Using Gamma CLI

Transactions are different from read-only queries by the fact they're able to change state. Transactions require consensus by several nodes whereas read-only queries can rely on a single node.

Send transactions to contracts by running gamma-cli send-tx and giving a JSON file containing the call arguments.

For example, to send the transaction with arguments in transfer.json

gamma-cli send-tx transfer.json -signer user1

Perform queries and call read-only contract methods by running gamma-cli run-query and giving a similar JSON file.

For example, to make the read call with arguments in get-balance.json

gamma-cli run-query get-balance.json -signer user1

Command parameters

gamma-cli send-tx <INPUT_FILE> -arg# [OVERRIDE_ARG_#] -signer [ID_FROM_KEYS_JSON]

gamma-cli run-query <INPUT_FILE> -arg# [OVERRIDE_ARG_#] -signer [ID_FROM_KEYS_JSON]

• <INPUT_FILE> Path of the JSON file containing the call arguments

• -signer Account ID of the signer of the call (from orbs-test-keys.json)

• -arg# Override the value of argument number # from the input call argument JSON

Call argument JSON

This simple JSON file is used to let Gamma CLI know which contract method should be executed and what arguments should be passed to it.

An example of such a JSON is

{
  "ContractName": "CounterExample",
  "MethodName": "add",
  "Arguments": [
    {
      "Type": "uint64",
      "Value": "25"
    }
  ]
}

The ContractName should be the name chosen during deployment of the contract with gamma-cli deploy. The method name should be one of the exported methods found in the contract source code.

The array of arguments should be given according to the declaration of the method in contract source code.

Supported argument types

• uint32 - Integer with 32 bit precision. Matches the uint32 type in Go contracts. Provided in the JSON as a string of a decimal number. For example

  {
    "Type": "uint32",
    "Value": "25"
  }

• uint64 - Integer with 64 bit precision. Matches the uint64 type in Go contracts. Provided in the JSON as a string of a decimal number. For example

  {
    "Type": "uint64",
    "Value": "10029999"
  }

• string - String. Matches the string type in Go contracts. Provided in the JSON as a UTF8 string. For example

  {
    "Type": "string",
    "Value": "Hello world"
  }

• bytes - An array of bytes (blob). Matches the []byte type in Go contracts. Provided in the JSON as a hex string. For example

  {
    "Type": "bytes",
    "Value": "00ff018e00ab2fe901"
  }

In addition to these primitives, Gamma CLI supports several aliases for convenience:

• gamma:keys-file-address - An account address by ID. The value should be an account ID from orbs-test-keys.json. An alias for the type bytes which means it matches the []byte type in Go contracts. Used to pass the account address in raw form.

  {
    "Type": "gamma:keys-file-address",
    "Value": "user3"
  }

Overriding arguments from command line

Consider a JSON for a typical transfer method

transfer-15.json
{
  "ContractName": "MyToken",
  "MethodName": "transfer",

  "Arguments": [
    {
      "Type": "uint64",
      "Value": "15"
    },
    {
      "Type": "bytes",
      "Value": "b3d1caa2b3680e2c8feffa269c207c553fbbc828"
    }
  ]
}

The first argument is the amount and the second argument is the recipient address.

If you want to send multiple transactions with different amounts or different addresses, creating multiple JSON files containing the different values can be a hassle.

Instead, use the optional -arg1 and -arg2 command line arguments to override values

gamma-cli send-tx transfer-15.json

will send 15 tokens to recipient b3d1caa2b3680e2c8feffa269c207c553fbbc828

gamma-cli send-tx transfer-15.json -arg1 22

will send 22 tokens to recipient b3d1caa2b3680e2c8feffa269c207c553fbbc828

gamma-cli send-tx transfer-15.json -arg2 7ccd7f7c18c0cb749dd8b8949f4b4e31f7188394

will send 15 tokens to recipient 7ccd7f7c18c0cb749dd8b8949f4b4e31f7188394