An Experimental Project for Writing Smart Contract With Python Base on The Development of EOSIO

Building PyEos
Creating Your First Python Smart Contract
Smart Contract Debugging
PyEos api overview

Building PyEos

Downloading Source Code

git clone https://www.github.com/learnforpractice/pyeos
cd pyeos
git submodule update --init --recursive

Installing dependencies (Ubuntu)

sudo apt-get install libleveldb-dev
sudo apt-get install libreadline-dev

Installing dependencies (macOS)

brew install leveldb
brew install readline

Building

./eosio_build.sh

Creating Your First Python Smart Contract

Running PyEos

Open a terminal, cd to [PROJECT_DIR]/build/program, run the following command

./pyeos/pyeos --manual-gen-block --debug -i

If it's the first time you start PyEos, PyEos will create a testing wallet for you, which placed in data-dir/mywallet.wallet, and then console will print the wallet password as below:

wallet password: PW5JWE5g6RZ7Fyr2kmCphDqZo4uivdeGpUpndgFZ52rsduhtf9PRJ

Since it's for testing only, password will save to data-dir/data.pkl, So next time you start pyeos for testing, pyeos will unlock wallet for you.

Also PyEos will import three private key to the wallet, which is useful for testing.

'5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3',
'5JEcwbckBCdmji5j8ZoMHLEUS8TqQiqBG1DRx1X9DN124GUok9s',
'5JbDP55GXN7MLcNYKCnJtfKi9aD2HvHAdY7g8m67zFTAFkY1uBB'

Keep in mind that these private key should never be used in real account, otherwise you will lose all of your crypto property in the account.

Beside that, PyEos will create four important accounts for you:

eosio.bios, eosio.msig, eosio.system, eosio.token

and publish their smart contract on testnet.

Although the above steps will never happen in the real world, but it's really provide a great convenience for testing smart contract. Thus save a lot of your precious time and make the development more efficient.

Generating source code with sketch

Run the following command in PyEos console,

sketch.build('hello', 'helloworld', 'py')

That will create a helloworld directory under your current directory with hello as the testing account name. There are three file generated in the directory:

helloworld.py
helloworld.abi
t.py

Which hello.py is the Python smart contract source code, hello.abi is the ABI(Application Binary Interface) file for smart contract, t.py contains code for testing the smart contract, let's talk about it later in detail.

In addition, sketch can also create a wasm smart contract project for you, just type the following code in PyEos console, and the testing process has no difference with Python smart contract.

sketch.build('helloworld', 'helloworld', 'cpp')

Testing

Now it's time to run your helloworld smart contract program. Type or copy the following command to the PyEos console:

from helloworld import t
t.test()

You will see the following output on console in green words:

3289633ms thread-1   mpeoslib.cpp:63               print                ] hello,world

Congratulations, you have successfully run your first Python smart contract.

Now you can open hello.py for coding. Once it's done, just run t.test() again, there is no need to run other command to publish your testing smart contract, the smart contract will be automatically republish to the testnet if it's been changed during the running of t.test(). You can also edit the testing code in t.py to test your smart contract. Once it's done, just run t.test() again, there is no need to run reload(t), PyEos has do the magic for you. That also works at the situation of adding a new function in test.

There are a lot of examples in programs/pyeos/contracts. Some of them are still in develop, if the example throws exception, then it's probably not done yet. Pick up an example you interest in and play with it as you want.

Smart Contract Debugging

Python smart contract support source level debugging. Developers can debug their smart contract in Eclipse IDE with pydevd Eclipse pluging, other IDE such as Visual Studio Code may also be supported, Please search for online resources to find out how to debug Python source remotely. for pydevd, there is a reference from here manual_adv_remote_debugger. After the environment has been successfully setting up, run the following command in PyEos console to enable debugging.

debug.enable()

Set breakpoint at your python smart contract source code in Eclipse. If your Python smart contract source code does not placed in pyeos/contracts directory, them you need to run the following code to specify your source code directory and your smart contract source code file must under directory with the same name.

 sys.path.append(<folder where source code directory in>)

Deploy your smart contract to the testnet, Use hello contract in pyeos/contracts as example, set breakpoint at hello.py, and run the following code to call hello.py

from hello import t
t.test()

Smart contract execution will be stopped when the code at the line of breakpoint is being executed.

To disable debugging, run the following code.

debug.disable()

PyEos api overview

eosapi.get_info

info = eosapi.get_info()
info

{
    "server_version": "00000000",
    "head_block_num": 127,
    "last_irreversible_block_num": 126,
    "head_block_id": "0000007fbd1ff82f29668dfa89d927a0510c657cce292c033496ccaacf04c12a",
    "head_block_time": "2018-05-06T07:57:44",
    "head_block_producer": "eosio"
}

info.head_block_time

'2017-09-23T15:16:18'

info.head_block_num

wallet.create

PyEos will create a testing wallet for you the first time you start it, but you can also create other wallet wit wallet.create API

psw = wallet.create('mywallet2')
psw

'PW5JCWXaGkA15s6th6AWCabHewuGASAtrUJjTWoL1Ybx6sG9QzrSb'

You can see you wallet now. The * behind mywallet means the wallet is unlocked.

wallet.list_wallets()

['mywallet *']

wallet.open wallet.unlock

wallet.open('mywallet2')
wallet.unlock('mywallet2','PW5JCWXaGkA15s6th6AWCabHewuGASAtrUJjTWoL1Ybx6sG9QzrSb')

wallet.import_key

Let's import the private key of inita. Please refer to Setting up a wallet and importing account key for more information.

wallet.import_key('mywallet2','5KQwrPbwdL6PhXujxW37FSSQZ1JiwsST4cqQzDeyXtP79zkvFD3')

eosapi.create_key

Create owner key

eosapi.create_key()

{'public': 'EOS61MgZLN7Frbc2J7giU7JdYjy2TqnfWFjZuLXvpHJoKzWAj7Nst', 'private': '5JEcwbckBCdmji5j8ZoMHLEUS8TqQiqBG1DRx1X9DN124GUok9s'}

Create active key

eosapi.create_key()

{'public': 'EOS5JuNfuZPATy8oPz9KMZV2asKf9m8fb2bSzftvhW55FKQFakzFL', 'private': '5JbDP55GXN7MLcNYKCnJtfKi9aD2HvHAdY7g8m67zFTAFkY1uBB'}

Import owner key

wallet.import_key('mywallet2','5JEcwbckBCdmji5j8ZoMHLEUS8TqQiqBG1DRx1X9DN124GUok9s')

Import active key

wallet.import_key('mywallet2','5JbDP55GXN7MLcNYKCnJtfKi9aD2HvHAdY7g8m67zFTAFkY1uBB')

eosapi.create_account

It's time to create an account, key1 and key2 are the public key you created before.

key1 = 'EOS61MgZLN7Frbc2J7giU7JdYjy2TqnfWFjZuLXvpHJoKzWAj7Nst'
key2 = 'EOS5JuNfuZPATy8oPz9KMZV2asKf9m8fb2bSzftvhW55FKQFakzFL'
eosapi.create_account('eosio', 'currency',key1,key2)

{
    "transaction_id": "f6c43148dfac54105031fbaf966958d36309dd94e665c506eb2769e43febedba",
    "processed": {
        "status": "executed",
        "kcpu_usage": 100,
        "net_usage_words": 44,
        "id": "f6c43148dfac54105031fbaf966958d36309dd94e665c506eb2769e43febedba",
        "action_traces": [
            {
                "receiver": "eosio",
                "context_free": false,
                "cpu_usage": 0,
                "act": {
                    "account": "eosio",
                    "name": "newaccount",
                    "authorization": [
                        {
                            "actor": "eosio",
                            "permission": "active"
                        }
                    ],
                    "data": {
                        "creator": "eosio",
                        "name": "currency",
                        "owner": {
                            "threshold": 1,
                            "keys": [
                                {
                                    "key": "EOS61MgZLN7Frbc2J7giU7JdYjy2TqnfWFjZuLXvpHJoKzWAj7Nst",
                                    "weight": 1
                                }
                            ],
                            "accounts": []
                        },
                        "active": {
                            "threshold": 1,
                            "keys": [
                                {
                                    "key": "EOS5JuNfuZPATy8oPz9KMZV2asKf9m8fb2bSzftvhW55FKQFakzFL",
                                    "weight": 1
                                }
                            ],
                            "accounts": []
                        },
                        "recovery": {
                            "threshold": 1,
                            "keys": [],
                            "accounts": [
                                {
                                    "permission": {
                                        "actor": "eosio",
                                        "permission": "active"
                                    },
                                    "weight": 1
                                }
                            ]
                        }
                    },
                    "hex_data": "0000000000ea30550000001e4d75af4601000000010002934a4748562795f31685de7b0112c3f4428255d42aa8ea420701c29542ede46501000001000000010002376f7109de7a6cf12a8d6c713fa7f4d4df8a9e08ecee47e9001583c7b8fcc9750100000100000000010000000000ea305500000000a8ed32320100"
                },
                "console": "",
                "data_access": [
                    {
                        "type": "write",
                        "code": "eosio",
                        "scope": "eosio.auth",
                        "sequence": 39
                    }
                ],
                "_profiling_us": 38
            }
        ],
        "deferred_transaction_requests": [],
        "read_locks": [],
        "write_locks": [
            {
                "account": "eosio",
                "scope": "eosio.auth"
            }
        ],
        "cpu_usage": 102400,
        "net_usage": 352,
        "packed_trx_digest": "373a3125c5728b7feb7a4b5d04330e9de64e5f393123e660ff210ca558864c99",
        "region_id": 0,
        "cycle_index": 1,
        "shard_index": 0,
        "_profiling_us": 66,
        "_setup_profiling_us": 127
    },
    "cost_time": 608
}

eosapi.produce_block

this command is used for generate a block when you are testing your smart contract.

eosapi.produce_block()

eosapi.get_transaction

we can test get_transaction now, replace 'f6c43148dfac54105031fbaf966958d36309dd94e665c506eb2769e43febedba' with the transcation id in the create_account output, you will notice the output is the same as the output of create_account command above.

r = eosapi.get_transaction('f6c43148dfac54105031fbaf966958d36309dd94e665c506eb2769e43febedba')
r
r.transaction.signatures
r.transaction.packed_trx

eosapi.get_account

info = eosapi.get_account('eosio')
info

{
    "account_name": "eosio",
    "permissions": [
        {
            "perm_name": "active",
            "parent": "owner",
            "required_auth": {
                "threshold": 1,
                "keys": [
                    {
                        "key": "EOS6MRyAjQq8ud7hVNYcfnVPJqcVpscN5So8BhtHuGYqET5GDW5CV",
                        "weight": 1
                    }
                ],
                "accounts": []
            }
        },
        {
            "perm_name": "owner",
            "parent": "",
            "required_auth": {
                "threshold": 1,
                "keys": [
                    {
                        "key": "EOS6MRyAjQq8ud7hVNYcfnVPJqcVpscN5So8BhtHuGYqET5GDW5CV",
                        "weight": 1
                    }
                ],
                "accounts": []
            }
        }
    ]
}

eosapi.set_contract

Publish python smart contract to the blockchain

r = eosapi.set_contract('hello','../../programs/pyeos/contracts/hello/hello.py','../../contracts/hello/hello.abi',1)
r

eosapi.get_table

...

eosapi.push_action

...

gavinzheng / pyeos

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