Dymka

Swiss-knife command line tool for interacting with Ethereum-based blockchains.

Install the tool:

pip3 install --user dymka

Following are the usage examples.

Configuring provider and 'from' account

Unless your web3 provider is 'http://localhost:8545', you can use the --provider and specify it every time you run the tool. Or you may create a file myprovider with the following content:

--provider https://eth.llamarpc.com

and run the tool with it: dymka @myprovider exec eth_blockNumber. Or you may use environment variable like the following:

export WEB3_PROVIDER=https://eth.llamarpc.com

To specify the account that you use to transact from, use --from to specify account keystore file (and --password to specify the file with its pass phrase) or specify a private key.

Similarly to above, you can put this to a file, say myaccount:

--from account.json --password account.password.txt

and run the tool with it: dymka @myprovider @myaccount balance. Or just

export WEB3_FROM=...

In the following examples I assume you specify both provider and 'from' account.

Raw RPC requests

$ dymka exec web3_clientVersion
{
    "id": 0,
    "jsonrpc": "2.0",
    "result": "EthereumJS TestRPC/v2.8.0/ethereum-js"
}

$ dymka exec rpc_modules
{
    "id": 0,
    "jsonrpc": "2.0",
    "result": {
        "eth": "1.0",
        "net": "1.0",
        "rpc": "1.0",
        "web3": "1.0",
        "evm": "1.0",
        "personal": "1.0"
    }
}

$ dymka exec web3_sha3 "'0x68656c6c6f20776f726c64'"
$ dymka exec web3_sha3 "'hello world'"
{
    "id": 0,
    "jsonrpc": "2.0",
    "result": "0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad"
}

(or alrernatively use dymka keccak256 'hello world')

See note about arguments below for why we need double quotes here.

See Ethereum wiki JSON-RPC and Management APIs for more details.

Accounts, Balance and nonce

$ dymka accounts
[
    "0xB18aE0D7F12105e36a430523721622e5930879cC"
]

$ dymka balance 0xD6F0d25305cD6F53829aF54945d6FDEC370e20a5
[
    {
        "account": "0xD6F0d25305cD6F53829aF54945d6FDEC370e20a5",
        "result": 99945104760000000000
    }
]

$ dymka nonce 0xD6F0d25305cD6F53829aF54945d6FDEC370e20a5
[
    {
        "account": "0xD6F0d25305cD6F53829aF54945d6FDEC370e20a5",
        "result": 40
    }
]

Send money

dymka send --to 0xb92FbF90bFAC4a34557bbA17b91204C8D36a5055 \
           --value 1000000000000000000 \
           --gasPrice 1000000000 -e

Note that -e or --estimate stands for 'estimate gas'. Alternatively you can specify --gas 21000.

Compile contract

There is Demo contract, compile it like the following so we get demo.json.

solc --combined-json abi,bin --optimize demo.sol >demo.json

or with docker image

cd tests
docker run --rm -v $PWD:/src:ro ethereum/solc:0.5.9 \
    /src/demo.sol --combined-json abi,bin --optimize >demo.json

Deploy contract

$ dymka -c demo deploy
{
    "hash": "0xe4a8eeb6dc8a21e430077d460d2618c6a0a380e71dfecadcf4ceb252bae729b3",
    "receipt": {...
        "contractAddress": "0xbABA05e6c21551bb50caF7C684a1Fc9B57B02A9A",
    ...}
}

If you need to send money to the contract being deployed, use --value.

For convenience, export the address as environment variable as following.

export WEB3_CONTRACT_DEMO=0xbABA05e6c21551bb50caF7C684a1Fc9B57B02A9A

Alternatively, you may specify the address every time you want to call/send to the contract with -a 0xbABA05e6c21551bb50caF7C684a1Fc9B57B02A9A.

Call contract

$ dymka -c demo call value
{
    "result": 42
}

$ dymka -c demo call compare 45
{
    "result": [
        false,
        true
    ]
}

Invoke contract

dymka -c demo send set 42 100
dymka -c demo send act

If you need to send money to the contract, use --value.

Events

To list the events of the contract for blocks from 1 till 3:

$ dymka -a 0xbABA05e6c21551bb50caF7C684a1Fc9B57B02A9A -j demo.abi.json events 1-3

Gas price

Displays gas price of the current provider (web3.eth.gasPrice).

$ dymka gas
{
    "gasPrice": 20000000000
}

Other commands

• accounts - list available accounts,
• checksum - calculate correct checksummed string for the given address,
• show - display used provider and from address,
• transaction - show transaction details for the given hash,
• receipt - show receipt for the given hash,
• keccak - calculate Keccak-256 of the given string argument,
• chain - return an integer value for the currently configured “Chain Id” value introduced in EIP-155 (delegates to eth_chainId RPC Method),
• selector - returns contract's function by given selector,
• events, logs - Returns emitted events of the given contract for the specified block range (last 1000 blocks by default),
• help - shows full list of commands and short command description.

Note about arguments

Arguments for deploy, call and send contracts are first evaluated with python (eval()). Thus addresses should be quoted twice like the following.

$ dymka -c demo send teardown "\"0x0000000000000000000000000000000000000000\""

The outer quotes are consumed by your shell (e.g. bash) and the inner (escaped) quotes are consumed by python to make sure your address is not evaluated to the plain number 0. Use -vd (verbose and dry run) to see how your arguments are evaluated.

Troubleshooting

Use -v and -vv flags to see more information. File an issue or send a pull request so I try to help and review.

Why should I trust dymka

Dymka source code is open and kept reasonably small for review, it resides in a single file dymka for simplicity. The only runtime dependency is a Web3 python library that does all actions. Dymka actually is a thin command-line wrapper over it. Dymka can be used with no Internet access, it only needs to access its web3 provider (gateway node). No telemetry or other requests are ever made.

Donate

If you find the tool useful, please donate to ethereum address 0xb92FbF90bFAC4a34557bbA17b91204C8D36a5055.

Happy hacking 🐱.