr, fn, in, &out)	hive.call	errors are *CallError (CallModuleNotFound −1, CallFunctionNotFound −2, CallFailed −3, CallDepthExceeded −5, CallBadAddress −6)
Hash(data) string	crypto.hash	Keccak-256 as 0x…
Log(msg), Logf(...)	console.log
Abort(msg)	hive.abort	fails the call; nothing written or emitted is kept

Floats

Event data must not contain non-integral numbers. encoding/json writes a whole-valued float64 such as 42.0 as 42, which is accepted, but 0.5 in an event fails the call. Use integer minor units. Function outputs are plain text and may contain floats.

Panics (index out of range, nil map write) trap the call; recover is not available on this target, so return errors instead.

Build, inspect, run

hivec build ./examples/math_module          # → dist/math_module.hbc
hivec inspect dist/math_module.hbc
hivec functions dist/math_module.hbc
hivec run dist/math_module.hbc multiply '{"a":7,"b":6}'

# state persists between runs; flags go before the file
hivec run -data-dir ./state dist/price_oracle.hbc submit '{"pair":"ETH/USD","source":"a","price":320012}'
hivec run -data-dir ./state dist/price_oracle.hbc price '{"pair":"ETH/USD"}'

# make another module callable through hive.call
hivec run -module dist/math_module.hbc dist/ledger.hbc record '{"math":"0x<math address>","a":6,"b":7}'

hivec build flags: -o DIR, -name, -version, -description, -tinygo PATH, -gc, -keep-wasm. hivec package module.wasm -name N packages a wasm you built yourself. Without ndsr (or with -local) hivec run falls back to a built-in runner with no gas metering and no receipt, for quick iteration only.

Examples in the SDK

hivekit-go/examples/: math_module (pure), price_oracle (sources submit prices, median in storage), ledger (hive.call into math_module, storage, events, crypto.hash). Built from source with TinyGo 0.42.0 they reproduce the testnet addresses: math_module = 0x5b89b7c4f37ab4cf68f30999424ee32775d5c137d35c066e8ce9ce75563887bb, ledger = 0x8c69b941c33d72a06c7275087adad4602f7f039bf742e0c25802dc0a53a9ce1d.

Testing: Testing modules.